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Green hydrogen, proposed as a sustainable alternative for conventional fuels, has gained utmost importance due to its reduced carbon footprint and potential application in maintaining balance between energy generation and demand. Utilization of hydrogen-based systems are challenged by cost effective storage methods. Bio-hydrogen storage technologies using cryogenic and adsorptive methods are discussed in this review paper, along with their operating conditions and storage capacities. An analysis of operational challenges and recent advancements in hydrogen storage techniques is presented. With a storage pressure of 70 MP, cryogenic hydrogen is almost twice as dense as compressed hydrogen. Technical challenges such as material cost and explosion risk can be addressed by hydrogen adsorption on activated carbon active sites. Maximum hydrogen storage capacity are reported by activated carbon obtained from Chitosan (6.77 wt%), Bamboo (6.6 wt%) and African palm shell (6.5 wt%) at 77 K and 4–20 Mpa. Further, nanotechnology approaches are presented in detail for increasing hydrogen storage capacity in pristine Si and Mg. The future perspectives in terms of technological, and economic aspects are discussed. • Detailed review on hydrogen storage methods is presented. • Role of cryogenics and adsorptive media are discussed. • The comparative performance of various methods is tabulated. • Existing research gap and future perspectives are analyzed. [ABSTRACT FROM AUTHOR]

The pressure on reducing greenhouse gas emissions has increased since the focus on climate change mitigation has grown. As the human development index is directly related to per capita energy consumption, sustainable energy production with reduced carbon footprint is the essential pathway for cleaner environment. Over numerous existing biological processes, hydrogen production via photo fermentation and photolysis of water is considered a more sustainable and economical method of hydrogen production. While both biological modes suffer from certain limitations, such as low yields and low production rates, practical implementation is still a long way off due to these limitations. The unique properties of nanomaterials (NMs) can help increase the efficiency of the biomass to biohydrogen process in significant ways. Applications of organic and inorganic nanoparticles in photocatalytic and photo fermentative hydrogen production is discussed in this paper. This review reports a wide range of applications of nanomaterials including the details of photo fermentative microorganisms and their mechanism of action. The maximum photo fermentative bio-H 2 production was reported in the presence of SiC–Fe 3 O 4 (3.02 mol H 2 /mol acetate), Ni (41 mol H 2 /mol sugar), graphite-C 3 N 4 (64.2 mol H 2 /mol sugar) whereas photocatalytic bio-H 2 yield was highest when Pd–Ni/CdS (54 mmol/g.h), Ni-MO/g-C 3 N 4 (1785 mmol/g.h) and CuO/TiO 2 (20.3 mmol/g.h) nanoparticles were employed. To design photocatalytic systems for practical and scalable use, the future research should be focused on deeper theoretical knowledge of mechanisms of light harvesting, ± charge separation and transport, surface biochemical reactions, semiconductor–liquid interactions, and reactor dynamics. [Display omitted] • Recent developments for improving water photolysis and photo-fermentation are reviewed. • Applications of organic and inorganic nanoparticles in hydrogen production are discussed. • The working principle and mechanism of hydrogen production are discussed. • The influence of key operating factors are presented. • Scope for future research was presented. [ABSTRACT FROM AUTHOR]

Environmental contamination caused by oxyanions like nitrate, selenate, chromate, and other related functional groups in water and wastewater is identified as a serious threat to human health. Among the different techniques attempted to remove or convert these compounds, reduction with the use of microorganisms has gained importance due to high selectivity and efficiency. Hydrogen-based membrane bioreactor (HMBR) is identified as a suitable method due to the non-toxic properties of hydrogen as an electron-donor, reduced secondary pollution, and easy generation of hydrogen through cost-effective novel methods. This research article is focused on the principle and mechanism of removal of anions, organic compounds, heavy toxic polyatomic metal ions, and antibiotics using hydrogen mediated microbial reduction process. Denitrification studies in HMBR at different operating conditions, namely membrane type, pH, nitrate concentration, and hydrogen partial pressure, are reviewed and the commonly reported efficiency ranges between 70 and 100%. The removal efficiencies attained by HMBR are as follows: perchlorate 30–100%, selenate 92–100%, phenol 87–99%, arsenate 60–68% and halogenoalkanes 45–99%. The mechanism of reduction in HMBR was explained with reference to nitrate, arsenate, chlorophenol, and chromate. [Display omitted] • Mechanism of Hydrogen based Membrane Reactor and applications for removal of pollutants are reviewed. • The working principle is discussed with schematic illustration. • The influence of key operating variables is discussed. • Scope for future research and research gap is presented. [ABSTRACT FROM AUTHOR]

The present investigation explored the feasibility of newly synthesised hydroxy apatite-carbon nanotubes based hybrid nanocomposite adsorbent and its potential application for the removal of Mn(II) from aqueous solution to avoid water pollution. The nanocomposite adsorbent was characterised using a scanning electron microscopic, energy dispersive x-ray spectroscopic, Fourier transform infrared spectroscopic, and BET surface area analysis. The effect of operating parameters namely initial pH (3–11), manganese concentration (50–200 mg/L), nanocomposite dose (0.5–6.0 g/L), and agitation speed (0–300 rpm) on the manganese uptake was investigated. Acidic pH does not favour the higher metal uptakes and the manganese uptake decreased with an increase in dose. The optimal pH and nanocomposite dose were found to be 6.0 and 2.0 g/L, respectively. The metal uptake capacity of nanocomposite was achieved as 70.95 mg/g. Langmuir and Freundlich isotherms were fitted to the experimental data and the Langmuir separation factor ( R L < 1) confirmed favourable adsorption. The pseudo-second-order model represented the data well with a rate constant of 2.26 × 10−3 g/mg. min. The synthesised material can be an alternative to other adsorbents for the effective separation of manganese from aquatic system. [ABSTRACT FROM AUTHOR]

PAHs is the group of emerging micro-pollutants present in most environmental matrices that has the tendency to bioaccumulate and cause carcinogenic effects to human health. The present research involved the quantification and treatment of leachate produced from secured landfill, to eliminate the PAHS. Electro-Fenton process, a class of advanced oxidation process, is adopted to degrade the PAHs using titanium electrodes as both anode and cathode. Artificial intelligence based statistical tool "Central Composite Design" a module of JMP -19 software was used to design the experiments and optimize the critical parameters involved in the research. It was observed that the value of P is significant (P < 0.05) for all the independent variables evidencing the significant correlation between experimental values and predicted values of the software. The value of R2 obtained was 0.96 and 0.97 for COD and PAHs respectively. The maximum removal efficiency of COD and PAH was found to be 84.24% and 90.78% respectively. The optimized conditions obtained from the central composite design were: pH = 5; Fe2+ = 0.1 g/L; H 2 O 2 = 2 g/L; reaction time = 60 min; and electric intensity = 0.2 A. Additionally, optimized experimental conditions were used to study the removal efficiencies of individual 16 PAHs and are also reported. From the close proximity of experimental and predicted results of the software it can be proved that central composite design is efficient enough to be used as a statistical tool in design and analysis for treatment of landfill leachate. [Display omitted] • Electro Fenton method was used to remove PAHs. • Artificial intelligence based optimization is applied for leachate treatment. • The removal efficiency of COD and PAH were found to be 84.24% and 86.05%. • Removal efficiency of 16 individual PAHs are determined. [ABSTRACT FROM AUTHOR]

Chlorpyrifos (CPF) is a highly toxic phosphate-rich organic pesticide (OP), identified as an emerging contaminant and used extensively in agricultural production. CPF persistence in the environment and its potential health hazards has become increasingly concerning worldwide in recent years due to exponential rise in food demand. Biodegradation of chlorpyrifos by microbial cultures is a promising approach to reclaiming contaminated soil and aquatic environments. The purpose of this review is to summarize the current understanding of microbiological aspects of xenobiotic chlorpyrifos biodegradation, including microbial diversity, metabolic pathways, and factors that modulate it. In both aerobic and anaerobic environments, CPF is biochemically broken down by a broad spectrum of bacteria and fungi. Hydrolysis, dehalogenation, and oxidation of chlorpyrifos are all enzymatic reactions that lead to its degradation. Biodegradation rate and efficiency are strongly influenced by parametric variables such as co-substrates abundance, pH, temperature, and initial chlorpyrifos concentration. The review provides evidence that microbial biodegradation is a viable method for remediating chlorpyrifos-contaminated sites in a sustainable and safe manner. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COF) have emerged as a potential class of materials for a variety of applications in a wide number of sectors including power storage, environmental services, and biological applications due to their ordered and controllable porosity, large surface area, customizable structure, remarkable stability, and diverse electrical characteristics. COF have received a lot of attention in recent years in the field of environmental remediation, It also find its way to eliminate the emerging pollutant from the environment notably pesticide from polluted water. This review more concentrated on the application of COF in pesticide removal by modifying COF structure, COF synthesis and material properties. To increase the adsorption ability and selectivity of the material towards certain pesticides removal, the synthesis of COF involves organic linkers with various functional groups such as amine, carboxylic acid groups etc. The COF have a high degree of stability and endurance make them suitable for intermittent usage in water treatment applications. This review manifests the novel progress where modified COFs employed in a prominent manner to remove pesticides from polluted water. Some examples of COF application in the eradication of pesticides are triformyl phenylene framework functionalized with amine groups has capacity to remove up to 50 mg/l of Organophosphorus – chlorpyrifos. COF modified to improve their photocatalytic capacity to breakdown the pesticide under visible light irradiation. COF tetraphenyl ethylene linked with carboxylic acid group shows efficient photocatalytic degradation of 90% of organochlorine insecticide endosulfan when subjected to visible light. Atrazine and imidacloprid are reduced from 100 ppm to 1 ppm in aqueous solutions by COF based on high adsorption capacity. In addition, the strategies, technique, synthesis and functional group modification design of COF are discussed. [ABSTRACT FROM AUTHOR]

