Search

In the present study, rice straw‐derived cellulose was converted into carboxymethylcellulose (CMC) using alkalization followed by an etherification reaction. The synthesis conditions for this chemical modification were optimized such that CMC with a high degree of substitution (1.02) was obtained. Infrared spectra of the synthesized CMC clearly showed an increased intensity of the C═O bond at 1600 cm−1, confirming successful carboxymethylation. Further, X‐ray diffraction analysis demonstrated a decrease in cellulose crystallinity owing to partial rearrangement from a crystalline to an amorphous phase during initial alkalization reaction. The obtained CMC biopolymer was subsequently cross‐linked to form a composite hydrogel matrix reinforced with bentonite clay. The hydrogel showed about 91% adsorption capacity for methylene blue dye as a model contaminant in aqueous media. Therefore, this study shows that lignocellulosic agrowaste is a rich source of cellulose, and its derivatives such as CMC possess the potential to realize the waste to wealth sustainability goal. [ABSTRACT FROM AUTHOR]

The cashew nut shell is an agricultural residue generated in the production of cashew nuts. This residue is a hard-management biomass that can be efficiently transformed using pyrolysis, into a biochar. Conversely, potable water security requires the development of efficient adsorbents using novel and renewable materials. Then, in this work, a pyrolysis-derived carbon was chemically activated with KOH to remove phenol from an aqueous solution at 200 ppm that could represent health risk for life. The activated carbon was characterized rigorously, whereas adsorption kinetics and adsorption isotherms were evaluated to determine the suitability of this material to remove phenol. The activated carbon presented a chemical composition of 64.4 wt%; 33.2 wt%, and 1.98 wt% of carbon, oxygen, and hydrogen, respectively. Also, it presented a surface adsorption area of 863 m2/g, with a pore volume of 0.476 cm3/g. The surface chemistry presented -OH groups and the morphology revealed an organized material with the occurrence of porosity. The pseudo-second-order adequately described the kinetics of adsorption (80.93 mg/g and 0.0044 g/mg min, for equilibrium concentration (qe), and adsorption rate constant (kPSO), respectively). Additionally, the Toth isotherm model described reasonably the adsorption mechanism suggesting that a monolayer chemisorption that is independent of concentration of phenol took place for activated carbon. The efficiency of phenol uptake in the present work was about 79%, indicating that activated carbon derived from cashew nut shells has the potential for water remediation. [ABSTRACT FROM AUTHOR]

This paper presented the preparation, characterization, and adsorption properties of Brazil nut shell activated carbon for catechol removal from aqueous solutions. The equilibrium adsorption of catechol molecules on this activated was experimentally quantified at pH 6 and temperatures ranging from 25 to 55 °C, and at 25 °C and pH ranging from 6 to 10. These results were utilized to elucidate the role of surface functionalities through statistical physics calculations. All these experimental adsorption isotherms were fitted and interpreted via a monolayer model with one energy, which was chosen as the optimal model. Model physicochemical parameters, which may be categorized as stereographic parameters such as the maximum adsorbed quantity (QM), the number of adsorbed catechol molecules per one Brazil nut shell activated carbon binding site (n), and the number of effectively occupied binding sites (NM) and energetic parameter such as the half saturation concentration (CHS), were analyzed. Microscopically speaking, these modeling results were employed to stereographically and energetically investigate the phenol derivative adsorption mechanism. The maximum catechol adsorbed quantities on this activated carbon ranged from 89.98 to 103.16 mg/g under the tested operating conditions. The adsorption of catechol molecules was found to be exothermic where the maximum adsorbed quantity augmented with solution temperature and the maximum adsorption efficiency was found 103.16 mg/g at 55 °C. In addition, it was found that the catechol molecules were adsorbed with nonparallel orientations on the activated carbon adsorbent since the numbers of catechol molecules per site were superior to 1 (1.10 < n < 1.86). Moreover, the calculated molar adsorption energies, which varied between 19.04 and 22.37 kJ/mol, showed exothermic (ΔE > 0) and physical (ΔE < 40 kJ/mol) adsorption process involving hydrogen bonds, π-π interactions, electron donor-acceptor interactions, and dispersion forces. Finally, the tested adsorbent exhibited unimodal pore size and site energy distributions with peaks centered at pore radius ranging from 2.26 to 2.68 nm, and at adsorption energy ranging from 20.01 to 23.78 kJ/mol, respectively. Macroscopically speaking, three thermodynamic potentials, including the adsorption entropy, internal energy of adsorption, and Gibbs free energy, suggested that the adsorption of catechol on Brazil nut shell activated carbon was a spontaneous and exothermic mechanism. [ABSTRACT FROM AUTHOR]

