Wastewater Treatment Strategies Research Articles

Biopolymer Hydrogel-Based Salt-Resistant Evaporator for Solar-Energy-Driven Desalination and Water Purification.

Interfacial solar steam generation (ISSG) has recently received much attention as a low-carbon-footprint and high-energy-efficient strategy for seawater desalination and wastewater treatment. However, achieving the goals of a high evaporation rate, ecofriendliness, and high tolerance to salt ions in brine remains a bottleneck. Herein, a novel hydrogel-based evaporator for effective solar desalination was synthesized on the basis of sodium alginate (SA) and carboxymethyl chitosan (CMCS) incorporating a carbon nanotube (CNT)-wrapped melamine sponge (MS) through a simple dipping-drying-cross-linking process. The hydrogel-based evaporator reaches a high evaporation rate of 2.18 kg m-2 h-1 in 3.5 wt % brine under 1 sun irradiation. Furthermore, it demonstrated excellent salt ion rejection in high-concentration salt water. Simultaneously, it exhibits excellent purification functionality toward heavy metals and organic dyes. This study provides a simple and efficient strategy for seawater desalination and wastewater treatment.

A bio-based strategy for efficient industrial wastewater treatment using TiO2 photocatalysis

A bio-based strategy for efficient industrial wastewater treatment using TiO2 photocatalysis

Environmental stewardship in the oil and gas sector: Current practices and future directions

This paper provides an overview of the current practices and future directions in environmental stewardship within the oil and gas industry, focusing on key areas of concern and strategies for improvement. The oil and gas industry has made significant strides in environmental stewardship in recent years, driven by a combination of regulatory requirements, corporate initiatives, and stakeholder pressure. One of the primary areas of focus has been the reduction of greenhouse gas emissions associated with extraction, refining, and transportation processes. Companies have implemented technologies such as carbon capture and storage to minimize their carbon footprint, alongside investments in renewable energy sources and energy efficiency measures to transition towards cleaner energy alternatives. Furthermore, the industry has placed increasing emphasis on the responsible management of water resources, recognizing the potential environmental impacts of water extraction and usage in oil and gas operations. Strategies for water recycling, reuse, and wastewater treatment have been adopted to mitigate pollution and minimize strain on local ecosystems. Biodiversity conservation has also emerged as a critical aspect of environmental stewardship in the oil and gas sector, with companies undertaking environmental impact assessments and collaborating with conservation organizations to minimize habitat disruption and restore ecosystems affected by their operations. Community engagement and social responsibility are integral components of environmental stewardship, with companies seeking to address the social impacts of their operations through employment opportunities, infrastructure development, and social programs benefiting local communities. However, the industry continues to face challenges and limitations in its efforts to minimize environmental impact. Accidental spills, leaks, and other incidents pose significant ecological risks, highlighting the importance of stringent safety regulations and emergency response protocols. Moreover, the transition to renewable energy presents challenges for traditional oil and gas companies, requiring substantial capital investment and strategic planning. To address these challenges and advance environmental stewardship, several future directions are proposed. These include accelerating the transition to renewable energy, enhancing transparency and accountability in reporting environmental performance, strengthening environmental regulations and enforcement, investing in research and development of innovative technologies, and fostering collaboration among industry stakeholders, governments, NGOs, and local communities. Keywords: Stewardship, Oil, Gas, Sustainability, Climate, Mitigation

Molecular Simulation Studies of Pharmaceutical Pollutant Removal (Rosuvastatin and Simvastatin) Using Novel Modified-MOF Nanostructures (UIO-66, UIO-66/Chitosan, and UIO-66/Oxidized Chitosan).