The rapid consumption of metals and unorganized disposal have led to unprecedented increases in heavy metal ion concentrations in the ecosystem, which disrupts environmental homeostasis and results in agricultural biodiversity loss. Mitigation and remediation plans for heavy metal pollution are largely dependent on the discovery of cost-effective, biocompatible, specific, and robust detectors because conventional methods involve sophisticated electronics and sample preparation procedures. Carbon dots (CDs) have gained significant importance in sensing applications related to environmental sustainability. Fluorescence sensor applications have been enhanced by their distinctive spectral properties and the potential for developing efficient photonic devices. With the recent development of biomass-functionalized carbon dots, a wide spectrum of multivalent and bivalent transition metal ions responsible for water quality degradation can be detected with high efficiency and minimal toxicity. This review explores the various methods of manufacturing carbon dots and the biochemical mechanisms involved in metal detection using green carbon dots for sensing applications involving Cu (II), Fe (III), Hg (II), and Cr (VI) ions in aqueous systems. A detailed discussion of practical challenges and future recommendations is presented to identify feasible design routes. [Display omitted] • Applications of Biomass derived green carbon dots for sensing of metals are discussed. • Various methods of synthesis of green carbon dots are reviewed. • The mechanism of action of carbon dots is explained. • Future scope and challenges are discussed. [ABSTRACT FROM AUTHOR]

The access to drinkable water is a critical challenge in the context of the rising urbanization and industrialization, calling for advanced technologies to clean contaminated waters and wastewater. Here we review the use of metal oxides biochar composites to treat pollution by hevay metals and dyes. We focus on the synthesis of metal oxide nanobiochar; the treatment of pollution by mercury, lead, methylene blue and methyl orange; life cycle analysis; and techno-economical assessment. Metal oxide nanoparticles can act as photocatalysts to allow for the complete mineralization of organic pollutants. For instance, the doping of tin oxide nanoparticles into biochar surface degraded 99.5% of methylene blue dye after 105 min. Ball-milled magnetic nanobiochar achieves 99% mercury removal in 720 min. The presence of biochar enhanced the uptake of contaminants on nanoparticles and facilitated the photocatalytic reaction [ABSTRACT FROM AUTHOR]

Antibiotic resistance is a major health issue partly caused by the diffusion of antibiotic pollution in the natural environment, thus calling for advanced methods to remove antibiotics such as tetracyclines, a major class of pharmaceuticals. Here we review the use of MXene and nano-zero-valent iron-based materials to treat tetracycline in wastewater. MXenes are a class of two-dimensional nanomaterials represented as Mn+1XnTx, where M is an early transition metal, X refers to carbon or nitrogen, and T denotes surface termination groups. Values of n ranges between 1 and 4, and x indicate the number of surface functional groups. MXene and nano-zero-valent iron-based materials can be used as adsorbents, photocatalysts, electrocatalysts and membranes for removing tetracyclines. We review the toxicology of tetracycline, the synthesis and recycling of materials, the removal of tetracyclines and underlying mechanisms, and the use of materials as sensors. Remarkably, a MXene derived from carbide nitride and bismuth oxobromide removed 99% of tetracycline in 30 min. Similarly, a nano-zero-valent iron doped with graphene oxide and copper allowed 100% degradation of tetracycline in 15 min. [ABSTRACT FROM AUTHOR]

Selenium is targeted as a priority pollutant to be removed due to its high toxicity level and lethal effects. In this research, a novel nano sorbent was fabricated using ionic liquid on multiwalled carbon nanotubes (IL-MCNT) and employed for Selenium remediation from aqueous media. Besides solution pH, nanocomposite dosage, the initial selenium concentration, temperature and sorption time were also examined as operating variables. At optimal pH 2.0, 96% of the selenium was removed with maximum efficiency with 100 mg/L of IL-MCNT at 308 K, 45 min of contact time, and 110 g of IL-MCNT dosage. From kinetic studies, it appears that the Langmuir isotherm fits the observed data (R2 > 0.9813), supporting the hypothesis that monolayer attachment occurs. The Langmuir isotherm parameters are evaluated as qm = 125 mg/g and KL = 0.172 L/mg. As a result of testing several kinetic models, the pseudo-second-order model was the most suitable for experimental data (R2 > 0.9746). Scanning Electron Microscopy images, FTIR spectra, and thermogravimetric study were used to examine the synthesized nanomaterial. • Surface modification of CNT using IL is demonstrated. • SEM, FTIR and TGA analyses are carried out. • Optimal operating conditions are identified. • Kinetic and equilibrium studies are conducted. [ABSTRACT FROM AUTHOR]

Treatment of recalcitrant and xenobiotic pharmaceutical compounds in polluted waters have gained significant attention of the environmental scientists. Antibiotics are diffused into the environment widely owing to their high usages, very particularly in the last two years due to over consumption during covid 19 pandemic worldwide. Quinolones are very effective antibiotics, but do not get completely metabolized due to which they pose severe health hazards if discharged without proper treatment. The commonly reported treatment methods for quinolones are adsorption and advanced oxidation methods. In both the treatment methods, metal organic frameworks (MOF) have been proved to be promising materials used as stand-alone or combined technique. Many composite MOF materials synthesized from renewable, natural, and harmless materials by eco-friendly techniques have been reported to be effective in the treatment of quinolones. In the present article, special focus is given on the abatement of norfloxacin and ofloxacin contaminated wastewater using MOFs by adsorption, oxidation/ozonation, photocatalytic degradation, electro-fenton methods, etc. However, integration of adsorption with any advanced oxidation methods was found to be best remediation technique. Of various MOFs reported by several researchers, the MIL-101(Cr)–SO 3 H composite was able to give 99% removal of norfloxacin by adsorption. The MIL – 88A(Fe) composite and Fe LDH carbon felt cathode were reported to yield 100% degradation of ofloxacin by photo-Fenton and electro-fenton methods respectively. The synthesis methods and mechanism of action of MOFs towards the treatment of norfloxacin and ofloxacin as reported by several investigation reports are also presented. [Display omitted] • Applications of metal organic framework for removal of pharmaceutical components are discussed. • Toxicological properties of norfloxacin and ofloxacin are presented. • Action mechanisms of MOFs in treatment of quinolones are explained. • Future scope and existing research gaps are identified. [ABSTRACT FROM AUTHOR]

• Modified CNT was synthesised. • Porous structure characterization were performed. • Effect of variables on phenol removal was studied. • Kinetic and isotherm modeling studies were conducted. Carbon nano tubes are functionalized to enhance their surface properties and target specificity. In this research, a novel ionic liquid functionalized carbon nanotube (IL-CNT) material was synthesized using 1-Hexyl-3-methylimidazolium bis(trifluormethylsulfonyl)imide and investigated for the phenol removal. The parametric experiments were performed to identify the optimal conditions for high removal performance. With an initial concentration of 50 mg/L and an IL-CNT dosage level 100 mg, 95.36% phenol removal was attained at optimal pH 6.0. The occurrence of monolayer attachment was verified through equilibrium studies. The Langmuir isotherm parameters are evaluated as q m =109.9 mg/g and K L = 0.196 L/mg. The kinetic experiments followed Pseudo Second Order model (R2 > 0.990). The synthesized nanomaterial was characterized using Scanning Electron Microscopic imaging, Fourier Transform Infra-Red spectra, X-Ray Diffraction analysis and Thermo Gravimetric Analysis. [Display omitted] [ABSTRACT FROM AUTHOR]