Designing and developing clay-based adsorbents with a strong preference for removing copper and zinc metal ions, reduced cost, eco-friendliness, and good recyclability is a good strategy for water remediation. Herein, halloysite nanotubes (HNT) were activated by (3- chloropropyl) trimethoxy silane (CPTM) as a linker for polyethyleneimine to give HN-PEI. The hybrid organic/inorganic sorbent HN-PEI was analysed by Fourier-transform infrared spectroscopy, CHN/O (elemental analysis), scanning electron microscopy, textural properties (via the Brunauer – Emmett – Teller technique), X-ray diffraction, and thermogravimetry coupled with differential scanning calorimetry. The HN-PEI's textural properties show a reduced specific surface of 10.92 m2/g and pore size of 18.2 nm compared to its Pristine HNT (65.33 m2/g) and pore size (⁓10.1 nm), respectively with a dominant mesoporous structure. The selectivity and sorption characteristics of the Cu(II) and Zn(II) metal ions were exploited, while HN-PEI exhibited a remarkable improvement in terms of removing these ions from the aqueous media. At pH 4.5, the sorption capacities for Cu(II) were 2.8 mmol g−1 and for Zn(II) were 1.8 mmol g−1, with equilibrium reached within 120 and 150 min, respectively. There was an acceptable fitting of the pseudo-second-order and Langmuir equations, and the experimental data enabled mono-layer chemisorption reactions. The sorption was exothermic and spontaneous. The sorbent HN-PEI shows high durability over multiple cycles, and after 3 cycles, the sorption/desorption efficacy decreased by less than 6% using HCl (1 M) for Cu(II) and H2SO4 (1.5 M) for Zn(II). According to the bi-system solution sorption test, KSC(Cu(II)/Zn(II)) was ⁓2.0. Finally, HN-PEI had excellent selectivity and efficiency for Cu(II), Pb(II), and Zn(II) ions, especially for Cu(II). [ABSTRACT FROM AUTHOR]

Despite rapid technological progress, heavy metal water pollution, and particularly arsenic contamination, remains a significant global challenge. In addition, the stabilization of trivalent arsenic as neutral arsenite (AsIII) species hinders its removal by conventional sorbents. While adsorption of anionic arsenate (AsV) species is in principle more feasible, there are only few adsorbents capable of adsorbing both forms of arsenic. In this work, we explore the potential of two well‐known families of Metal‐Organic Frameworks (MOFs), UiO‐66 and MIL‐125, to simultaneously adsorb and photo‐oxidize arsenic species from water. Our results demonstrate that the formation of AsV ions upon light irradiation promotes the subsequent adsorption of AsIII species. Thus, we propose the combined utilization of photocatalysis and adsorption with Metal‐Organic Framework photocatalysts for water remediation purposes. [ABSTRACT FROM AUTHOR]

Designing new engineered materials derived from waste is essential for effective environmental remediation and reducing anthropogenic pollution in our economy. This study introduces an innovative method for remediating metal-contaminated water, using two distinct waste types: one biowaste (eggshell) and one industrial waste (fly ash). We synthesized three novel, cost-effective nanoadsorbent types, including two new tertiary composites and two biopolymer-based composites (specifically k-carrageenan and chitosan), which targeted chromium removal from aqueous solutions. SEM analysis reveals that in the first composite, EMZ, zeolite, and magnetite nanoparticles are successfully integrated into the porous structure of the eggshell. In the second composite (FMZ), fly ash and magnetite particles are similarly loaded within the zeolite pores. Each biopolymer-based composite is derived by incorporating the corresponding tertiary composite (FMZ or EMZ) into the biopolymer framework. Structural modifications of the eggshell, zeolite, chitosan, and k-carrageenan resulted in notable increases in specific surface area, as confirmed by BET analysis. These enhancements significantly improve chromium adsorption efficiency for each adsorbent type developed. The adsorption performances achieved are as follows: EMZ (89.76%), FMZ (84.83%), EMZCa (96.64%), FMZCa (94.87%), EMZC (99.64%), and FMZC (97.67%). The findings indicate that chromium adsorption across all adsorbent types occurs via a multimolecular layer mechanism, which is characterized as spontaneous and endothermic. Desorption studies further demonstrate the high reusability of these nanomaterials. Overall, this research underscores the potential of utilizing waste materials for new performant engineered low-cost composites and biocomposites for environmental bioremediation applications. [ABSTRACT FROM AUTHOR]

The contamination of seas, rivers, lakes, and groundwater by industrial, hospital, and domestic effluents is a global health problem. Scientific approaches are needed to assess and mitigate the impacts of those pollutants, seeking more sustainable alternatives that meet established environmental standards. Among the various contaminants that are released into water sources, phenobarbital (PHEN), a long-acting barbiturate, applied as a hypnotic, sedative, and in the treatment of seizures is an aquatic pollutant, raises significant concerns for human health and the environment. Based on the high surface area of carbon nanotubes (CNTs) and the magnetic properties of nickel ferrite (NiFe2O4) nanoparticles, this work presents, for the first time, the application of CNT@NiFe2O4 on the adsorption of PHEN. The employing of CNT as a barbiturate adsorber was investigated, using NiFe2O nanoparticles as a magnetic tool for recovering the nanocomposite from water. The PHEN adsorption study was performed in batch adsorption mode. Thermodynamic isotherms and kinect were performed using Langmuir, Freundlich, Sips, pseudo-first-order (PFO), pseudo-second-order (PSO), and Elovich diffusion models. CNT@NiFe2O4 showed an adsorption capacity of 76% for this drug, indicating it is a promising nanomaterial for removing PHEN from water. [ABSTRACT FROM AUTHOR]