The ubiquitous presence of pharmaceutical pollutants in the environment significantly threatens human health and aquatic ecosystems. Conventional wastewater treatment processes often fall short of effectively removing these emerging contaminants. Therefore, the development of high-performance adsorbents is crucial for environmental remediation. This research utilizes molecular simulation to explore the potential of novel modified metal-organic frameworks (MOFs) in pharmaceutical pollutant removal, paving the way for the design of efficient wastewater treatment strategies. Utilizing UIO-66, a robust MOF, as the base material, we developed UIO-66 functionalized with chitosan (CHI) and oxidized chitosan (OCHI). These modified MOFs' physical and chemical properties were first investigated through various characterization techniques. Subsequently, molecular dynamics simulation (MDS) and Monte Carlo simulation (MCS) were employed to elucidate the adsorption mechanisms of rosuvastatin (ROSU) and simvastatin (SIMV), two prevalent pharmaceutical pollutants, onto these nanostructures. MCS calculations demonstrated a significant enhancement in the adsorption energy by incorporating CHI and OCHI into UIO-66. This increased ROSU from -14,522 to -16,459 kcal/mol and SIMV from -17,652 to -21,207 kcal/mol. Moreover, MDS reveals ROSU rejection rates in neat UIO-66 to be at 40%, rising to 60 and 70% with CHI and OCHI. Accumulation rates increase from 4 Å in UIO-66 to 6 and 9 Å in UIO-CHI and UIO-OCHI. Concentration analysis shows SIMV rejection surges from 50 to 90%, with accumulation rates increasing from 6 to 11 Å with CHI and OCHI in UIO-66. Functionalizing UIO-66 with CHI and OCHI significantly enhanced the adsorption capacity and selectivity for ROSU and SIMV. Abundant hydroxyl and amino groups facilitated strong interactions, improving performance over that of unmodified UIO-66. Surface functionalization plays a vital role in customizing the MOFs for pharmaceutical pollutant removal. These insights guide next-gen adsorbent development, offering high efficiency and selectivity for wastewater treatment.

An attempt to augment performance of machine learning models in a pilot-scale urban wastewater treatment system

The challenge we face is striking a balance between ensuring the standards for wastewater treatment processes and minimizing energy consumption. As such, accurate predictive models become critical. With machine learning algorithms having the ability to discern relationships between inputs and outputs, broad interest has been shown in their applications in wastewater treatment. A key research focus is on effectively adjusting these generic machine learning algorithms to adapt to frequent fluctuations of water quality, inflow volume, and environmental variations. This study developed a Nonlinear Autoregressive neural network (NARX) model having an adaptive real-time updating module to predict the ammonium concentration in the treated effluent. The model has exhibited high predictive accuracy on the testing data, achieving an R2 value of 0.997. By incorporating an adaptive real-time updating module, the model's capability to predict effluent ammonium concentration on novel data sets has been significantly improved, with the R2 value for these predictions increasing from an initial 0.918 to a more refined range of 0.966 to 0.984. Our findings confirm that integrating real-time updating capabilities with machine learning algorithms substantially improves the stability and predictive performance of the models. These outcomes will prompt a broader integration of artificial intelligence in the domain of environmental engineering, which shall foster the implementation of more accurate and eco-friendly wastewater treatment strategies.

Enhanced biodegradation of phenol under Cr(VI) stress by microbial collaboration and potential application of machine learning for phenol biodegradation.

Cr(VI) and phenol commonly coexist in wastewater, posing a great threat to the environment and human health. However, it is still a challenge for microorganisms to degrade phenol under high Cr(VI) stress. In this study, the phenol-degrading strain Bacillus cereus ZWB3 was co-cultured with the Cr(VI)-reducing strain Bacillus licheniformis MZ-1 to enhance phenol biodegradation under Cr(Ⅵ) stress. Compared with phenol-degrading strain ZWB3, which has weak tolerance to Cr(Ⅵ), and Cr(Ⅵ)-reducing strain MZ-1, which has no phenol-degrading ability, the co-culture of two strains could significantly increase the degraded rate and capacity of phenol. In addition, the co-cultured strains exhibited phenol degradation ability over a wide pH range (7-10). The reduced content of intracellular proteins and polysaccharides produced by the co-cultured strains contributed to the enhancement of phenol degradation and Cr(Ⅵ) tolerance. The determination coefficients R2, RMSE, and MAPE showed that the BP-ANN model could predict the degradation of phenol under various conditions, which saved time and economic cost. The metabolic pathway of microbial degradation of phenol was deduced by metabolic analysis. This study provides a valuable strategy for wastewater treatment containing Cr(Ⅵ) and phenol.