Lead and Cadmium, identified as toxic heavy metals, cause significant imbalance in the eco-system due to their tendency to bioaccumulate. Remediation of heavy metals by conventional adsorptive materials suffer demerits related to low efficiency or removal. Among the variety of adsorbent materials used in the adsorption process, metal oxides- and graphene oxide magnetic nanocomposites have gained a considerable attention. The use of nanomaterials may help to reduce this contamination, but after use, they are difficult to remove from water. An added magnetic property to nanomaterials facilitates their retrieval after use. The magnetic properties of these hybrid magnetic nanocomposites, coupled with unique characteristics of organic and inorganic elements, have found extensive application in water treatment technology. Detailed discussion on functionalisation of magnetic nanocomposites and the enhanced performance are presented. Magnetic graphene oxide-covalently functionalized-tryptophan was reported to have the highest adsorption capacity of 766.1 mg/g for remediation of lead (II) ions and graphene oxide exhibited the highest adsorption capacity of 530 mg/g for Cd (II) ions. The adsorption mechanisms for heavy metal ions on the surface of novel adsorbents, particularly lead and cadmium, using magnetic nanocomposites have been explained with reference to the isotherm models studied. The future scope of research in this area of research is proposed. [ABSTRACT FROM AUTHOR]

• Detailed review on enhanced production of biohydrogen is presented. • Role of nanocatalysts, operating conditions and their mechanism of action are discussed. • Critical comparison of the nanocatalyst performance is tabulated. • Existing research gap and future perspectives are presented. Renewable energy research has gained momentum due to the fast consumption and lack of sustainability in conventional fuels. As biohydrogen emits no greenhouse gases and can be generated from a variety of waste biomass or feedstocks, it has been referred to as the most effective and cleanest form of energy among all biofuels. In spite of the success of photobiological and dark fermentation methods in generating biohydrogen, they are known to produce lower yields, creating serious obstacles for commercial production. The role of nanoscience and technology in improving the biohydrogen production is achieved through the use of nanomaterials with specific physiochemical and structural properties. In this review, metals, metal oxides, metal alloys, and inorganic nanomaterials are explored in order to improve biohydrogen production. Initial studies have focused on nano materials evaluation in biomass conversion and addressing the current status of nanomaterials in biohydrogen production. The best bio-H 2 yield is obtained in the presence of metal nanoparticles (NPs) such as Ag (2.4 mol H 2 / mol glucose), Cu (1.74 mol H 2 / mol glucose), Fe (3.10 mol H 2 / mol malate), alloys of Al/Cu/Fe (4.2 mol H 2 / sucrose) and Ni (2.54 mol H 2 /glucose). The review also addressed the mechanisms involved in changing feedstock into hydrogen through various microbial biorefineries. The life cycle analysis of various nanoparticles applications in biohydrogen production was discussed. [ABSTRACT FROM AUTHOR]

Membrane based filtration is one of the promising technologies for rehabilitation of wastewater streams for reuse and recycle. Many advancements have emerged with the use of novel materials and innovative integrated technologies. The present investigation focuses on the treatment methods based on submerged and stages systems of membranes for water purification. Ceramic, polymeric and mixed matrix type of membranes fabricated for specific type of effluents, their modification methods for accelerating the rejection efficiency, permeability, durability, stability and antifouling properties are detailed in this review. Graphene oxide is the most considered membrane material for adsorption purposes as it exhibits larger surface area, abundant functional groups contain oxygen and has good supply of ligands which is responsible in metal adsorption as it enhances electrostatic interaction by bonding metal ions with graphene oxide nanosheets. Energy derivation in terms of biogas production was also reported in some integrated methods. In many cases, embedded nanomaterial matrices yielded maximum efficiencies in both the submerged and staged operations. However, submerged type of membranes are reported more than the staged type due to simpler configuration with relatively lesser equipment, operational and maintenance issues. In treatment of a low strength wastewater, aluminum oxide based membrane in fluidized bed assembly was reported to yield promising results with reduced power requirement. [Display omitted] • Comprehensive review on novel membrane system application for removal of pollutants is presented. • Applications of submerged and staged membrane systems for wastewater treatment are discussed. • Removal performance using embedded nano materials is explained. • Bottlenecks and future perspectives on membrane research are presented. [ABSTRACT FROM AUTHOR]

Global warming is partly due to excessive carbon dioxide emissions, calling for methods to capture carbon dioxide for conversion into value-added materials and fuels. Here we review the microbial conversion of carbon dioxide into biomethane, bioethanol, polyhydroxybutyrate and succinic acid by bacteria, algae and yeast. We also present genetic engineering and machine learning to improve carbon dioxide capture and conversion. Photoautotrophic biosynthesis, dark fermentation and biodegradation are detailed. We observed that Chlorella vulgaris and Cyanobacteria are able to capture more than 90% of carbon dioxide in their cells and yield about 0.45 g/L.d of biomass in a typical photobioreactor. [ABSTRACT FROM AUTHOR]

• Detailed review on enhanced production of biodiesel by various methods is presented. • Role of nanomaterials and their mechanism of action are discussed. • Critical comparison of the nanocatalysts performance at different operating conditions is presented. • Effect of operating conditions on biodiesel production is described. The deterioration of fossil fuel supplies, combined with growing environmental concerns about fossil fuel extraction and consumption, has prompted worldwide communities to focus on renewable energy. Biodiesel production from various biomass feedstock is identified as an environmentally friendly and sustainable alternative. The application of nanomaterials as catalysts in the synthesis of biodiesel has enhanced the yield due to the selectivity. This review article is focused on the applications of potential nanoparticles in biodiesel production and their mechanism of action. The effect of operating variables, namely nanomaterial type, concentration, temperature, methanol to oil ratio, and water content on biodiesel production have been summarized. Under microwave-assisted transesterification, both sodium hydroxide and strontium oxide catalysts, produced highest yield (99%). For calcium oxide nanocatalyst, the highest biodiesel conversion obtained was 98.2% through microwave-assisted transesterification method of waste cooking oil. The optimal conditions for such a high conversion yield were methanol to oil ratio, reaction temperature, time, and catalyst loading of, 1:8, 65 °C, 76 mins, and 4 wt% respectively. The maximum biodiesel conversion yield achieved using KOH nanocatalyst was 96.44% in a microwave-assisted transesterification of waste cotton-seed cooking oil, at optimum conditions of 9.6 min, 0.65 wt% catalyst loading, and 7:1 methanol: oil ratio, respectively. Future perspectives on nanocatalysis for biodiesel production are explained. [ABSTRACT FROM AUTHOR]

Carbon based compounds have gained significant attention due to their environmental engineering applications with their favorable physical and chemical properties. Chitosan, a naturally available carbon based biopolymer, is identified as a potential surface protective agent and tested for its surface coverage properties to control the corrosion of mild steel. Chitosan nanoparticles (Ch-NP) were produced using a simple two-step synthesis to produce a corrosion protection agent for mild steel in 3.5% NaCl. The effect of immersion duration (4–24 h) was investigated using inhibitor extracts containing 400, 600, 800, and 1000 ppm at three temperatures, namely,305.15, 310.15, and 315.15 K. Inhibition efficiency increased with increase in the inhibitor dosage due to the development of protective surface film. An integrated electrochemical study was performed using electrochemical impedance spectroscopy, potentiodynamic polarization, and gravimetric measurement. Ch-NP has a mixed-type adsorption behavior for mild steel surface. The Langmuir isotherm was used to characterize the adsorption of Ch-NP molecules on the surface of mild steel. Tafel study confirmed the inhibitor examined as mixed type. Ch-NP demonstrated a high inhibitory effectiveness of 91% under the tested conditions and proved to be an effective alternative for industrial applications. [Display omitted] • Carbon-based eco friendly corrosion inhibitor was synthesized from crab shell. • Gravimetric, potentiodynamic and equilibrium studies are conducted. • Monolayer surface coverage was confirmed by Langmuir isotherm. • Chitosan nano particles exhibited a mixed-type adsorption behavior. [ABSTRACT FROM AUTHOR]

The eco-friendly plant extract based corrosion inhibitor, synthesized using Ziziphus spina-christi, was investigated for its corrosion control and surface protection potential for carbon steel under acidic conditions. The influence of process parameters, corrosion inhibitor concentration (160–810 ppm), operating temperature (330.15–315.15 K) and immersion time (4–24 h), on inhibition efficiency was evaluated. Based on mass loss experiments, the maximum inhibition efficiency achieved was found to be 91.35% at 810 ppm inhibitor concentration and 300.15 K. Corrosion rate decreased with increase in inhibitor dose which could be due to enhanced surface coverage. The activation energy associated with this process indicated surface interaction as the main mechanism and positive values of enthalpy change confirmed the endothermic nature. The electrochemical parameters, namely corrosion potential (E corr), anodic and cathodic Tafel constants (β a and β c), and corrosion current density (i corr) were calculated, and the inhibitor was found to be mixed type. Through double-layer capacitance, the increase in corrosion resistance was proved. The active functional groups associated with corrosion inhibitor were identified. [Display omitted] • Corrosion inhibition of carbon steel under acidic environment is studied using Ziziphus spina-christi extract. • Inhibition efficiency was studied using mass loss, polarization and EIS studies. • Surface characterization of corrosion inhibitor and metal specimen are conducted using ATR and SEM analyses. • The corrosion inhibitor is found to be mixed type. • Monolayer surface coverage of the metal by the corrosion inhibitor is confirmed. [ABSTRACT FROM AUTHOR]

