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The efficiency of coupling anodic oxidation (AO) at stainless steel (SS)/PbO2 anodes with biosorption by Luffa cylindrica (L.C) for the removal of Amaranth from aqueous solution was investigated. The effects of pH, contact time, salt, and initial concentration were studied. The regeneration of L.C was estimated on the basis of biosorption/desorption tests. The performance of the coupled process was evaluated on the basis of the removal of color, chemical oxygen demand, and total organic carbon, energy consumption, and time required for degradation of Amaranth. A comparison between AO and the coupled process in terms of increasing the lifetime of the anode was done. Increased chemical oxygen demand, total organic carbon, germination index, and Amaranth removal were observed with the coupled process. [ABSTRACT FROM AUTHOR]

The effect of coupling alternating current (AC) with biosorption using Tunisian corn stigmata on the removal of hexavalent chromium (Cr(VI)) from aqueous solution was studied. A comparative study was performed between biosorption alone and biosorption coupled with AC, for the removal of Cr(VI). The effects of various operating parameters were studied, such as the solution pH, the contact time, the initial concentration, the temperature, and the salt concentration. The comparison between biosorption in the presence and absence of an AC shows the importance of the AC in the acceleration of the biosorption process. The kinetic study showed that the fractal Brouers‐Sotolongo model was the best model for describing the random distribution of the active sites. [ABSTRACT FROM AUTHOR]

[Display omitted] • The removal of Hg from environmental water by advanced oxidation processes. • The removal of Hg from environmental water by adsorption. • Thermodynamic molecular modelling and simulation of Hg adsorption. • Hg adsorption mechanism, kinetics and column adsorption studies. • Regeneration and reusability studies. The review discusses the removal of mercury (Hg) from wastewater by advanced oxidation processes (AOPs) and adsorption. The Hg adsorption in batch and column method was described, and the mechanism was explained, followed by the equilibrium and kinetic modelling. Furthermore, thermodynamic molecular modelling and simulation of Hg adsorption were discussed. The results showed that the removal of Hg from the aqueous solution by AOPs was successfully applied. Some of the future perspectives include enhancing the efficiency of the AOPs for the removal of Hg. The efficiency of available technologies for the removal of heavy metals in general and Hg in particular, depend on three criteria, namely efficacy, cost, suitability, and conditions of application. Langmuir and Freundlich isotherm models are best-fit and also pseudo second order kinetic model. [ABSTRACT FROM AUTHOR]

The rapidly expanding global energy demand is forcing a release of regulated pollutants into water that is threatening human health. Among various wastewater remediating processes, electrocoagulation (EC) has scored a monumental success over conventional processes because it combines coagulation, sedimentation, floatation and electrochemical oxidation processes that can effectively decimate numerous stubborn pollutants. The EC processes have gained some attention through various academic and industrial publications, however critical evaluation of EC processes, choices of EC processes for various pollutants, process parameters, mechanisms, commercial EC technologies and performance enhancement via other degradation processes (DPs) integration have not been comprehensively covered to date. Therefore, the major objective of this paper is to provide a comprehensive review of 20 years of literature covering EC fundamentals, key process factors for a reactor design, process implementation, current challenges and performance enhancement by coupling EC with pivotal pollutant DPs including, electro/photo-Fenton (E/P–F), photocatalysis, sono-chemical treatment, ozonation, indirect electrochemical/advanced oxidation (AO), and biosorption that have substantially reduced metals, pathogens, toxic compound BOD, COD, colors in wastewater. The results suggest that the optimum treatment time, current density, pulse frequency, shaking speed and spaced electrode improve the pollutants removal efficiency. An elegant process design can prevent electrode passivation which is a critical limitation of EC technology. EC coupling (up or downstream) with other DPs has resulted in the removal of organic pollutants and heavy metals with a 20% improved efficiency by EC-EF, removal of 85.5% suspended solid, 76.2% turbidity, 88.9% BOD, 79.7% COD and 93% color by EC-electroflotation, 100% decolorization by EC-electrochemical-AO, reduction of 78% COD, 81% BOD, 97% color by EC-ozonation and removal of 94% ammonia, 94% BOD, 95% turbidity, >98% phosphorus by aerated EC and peroxicoagulation. The major wastewater purification achievements, future potential and challenges are described to model the future EC integrated systems. [ABSTRACT FROM AUTHOR]