Nanotechnology works at the interface of science and technology by providing innovative solutions through different nanomaterials such as nanoparticles, nanospheres, nanorods, nanocomposites, etc. Instead of traditional approaches available to synthesise these valuable products, green synthesis is attracting the interest of researchers with its environmental value. Agricultural waste is a by-product of agricultural production and various agriproducts processing industries. This waste is generally discarded and not disposed of causing major environmental pollution, an issue of concern. However, agricultural waste is a rich source of various phytochemicals and can be efficiently utilised to synthesise various value-added nanoparticles. This paper provides a detailed review of the innovative use of various agricultural wastes in the bio-synthesis of metal-based nanoparticles with potential applications in various sectors. The mechanism for the formation of zerovalent metal and metal oxide nanoparticles has been explored on the basis of the redox potential of the metal ion and the phytochemicals. The potential applications of these nanoparticles have also been explored in terms of antimicrobial potential, catalytic, and biomedical applications. Thus, the study strengthens the importance of various agri-wastes and their beneficiary role for the value-added resource recovery. [ABSTRACT FROM AUTHOR]

Graphene oxide–cobalt ferrite magnetic nanocomposite (M-GOC) was efficiently synthesised by microwave-assisted method for water remediation. The graphene oxide (GO) was synthesized by improved Hummers’ method, while cobalt ferrite (CoFe2O4) was synthesized by microwave-assisted combustion method. X-ray diffractograms indicated high phase-pure M-GOC with an average crystallite size of 18.5 nm. An enhancement in the absorbance was observed in the range of 220–280 nm due to the presence of additional π–π* transition of aromatic C–C bonds of GO. Appearance of a peak around 584 cm−1 corresponds to the stretching vibration of Co–O bond. Corrugated GO sheets were observed in SEM and HRTEM images with agglomerated spherical CoFe2O4 nanoparticles intercalated between the GO sheets. A particle size distribution curve was plotted that indicated an average particle size of ~11 nm of the CoFe2O4 nanoparticles. Raman spectra of GO confirmed the synthesis of pure GO sheets. Vibrating sample magnetometer was employed to investigate the magnetic behaviour of M-GOC, which showed a Mr/Ms ratio of 0.278. The adsorption study was performed, in which M-GOC nanocomposite exhibited an excellent adsorption capacity of 2229.9 mg g−1 for heavy metal i.e., cadmium ions (Cd+2). [ABSTRACT FROM AUTHOR]

Herbicide contamination in aquatic systems has become a global concern due to their long- term persistence, accumulation and health risks to humans. Paraquat, a widely used and cost-effective nonselective herbicide, is frequently applied in agricultural fields for pest control. Consequently, the removal of paraquat from contaminated water is crucial. This research presents a sustainable and environmentally benign method for paraquat removal from aqueous system by integrating wetland plants (Eichhornia crassipes) with biochar derived from melamine-modified palm kernel shells. The prepared biochar was characterized by using various analytical techniques. The effectiveness of biochar in enhancing phytoremediation was evaluated through a series of experiments, showing significant paraquat removal efficiencies of 99.7, 98.3, and 82.8% at different paraquat concentrations 50, 100, and 150 mg L−1, respectively. Additionally, present study examined the impact of biochar on the growth of E. crassipes, highlighting its potential to reduce the toxic effects of paraquat even present at higher concentrations. The paraquat removal mechanism was elucidated, focusing on the synergistic role of biochar adsorption and phytoremediation capability of E. crassipes. This innovative approach is an effective, feasible, sustainable and eco-friendly technique that can contribute to the development of advanced and affordable water remediation processes for widespread application. NOVELTY STATEMENT: The novelty of this study lies in the implementation of combined approach by phytoremediation with biochar modified with melamine. This study highlighted synergistic integration of two concurrent systems. The biochar generated from waste palm kernel shells played a pivotal role in facilitating the plants' survival and resilience against the paraquat toxicity, rather than succumbing to its deleterious effects. This research delineates a robust methodology for the elimination of emerging pollutants, offering researchers a platform to make pioneering advancements in this scientific field for sustainable future. [ABSTRACT FROM AUTHOR]

Soft robots have drawn a lot of interest in the field of human–robot interfaces because they can mimic the propulsion of soft bodies and archive complex tasks that cannot be made by rigid robots such as performing the complex motion, avoiding collisions by absorbing impacts, and shape adaptation by elastic deformation. Herein, drawing inspiration from creatures in the Cambrian period, such as Hallucigenia, we develop a centimeter‐sized soft robot with multiple magnetic legs (referred to as a soft centirobot). This robot is equipped with graphitic carbon nitride (g‐C3N4) nanosheets to kill biological threats by photogenerated reactive oxygen species under black light illumination. The motion of g‐C3N4 soft centirobot is controlled by magnetic actuation even in complex wastewater samples (with a relative speed of 0.12 body lengths per second). The magnetic multilegs work as a propeller to walk across and cover large regions, and water disinfection is more efficient than what could be achieved by nano/micrometer scale sheets of g‐C3N4. Finally, factors affecting the accelerated propulsion of g‐C3N4 soft centirobot such as design principle, structure geometry, body mass, driving mechanism, and magnetic sensitivity, have been investigated. We envision that such a photoactive 2D material‐based integrated centimeter‐sized robot shall find application in many areas where pathogen removal is required. [ABSTRACT FROM AUTHOR]