Most dyes are pollutants that should be removed from waters due to their mutagenic and carcinogenic properties, requiring advanced adsorption methods. Here, we review polymeric nanocomposites with focus on their synthesis and functionalization, nanofillers, dispersion strategies, factors and mechanisms controlling dye adsorption, and applications. We detail composites including organic or inorganic complexes, carbon nanotubes, biowaste, polyaniline, polypyrrole, and magnetic materials. [ABSTRACT FROM AUTHOR]

Global warming and plastic pollution result from the massive use of fossil fuels, calling for the development of sustainable bioplastics derived from modern biomass. Bioplastic production is expected to increase to 2.43 million tons globally in 2024. In particular, the production of biopolymers from bioresources and organic waste should highly reduce waste accumulation. Biopolymers can be produced by employing microbes or by using monomers from agro-resources. Here we review the use of lignin and polylactic acid for polymer production using enzymes and microorganisms. Carnobacterium, Enterococcus and Aspergillus niger show high lactic acid productivity of about 0.4–1.4 g/L/h. Lignin and polylactic acid can also be transformed into value-added chemicals such as muconic acid, hydrouronic acid, adipic acid and terephthalic acid. [ABSTRACT FROM AUTHOR]

Environmentally benign plant extract compounds have gained significant attention in the corrosion prevention applications due to their biodegradability and eco-friendliness. The adsorptive corrosion control action of Prosopis juliflora plant extract was investigated using differential mass change experiments and the mechanism was validated using Tafel and Nyquist plots. The effect of green corrosion inhibitor concentration (0–800 ppm) on corrosion rate at different solution temperatures (305.15, 310.15 and 315.15 K) in 1 M HCl was studied. The corrosion inhibitor exhibited monolayer surface coverage and confirmed by Langmuir isotherm (R2 > 0.970). The negative values of Gibbs free energy (<20 kJ/mol) proved the electrostatic interaction between the inhibitor and metal surface. The enhanced energy barrier for the corrosion process was confirmed by changes in E a in the presence of biomass-based inhibitor on the mild steel surface. Electrochemical impedance study proved that the double layer capacitance (C dl) decreased and the resistance increased with increase in corrosion inhibitor concentration. The surface modifications on the metal were observed using scanning electroscope imaging. ATR studies were conducted for functional group identification of the corrosion inhibitor. [Display omitted] • Biomaterial based Corrosion inhibitor is synthesized using Prosopis juliflora. • Mild steel corrosion was investigated at different extract concentrations. • ATR for inhibitor and SEM analysis for metal specimens are performed. • Thermodynamic studies proved the feasibility of inhibition and physisorption. • Impedance spectroscopic experiments are conducted. [ABSTRACT FROM AUTHOR]

This research study investigated the synthesis of environmentally benign green emulsion liquid membrane (GELM) employing waste cooking oil (WCO) as diluent. The emulsion was prepared using D2EHPA as the carrier, Span 80 as surfactant, and sulphuric acid as internal/stripping agent. The influence of nine operating variables namely, Span 80 concentration, D2EHPA concentration, shaking time, shaking speed, pH of the feed, treat ratio (TR), H 2 SO 4 concentration, lead concentration in feed, and volume ratio of organic phase to aqueous phase (O/A) on the performance of lead extraction was studied. Plackett Burman design (PBD), was employed for the screening of variables. The Pareto analysis shows that six variables were the most significant variables at the confidence level of 95%. The selected variables were then screened applying Box-Behnken design (BBD). The optimum values of the variables were: D2EHPA concentration – 4.6 (v/v%), Span 80 concentration – 2.14 (v/v%), pH of the feed – 4.4, internal phase (H 2 SO 4) concentration – 2 M, initial lead concentration – 173 ppm, phase ratio (O/A) – 1.3. At these optimum conditions, a maximum lead extraction of 97.39% was obtained. The mechanism for the extraction of lead was analyzed. Reuse and recycling of membrane phase show that the GELM can be recycled for 7 cycles without reduction in lead extraction efficiency. Kinetic analysis of lead extraction was performed using zero, first, and second-order model at optimum condition. The experimental data fitted well with first-order (R2 – 0.9653). Thermodynamic studies indicated that the extraction procedure is endothermic, spontaneous in nature. [Display omitted] • Environmentally benign GELM employing WCO as diluent was used for lead extraction. • PBD and BBD were employed to screen and optimize the parameters respectively. • Lead extraction mechanism, stripping efficiency and reuse of GELM were explored. • A maximum lead extraction of 97.39% was achieved at optimum condition. • The lead extraction by GELM follows first-order model with R2 value of 0.9653 [ABSTRACT FROM AUTHOR]

In this study, a series of nickels supported on gamma alumina with a metal dosage ranging from 0.5 to 3 wt.% were prepared and employed as the catalysts. The effect of nickel dosage on material properties, reaction performance, and catalyst deactivation was investigated. At a low dosage, the nickel-free having low metal-support interaction contributed significantly to the total active site. The basicity of the material was enhanced along with the increase in nickel loading. The presence of active metal showed a great impact at the beginning leading to big improvements in feedstock conversion. However, beyond a nickel dosage of 2 wt.%, further additions did not noticeably influence the reaction performance. Regarding catalyst deactivation, different carbon species were observed on catalyst surface, depending on the nickel dosage. Catalysts with less than 2 wt.% nickel exhibited amorphous carbon as the dominant morphology on the spent catalyst. In contrast, catalysts with 2Ni/Al2O3 and 3Ni/Al2O3 compositions showed graphitic carbon as the main side product. These findings provide insights into the relationship between nickel dosage, catalyst properties, and catalytic performance in methane dry reforming. By understanding the effects of nickel loading on material properties and reaction behavior, researchers can optimize catalyst design and develop more efficient and stable catalysts for sustainable syngas production. [ABSTRACT FROM AUTHOR]

Dihydrogen, commonly named 'hydrogen', is a carbon–neutral and renewable fuel meeting environmental regulations in transportation and industrial production. Hydrogen is currently employed in fuel cells, hydrogen vehicles, and as an efficient energy carrier due to its high energy capacity of 121 kJ per g. Here we review hydrogen production by steam reforming of alcohols including methanol, ethanol, propanol, glycerol and butanol, with focus on catalysts, mechanisms, and analytical methods to characterize deposited carbon. In general, Ru- and Rh-based catalysts show efficient performance with almost 100% feedstock conversion and up to 89% of hydrogen yield, while Ni and Co catalysts exhibit lower ethanol conversion in the range of 40–100% depending on operating conditions. Nevertheless, Ni and Co catalysts have been mainly chosen as active metals for alcohols steam reforming due to their lower cost. [ABSTRACT FROM AUTHOR]

The contamination of aqueous environment by phenol poses a major threat due to its hyper toxic effects and removal of phenol is challenging due to its hydrophilic properties. This research study examines the surface encapsulation of iron oxide (IO) with bio-derived carbon-based date palm (DP) to make date palm-iron oxide (DP-IO) nanocomposite to potentially remediate phenol in aqueous environment. Phenol removal percentage is predominantly influenced by environmental factors, namely pH, nano sorbent loading, temperature, agitation speed, and initial phenol concentration. Under optimum conditions of 30 °C and pH 7.8, 80.30% of phenol was removed using a 0.75 g/L sorbent load with 100 mg/L initial phenol concentration. Langmuir isotherm fitted well (R2 > 0.997), supporting single-layer phenol attachment with maximum bio-sorption capacity of 72.46 mg/g. A pseudo-2nd-order (PSO) kinetic model is identified to be the most appropriate for the DP-IO sorption experiment (R2 >0.999). Scanning electron microscopic images, X-ray diffraction observations, FT-IR plots, and thermogravimetric analysis have been used to characterize. The removal mechanism involves unimolecular layer and chemisorption is identified as a rate determining step. The reuse potential proved that the synthesized nanocomposite as a sustainable solution for phenolic wastewater treatment. • Novel iron-oxide based nanocomposite was synthesized. • Optimal conditions for maximum phenol removal are identified. • Isotherm modeling was carried out. • Kinetic mechanism was studied. [ABSTRACT FROM AUTHOR]

