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Wastewater is contaminated water that must be treated before it may be transferred into other rivers and lakes in order to prevent further groundwater pollution. Over the last decade, research has been conducted on a wide variety of contaminants, but the emerging contaminants are those caused primarily by micropollutants, endocrine disruptors (EDs), pesticides, pharmaceuticals, hormones, and toxins, as well as industrially-related synthetic dyes and dye-containing hazardous pollutants. Most emerging pollutants did not have established guidelines, but even at low concentrations they could have harmful effects on humans and aquatic organisms. In order to combat the above ecological threats, huge efforts have been done with a view to boosting the effectiveness of remediation procedures or developing new techniques for the detection, quantification and efficiency of the samples. The increase of interest in biotechnology and environmental engineering gives an opportunity for the development of more innovative ways to water treatment remediation. The purpose of this article is to provide an overview of emerging sources of contaminants, detection technologies, and treatment strategies. The goal of this review is to evaluate adsorption as a method for treating emerging pollutants, as well as sophisticated and cost-effective approaches for treating emerging contaminants. • This review focuses on high-risk emerging contaminants (ECs) in the environment. • ECs are explored in terms of their occurrence, sources and important mechanisms. • The negative environmental and health effects of ECs are addressed. • Numerous emerging pollutants and improvements in their remediation are reviewed. • Recent progress and possible advances in emerging pollutant adsorption are reviewed. [ABSTRACT FROM AUTHOR]

Creating mesoporous architecture on the surface of metal oxides without using pore creating agent is significant interest in electrochemical sensors because these materials act as an efficient electron transfer process between the electrode interface and the analytes. Recent advances in mesoporous titanium dioxide (TiO 2)-based materials have acquired extraordinary opportunities because of their interconnected porous structure could act as a host for doping with various transition metals or heteroatoms to form a new type of heterojunction. Herein, a simple method is developed to synthesize mesoporous copper oxide (CuO) decorated on TiO 2 nanostructures in which homogenous shaped CuO nanocrystals act as dopants decorated on the mesoporous structure of TiO 2 , resulting in p-n heterojunction nanocomposite. The TiO 2 particles exhibit a mesoporous structure with a pore volume of about 0.117 cm3/g is capable to load CuO nanocrystals on the surface. As a result, large pore volume 0.304 cm³/g is obtained for CuO–TiO 2 heterojunction nanocomposite with the loading of uniform-shaped CuO nanocrystals on the mesoporous TiO 2. The resulting CuO–TiO 2 nanocomposite on modified glassy carbon (GC) electrode exhibits good electrochemical performance for oxidation of catechol with the observation of strong enhancement in the anodic peak potential at +0.36 V. The decrease in the overpotential for the oxidation of catechol when compared to TiO 2 /GC is attributed to the presence of CuO nanocrystals providing a large surface area, resulting in wide linear range 10 nM to 0.57 μM. Moreover, the resultant modified electrode exhibited good sensitivity, selectivity and reproducibility and the sensor could able to determine the presence of catechol in real samples such as lake and river water. Therefore, the obtained CuO–TiO 2 nanocomposite on the modified GC delivered good electrochemical sensing performance and which could be able to perform a promising strategy for designing various metal oxide doped nanocomposites for various photochemical and electrocatalytic applications. [ABSTRACT FROM AUTHOR]

This study investigated the effectiveness of extended aeration system (EAS) and rice straw activated carbon-extended aeration system (RAC-EAS) in the treatment of pulp and paper biorefinery effluent (PPBE). RAC-EAS focused on the efficient utilization of lignocellulosic biomass waste (rice straw) as a biosorbent in the treatment process. The experiment was designed by response surface methodology (RSM) and conducted using a bioreactor that operated at 1–3 days hydraulic retention times (HRT) with PPBE concentrations at 20, 60 and 100%. The bioreactor was fed with real PPBE having initial ammonia-N and total phosphorus (TP) concentrations that varied between 11.74 and 59.02 mg/L and 31–161 mg/L, respectively. Findings from the optimized approach by RSM indicated 84.51% and 91.71% ammonia-N and 77.62% and 84.64% total phosphorus reduction in concentration for EAS and RAC-EAS, respectively, with high nitrification rate observed in both bioreactors. Kinetic model optimization indicated that modified stover models was the best suited and were statistically significant (R2 ≥ 0.98) in the analysis of substrate removal rates for ammonia-N and total phosphorus. Maximum nutrients elimination was attained at 60% PPBE and 48 h HRT. Therefore, the model can be utilized in the design and optimization of EAS and RAC-EAS systems and consequently in the prediction of bioreactor behavior. [ABSTRACT FROM AUTHOR]