Intensify Mass Transfer and Molecular Oxygen Activation by Defect‐Bridged Asymmetric Catalytic Sites Toward Efficient Membrane‐Based Nanoconfined Catalysis

AbstractEfficient spontaneous molecular oxygen (O2) activation is expected in advanced oxidation processes. However, it remains a great challenge to promote the reactants adsorption and accelerate the interfacial electron transfer to boost the activation kinetic of O2. Herein, defect‐rich N‐doped reduced graphene oxide/CoFe2O4 (NGCF‐OV) membrane containing asymmetric Co‐OV‐Fe sites is prepared for O2 activation. The intrinsic catalytic activity is that the asymmetric Co‐OV‐Fe sites regulate the O─O bond length, promoting more and faster electron transfer to O2 for selectively producing 1O2. Meanwhile, the adjacent graphitic N sites help confine organics to the surface and thus greatly shorten the reaction distance of 1O2 and improve its utilization efficiency. The NGCF‐OV membrane demonstrates complete degradation of bisphenol A within a retention time of 86 ms, achieving a k‐value of 0.047 ms−1, which exceeds the performance of most Fenton‐like systems. This work provides new horizons for designing an efficient and stable catalytic membrane, enriching the domain of advanced wastewater treatment strategies.

Neodymium-doped nickel cobaltite reinforced with 2D MXene nanocomposite (Nd-NiCo2O4/MXene) for enhanced photocatalytic degradation of the organic pollutants

In the quest for sustainable strategies for environmental remediation and wastewater treatment, composite material-based visible light-responsive photocatalysis has emerged as a highly efficient method that is not only facile but also economical. Herein, we have synthesized pure (NiCo2O4) and Nd-doped (Nd-NiCo2O4) nickel cobaltite nanoparticles and incorporated doped material on 2D MXene to fabricate nanocomposite (Nd-NiCo2O4/MXene). The prepared samples were characterized to exploit the effect of Nd-doping and composite formation on structural, electrical, and optical properties. The photocatalytic potential of composite material was investigated by targeting malachite green and pendimethalin. In comparison to pure and doped materials, the nanocomposite demonstrated superior photocatalytic efficiency for the degradation of targeted pollutants. This enhanced catalytic activity is attributed to the synergism of rare earth metal doping and composite formation which result in enhanced absorption in visible light and lower coupling of charge carriers. Systematic studies revealed the promising potential of the Nd-NiCo2O4/MXene nanocomposite for solar light harvesting in wastewater remediation applications.

Nonradical-dominated peroxymonosulfate activation by perylenetetracarboxylic acid nanosheet photocatalyst for efficient degradation of bisphenol a under visible-light irradiation

As a green, highly efficient, and sustainable technology, photocatalytic peroxymonosulfate (PMS) activation is a promising strategy for wastewater treatment. Moreover, the development of photocatalysts with excellent PMS activation performance is highly desirable for removing refractory organic contaminants from wastewater. Herein, perylenetetracarboxylic acid (PTA) nanosheets obtained using a facile method were explored as a highly efficient photocatalyst with a high PMS activation ability for bisphenol A (BPA) removal. Experimental results indicated that BPA can be removed within 16 min using PTA under optimal conditions. As confirmed through radical quenching, electron paramagnetic resonance spectroscopy, galvanic-oxidation-process experiments, and density functional theory calculations, photoinduced electrons and holes from PTA trigger PMS activation and thereby convert the reaction routes of BPA degradation from radical- to nonradical-dominated. The BPA degradation pathway was also studied using intermediate analysis and Fukui functions. Overall, the findings of this study shed light on organic semiconductor photocatalysts for nonradical-dominated PMS activation with regard to recalcitrant-organic-pollutant removal.

Promoted adsorption-photocatalysis synergistic removal of contaminants via surface regulation by a tree-like nanofiber membrane substrate