Discharging untreated dye-containing wastewater gives rise to environmental pollution. The present study investigated the removal efficiency and adsorption mechanism of Acid Red 18 (AR18) utilizing hexadecyl-trimethyl ammonium chloride (HDTMA.Cl) modified Nano-pumice (HMNP), which is a novel adsorbent for AR18 removal. The HDTMA.Cl is characterized by XRD, XRF, FESEM, TEM, BET and FTIR analysis. pH, contact time, initial concentration of dye and adsorbent dose were the four different parameters for investigating their effects on the adsorption process. Response surface methodology-central composite design was used to model and improve the study to reduce expenses and the number of experiments. According to the findings, at the ideal conditions (pH = 4.5, sorbent dosage = 2.375 g/l, AR18 concentration = 25 mg/l, and contact time = 70 min), the maximum removal effectiveness was 99%. The Langmuir (R2 = 0.996) and pseudo-second-order (R2 = 0.999) models were obeyed by the adsorption isotherm and kinetic, respectively. The nature of HMNP was discovered to be spontaneous, and thermodynamic investigations revealed that the AR18 adsorption process is endothermic. By tracking the adsorption capacity of the adsorbent for five cycles under ideal conditions, the reusability of HMNP was examined, which showed a reduction in HMNP's adsorption effectiveness from 99 to 85% after five consecutive recycles. [ABSTRACT FROM AUTHOR]

Discharging untreated dye-containing wastewater gives rise to environmental pollution. The present study investigated the removal efficiency and adsorption mechanism of Acid Red 18 (AR18) utilizing hexadecyl-trimethyl ammonium chloride (HDTMA.Cl) modified Nano-pumice (HMNP), which is a novel adsorbent for AR18 removal. The HDTMA.Cl is characterized by XRD, XRF, FESEM, TEM, BET and FTIR analysis. pH, contact time, initial concentration of dye and adsorbent dose were the four different parameters for investigating their effects on the adsorption process. Response surface methodology-central composite design was used to model and improve the study to reduce expenses and the number of experiments. According to the findings, at the ideal conditions (pH = 4.5, sorbent dosage = 2.375 g/l, AR18 concentration = 25 mg/l, and contact time = 70 min), the maximum removal effectiveness was 99%. The Langmuir (R2 = 0.996) and pseudo-second-order (R2 = 0.999) models were obeyed by the adsorption isotherm and kinetic, respectively. The nature of HMNP was discovered to be spontaneous, and thermodynamic investigations revealed that the AR18 adsorption process is endothermic. By tracking the adsorption capacity of the adsorbent for five cycles under ideal conditions, the reusability of HMNP was examined, which showed a reduction in HMNP's adsorption effectiveness from 99 to 85% after five consecutive recycles. [ABSTRACT FROM AUTHOR]

• Biological sequestration techniques for CO 2 reduction are described. • Bioenergy with carbon capture and storage concept is reviewed. • The economic feasibility and environmental outlook are reviewed. • A novel illustration of the artificial photosynthesis process is addressed. Drastic changes in climatic conditions accelerate the need for the implementation of emission reduction techniques to restrict global warming. Conventional technologies do face severe drawbacks in reducing carbon emissions. Carbon neutrality is considered as the most essential concept as it can alleviate the issues of greenhouse gas emissions while deriving energy and fuels from fossil origin. Several reduction technologies are proposed in the recent past, in which the integration of renewable energy resources such as solar and wind power are signified. The review aims to provide an understanding of the technology transition to attain carbon neutrality through production of carbon-free energies such as hydrogen and bioenergy. Despite the chemical and physical sequestration methods, the biological sequestration technique is given special attention for the mitigation of CO 2 emissions by utilizing photosynthetic microalgae. Of numerous microalgae, Chlorella vulgaris , a common eukaryotic microalga found in freshwater showed a maximum CO 2 fixation rate of about 3.35 g/L/d with 10 % CO 2 input. Apart from capturing and storing carbon in the geological site, the concept of utilizing and converting carbon into valuable byproducts is described elaborately. The possibilities for utilizing renewable energy sources for carbon-free energy production through unique prototypes are reviewed and elaborated. It mainly aids to utilize renewable resources more than conventional, which significantly minimizes the carbon footprint. The integration of bioenergy, carbon capture and storage concepts with renewable energy sources extends opportunities to minimize emissions and transition towards carbon neutrality and indeed can aid in achieving carbon negativity. The aforementioned concept was reported to produce about 12.5 million tons ton of hydrogen with 133 million tons of CO 2 recovery. An innovative prototype to resolve emission issues other than CO 2 was also addressed. Illustrations of the artificial photosynthesis process, convective vortex system and integrated multi energy system are disc proposed innovative carbon reduction technologies' economic feasibility and environmental outlook technologies are reviewed and presented. [ABSTRACT FROM AUTHOR]

In this research, a novel porous nanocomposite, namely Chitosan-iron-oxide @ Azolla pinnata nanocomposite, has been synthesized by co-precipitation and hydrothermal method. The effect of process parameter on adsorption process was investigated. Batch removal of chromium (Cr) was optimized with respect to solution pH, batch stirring time, sorbent dose, initial chromium concentration and temperature. The maximum removal efficiency was found to be 98.58%. The Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM) analysis of the nano composite confirmed the presence of characteristic functional groups and porous structure of synthesized nanocomposite. The adsorption data fitted well with Langmuir adsorption isotherm (R2 = 0.996) confirming mono layer sorption and the maximum uptake was found to be 294.12 mg/g. The adsorption was found to follow pseudo second order model (R2 = 0.997). Thermodynamic studies revealed that adsorption is endothermic and spontaneous. Reusability studies have confirmed that removal efficiency attained was 85% after completion of five adsorption-desorption cycles. Electrostatic attraction, ion exchange, coordination bonding and reduction are the major mechanisms responsible for removal of chromium. Surface modification of Azolla pinnata with chitosan and iron oxide improved the ability of Azolla in the adsorption of chromium from aqueous media. The combined effects of facile synthesis, improved adsorption features and easier magnetic separation promotes Chitosan-iron-oxide @ Azolla pinnata nanocomposite as a novel adsorbent. • Novel porous nanocomposite, Chitosan-iron-oxide @ Azolla pinnata has been synthesized. • Synthesized nanocomposite were studied by FTIR, SEM, EDX. • Maximum uptake of chromium (Cr) is an uptake of 294.12 mg/g. • Reusability confirmed that removal efficiency of 85% is attained after 5 cycles. [ABSTRACT FROM AUTHOR]

Endocrine disruptors are hazardous chemicals with chronic health effects for most living organisms, inducing homeostasis, hormonal imbalances, cancer, reproductive and neurological disorders, cardiovascular diseases, vulnerability to fetus and neonates. Over 1,000 chemicals display endocrine disrupting characteristics. Endocrine disruptors are found among industrial chemicals, pharmaceuticals, heavy metals, plastic materials, fertilizers, pesticides, herbicides and fungicides. Endocrine disruptors enter human organs via ingestion, inhalation and diffusion through the skin. Here, we review the detection, toxicity, hazard identification and remediation methods of three classes of endocrine disruptors: steroid hormones, pharmaceutical and personal care products, and pesticides. Remediation methods include biological, physical, chemical, electrochemical and radiative methods. Bisphenol A was removed of 99% by biodegradation and ultraviolet with hydrogen peroxide, 98.4% by electropolymerization, 97.5% by photoelectrolysis and 80% by sand filtration. We present advanced treatment chemicals and discuss the performance of remediation using the combination of 2–3 treatment methods. In silico methods and machine learning for predicting toxicity and remediation are discussed [ABSTRACT FROM AUTHOR]

Electro deionization using microbial communities has been proven as a competent method for desalination and abatement of water pollution by removing ionic chemicals from the target waters. Microbial Desalination Cell (MDC) facilitates microbial deionization which can either support or be a substitute for the conventional desalination methods. Generation of electricity is accomplished by the bio electrochemical oxidation of organic compounds present as contaminants in wastewater which in turn attribute to the migration of ions in MDC system. The present review aims to elucidate the theory, principles and the application of microbial desalination cell and microbial fuel cell (MFC) in treatment of saline and wastewaters. Air cathode MDC and stacked MDC for purification of saline water are found to give promising results. Air pump assisted microbial desalination cell reported 150.39 ppm h−1 of salt removal with an operational time period of 80 h and showed consistent results. Hence the air cathode assisted MDC showed dominant capacity of salt removal compared to stacked MDC. Also, three major types of microbial fuel cell, namely photosynthetic biofilm MFC, constructive wetland MFC and ceramic membrane supported MFC are reviewed for their potentials in wastewater treatment by deionization method and electricity generation. Complete (100%) removal of chemical oxygen demand was reported by photosynthetic microbial fuel cell operated for 16 days having 435.8 Ω of external resistance. When constructive wetland microbial fuel cell was operated for 10 days with 1000 ohms of external resistance, it exhibited complete (100%) removal of chemical oxygen demand from the wastewater. About 92% of chemical oxygen demand removal was demonstrated by ceramic membrane supported microbial fuel. Compared to ceramic membrane microbial fuel cell, photosynthetic and constructive wetland microbial fuel cell displayed better performance in terms of pollutant removal capacity and economical factor. Ability of the electrogenic species, namely Geobacter, Shewanella, Clostridium and Bacillus and the photosynthetic species, namely Chorella Vulgaris Rhodopsuedomonas, and Scenedesmus abundans in microbial deionization methods and their performance levels reported by several researchers are presented. [ABSTRACT FROM AUTHOR]