Management of basic natural resources and the spent industrial and domestic streams to provide a sustainable safe environment for healthy living is a magnum challenge to scientists and environmentalists. The present remedial approach to the wastewater focuses on recovering pure water for reuse and converting the contaminants into a solid matrix for permanent land disposal. However, the ground water aquifers, over a long period slowly leach the contaminants consequently polluting the ground water. Synthetic adsorbents, mainly consisting of polymeric resins, chelating agents, etc. are efficient and have high specificity, but ultimate disposal is a challenge as most of these materials are non-biodegradable. In this context, it is felt appropriate to review the utility of adsorbents based on natural green materials such as agricultural waste and restricted to few model contaminants: phenols, and heavy metals chromium(VI), and cadmium(II) in view of the vast amount of literature available. The article discusses the features of the agricultural waste material-based adsorbents including the mechanism. It is inferred that agricultural waste materials are some of the common renewable sources available across the globe and can be used as sustainable adsorbents. A discussion on challenges for industrial scale implementation and integration with advanced technologies like magnetic-based approaches and nanotechnology to improve the removal efficiency is included for future prospects. • Phenols, Cr(VI) and Cd(II) have hazardous impact on biota and environment. • Agricultural waste materials are effective in adsorbing phenols, Cr(VI) and Cd(II). • Interaction mechanisms governing adsorption on agricultural wastes are elucidated. • Challenges and future prospects of agricultural waste adsorbents are discussed. [ABSTRACT FROM AUTHOR]

• Properties and uses of lignocellulosic fibers towards adsorption. • Advantages of Biochar towards adsorption enhanced photocatalytic removal of pollutants. • Analysis of process parameters and adsorption kinetics. The enormous growth of industries and the increased release of untreated effluents containing emerging pollutants are major problems that contaminate the water resources. Current efforts are oriented towards developing cost-effective, eco-friendly alternatives to remove a wide range of water pollutants. This paper provides critical insight on various lignocellulosic fibers used for colored and wastewater decontamination. The potential of various agricultural waste materials and their adsorptive capacity of pollutants compared to activated carbon was discussed. Furthermore, an outline of the mathematical modeling describing the kinetics, isotherms, the type of adsorption, and the significant factors influencing the adsorption process were reported. Also, a discussion of the new trends proposed for valorizing vegetable materials in wastewaters decontamination was pointed out. The proposed mechanism for the surface-based adsorption of pollutants onto the lignocellulosic fiber surface was discussed. The challenges and future scope of research on the surface-based removal of pollutants were also discussed. [ABSTRACT FROM AUTHOR]

This study aims to investigate the efficacy of photocatalytic and Fenton-like photocatalytic processes using the FeNi3/SiO2/CuS nanocomposite in the removal of metronidazole (MNZ) from aqueous solutions in the presence of ultraviolet (UV) light. The desired magnetic nanocomposite was first synthesised and then characterised using electron microscopy (TEM), x-ray diffraction device (XRD), fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), energy dispersive spectroscopy (EDS), and scanning electron microscopy (FESEM). The effects of various physicochemical parameters on the degradation process like the initial MNZ concentrations, the nanocomposite dose, the hydrogen peroxide (H2O2) concentrations, the contact time, and the pH were investigated. According to TEM and FESEM analyses, it was found that the obtained nanoparticles tend to accumulate due to their magnetic properties; hence, the particle size (about 52 nm) was greater than that obtained from the Scherrer equation in the XRD analysis. VSM analysis results revealed that the studied nanocomposite was dispersed in water and could be easily separated by an external magnetic field in a short time, and then be easily re-dispersed with shaking slightly. The maximum removal efficiency was obtained by an exposure time of 200 min, pH of 7, MNZ concentration of 20 mg/L, and a catalyst dosage of 0.02 g/L in the photocatalytic degradation stage. Optimum conditions in the Fenton-like photo-catalytic stage were a pH of 7, a time of 180 min, MNZ concentration of 20 mg/L, a catalyst dose of 0.01 g/L, and an H2O2 concentration of 150 mg/L. The photocatalytic degradation of MNZ has followed the pseudo-first-order kinetic model. Results of catalyst recovery and recycling tests showed that the synthesised nanocomposite had a very high recovery and recycling capacity, with only a 5.05% reduction in contaminant degradation efficiency after six alternating cycles. In the Fenton-like photo-catalytic degradation stage, the difference of catalyst degradation percentage was very small among the cycles, showing a decrease of 2.84% from the first to the last cycles. Therefore, the magnetic nanocomposite synthesised in the photocatalytic and heterogeneous Fenton-like photocatalytic degradation of MNZ can be used as a suitable catalyst in the removal and degradation of resistant organic drugs contaminants. [ABSTRACT FROM AUTHOR]