Over the last years, the strategy of employing inevitable organic waste and residue streams to produce valuable and greener materials for a wide range of applications has been proven an efficient and suitable approach. In this research, sulfur-doped porous biochar was produced through a single-step pyrolysis of birch waste tree in the presence of zinc chloride as chemical activator. The sulfur doping process led to a remarkable impact on the biochar structure. Moreover, it was shown that sulfur doping also had an important impact on sodium diclofenac (S-DCF) removal from aqueous solutions due to the introduction of S-functionalities on biochar surface. The adsorption experiments suggested that General and Liu models offered the best fit for the kinetic and equilibrium studies, respectively. The results showed that the kinetic was faster for the S-doped biochar while the maximum adsorption capacity values at 318 K were 564 mg g−1 (non-doped) and 693 mg g−1 (S-doped); highlighting the better affinity of S-doped biochar for the S-DCF molecule compared to non-doped biochar. The thermodynamic parameters (ΔH0, ΔS0, ΔG0) suggested that the S-DCF removal on both adsorbents was spontaneous, favourable, and endothermic. • Sustainable synthesis of sulfur-doped carbon with superior adsorptive properties. • High surface area Sulfur-doped carbon (1809 m2 g−1) with predominant mesoporosity. • Sulfur doping boosted diclofenac removal due to the number of S-functionalities. [ABSTRACT FROM AUTHOR]

The escalating consumer demand for crabs results in a growing amount of waste, including shells, claws, and other non-edible parts. The resulting crab shell waste (CSW) is disposed of via incineration or landfills which causes environmental pollution. CSW represents a potential biological resource that can be transformed into valuable resources via pyrolysis technique. In this study, microwave pyrolysis of CSW using self-purging, vacuum, and steam activation techniques was examined to determine the biochar production yield and its performance in treating palm oil mill effluent (POME). The biochar produced through microwave pyrolysis exhibits yields ranging from 50 to 61 wt%, showing a hard texture, low volatile matter content (≤34.1 wt%), and high fixed carbon content (≥58.3 wt%). The KOH-activated biochar demonstrated a surface area of up to 177 m2/g that is predominantly composed of mesopores, providing a good amount of adsorption sites for use as adsorbent. The biochar activated with steam removed 8.3 mg/g of BOD and 42 mg/g of COD from POME. The results demonstrate that microwave pyrolysis of CSW is a promising technology to produce high-quality biochar as an adsorbent for POME treatment. [Display omitted] • Different microwave pyrolysis methods are examined for biochar production. • Biochar is further microwave-activated via steam and KOH. • High yield of biochar and activated biochar is obtained. • These biochar show desirable adsorption efficiency of COD and BOD. [ABSTRACT FROM AUTHOR]

Bioaugmentation helps to obtain a microbiome capable of remediating polycyclic aromatic hydrocarbons (PAHs). In this study, acclimation of microorganisms to soil supplemented with phenanthrene (PHE) led to enrichment with PAH-degraders, including those in Actinobacteriota and in the genera Streptomyces , Rhodococcus , Nocardioides , Sphingomonas , and Mycobacterium. Aqueous (28 °C, pH 6.5) and soil cultures inoculated with PHE-acclimated soil showed a high PHE (ca. 50 mg L−1) degradation efficiency. The PHE degradation kinetics in aqueous and soil incubations fitted to the Gompertz equation and the first-order kinetic equation, respectively. Indigenous microorganisms adapted to PHE in their environment, and this increased their capacity to degrade PHE. The effect of co-contaminants and pathway intermediates on PHE degradation showed that the degradation of PHE improved in the presence of diesel while being hindered by lubricant oil, catechol, salicylic and phthalic acid. Our findings provide theoretical and practical support for bioremediationof PAHs in the environment. • Phenanthrene (PHE) soil acclimation enriches indigenous degraders. • It accelerates PHE degradation in aqueous and soil cultures. • Diesel improves but lubricant oil impairs PHE degradation. • Catechol, salicylic acid and phthalic acid inhibit PHE degradation. [ABSTRACT FROM AUTHOR]