Graphene is a high surface area special carbon compound with exceptional biological, electronic and mechanical properties. Graphene-based materials are potential components used in water treatment on different modes and processes. Ibuprofen and ciprofloxacin are two commonly found pharmaceutical contaminants discharged into water bodies from industrial, domestic and hospital sources. Their concentration levels in water bodies are reported in the range of 1 μg/L to 6.5 mg/L and 0.050–100 μg/L respectively. Their toxic effects pose very high risk to the inhabiting organisms. Their ability to resist biodegradation and capacity to bioaccumulate makes the conventional methods less effective in removal. In the present article, treatment of these compounds via three methods, adsorption, photocatalytic degradation and electro–fenton reactions using graphene-based materials along with the methods adopted for synthesis and treatment are reviewed. The uptakes obtained by graphene-derived adsorbents are presented along with the optimal operating conditions. Studies reported complete removal of ibuprofen from wastewater was achieved at 7 pH for 60 min using graphene membrane as adsorbent and uptake of 99% of ciprofloxacin was exhibited for graphene nanoplates/boron nitrate aerogel at a pH of 7 and 60 min. The reduced graphene oxide surface exhibits higher affinity to light adsorption which leads to the formation of photo generated electrons. The future perspectives for improved applications of graphene-based materials and the research gap currently existing are highlighted. [Display omitted] • Applications of graphene based materials for removal of pharmaceutical components are reviewed. • Mechanism of ibuprofen and ciprofloxacin removal is described. • Toxicological properties are discussed. • Photocatalytic degradation of ibuprofen and ciprofloxacin is described. [ABSTRACT FROM AUTHOR]

The excessive and unorganised utilisation of pesticides have posed negative impacts on soil and water at higher levels. Pesticides are a major class of persistent organic compounds with high resistance to natural biodegradation and enhanced tendency to bio accumulate. The severe health hazards imposed on the living organisms hinder the ecosystem and lead to chronic and irreversible health issues. Photocatalytic method is reported as a potential alternative with a variety of techniques and materials that are safer, easier, durable, cost-effective and efficient. Nanomaterials play a key role in this domain due to their versatility. In particular, nanostructured materials of organized shapes and morphological properties have gained enormous attention in research and real-time applications. Specifically, nanomaterials like nanotubes, nanorods and nanowires have unique properties and anisotropic structure that make them more suitable for treating pesticide wastes with photocatalysis. Variety of tuning methods and materials are emerging to enhance the activity of titanium and zinc based nanocatalysts in remediation methods. In the present article, four pesticides, namely, atrazine, chlorpyrifos, paraquat and naphthalene are chosen due to their common occurrence and usage in agricultural applications. These pesticides are highly toxic and need special attention to explore appropriate remediation methods. The report also details the latest innovations reported by several research studies in exploring the potential of specially synthesised nanoparticles for photocatalytic removal of pesticide pollutants from environment. For zinc-based hybrid nanomaterials, the maximum disintegration reported were 99%, 98%, 73.3% and 92.3% for atrazine, chlorpyrifos, paraquat and naphthalene, respectively. [Display omitted] • Photocatalytic remediation technologies for pesticide pollutants are discussed. • Removal of atrazine, chlorpyrifos, paraquat and naphthalene are described. • Mechanism of photocatalytic degradation and the pathways are elaborated. • Existing research gaps and future perspectives are explained. [ABSTRACT FROM AUTHOR]

Dihydrogen (H2), commonly named "hydrogen", is attracting research interest due to potential applications in fuel cells, vehicles, pharmaceuticals and gas processing. As a consequence, the recent discoveries of natural gas reservoirs have prompted the development of technologies for methane conversion to hydrogen. In particular, the catalytic decomposition of methane is a promising technology to generate COx-free hydrogen and multi-wall carbon materials. Carbon nanomaterial byproducts can be used in electronics, fuel cells, clothes, and for biological and environmental treatments. Recent research has investigated the performance of hydrogen production and the characteristic of carbon nanomaterials. Here, we review the decomposition of methane on Ni-based catalysts, with focus on the influence of reaction temperature, gas hourly space velocity, support, and promoter. Ni-based catalysts allow CH4 conversion higher than 70% with H2 yield of about 45% at more than 700 °C. We present catalyst regeneration by various techniques such as combustion. Reactors used for catalytic decomposition of methane include fluidized bed, fixed-bed and plasma reactors. [ABSTRACT FROM AUTHOR]

Micro-tubular solid oxide fuel cells (MT-SPFC) have emerged as a potential alternative for efficient energy generation. This study investigates the impact of cathode extrusion rates (ranging from 3 to 6 mL min−1) on the triple layer anode/electrolyte/cathode MT-SOFC fabricated via a simplified phase inversion-based co-extrusion/co-sintering technique. Higher cathode extrusion rates (6 mL min−1) indirectly thin the electrolyte layer, improving ion hopping efficiency between the cathode and anode. Moreover, increasing the extrusion rate enhances anode thickness, providing ample electrode reaction sites and thereby enhancing the gas diffusion process. The C6 sample attains a peak power density of 1.46 W cm−2 with 1.08 V OCV at an optimum 800 °C operating temperature, which is high for MT-SOFCs in high-temperature applications. There was a 71.8 % increase in power density for C6 when the temperature changed from 750 °C to 800 °C. The composite cathode material fulfilled both the electronic and ionic conductivity requirements. The optimal cathode extrusion rate for this simplified MT-SOFC fabrication was found to be 6 mL min−1. • 6 mL min−1 of cathode extrusion rate suitable for fabricating MT-SOFC via simplified technique. • Thin electrolyte promotes better ions hoping mechanism. • Sufficient electrode thickness provides more active sites for redox reaction. [ABSTRACT FROM AUTHOR]

Endocrine-disrupting chemicals (EDCs) have a wide range of detrimental effects on health, particularly on the human endocrine system. Efflux This research study involves the application of - molybdenum trioxide, zinc oxide and graphene oxide (MoO 3 /ZnO/GO) with polyvinylidene fluoride (PVDF) membrane as photocatalytic dual layer hollow fiber (DLHF) membrane as novel energy storage photocatalytic membrane towards efficient degradation of EDCs under visible light illumination. Ternary MoO 3 /ZnO/GO was synthesized using hydrothermal method and was embedded on the surface of dual layer hollow fiber membrane by dry-wet spinning method by varying the GO loading at 0.1, 0.25 and 0.5 wt%. The results indicated that the 0.5 PVDF/MoO 3 /ZnO/GO DLHF photocatalytic membrane exhibited improved wettability, high porosity, good water flux, and exceptional EDCs removal, achieving removal rates of 73.08%, 75.80%, 73.65%, 100%, 95.57%, and 53.50% for 1 mg/L BPA, 1 μg/L BPA, 2 μg/L gabapentin, 1 μg/L diclofenac, 10 μg/L caffeine, and 6 μg/L nonylphenol, respectively after 240 min of light exposure. Besides, energy storage capability achieved 96.07% rejection of 1 mg/L BPA in dark condition while stability and reusability test showed 0.5 PVDF/MoO 3 /ZnO/GO DLHF achieve 74.02% regeneration efficiency after 3 consecutive cycles. Furthermore, the photocatalytic properties of 0.5 PVDF/MoO 3 /ZnO/GO DLHF could assure a self-cleaning property and increase its lifetime. The PVDF/MoO 3 /ZnO/GO DLHF photocatalytic membrane served as a versatile 3-in-1 solution, enhancing photocatalytic degradation and rejection capabilities while also serving as a promising energy storage material with self-cleaning properties for removing EDCs from aquatic environments, regardless with or without the presence of light. [Display omitted] • Fabricated PVDF/MoO 3 /ZnO/GO DLHF membrane with 0.1, 0.25 and 0.5 wt% of GO loading. • Excellent removal of 5 types of EDCs by photocatalysis and rejection process. • Energy storage performance achieved 96.03% of BPA rejection in dark conditions. • Photocatalytic membrane achieves 74.02% regeneration efficiency after 3 cycles. • Versatile 3-in-1 functions of photocatalytic membrane with self-cleaning property. [ABSTRACT FROM AUTHOR]