Anodic oxidation process is considered as an effective solution for the treatment of refractory effluents. Its performance is strongly depending on the stability of the anodes used during the process. For this reason, we aim to enhance the stability of the SS/PbO 2 anodes electrodeposited by pulsed current while studying their performance for the anodic oxidation of methylene blue and industrial textile wastewater. The basic idea deals with the possibility to replace the expensive alternatives used for reinforcing the steadiness of the anodes during the anodic oxidation by a simple method based on coupling electrochemical oxidation with biosorption by vegetable material (Luffa cylindrica). The performance of the coupling process was optimized based on its performance in colored and industrial wastewater depollution. Results confirmed the efficiency of the coupling process where 98.7 and 80.02% of methylene blue were removed, respectively, after 60 and 120 min for alternating and direct current. Otherwise, 62.84 and 46.87% of methylene blue were removed by anodic oxidation, respectively, after 120 and 180 min for alternating and direct current. The % COD obtained for the anodic oxidation and the coupling process reached 57.45, 33.61, 91.32 and 75.48% respectively for alternating and direct current. The use of alternating current for both processes has enhanced the speed and the efficiency. Atomic absorption analysis has confirmed that the rates obtained of Pb2+ complied with those allowed by the Standards. LC/MS analysis allowed the identification of by-products generated and the germination tests proved the reuse of the treated water. • A new alternative was proposed by adopting alternating current for pollutant removal. • Coupling biosorption with anodic oxidation has enhanced the pollutant removal speed. • SS/PbO 2 anodes performance was enhanced by a low-cost alternative. [ABSTRACT FROM AUTHOR]

Nowadays, nanoparticles (NPs) and nanomaterials (NMs) are used extensively in various streams such as medical science, solar energy, drug delivery, water treatment, and detection of persistent pollutants. Intensive synthesis of NPs/NMs carried out via physico-chemical technologies is deteriorating the environment globally. Therefore, an urgent need to adopt cost-effective and green technologies to synthesize NPs/NMs by recycling of secondary waste resources is highly required. Environmental wastes such as metallurgical slag, electronics (e-waste), and acid mine drainage (AMD) are rich sources of metals to produce NPs. This concept can remediate the environment on the one hand and the other hand, it can provide a future roadmap for economic benefits at industrial scale operations. The waste-derived NPs will reduce the industrial consumption of limited primary resources. In this review article, green emerging technologies involving lignocellulosic waste to synthesize the NPs from the waste streams and the role of potential microorganisms such as microalgae, fungi, yeast, bacteria for the synthesis of NPs have been discussed. A critical insight is also given on use of recycling technologies and the incorporation of NMs in the membrane bioreactors (MBRs) to improve membrane functioning and process performance. Finally, this study aims to mitigate various persisting scientific and technological challenges for the safe disposal and recycling of organic and inorganic waste for future use in the circular economy. • Potential recycling of inorganic and organic waste streams has been provided. • Green alternatives for nanoparticles (NPs) and nanomaterials (NMs) are highlighted. • Applications and challenges for biosynthesis of NPs and NMs have been discussed. • Future prospective on the scale-up of biogenic NPs and NMs has been provided. [ABSTRACT FROM AUTHOR]

This paper reports the electrochemical oxidation treatment of 80 mL of acidic aqueous solutions with 0.2 mM of the drug tetracycline in 25 mM Na 2 SO 4 using a lab-scale electrochemical cell. The performance of tetracycline removal with Ru-coated graphite by the chemical bath deposition (CBD) and raw graphite anode has been demonstrated. The effects of operating parameters were tested such as pH, applied current, supporting electrolyte concentration, and initial tetracycline concentration. The best tetracycline degradation was obtained with Ru-coated graphite anode due to its higher oxidation power, which allowed the complete degradation of refractory compounds. The modified surface structure of the Ru-coated graphite anode was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy-dispersive X-ray (EDX). The EO process with Ru-coated graphite anode allowed 93.8% tetracycline abatement after 100 min of electrolysis at an applied current of 100 mA. In all cases, tetracycline decay obeyed pseudo-first-order kinetics. The tetracycline removal performance of graphite electrodes with nano coating on graphite has offered a performing alternative. A Comparative study revealed that electrolysis with Ru-coated graphite acted as a better electrode material than raw graphite for the catalytic reaction. [Display omitted] • Tetracycline was removed from the aqueous solution without external chemical addition. • The removal performance of electrooxidation was compared with raw and Ru-coated graphite anodes. • Ru-coated graphite can be used as an inexpensive and effective anode material in EO treatment. • Ru-coated graphite 4% more tetracycline removed than raw graphite anode. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pathways of CAP to enter the environment. • Effectiveness of novel adsorbents, AOPs, and biodegradation. • Isotherms, thermodynamic and molecular simulations. • Effect of water matrix on the performance of the adsorbents. • Clean regeneration technique for the CAP-exhausted adsorbents. Despite the carcinogenic and other adverse health effects ofchloramphenicol (CAP), it is frequently detected in different water sources (e.g., groundwater, surface water, wastewater effluents, etc.) due to ongoing, illegal, and abusive application of CAP in veterinary medicine. Although extensive research has been carried out to develop effective treatment technologies to remove the persistent CAP from aqueous mediums, yet there is no critical review of these studies to the best of our reach This review will be the first in the literature to comprehensively summarize the state-of-the-art treatment techniques for CAP removal from water. We report the removal of CAP by adsorption, biodegradation, nanoscale zerovalent iron technology (nZVI), and advanced oxidation processes (AOPs). The result shows that carbon-based adsorbents have more q max equal 892.86 mg/g for Porous carbon material from Enteromorpha prolifera. The Langmuir- Freundlich isotherm and pseudo-second order kinetics model were reported to best describe the isotherm and kinetic model respectively. Removing the CAP via biodegradation would achieve the advantages of low operating costs, and environmental friendliness. The process of AOPs among the various treatment options can be a promising method for CAP degradation in water. This review comprehensively summarizes the state-of-the-art treatment techniques for CAP removal from water. Particularly, serving as an inclusive reference for future researchers to easily define the research gabs in the literature and plan for their future work in developing novel treatment methods to decontaminate CA-contaminated waters. [ABSTRACT FROM AUTHOR]