Photocatalysis represents a promising strategy for wastewater treatment, but the widely used powder photocatalysts are still limited by sluggish interfacial mass transfer and chemical processes. In this study, a tree-like PVDF nanofiber membrane (T-PVDF) was explored to enhance the photocatalytic activity of TiO2 and TiO2/BiOI heterojunction through different pathways. TiO2 was first integrated into the T-PVDF substrate via a one-step electrospinning method. The dendritic architecture greatly favored the contaminant adsorption on the catalytic surface and thus boosted the photodegradation of RhB under UV or visible light irradiation. Especially for the visible light driven dye-sensitive photocatalysis, the integrated TiO2@T-PVDF outperformed the powder TiO2 and pristine PVDF membrane anchored TiO2 by 17.9 and 2.4 times, respectively. In addition, the construction of TiO2/BiOI heterojunction on the T-PVDF substrate was realized by further growing BiOI nanosheets via a solvothermal method. The irregular growth of BiOI on the multiscale nanofiber substrate formed a rough surface with unexpected high hydrophobicity, which allowed the accumulation of high-concentrated O2 at the catalytic interfaces. This greatly boosted the O2 reduction and inhibited the competitive H2 evolution under visible light irradiation, resulting in 3.8-fold higher reaction kinetics than that obtained for hydrophilic powder TiO2/BiOI heterojunction.

Sequential high-recovery nanofiltration and electrochemical degradation for the treatment of pharmaceutical wastewater

The presence of antibiotics in aquatic ecosystems poses a significant concern for public health and aquatic life, owing to their contribution to the proliferation of antibiotic-resistant bacteria. Effective wastewater treatment strategies are needed to ensure that discharges from pharmaceutical manufacturing facilities are adequately controlled. Here we propose the sequential use of nanofiltration (NF) for concentrating a real pharmaceutical effluent derived from azithromycin production, followed by electrochemical oxidation for thorough removal of pharmaceutical compounds. The NF membrane demonstrated its capability to concentrate wastewater at a high recovery value of 95% and 99.7 ± 0.2% rejection to azithromycin. The subsequent electrochemical oxidation process completely degraded azithromycin in the concentrate within 30 min and reduced total organic carbon by 95% in 180 min. Such integrated treatment approach minimized the electrochemically-treated volume through a low-energy membrane approach and enhanced mass transfer towards the electrodes, therefore driving the process toward zero-liquid-discharge objectives. Overall, our integrated approach holds promises for cost-effective and sustainable removal of trace pharmaceutical compounds and other organics in pharmaceutical wastewater.

Impact of CeO2 modified cathode and PANI modified anode on tannery wastewater fed microbial fuel cell performance

Microbial fuel cell (MFC) technology is getting acceptance as an emphatic, sustainable and energy efficient alternative of conventional wastewater treatment strategies. MFCs utilize exoelectrogens as biocatalysts to degrade the complex organic substances present in wastewater with simultaneous power generation. The present study was aimed at investigating the impact of MFC electrode’s modification with CeO2 nanoparticles and polyaniline (PANI) on its performance characteristics. The hydrothermal approach was employed for the synthesis of CeO2 nanoparticles followed by their deposition on carbon cloth (CC) as MFC cathode, Whereas MFC’s anode i.e., CF/NF was modified by in-situe deposition of PANI. The synthesized material was characterized with FTIR, XRD, SEM, EDX and BET analysis. The experiments were performed using dual chambered MFC fed with leather tannery wastewater using modified and unmodified electrodes. The highest outcomes of power density and corresponding current density were observed with PANI@NF composite anode and CeO2@CC as cathode i.e., 279.3 mW/m2 corresponding to the current density of 581.8 mA/m2. The same MFC electrode configuration resulted in highest COD reduction, i.e., 80 % and coulombic efficiency of 19.86 %. On the other hand, MFC equipped with PANI@CF anode and CeO2@CC cathode also displayed comparable results. It was ascertained that modification of NF/CF anode with PANI (conductive polymer) and CC cathode with CeO2 nanoparticles have significantly improved the overall MFC operational performance regarding tannery wastewater treatment and bioelectricity generation.

Efficient incorporation of highly migratory thallium into struvite structure: Unraveling the stabilization mechanisms from a mineralogical perspective

The remediation of high-concentration thallium (Tl+) contaminated wastewater is a critical environmental concern. Current research emphasizes the effectiveness of adsorption and oxidation methods for Tl+ treatment, yet challenges persist in enhancing their performance. This study explores the feasibility of emergency Tl+ wastewater treatment and elucidates the mechanisms of Tl+ incorporation into mineral structures, with a focus on the struvite mineral as a framework for Tl+ integration via NH4+ ion exchange. To assess the efficacy and mechanisms of Tl+ immobilization, we utilized comprehensive analytical techniques, including X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDS), Thermogravimetric Analysis (TG), and Density Functional Theory (DFT) calculations. The findings reveal that struvite adsorbs Tl+ onto its surface, followed by an ion exchange process between monovalent cations (NH4+/K+) within the structure and Tl+. Ultimately, Tl+ is incorporated in the form of a (NH4,Tl)MgPO4 solid solution within the structure, achieving a remarkable maximum incorporation capacity of 320.56 mg/g, which significantly surpasses the capacity of typical adsorbents. The findings demonstrate significant Tl+ incorporation, validating the approach for emergency wastewater treatment and suggesting the potential of mineralogy in environmental remediation. This research contributes to advancing heavy metal wastewater treatment strategies, offering a foundation for further investigation.