With the increasing population worldwide more wastewater is created by human activities and discharged into the waterbodies. This is causing the contamination of aquatic bodies, thus disturbing the marine ecosystems. The rising population is also posing a challenge to meet the demands of fresh drinking water in the water-scarce regions of the world, where drinking water is made available to people by desalination process. The fouling of composite membranes remains a major challenge in water desalination. In this innovative study, we present a novel probabilistic approach to analyse and anticipate the predominant fouling mechanisms in the filtration process. Our establishment of a robust theoretical framework hinges upon the utilization of both the geometric law and the Hermia model, elucidating the concept of resistance in series (RIS). By manipulating the transmembrane pressure, we demonstrate effective management of permeate flux rate and overall product quality. Our investigations reveal a decrease in permeate flux in three distinct phases over time, with the final stage marked by a significant reduction due to the accumulation of a denser cake layer. Additionally, an increase in transmembrane pressure leads to a correlative rise in permeate flux, while also exerting negative effects such as membrane ruptures. Our study highlights the minimal immediate impact of the intermediate blocking mechanism (n = 1) on permeate flux, necessitating continuous monitoring for potential long-term effects. Additionally, we note a reduced membrane selectivity across all three fouling types (n = 0, n = 1.5, n = 2). Ultimately, our findings indicate that the membrane undergoes complete fouling with a probability of P = 0.9 in the presence of all three fouling mechanisms. This situation renders the membrane unable to produce water at its previous flow rate, resulting in a significant reduction in the desalination plant's productivity. I have demonstrated that higher pressure values notably correlate with increased permeate flux across all four membrane types. This correlation highlights the significant role of TMP in enhancing the production rate of purified water or desired substances through membrane filtration systems. Our innovative approach opens new perspectives for water desalination management and optimization, providing crucial insights into fouling mechanisms and proposing potential strategies to address associated challenges. [Display omitted] • Membranes comprise of high surface area, selective permeability, and ability to adsorb various contaminants. • The study introduces a novel probabilistic method to analyse fouling mechanisms. • Permeate flux steadily decreased due to the increasing strength of the cake layer. • Full membrane fouling significantly reduces desalination plant productivity, emphasizing the need for innovative solutions. [ABSTRACT FROM AUTHOR]

Some pharmaceutical and personal care products, including endocrine disruptors, are polluting ecosystems, thus requiring advanced materials and methods for detection and remediation. Here we review carbon nanotubes for detection and remediation of pharmaceutical and personal care products, with focus on green synthesis of hybrid carbon nanotubes, removal of pollutants, and deep learning networks to predicts adsorption. Pollutants include bisphenol, phthalates, tetracycline, and ciprofloxacin. We found that magnetic carbon nanotubes are easily recovered from water with a relatively low production cost. Functionalized carbon dots/carbon nanotube hybrids can detect ciprofloxacin contamination at 0.001 mg/L. Some studies report the adsorption of 95% or the photocatalytic degradation of 100% of pollutants using magnetic carbon nanotubes. [ABSTRACT FROM AUTHOR]

The rising global population is inducing a fast increase in the amount of municipal waste and, in turn, issues of rising cost and environmental pollution. Therefore, alternative treatments such as waste-to-energy should be developed in the context of the circular economy. Here, we review the conversion of municipal solid waste into energy using thermochemical methods such as gasification, combustion, pyrolysis and torrefaction. Energy yield depends on operating conditions and feedstock composition. For instance, torrefaction of municipal waste at 200 °C generates a heating value of 33.01 MJ/kg, while the co-pyrolysis of cereals and peanut waste yields a heating value of 31.44 MJ/kg at 540 °C. Gasification at 800 °C shows higher carbon conversion for plastics, of 94.48%, than for waste wood and grass pellets, of 70–75%. Integrating two or more thermochemical treatments is actually gaining high momentum due to higher energy yield. We also review reforming catalysts to enhance dihydrogen production, such as nickel on support materials such as CaTiO3, SrTiO3, BaTiO3, Al2O3, TiO3, MgO, ZrO2. Techno-economic analysis, sensitivity analysis and life cycle assessment are discussed. [ABSTRACT FROM AUTHOR]

Pharmaceutical waste generation in domestic and industrial discharges is a major challenge requiring adapted treatment solutions. Antibiotics, pain killers, lifesaving drugs, birth control pills, and tetracycline are released by human activities. Biochar has recently drawn attention as an adsorbents to remove pharmaceutical pollutants. Here we review biochar applications for the treatment of tetracycline, sulfonamides, quinolones and non-steroidal anti-inflammatory drugs. We discuss production methods, biochar properties, post-treatment methods and agents for biochar activation, adsorption mechanisms involved, performance of the biochar with respect to the sorbate, and operating conditions. Biochars from renewable materials show 100% recovery of pharmaceutical pollutants. Unlike other adsorbents, biochar can be recycled up to 8 times with a very low decline of efficiency. The highest recoveries of pharmaceutical pollutants using biochars is 1163 mg/g for tetracycline by biochar from Eucommia ulmoides; 400 mg/g for sulfamethoxazole with sugarcane bagasse biochar; 596 mg/g for naproxen by peanut shell biochar, and 698.6 mg/g for norfloxacin by corncob-derived biochar. [ABSTRACT FROM AUTHOR]

This study aims to determine the sustainability and energy efficiency of co-pyrolysis scenarios as treatment processes for municipal sewage sludge through a life cycle assessment (LCA). In addition, sensitivity and energy recovery analyses are conducted to determine the possible methods for optimizing the co-pyrolysis process from a circular bioeconomy perspective. Corncob and wood residue have been selected as potential co-feed materials for co-pyrolysis with sewage sludge at three mixing ratios (25, 50, and 75 wt%). The functional unit (FU) for this study is 1000 kg of dried single or mixed feedstock. LCA results indicate that sewage sludge, in a singular pyrolysis scenario, demonstrated the most unfavorable outcome by causing a rise in all negative environmental indicators. In contrast, the overall environmental impacts are reduced by up to 48 %, when the sewage sludge is mixed with co-feed biomass (wood or corncobs), with corncob co-pyrolysis performing better than wood residue in most impact indicators. Energy recovery from a gas turbine provides significant benefits, generating about nine times of the required energy for gas turbine operation and supplying sufficient energy to sustain the whole process. This is notably evident for corncob co-pyrolysis, where the energy produced from gas recovery is equivalent to 59–181 % of energy requirement of the whole process and achieved the highest net positive energy balance (+1368 kWh/FU). Sensitivity analysis indicates that co-pyrolysis is more sensitive to bio-oil yield fluctuations and feedstock transportation. In conclusion, this study establishes that sewage sludge co-pyrolysis is a more environmentally friendly treatment approach when compared to single pyrolysis. [Display omitted] • Sewage sludge single pyrolysis increased global warming and ecotoxicity indicators. • Co-pyrolysis scenarios reduced all environmental impact indicators by 10–90 %. • Co-pyrolysis scenarios achieved the highest energy recovery of up to 1368 kWh/FU. • Co-pyrolysis is more sensitive to bio-oil yield fluctuations and transportation. [ABSTRACT FROM AUTHOR]

Remediation of synthetic dyes found in aqueous environment poses a serious challenge for treatment due to their resistance to chemical and biological degradation. This research study investigated the application of Chitosan-ZnO-Seaweed bio nanocomposite in the remediation of congo red. The novel bionanocomposite was characterised by FTIR, SEM, TEM, EDS and XRD studies. The FTIR spectra and SEM images indicated the adsorption of congo red onto the synthesized bionanocomposite. The batch wise experimental studies were done to explore the influence of process variables on removal of congo red from synthetic wastewater and to determine optimized conditions. Under optimized conditions of pH 3, temperature 40 °C, initial congo red concentration 50 mg/L, bionanocomposite quantity 0.03 g/L and interaction period 30 min, the bionanocomposite removed 95.64% of congo red. Thermodynamic studies were carried out and the parameters, ΔH° and ΔS° were found to be 38.386 kJ/mol and 0.1451 kJ/mol. K, respectively. The isotherm and kinetic study showed that monolayer Langmuir model was obeyed (R2 = 0.968) and the experimental value of congo red adsorption correlated well with pseudo second order model (R2 = 0.9938) respectively. The maximum adsorption capacity was found to be 303.03 mg/g. Protonated amino group of chitosan, hydroxyl group of seaweed accounts for congo red adsorption along with zinc oxide. [Display omitted] • Biomass modified with chitosan - zinc oxide nanocomposite was synthesized • Chitosan-ZnO-Seaweeed nanocomposite showed a maximum adsorption capacity of 303.03 mg/g. • Adsorption followed monolayer adsorption • Protonated amino group of chitosan, hydroxyl group of seaweed accounts for CR sorption along with ZnO [ABSTRACT FROM AUTHOR]