Water contamination has become a global concern, and the prevalence of complex substances known as emerging contaminants constitute a risk to human health and the environment. This work focused on an innovative approach of integrating sonolysis and photocatalysis to remove a standard textile dye efficiently. A highly photo-active, bismuth ferrite (BiFeO3) nanocatalyst with single particle sizes between 86 and 265 nm was obtained by a novel one-pot combustion method using a deep eutectic solvent as a precursor. The said catalyst was thoroughly characterized and evaluated for photocatalytic and sono-photocatalytic degradation of rhodamine B (RhB). Photocatalytic experiments were conducted under visible light irradiation (450–600 nm). Sono-photocatalytic (SPC) experiments were conducted, focusing on the influence of operational parameters (frequency, power, and pH) on the degradation performance. High-frequency values of 578, 866, and 1138 kHz were explored to promote cavitation dynamics and reactive species generation, improving removal efficiency. Results demonstrated that when sonolysis and photocatalysis were performed separately, the degradation efficiency ranged between 85 and 87%. Remarkably, when the combined SPC degradation was carried out, the RhB removal reached about 99.9% after 70 min. It is discussed that this behavior is due to the increased generation of OH• radicals as a product of the cavitation phenomena related to the ultrasound-assisted process. Moreover, it is argued that SPC significantly improves reaction kinetics and mass transfer rates, facilitating catalyst dispersion and contact with the RhB molecules. Finally, the stability of the catalyst was evaluated in five repeated RhB removal cycles, where the activity remained consistently strong. [ABSTRACT FROM AUTHOR]

The colored effluents causing environmental pollution pose a threat to the world. This study aims to assess the effectiveness of nickel oxide/zinc oxide/kaolin nanocomposite (NiO/ZnO/Ka) in removing methylene blue (MB) from water. Furthermore, it aims to examine the impact of synergetic adsorption/photocatalytic degradation (APCD) on the MB adsorption capacity as well as the suitability of the nonlinear adsorption isotherm and kinetic modeling in analyzing the process. The composites ZnO/Ka and NiO/ZnO/Ka were synthesized by the sol–gel method and were characterized by X-ray diffraction, Fourier transform infra-red, field emission scanning electron microscopy, and Brunauer–Emmett–Teller. The impacts of various parameters, such as pH, initial concentration of MB, dose, ionic strength, and temperature, on MB removal were studied using adsorption and APCD. The results showed that ZnO/Ka had the maximum adsorption capacity of MB (39.31 mg/g) and the maximum removal (78.61%) under optimal conditions of pH 10, clay dosage of 0.1 g/25 mL, initial concentration of MB 200 mg/L, contact time of 15 min, and 298 K, while NiO/ZnO/Ka showed the maximum adsorption capacity of MB (40.88 mg/g) and maximum removal (83.74%) at pH 7. It was also noticed that Temkin and Fritz–Schlunder models are the best isotherm models, with the highest R2 (1 and 0.842) for ZnO/Ka and NiO/ZnO/Ka, respectively. Moreover, the data of adsorption and photodegradation of MB onto ZnO/Ka and NiO/ZnO/Ka were revealed to follow pseudo-first-order and Avrami kinetic models with R2 (0.897) for ZnO/Ka and (0.986) for NiO/ZnO/Ka. Overall, NiO/ZnO/Ka showed better removal of MB than ZnO/Ka, and the hybrid process (photodegradation process after adsorption) enhanced the overall efficiency of MB removal than adsorption alone. [ABSTRACT FROM AUTHOR]

The present work intended to produce new cost-effective alkali-activated adsorbents from chestnut shells with the purpose of removing fluoride from water, and to explore the effect of pyrolysis temperature on fluoride decontamination at different operational and environmental parameters. The microstructure and morphological characteristics of the resulting activated carbons were thoroughly investigated using BET, FTIR, XRD and SEM. The effectiveness of the prepared adsorbent materials in treating and remediating fluorinated water was evaluated. The impacts of several factors, including the dose of the adsorbent, the initial contamination level of fluoride, and pH on the fluoride removal efficiency were investigated. In accordance with the data, the highest adsorption was found to be at a 6 pH during 5 hours of processing duration and 0.5 g/L of dosage of adsorbent. The experimental results were well-fit by the Freundlich isotherm model and the pseudo-second-order kinetic model. The highest fluoride removal efficiency was found to be 78% at adsorption medium pH 6 and initial fluoride concentration of 10 mg/L by the adsorbent prepared at 800°C. Additional research on adsorption along with rejuvenation revealed that the reduction in adsorption potential to 10% following four repetitions of operation involving regeneration, thereby showcasing the adsorbent's versatile applicability for repeated use. [ABSTRACT FROM AUTHOR]