Advances in amelioration of air pollution using plants and associated microbes: An outlook on phytoremediation and other plant-based technologies

Globally, air pollution is an unfortunate aftermath of rapid industrialization and urbanization. Although the best strategy is to prevent air pollution, it is not always feasible. This makes it imperative to devise and implement techniques that can clean the air continuously. Plants and microbes have a natural potential to transform or degrade pollutants. Hence, strategies that use this potential of living biomass to remediate air pollution seem to be promising. The simplest future trend can be planting suitable plant-microbe species capable of removing air pollutants like SO2, CO2, CO, NOX and particulate matter (PM) along roadsides and inside the buildings. Established wastewater treatment strategies such as microbial fuel cells (MFC) and constructed wetlands (CW) can be suitably modified to ameliorate air pollution. Green architecture involving green walls and green roofs is facile and aesthetic, providing urban ecosystem services. Certain microbe-based bioreactors such as bioscrubbers and biofilters may be useful in small confined spaces. Several generative models have been developed to assist with planning and managing green spaces in urban locales. The physiological limitations of using living organisms can be circumvent by applying biotechnology and transgenics to improve their potential. This review provides a comprehensive update on not just the plants and associated microbes for the mitigation of air pollution, but also lists the technologies that are available and/or can be modified and used for air pollution control. The article also gives a detailed analysis of this topic in the form of strengths-weaknesses-opportunities-challenges (SWOC). The strategies mentioned in this review would help to attain corporate Environmental Social and Governance (ESG) and Sustainable Development Goals (SDGs), while reducing carbon footprint in the urban scenario. The review aims to emphasise that urbanization is possible while tackling air pollution using facile, green techniques involving plants and associated microbes.

Elastic, Janus 3D evaporator with arch-shaped design for low-footprint and high-performance solar-driven zero-liquid discharge

Solar-driven zero-liquid discharge (ZLD) is a promising wastewater management strategy for freshwater recovery and solid waste harvesting. However, practical application of the solar-driven ZLD is severely constrained due to its low evaporation efficiency, large footprint, and rapid salt accumulation. Here, we present a Janus arch-shaped solar-driven evaporator (▪) comprising a hydrophobic top photothermal layer for effective light absorption, solar-thermal conversion, and vapor evaporation, which exhibits an evaporation rate of 2.82 kg∙m−2∙h−1 in pure water. The design also includes shapable delignified longitudinal wood (D-L-wood) serving as the hydrophilic bottom water transport layer, which enables dual-directional saltwater transportation and salt crystallization. D-L-wood, with numerous aligned channels, exhibits a low thermal conductivity of 0.04 W·m−1·K−1 along perpendicular direction and can effectively localize heat on the photothermal layer of the evaporator. D-L-wood has excellent hydrophilicity, and the salty water can be transferred quickly along both ends of the wood, providing sufficient salty water for rapid evaporation. The anisotropy of the wood makes the heat transfer quickly along the channel, improving the thermal management ability of the evaporator. Moreover, during vapor evaporation on the hydrophilic-hydrophobic interface, salt is crystallized at the hydrophilic layer, resulting in an enhanced anti-salt performance, a 1.5 folds evaporation rate compared with non-Janus evaporator after 15 h test. Under the conditions of a salt concentration of 3.5 %, a high salt harvest performance of 62.4 g∙m−2∙h−1 can be obtained under AM 1.5 solar irradiation. The arch-shaped design fully utilizes the upper space and effectively reduces evaporator footprint, resulting in an evaporation area to footprint ratio of 1.57:1. The designed evaporator can also be utilized for ZLD treatment of other heavy metal polluted water including Cu2+, CrO42−, Co2+, and so on. Therefore, the Janus-arch-shaped, solar-driven evaporator enables a potentially low-footprint, low-cost, scalable, and practical ZLD strategy for sustainable wastewater treatment.