Due to their widespread occurrence and detrimental effects on human health and the environment, endocrine-disrupting hazardous chemicals (EDHCs) have become a significant concern. Therefore, numerous physicochemical and biological remediation techniques have been developed to eliminate EDHCs from various environmental matrices. This review paper aims to provide a comprehensive overview of the state-of-the-art remediation techniques for eliminating EDHCs. The physicochemical methods include adsorption, membrane filtration, photocatalysis, and advanced oxidation processes. The biological methods include biodegradation, phytoremediation, and microbial fuel cells. Each technique's effectiveness, advantages, limitations, and factors affecting their performance are discussed. The review also highlights recent developments and future perspectives in EDHCs remediation. This review provides valuable insights into selecting and optimizing remediation techniques for EDHCs in different environmental matrices. • Comprehensive overview of EDHCs remediation techniques. • Physico-chemical and biological approaches discussed. • Effectiveness, advantages, and limitations highlighted. • Future perspectives in EDHCs remediation presented. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocharbons (PAHs) are a class of highly toxic pollutants that are highly detrimental to the ecosystem. Landfill leechate emanated from municipal solid waste are reported to constitute significant PAHs. In the present investigation, three Fenton proceses, namely conventional Fenton, photo-fenton and electro-fenton methods have been employed to treat landfill leehcate for removing PAHs from a waste dumpig yard. Response surface methodology (RSM) and artificial neural network (ANN) methodologies were adopted to optimize and validate the conditions for optimum oxidative removal of COD and PAHs. The statistical analysis results showed that all independent variables chosen in the study are reported to have significant influence of the removal effects with P-values <0.05. Sensitivity analysis by the developed ANN model showed that the pH had the highest significance of 1.89 in PAH removal when compared to the other parameters. However for COD removal, H 2 O 2 had the highest relative importance of 1.15, followed by Fe2+ and pH. Under optimal treatment conditions, the photo-fenton and electro-fenton processes showed better removal of COD and PAH compared to the Fenton process. The photo-fenton and electro-fenton treatment processes removed 85.32% and 74.64% of COD and 93.25% and 81.65% of PAHs, respectively. Also the investigations revelaed the presence of 16 distinct PAH compunds and the removal percentage of each of these PAHs are also reported. The PAH treatment research studies are generally limited to the assay of removal of PAH and COD levels. In the present investigation, in addition to the treatment of landfill leachate, particle size distribution analysis and elemental characterization of the resultant iron sludge by FESEM and EDX are reported. It was revealed that elemental oxygen is present in highest percentage, followed by iron, sulphur, sodium, chlorine, carbon and potassium. However, iron percentage can be reduced by treating the Fenton-treated sample with NaOH. • Realtime landfill leachate treated using three distinct Fenton oxidation methods. • Photo-Fenton treatment removal attained 85.32% for COD and 93.25% for PAH. • Electro-Fenton treatment removal attained 74.64% for COD and 81.65% for PAH. • Degradation of 16 distinct PAHs, classified by USEPA, is reported. • Sludge characterization was accomplished using FESEM and EDX. [ABSTRACT FROM AUTHOR]

Biobutanol is gaining more interest as advanced biofuel owing to its characteristics such as higher energy content, density and lesser corrosiveness. Deriving butanol from biological sources is an approach to attain carbon neutrality by exploiting renewable and sustainable reserves for biorefineries. Lignocellulosic materials are regarded as the suitable resources for the manufacture of butanol and several value-added products. The yield and quality of biobutanol largely rely on three factors, namely, the pretreatment of lignocellulosic feedstock, bioconversion methods adopted and the downstream oil upgradation. In the present report, a critical review on six pretreatment methods, namely, radiative treatment, ultrasonication, hydrothermal methods, organic solvation, ionic liquids solvation and biological treatment of distinct lignocellulosic materials along with their performance levels are presented. The recent strategies devised in the utilization and modification of yeast and bacterial strains for the biorefinery approach in the synthesis of biobutanol are described. The optimal butanol yield of 13.3 g/L was reported using from rice straw and mixed culture of Saccharomyces cerevisiae and Pichia species by enzymatic hydrolysis. [ABSTRACT FROM AUTHOR]

The considerable increase in world energy consumption owing to rising global population, intercontinental transportation and industrialization has posed numerous environmental concerns. Particularly, in order to meet the required electricity supply, thermal power plants for electricity generation are widely used in many countries. However, an annually excessive quantity of waste fly ash up to 1 billion tones was globally discarded from the combustion of various carbon-containing feedstocks in thermoelectricity plants. About half of the industrially generated fly ash is dumped into landfills and hence causing soil and water contamination. Nonetheless, fly ash still contains many valuable components and possesses outstanding physicochemical properties. Utilizing waste fly ash for producing value-added products has gained significant interests. Therefore, in this work, we reviewed the current implementation of fly ash-derived materials, namely, zeolite and geopolymer as efficient adsorbents for the environmental treatment of flue gas and polluted water. Additionally, the usage of fly ash as a catalyst support for the photodegradation of organic pollutants and reforming processes for the corresponding wastewater remediation and H 2 energy generation is thoroughly covered. In comparison with conventional carbon-based adsorbents, fly ash-derived geopolymer and zeolite materials reportedly exhibited greater heavy metal ions removal and reached the maximum adsorption capacity of about 150 mg g−1. As a support for biogas reforming process, fly ash could enhance the activity of Ni catalyst with 96% and 97% of CO 2 and CH 4 conversions, respectively. [Display omitted] • Waste fly ash is converted into value-added materials via different methods. • The utilization of fly ash-derived materials has been comprehensively discussed. • Fly ash-based materials are effectively used as adsorbents and catalysts. [ABSTRACT FROM AUTHOR]

MXene is a magical class of 2D nanomaterials and emerging in many applications in diverse fields. Due to the multiple advantageous characteristics of its fundamental components, such as structural, physicochemical, optical, and occasionally even biological characteristics. However, it is limited in the biomedical industry due to poor physiological stability, decomposition rate, and lack of controlled and sustained drug release. These limitations can be overcome when MXene forms composites with other 2D materials. The efficiency of pure MXene in biomedicine is inferior to that of MXene-based composites. The availability of functionality on the exterior part of MXene has a key role in the modification of their surface and their characteristics. This review provides an extensive discussion on the synthesizing of MXene and the role of the surface functionalities on the efficiency of MXene. In addition, a detailed discussion of the biomedical applications of MXene, including antibacterial activity, regenerative medicine, CT scan capability, drug delivery, diagnostics, MRI and biosensing capability. Furthermore, an outline of the future problems and challenges of MXene-based materials for biomedical applications was narrated. Thus, these salient features showcase the potential of MXene-based material and will be a breakthrough in biomedical applications in the near future. • MXenes-based materials are excellent candidates for biomedical applications. • MXene has superior biomedical performance as compared to other 2D materials. • MXene-based materials for effective coating for biomedical application was narrated. • The impact of synthesizing techniques on the Surface functionalities of MXene has been addressed. [ABSTRACT FROM AUTHOR]

An efficient BiVO 4 nanocatalyst with Erbium (Er) and Yttrium (Y) doping was synthesized via a facile microwave irradiation route and the obtained materials were further characterized through various techniques such as p-XRD, FT-IR, FE-SEM, HR-TEM, UV–Vis DRS, PL, LSV, and EISanalysis. The obtained results revealed that the rare metals induce the stabilization of the monoclinic-tetragonal crystalline structure with a distinct morphology. The yttrium doped BiVO 4 (Y–BiVO 4) monoclinic-tetragonal exhibited anefficient photoelectrochemical water splitting and photocatalytic performanceare compared to bare BiVO 4. TheY-BiVO 4 indicated increased results of photocurrent of 0.43 mA/cm2and bare BiVO 4 0.24 mA/cm2. Also, the Y-doped BiVO 4 nanocatalyst showed the maximum photocatalytic activity for the degradation of MB, MO, and RhB. A maximum degradation of 93%, 85%, and 91% was achieved for MB, MO, and RhB respectively, within 180 min under the visible light illumination. The photocatalytic decomposition of acetaldehyde also was performed. The improved photoelectrochemical water splitting and photocatalytic activity are due to the narrowing the bandgap, leading to extending the photoabsorption capability and reducing the recombination rate of photoexcited electron-hole pairs through the formation inner energy state of the rare earth metals. The current study disclosed that the synthesis of nanomaterials with crystal modification could be a prospectivecontender forhydrogen energy production as well as to the photocatalytic degradation of organic pollutants.To the best of our knowledge, both photocatalytic and photoelectrochemical studies were never been reported before for this type of material. [Display omitted] • BiVO 4 nanocatalystdoped with Erbium (Er) and Yttrium (Y) was synthesized. • Nanocatalysts were characterized by p-XRD, FT-IR, FE-SEM, HR-TEM, UV–Vis DRS, PL, LSV, and EIS. • Raman analysis confirms the successful incorporation of rare metals into the BiVO 4 structure. • Y–BiVO 4 exhibited efficient photoelectrochemical water splitting and photocatalytic performance. • Maximum degradation of 93%, 85%, and 91% was achieved for MB, MO, and RhB respectively. [ABSTRACT FROM AUTHOR]