The hybrid material created by combining cellulose and MOF is highly promising and possesses a wide range of useful properties. Cellulose-based metal–organic frameworks (CelloMOFs) combine the inherent biocompatibility and sustainability of cellulose with the tunable porosity and diverse metal coordination chemistry of MOFs. Cellulose-MOF hybrids have countless applications in various fields, such as energy storage, water treatment, air filtration, gas adsorption, catalysis, and biomedicine. They are particularly remarkable as adsorbents that can eliminate pollutants from wastewater, including metals, oils, dyes, antibiotics, and drugs, and act as catalysts for oxidation and reduction reactions. Furthermore, they are highly efficient air filters, able to remove carbon dioxide, particulate matter, and volatile organic compounds. When it comes to energy storage, these hybrids have demonstrated exceptional results. They are also highly versatile in the realm of biomedicine, with applications such as antibacterial and drug delivery. This article provides an in-depth look at the fabrication methods, advanced applications of cellulose-MOF hybrids, and existing and future challenges. [ABSTRACT FROM AUTHOR]

Polymers derived from renewable carbon feedstock are destined to play a pivotal role in the transition to a sustainable circular economy, displacing conventional fossil‐carbon materials. Chitin (CT) and chitosan (CS) are well‐suited to develop multifunctional materials that are mechanically resilient and easy to process. Their abundance of hydroxyl and amine groups facilitates hydrogen bonding and electrostatic interactions, making them suitable for persistent pollutant removal from drinking water. Therefore, porous CS cryogels are fabricated by dissolution in acetic acid, coagulation, and subsequent freeze‐drying. To enhance durability in harsh environments, CT cryogels are obtained through acetylation. Furthermore, Fe3O4 nanoparticles are incorporated to enable removal by external magnetic fields. The rapid removal of per‐ and polyfluoroalkyl substances (PFASs) with capacities reaching 451 mg g−1 offers competitive performance against state‐of‐the‐art materials. The shear‐thinning properties of CS enable rapid additive manufacturing in predetermined free‐standing shapes, useful for accessing sites with complex geometries. Life cycle assessment (LCA) confirms the suitability of chitosan and CT cryogels for low environmental impact water remediation applications. Furthermore, the cryogels can be recycled, closing the material loops back into the economic cycle. Altogether, this work demonstrates the potential of chitosan and CT as competitive alternatives to fossil‐carbon derived systems for sustainable environmental remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficient dual-adsorption of MO and Cd(II) using biogenic fibrous silica. • Crown ether ionic liquid functionalization enhances pollutant interaction with the adsorbent. • Sustainable adsorbent derived from sorghum waste prepared by an eco-friendly synthesis. • Adsorption processes confirmed as spontaneous and highly efficient. • High surface area and pore volume of the adsorbent provide abundant active sites. In pursuit of sustainable nanomaterial production, this study presents a novel biogenic fibrous silica sphere functionalized with a crown ether ionic liquid for advanced dual-adsorption of methyl orange and Cd(II) from aqueous solution. Sorghum waste serves as the silica source in the adsorbent preparation process, ensuring an eco-friendly approach. The benzo-15-crown-5 ionic liquid is coupled to thiol-functionalized fibrous silica spheres through an efficient thiol-ene click reaction. Under constant conditions (temperature: 298 K, solution volume = 50 mL, adsorbent dosage = 5 mg, pH = 7, shaking speed = 200 rpm), the synthesized material demonstrates maximum adsorption capacities of 507.1 mg g−1 and 306.3 mg g−1 for methyl orange and Cd(II), respectively, according to the Langmuir model. Thermodynamic investigations reveal exothermic adsorption for methyl orange with an enthalpy change of −77.49 KJ mol−1, while endothermic adsorption is observed for Cd(II) with an enthalpy of +24.10 KJ mol−1. The entropy change of adsorption is −0.153 KJ mol−1 K−1 for methyl orange, indicating a more ordered state, and + 0.192 KJ mol−1 K−1 for Cd(II), suggesting increased disorder. The change in Gibbs free energy ranges from −32.66 to −29.60 KJ mol−1 for methyl orange and −32.29 to −35.99 KJ mol−1 for Cd(II), demonstrating that both adsorption processes are spontaneous. These results indicate that the adsorbent has potential as a dual-adsorption material for water remediation applications. [ABSTRACT FROM AUTHOR]

In terms of environmental pollution, water pollution is the most significant problem facing living organisms worldwide. Pollutants of various types, including toxic, inorganic, and organic materials, have a detrimental impact on terrestrial and aquatic ecosystems. Materials with layers, such as layered double hydroxides (LDHs), a type of synthetic anion clay, have a wide range of potential applications. In this comprehensive study, we have discussed variety of LDHs, and their explicit properties which have significant advantages for the removal of a variety of pollutants from water. Besides these, LDHs are easily synthesized with high yield and, tuneable structure based on choice of metals, etc. Based on these unique potentials, we have summarized how layered double hydroxides and their hybrids are synthesized efficiently. The performance and applications in removing water pollutants involving heavy metals, inorganic anions, and organics at different parameters such as temperature, adsorbent dosage, pH, and contact time are discussed. Consolidated information has been provided regarding the LDH synthesis, conditions for adsorption, and reference of the particular work. The worked‐up LDH's regeneration potential and methods evolved for regenerating it, different kinetic models and isotherms are also discussed. [ABSTRACT FROM AUTHOR]