In the present work, mixed-spinel ferrite anchored onto graphitic carbon nitride (GCN) was synthesized for mineralization of antibiotic pollutant from waste water. A Z-scheme g-C 3 N 4 /Ni 0.5 Zn 0.5 Fe 2 O 4 nano heterojunction was fabricated by three step procedure: pyrolysis, solution combustion and mechanical grinding followed by annealing. The prepared photocatlyst was tested for degradation of Doxycycline (DC) drug under the natural sun light. Results revealed that the prepared heterojunction has maximum degradation efficiency of 97.10% pollutant in 60 min experiment. The Z-scheme heterojunction between g-C 3 N 4 and Ni–Zn ferrite improves the photoinduced charges separation and protection of redox capability and therby increases the photo degradation efficiency. The scavenging experiments suggested that O 2 −● and h+ as main active species responsible for degradation of the antibiotic. In addition, the dopant variation can drive the shists in band gap and energy band positiong too which makes then excellent candidates for synthesizing tunable heterostructures with organic semiconductors. The work focusses on designing and developing of saimpler but efficient magnetic heterojunctions with superior redox capability for solar powered waste water treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Fruit waste disposal is a serious global problem with only 20% of such waste being routinely treated prior to discharge. Two of the most polluting fruit wastes are orange peel and walnut shell and new methods are urgently required to valorize such waste. In the present study, they where valorized via conversion into biochars at 500 °C (OPB500 for orange peel-based biochar produced at 500 °C and WaSB500 for walnut shell-based biochar produced at 500 °C), and evaluated for arsenic adsorption. A pore-rich surface morphology was observed with a low H/C ratio indicating high stability. Spectroscopic studies revealed the presence of minerals and surface functional groups (amide, carbonyl, carboxyl, and hydroxyl) suggesting high potential for arsenic immobilization. Adsorption studies revealed an arsenic removal efficiency of 88.8 ± 0.04% for WaSB500 exposed to initial arsenic concentration of 8 ppm for 5% biochar dose at 25 °C and 30 min contact time. In comparison, OPB500 showed slightly lower removal efficiency of 80.7 ± 0.1% (10 ppm initial concentration, 5% dose, 25 °C, 90 min contact time). Peak shifts in XRD and FTIR spectra together with isotherm, kinetic, and thermodynamic studies suggested arsenic sequestration was achieved via a combination of chemisorption, physisorption, ion exchange, and diffusion. The present investigation suggests valorization of fruit waste into thermo-stable biochars for sustainable arsenic remediation in dynamic soil/water systems and establishes biochar's importance for waste biomass minimization and metal (loid) removal from fertile soils. [Display omitted] [ABSTRACT FROM AUTHOR]

The valorisation of wastewaters for minerals recovery and their potential beneficiation has gained enormous attention recently. In this study the removal of phosphate and ammonia from municipal wastewater using activated magnesite resulted in the formation of struvite. The optimum conditions for the synthesis of struvite were 60 min of mixing, 300 rpm mixing speed, 1 g of activated magnesite and room temperature, whilst optimum conditions for the treatment of acid mine drainage (AMD) using the synthesized struvite were 45 min of mixing, 20 g of struvite dosage, 1000 mL, and 300 rpm mixing speed. The efficacy of struvite for neutralisation of AMD and attenuation of inorganic contaminants were ≥98.99% for metals (Al3+, Fe3+, and Mn2+) and ≥30% for SO 4 2 − . Traces of other metals such as Zn, Cu, Ni, Pb, and Cr were significantly attenuated. Phosphate was fully attenuated from the aqua-sphere. PHREEQC predicted the removal of minerals as oxy-(hydro)-sulphates, oxy-(hydro)-phosphate, metals hydroxides, and other complexes. FE-SEM equipped with FIB and an EDX, XRD, XRF, and FTIR confirmed the synthesis of struvite and fate of chemical species after treatment. This study confirmed the feasibility of recovering phosphate and ammonia as struvite which can be employed for the treatment of AMD. • Activated cryptocrystalline magnesite- MWW interaction formed high grade struvite. •Struvite neutralized AMD and removed more than 90% of metals in solution. •Minerals removal as oxy-(hydro)-sulphates, oxy-(hydro)-phosphate and hydroxides. •MWW can be treated and valorized by recovering phosphate and ammonia as struvite. •Effective application of struvite for AMD treatment ensures circular economy. [ABSTRACT FROM AUTHOR]