Enabling Logistics Automation in Nanofactory: Cobalt Phosphide Embedded Metal-Organic Frameworks for Efficient Electrocatalytic Nitrate Reduction to Ammonia.

Electrocatalytic nitrate reduction reaction (NitRR) in neutral condition offers a promising strategy for green ammonia synthesis and wastewater treatment, the rational design of electrocatalysts is the cornerstone. Inspired by modern factory design where both machines and logistics matter for manufacturing, it is reported that cobalt phosphide (CoP) nanoparticles embedded in zinc-based zeolite imidazole frameworks (Zn-ZIF) function as a nanofactory with high performance. By selective phosphorization of ZnCo bimetallic zeolite imidazole framework (ZnCo-ZIF), the generated CoP nanoparticles act as "machines" (active sites) for molecular manufacturing (NO3 - to NH4 + conversion). The purposely retained framework (Zn-ZIFs) with positive charge promotes logistics automation, i.e., the automatic delivery of NO3 - reactants and timely discharge of NH4 + products in-and-out the nanofactory due to electrostatic interaction. Moreover, the interaction between Zn-ZIF and CoP modulates the Co sites into electron insufficient state with upshifted d-band center, facilitating the reduction/hydrogenation of NO3 - to ammonia and restricting the competitive hydrogen evolution. Consequently, the assembled CoP/Zn-ZIF nanofactory exhibits superior NitRR performances with a high Faraday efficiency of ≈97% and a high ammonia yield of 0.89mmol cm-1 h-1 in neutral condition, among the best of reported electrocatalysts. The work provides new insights into the design principles of efficient NitRR electrocatalysts.

Regulating charge transfer for enhanced PAA activation over sulfur-doped magnetic CoFe2O4: A novel strategy for simultaneous micropollutants degradation and bacteria inactivation

Micropollutants and bacteria are prevalent pollutants in wastewater, posing significant risks to ecosystems and human health. As peracetic acid (PAA) is being increasingly used as a disinfectant, activation of PAA by low-cost and high-performance activators is a promising strategy for wastewater treatment. In this study, the sulfur-doped magnetic CoFe2O4 (SCFO) is successfully developed for efficient PAA activation to simultaneously decontaminate and disinfect wastewater. PAA/SCFO-0.3 exhibits exceptional performance, degrading 100 % of 8 μM sulfamethoxazole (SMX) with a first-pseudo reaction rate of 1.275 min−1, and achieving 5.3-log inactivation of Escherichia coli (E. coli) within 3 min at a PAA dosage of 0.2 mM and catalyst dosage of 0.025 g/L (initial pH 6.5). Scavenging experiments and electron paramagnetic resonance (EPR) analysis identify CH3C(O)O• and CH3C(O)OO• as the dominant reactive species for SMX degradation. The sulfur species in SCFO-0.3 facilitate Co2+ regeneration and regulate charge transfer, promoting PAA activation for SMX degradation. Moreover, the PAA/SCFO-0.3 system demonstrates operational feasibility over a broad range of water matrices and has excellent stability and reusability (maintaining 93 % removal of SMX after 5 cycles), demonstrating its potential for industrial applications. This study provides insights into enhancing PAA activation through sulfur doping in transition metal catalysts and highlights the practical applicability of the PAA/SCFO-0.3 system as an advanced alternative to conventional disinfection for simultaneous decontamination and disinfection in wastewater.