The lasting impact of ancestral energy production operations and global manufacturing has not only generated substantial CO2 emissions, but it has also led to the release of metal-based pollutants into Earth's water bodies. As we continue to engineer, mine (coal and metals), and now bore into geothermal wells/fracking sites for alternative energy sources, we continue to contaminate drinking water supplies with heavy metals through infiltration and diffusion, limiting progress towards achieving Sustainable Development Goals 3 (Sustainable Development Goal 3: Good health and well-being), 6 (Sustainable Development Goal 6: Clean water and sanitation), 14 (Sustainable Development Goal 14: Life below water), and 15 (Sustainable Development Goal 15: Life on land). This review shows how the research community has designed and developed mesoporous biochars with customizable pore systems, as well as functionalized biochars, to extract various heavy metals from water sources. This article investigates how biochar materials (non-activated, activated, functionalized, or hybrid structures) can be adapted to suit their purpose, highlighting their recyclability/regeneration and performance when remediating metal-based pollution in place of conventional activated carbons. By utilizing the wider circular economy, "waste-derived" carbonaceous materials will play a pivotal role in water purification for both the developed/developing world, where mining and heavy manufacturing generate the most substantial contribution to water pollution. This review encompasses a wide range of global activities that generate increased heavy metal contamination to water supplies, as well as elucidates emerging technologies that can augment environmental remediation activities, improving the quality of life and standard of living for all. [ABSTRACT FROM AUTHOR]

Amine-functionalized graphene oxide (GO-NH2) was prepared by synthesizing graphene oxide (GO) using the Hummer's method, followed by reacting with (3-aminopropyl)triethoxysilane (APTES). The obtained GO-NH2 was utilized for immobilizing and stabilizing Rh(0) nanoparticles (NPs) to create Rh@GO-NH2 material. The synthesized Rh@GO-NH2 material was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), elemental mapping, and X-ray photoelectron spectroscopy (XPS) analysis. The results indicated that the Rh(0) NPs were successfully decorated on the GO-NH2 surface. The catalytic activity of Rh@GO-NH2 was examined for the hydrogenation of nitroaromatic compounds using NaBH4 as a reducing agent. Results demonstrated that Rh@GO-NH2 effectively catalyzed the hydrogenation of nitroaromatics into the corresponding aniline derivatives in aqueous media at a moderate temperature. Nitroaromatic compounds are considered high toxic water contaminants. The simple preparation of the catalyst, low catalyst loading, and the recoverability of the catalyst are some advantages of this work. [ABSTRACT FROM AUTHOR]

Methylene blue (MB) is a dye hazardous pollutant widely used in several industrial processes that represents a relevant source of water pollution. Thus, the research of new systems to avoid their environmental dispersion represents an important goal. In this work, an efficient and sustainable nanocomposite material based on green gold nanoparticles for MB water remediation was developed. Starting from the reducing and stabilizing properties of some compounds naturally present in Lambrusco winery waste (grape marc) extracts, green gold nanoparticles (GM-AuNPs) were synthesized and deposited on a supporting membrane to create an easy and stable system for water MB decontamination. GM-AuNPs, with a specific plasmonic band at 535 nm, and the modified membrane were first characterized by UV–vis spectroscopy, X-ray diffraction (XRD), and electron microscopy. Transmission electron microscopy analysis revealed the presence of two breeds of crystalline shapes, triangular platelets and round-shaped penta-twinned nanoparticles, respectively. The crystalline nature of GM-AuNPs was also confirmed from XRD analysis. The photocatalytic performance of the modified membrane was evaluated under natural sunlight radiation, obtaining a complete disappearance of MB (100%) in 116 min. The photocatalytic process was described from a pseudo-first-order kinetic with a rate constant (k) equal to 0.044 ± 0.010 min−1. The modified membrane demonstrated high stability since it was reused up to 20 cycles, without any treatment for 3 months, maintaining the same performance. The GM-AuNPs-based membrane was also tested with other water pollutants (methyl orange, 4-nitrophenol, and rhodamine B), revealing a high selectivity towards MB. Finally, the photocatalytic performance of GM-AuNPs-based membrane was also evaluated in real samples by using tap and pond water spiked with MB, obtaining a removal % of 99.6 ± 1.2% and 98.8 ± 1.9%, respectively. [ABSTRACT FROM AUTHOR]

Anodic TiO2 nanotube arrays decorated with Ni, Cu, and NiCu alloy thin films were investigated for the first time for the photocatalytic degradation of paracetamol in water solution under UV irradiation. Metallic co-catalysts were deposited on TiO2 nanotubes using magnetron sputtering. The influence of the metal layer composition and thickness on the photocatalytic activity was systematically studied. Photocatalytic experiments showed that only Cu-rich co-catalysts provide enhanced paracetamol degradation rates, whereas Ni-modified photocatalysts exhibit no improvement compared with unmodified TiO2. The best-performing material was obtained by sputtering a 20 nm thick film of 1:1 atomic ratio NiCu alloy: this material exhibits a reaction rate more than doubled compared with pristine TiO2, enabling the complete degradation of 10 mg L−1 of paracetamol in 8 h. The superior performance of NiCu-modified systems over pure Cu-based ones is ascribed to a Ni and Cu synergistic effect. Kinetic tests using selective holes and radical scavengers unveiled, unlike prior findings in the literature, that paracetamol undergoes direct oxidation at the photocatalyst surface via valence band holes. Finally, Chemical Oxygen Demand (COD) tests and High-Resolution Mass Spectrometry (HR-MS) analysis were conducted to assess the degree of mineralization and identify intermediates. In contrast with the existing literature, we demonstrated that the mechanistic pathway involves direct oxidation by valence band holes. [ABSTRACT FROM AUTHOR]