In the last three decades, pharmaceutical research has increased tremendously to offer safe and healthy life. However, the high consumption of these harmful drugs has risen devastating impact on ecosystems. Therefore, it is worldwide paramount concern to effectively clean pharmaceuticals contaminated water streams to ensure safer environment and healthier life. Nanotechnology enables to produce new, high-technical material, such as membranes, adsorbent, nano-catalysts, functional surfaces, coverages and reagents for more effective water and wastewater cleanup processes. Nevertheless, nano-sorbent materials are regarded the most appropriate treatment technology for water and wastewater because of their facile application and a large number of adsorbents. Several conventional techniques have been operational for domestic wastewater treatment but are inefficient for pharmaceuticals removal. Alternatively, adsorption techniques have played a pivotal role in water and wastewater treatment for a long, but their rise in attraction is proportional with the continuous emergence of new micropollutants in the aquatic environment and new discoveries of sustainable and low-cost adsorbents. Recently, advancements in adsorption technique for wastewater treatment through nanoadsorbents has greatly increased due to its low production cost, sustainability, better physicochemical properties and high removal performance for pharmaceuticals. Herein, this review critically evaluates the performance of sustainable green nanoadsorbent for the remediation of pharmaceutical pollutants from water. The influential sorption parameters and interaction mechanism are also discussed. Moreover, the future prospects of nanoadsorbents for the remediation of pharmaceuticals are also presented. [ABSTRACT FROM AUTHOR]

The water resources contamination in an alarming concern for sustainable environment. This has led to development of new technologies and materials for waste water detoxification. In the present study, we have fabricated novel trimetallic based mixed oxides decorated reduced graphene oxide (rGO) composite using facile microwave method and utilized it as an adsorbent for the removal of congo red dye from aqueous solution. The final composite showed highly agglomerated metal oxides present on the rGO surface. The high surface area and activity of the synthesized adsorbent resulted in its high adsorption capacity of 333.32 mg/g for congo red. The Langmuir model better explained the isotherm data indicating the monolayer adsorption of congo red molecules onto Ag 2 O–Al 2 O 3 –ZrO 2 /rGO surface. The grander adsorption ability of Ag 2 O–Al 2 O 3 –ZrO 2 /rGO towards organic dye indicate its probable utilization in the removal of other dyes also from wastewater. • Trimetallic oxides decorated into rGO matrix were synthesized. • Adsorption of congo red from aqueous solution was investigated. • Maximum adsorption capacity of 333.32 mg/g was obtained using Langmuir isotherm. • Langmuir model better explained the adsorption isotherm data and mechanism. [ABSTRACT FROM AUTHOR]

This work reports synthesis of a dual-function facile heterojunction and investigation of role of the charge transfer dynamism between individual semiconductor components for superior photocatalytic and electrochemical sensing application. The bio-benevolent and sturdy ZnO/Fe 2 O 3 heterojunctions were utilized for visible light facilitated photo-degradation of sulfamethoxazole (SMX) antibiotic and electrochemical sensing of dopamine drug (DA). The fabricated heterojunction were characterized for structural, optical, and magnetic properties. Structural studies revealed the formation of nano heterojunction containing both phases. Magnetic studies confirmed the highly pure magnetic nature of photocatalysts. ZnO/30 wt%Fe 2 O 3 heterojunction (S2) shows 95.2% SMX degradation under visible light and high retention of performance under solar light. The scavenging experiments infer that OH radicals are the active species responsible for degradation. A Z-scheme photocatalytic mechanism was predicted for higher performance with protection of high potential VB of ZnO and CB of Fe 2 O 3 for high generation of reactive oxygen species. LC-MS was employed to predict a plausible degradation route. The sample modified glassy carbon electrodes (GCE) were used for electrochemical sensing of dopamine via cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The S2 junction exhibited 0.18 μM limit of detection with concentration range of 1 μM–50 μM. The stability test was successfully carried out at room temperature for 15 days. In addition, the S2 modified electrodes were spiked in real urine samples and good results were obtained. DPV reveals that S2 modified electrode is best sensor for dopamine sensing among all synthesized heterojunctions. The detection mechanism was also discussed in detail. The in-built metal redox i.e Zn2+/Zn+ and Fe3+/Fe2+ facilitate the Z-scheme transfer, improve the charge transfer capacity and reduce the recombination. This study is beneficial because it reports utilization of popular and well-tested semiconductor metal oxides to form heterojunctions with dual capabilities of environmental detoxification and cost-effective electrochemical detection of biomolecules. [Display omitted] • Dual functional facile ZnO/Fe 2 O 3 Z-scheme heterojunction with in-built metal redox. • Visible light assisted high performance photocatalytic removal of sulfamethoxazole. • OH as active species high potential band protection-Z-scheme • Sensitive and selective dopamine sensing with 0.18 μM limit of detection. [ABSTRACT FROM AUTHOR]