Furfural contamination of water is a serious problem in the world. The review article highlights on furfural ecotoxicology and the associated molecular mechanisms involved in its toxicity, efficacy of novel adsorbents for the removal of furfural from polluted water, adsorption capacities of adsorbents under different conditions, such as surface area, concentration, adsorption capacity, pH, time, temperature, applicable isotherm models, characterization and percentage removal of furfural. It was showed from the review that CTAB-bentonite is the best adsorbents for the removal of furfural (q max = 538 mg/g) from aqueous media.A wide range of values for the thermodynamic parameters (both negative and positive) were reported for furfural across different studies. Furfural uptake best-fit both for the Langmuir and Freundlich isotherm models as well as a pseudo second order kinetic model. Additionally, the review also highlighted the molecular modelling and simulations of furfural adsorptions and detail about its future prospects. Among the different treatment options, advanced oxidation processes (AOPs) are likely promising for efficient degradation of furfural in water and wastewater. [Display omitted] • Ecotoxicology effects of furfural. • Adsorption and Advanced oxidation processes (AOPs) removal of furfural from industrial effluents. • Empirical results on equilibrium isotherms, kinetics and thermodynamics. • Molecular modelling and simulation of furfural adsorption. [ABSTRACT FROM AUTHOR]

• Efficiency of new generation adsorbents and their adsorption capacities. • Equilibrium isotherms and kinetic modelling for fluoride adsorption. • Thermodynamic studies for adsorption of fluoride onto novel adsorbents. • Molecular modelling and simulation. • Knowledge gap and future perspectives. Water is essential for life and is threatened by the pollution and contamination generated by human activity and industries. Fluoride contamination of water is a serious problem in the world. The review article highlights on new generation adsorbents including carbon-based adsorbents, nano-adsorbents, bio-sorbents, inorganic materials, modified and composite adsorbents for purification of fluoride from water. It was indicated from the review that a Zinc oxide nanoparticles is the best adsorbents for the removal of fluoride from aqueous media, with a capacity adsorption (q max) of 100 mg/g. The f l u o r i d e uptake best-fit both the Langmuir and Freundlich isotherm models as well as a pseudo second order kinetic model. A wide range of values for the thermodynamic parameters (both negative and positive) were reported for fluoride across different studies. Kinetic and thermodynamic, molecular modelling and simulations, knowledge gaps and future prospects are also presented. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aniline as a toxic aromatic uptake from industrial effluents was reviewed. • The different empirical findings on the equilibrium isotherms, kinetics and thermodynamics. • Molecular modelling and simulation of aniline adsorption. • Azo-linked porous organic polymer is the best adsorbents for the removal of aniline. • The best fit kinetic model for aniline adsorption is the pseudo-second-order model. This review aims to report the efficiency of the adsorption of industrial pollutants, aniline, from wastewater. It was observed from the review that an Azo-linked porous organic polymer (AZO-POP-1) is the best adsorbents for the removal of aniline from aqueous media, with a capacity adsorption (q max) of 1059 mg/g. In terms of factors that affect the efficiency of adsorbents, temperature seems to be the most influential. Aniline uptake best-fit both the Langmuir and Freundlich isotherm models as well as a pseudo second order kinetic model. Different potential adsorbents have been examined through simulations, usually using density functional theory (DFT) or ab-initio method. Most of the time they are simulated in the gas phase, but for a realistic adsorption model, they should be simulated in the solvent phase. Although some studies have been reported on molecular modeling of aniline adsorption using a different range of computational approaches, there are still a lot of issues to be addressed. These issues include the solvent effects which are not properly modeled, the calculation of adsorption energy which is not taking the environment into account, and possibly the temperature effects. [ABSTRACT FROM AUTHOR]