The objective of this study is to map, describe, and identify "water treatment using catalysts and/or nanomaterials" and their derivable aspects. A comprehensive search was conducted in academic databases such as WoS and Scopus, following the PRISMA methodology, to identify relevant studies published between 2010 and 2024. Inclusion and exclusion criteria were applied to select articles that address both experimental and theoretical aspects of photocatalysis in wastewater treatment. The methodology is developed through exploratory data analysis and the use of the Tree of Science algorithm. The first results indicate the roots, in which it is possible to gain knowledge of the environment for the implementation of a photoreactor it uses as a photocatalyst agent. A total of 94 relevant articles were identified. The results show that most studies focus on the degradation of organic pollutants using TiO2 as a photocatalyst. Additionally, there has been a significant increase in the number of publications and citations in recent years, indicating growing interest in this field. Then, in the trunk, some more solid ideas in terms of basic concepts, techniques and possible variations for the application of knowledge and development of future research related to the initial topic are indicated. Finally, through the leaves, new modifications and combinations of the photocatalytic materials are obtained, in search of improving their performance in terms of reduction in water contaminants. From the above, centrality in photocatalysis is identified as an alternative for water remediation using different photocatalysts. It is concluded that the total citation network contains, within the most important nodes, articles of high interest in the community, such as those authored by Zhang, Xiaofei; Nezamzadeh-Ejhieh, Alireza; or Li, Jingyi, from countries in the Middle East and the Asian continent, justified not only by the research capabilities of these countries, but also by the needs and problems that these regions face in terms of water scarcity. Future work indicates the need for and interest in improving various characteristics such as photocatalytic performance, the number of cycles that the material supports, and its reduction capacity in the presence of high concentrations of contaminants, with the intention of maximizing the benefits of its applicability in water treatment. [ABSTRACT FROM AUTHOR]

The transition from lab-scale studies to pilot-scale applications is a critical step in advancing water remediation technologies. While laboratory experiments provide valuable insights into the underlying mechanisms and method effectiveness, pilot-scale studies are essential for evaluating their practical feasibility and scalability. This progression addresses challenges related to operational conditions, effectiveness and energy requirements in real-world scenarios. In this study, the potential of nanopulsed plasma bubbles, when scaled up from a lab environment, was explored by investigating critical experimental parameters, such as plasma gas, pulse voltage, and pulse repetition rate, while also analyzing plasma-treated water composition. To validate the broad effectiveness of this method, various classes of highly toxic organic pollutants were examined in terms of pollutant degradation efficiency and energy requirements. The pilot-scale plasma bubble reactor generated a high concentration of short-lived reactive species with minimal production of long-lived species. Additionally, successful degradation of all pollutants was achieved in both lab- and pilot-scale setups, with even lower electrical energy-per-order (EEO) values at the pilot scale, 2–3 orders of magnitude lower compared to other advanced oxidation processes. This study aimed to bridge the gap between lab-scale plasma bubbles and upscaled systems, supporting the rapid, effective, and energy-efficient destruction of organic pollutants in water. [ABSTRACT FROM AUTHOR]

The challenge of microcontaminants (MCs) in wastewater effluent has been addressed by using different technologies, including advanced oxidation processes (AOPs) and adsorption. This work evaluates the benefits and synergies of combining these two processes. The AOPs were photo-Fenton and UV/H2O2 operated under natural pH but with different reagents dosages, lamps, and chelating agents. Chelating agents were used at analytical (ethylenediamine-N,N-disuccinic acid and citric acid) and technical grade (citric acid) to simulate scaling-up conditions. The adsorption process was studied via granular activated carbon (GAC) filtration using fresh and regenerated GAC. Four AOP scenarios were selected and coupled with GAC filtration, showing benefits for both processes. AOP treatment time decreased from 10–15 min to 5 min, resulting in a reduction in energy consumption of between 50 and 66%. In the photo-Fenton process, it was possible to work with low reagent dosages (1.5 mg L−1 iron and 20 mg L−1 of H2O2). However, the use of UV/H2O2 showed close removal, highlighting it as a real alternative. An extension of the GAC lifetime by up to 11 times was obtained in all the scenarios, being higher for regenerated than for fresh GAC. Furthermore, the toxicity and phytotoxicity of the treated wastewater were evaluated, and no acute toxicity or slight variation in the phytotoxicity was observed in the combination of these processes. [ABSTRACT FROM AUTHOR]

Nanorobots are being received with a great attention for their move‐sense‐and‐act capabilities that often originate from catalytic decomposition of fuels. In the past decade, single‐atom engineering has demonstrated exceptional efficiency in catalysis, energy‐related technologies, and medicine. Here, a novel approach involving point defect engineering and the incorporation of platinum (Pt) single atoms and atomic level species onto the surface of titanium dioxide nanotubes (TiO2‐NT)‐based nanorobots is presented and its impact on the propulsion capabilities of the resulting nanorobots is investigated. The achievement of point defect engineering is realized through the annealing of TiO2‐NT in a hydrogen atmosphere yielding to the point‐defect decorated nanotube (TiO2‐HNT) nanorobots. Subsequently, the atomic level Pt species decorated TiO2 nanotube (TiO2‐SA‐NT) nanorobots are achieved through a wet‐chemical deposition process. Whereas TiO2‐SA‐NT nanorobots showed the highest negative photogravitaxis when irradiated with ultraviolet (UV) light, TiO2‐HNT nanorobots reached the highest velocity calculated in 2D. Both TiO2‐HNT and TiO2‐SA‐NT nanorobots demonstrated a pronounced affinity for microplastics, exhibiting the capability to irreversibly capture them. This pioneering approach utilizing point‐defect and atomic level Pt species nanorobotics is anticipated to pave the way for highly efficient solutions in the remediation of nano‐ and microplastics and related environmental technologies. [ABSTRACT FROM AUTHOR]

Introduction: Overusing and misusing pesticides, including paraquat (PQ), have led to numerous environmental contamination complications. PQ is an emerging bio-accumulative contaminant that is present in environmental aqueous matrices. Adsorption techniques are part of a set of technologies applied in ecological remediation, known for their high effectiveness in removing aqueous PQ. A study of the PQ adsorption capacity of three cyclodextrin-silica nanocomposites (a-CDSi, p-CDSi, and y-CDSi) from contaminated waters is presented in this paper. Methods: The cyclodextrin-silica nanocomposites were synthesized via an esterification reaction between the inorganic matrix and cyclodextrins (CDs) (a, p, and Y) and were characterized physicochemically by spectroscopic, thermal, and surface methods. Their PQ removal performance from contaminated aqueous media was studied under different experimental conditions. Results and Discussion: The results showed a fast adsorptive response in removal treatment studies over time. Adsorption capacities of 87.22, 57.17, and 77.27 mg.g-1 were found for a-CDSi, p-CDSi, and Y-CDSi, respectively, at only 30 min of treatment. Thermodynamic studies indicated spontaneous and exothermic adsorption processes. The removal assays responded mainly to physisorption mechanisms with contributions from chemisorption mechanisms. Spectroscopic assays showed a strong interaction of PQ with the adsorbents used. Innovative CDSi nanocomposites have proven to be highly efficient in applying aqueous PQ remediation, thus proving to be sustainable adsorbents of contaminants of emerging importance worldwide. [ABSTRACT FROM AUTHOR]

Progesterone (PGT) is a steroid hormone produced naturally by pregnant women. Advent of pharmaceuticals gave rise to synthetic production of PGT as a medicine for various pregnancy-related issues. As a result of synthetic production and high utilization rate of PGT, they have become an emerging contaminant in water sources worldwide. Conventional wastewater treatment is not competent enough to remove steroid contaminants. Hence, the current study attempted the degradation of 10 mg L−1 of PGT in water using photocatalysis (PC) followed by electrocatalytic oxidation (EC) using vanadium pentoxide (V2O5) and carbon-coated titanium (C/Ti) anode. Optimization studies found UV-C irradiation, pH 5, 50-mg L−1 catalyst dosage, 180-min PC followed by 300-min EC, and 69 mA cm−2 current density eliminating 96% COD and 71.5% TOC. Comparative studies showed that PC(UV-C) + EC was 50% and 25% more efficient than electrochemical oxidation and electrocatalytic oxidation for TOC removal. Photocatalytic pretreatment brought down current consumption of the process by 23 mA cm−2. High-resolution mass spectrometry (HRMS) studies were utilized to propose the degradation pathway that involved hydroxylation, demethylation, dehydroxylation, and decarboxylation mechanisms. [ABSTRACT FROM AUTHOR]

The development of cost-effective and high-performance technologies for wastewater treatment is essential for achieving a sustainable economy. Among the various methods available for water remediation, adsorption is widely recognized as an effective and straightforward approach for removing a range of pollutants. Gel materials, particularly hydrogels and aerogels, have attracted significant research interest due to their unique properties. Hydrogels, for instance, are noted for their ability to be regenerated and reused, ease of separation and handling, and suitability for large-scale applications. Additionally, their low cost, high water absorption capacity, and contribution to environmental protection are important advantages. Aerogels, on the other hand, are distinguished by their low thermal conductivity, transparency, flexibility, high porosity, mechanical strength, light weight, large surface area, and ultralow dielectric constant. This review provides a comprehensive analysis of the current literature, highlighting gaps in knowledge regarding the classification, preparation, characterization, and key properties of these materials. The potential application of hydrogels and aerogels in water remediation, particularly in removing contaminants such as dyes, heavy metals, and various organic and inorganic pollutants, is also discussed. [ABSTRACT FROM AUTHOR]