ТЕРМОДИНАМИЧЕСКИЙ АНАЛИЗ ОКИСЛИТЕЛЬНО – ВОССТАНОВИТЕЛЬНЫХ РЕАКЦИЙ, ПРОТЕКАЮЩИХ ПРИ ГАЛЬВАНОКОАГУЛЯЦИОННОЙ ОЧИСТКЕ СТОКОВ

Abstract. One of the most important environmental problems is the purification of industrial wastewater from heavy metal ions. Various methods are used to solve this problem: chemical, physico-chemical, sorption, but the most promising method for cleaning industrial wastewater containing heavy metal ions, namely copper, nickel and zinc, is the galvanocoagulation method. However, the literature does not sufficiently cover the processes of cementation of heavy metals on cathode loading. A physico-chemical approach to this process is necessary to confirm the process of separation of heavy metal ions from wastewater in the form of sediment and the creation of new industrial wastewater treatment schemes. The composition of the loading is essential in galvanocoagulation neutralization, therefore, in order to determine the effect of the type of active loading, a carbon mineral sorbent (SGN) obtained from ores of cryptocrystalline graphite (Noginsky deposit of the Krasnoyarsk Territory) was used. The studies were carried out in a galvanocoagulation module by passing wastewater through a loading consisting of a mixture of iron shavings and granules of carbon mineral sorbent based on ores of cryptocrystalline graphite (SGN). At the same time, the air dispersed in the lower part of the device was bubbled through the loading. As a result of the operation of the Fe-SGN short-circuited galvanic cell, iron scrap was dissolved and its intensive oxidation to Fe3+ by air oxygen. The article considers the mechanism of galvanocoagulation neutralization of wastewater based on thermodynamic analysis of redox reactions occurring during galvanocoagulation wastewater treatment.
 Subject of the study: both model and real wastewater from the production of electroplating coatings containing copper, zinc and nickel ions with the following concentrations were used: =60 mg/dm3; =15 mg/dm3; =20 mg/dm3
 Materials and methods: galvanocoagulation neutralization using a short-circuited Fe-SGN galvanic cell (carbon mineral sorbent)
 Results: the physico-chemical patterns of the galvanocoagulation process of wastewater treatment have been studied and the thermodynamic parameters of heavy metal ion reduction reactions have been determined
 Conclusions. It has been experimentally established that it is possible to intensify the process of galvanocoagulation of wastewater containing heavy metal ions by using a carbon mineral sorbent as a cathode loading, which reduces the processing time with a high purification effect and a difficult-to-dissolve precipitate is formed.

Unraveling the role of inert biomass in membrane aerated biofilm reactors for simultaneous nitrification and denitrification

This study presents an innovative 2D spatio-temporal model that sheds light on the intricate formation of biofilms, incorporating two essential biomass decay pathways: cell lysis and endogenous respiration. The model encompasses heterotrophic bacteria (HB), anaerobic heterotrophic bacteria (AHB), and autotrophic bacteria (AB), offering a comprehensive understanding of multi-species biofilm development. Through meticulous simulations, we explore the primary mechanisms behind inert biomass formation in biofilms, revealing the key roles played by the lysis of HB, AHB, and AB, as well as the endogenous respiration of HB. Moreover, the simulations reveal how species of higher abundance contribute significantly to inert biomass generation, reshaping our understanding of biofilm dynamics. Crucially, this study highlights the indispensability of considering biofilm inert biomass when modeling the nitrification and denitrification behaviors of a membrane aerated biofilm reactor (MABR). The distribution of oxygen and acetate across biofilm thickness is remarkably different when inert biomass is factored in, underscoring the necessity for a more holistic approach to modeling biofilm behavior. With the introduction of the inert biomass inclusive biofilm model, our simulations explore the interactive effects of key process conditions - bulk concentrations of oxygen ($O_{\infty}$), ammonium nitrogen ($N_{1\infty}$), acetate ($A_{\infty}$), and biofilm thickness - on the nitrification and denitrification performance of MABR. A compelling correlation emerges between higher bulk concentrations of oxygen and ammonium nitrogen and optimal nitrification rates, achieving an impressive range of 0.3 to 1.1 g ammonium/$m^{2}/d. Delving into denitrification, we observe that high $O_{\infty}$, low $N_{1\infty}$, and either high or low $A_{\infty}$ levels impede AHB formation and consequently hinder denitrification. Our findings provide a roadmap for achieving simultaneous nitrification and denitrification, contingent on specific conditions: $10[gm^{-3}] < O_{\infty} < 15[gm^{-3}]$, $12[gm^{-3}] < N_{1\infty} < 20[gm^{-3}]$, $A_{\infty}$ ranging from $3[gm^{-3}]$ to $12[gm^{-3}]$, and a biofilm thickness $> 1.4[mm]$. While our study reveals promising avenues for simultaneous nitrification and denitrification, denitrification rates still lag behind nitrification rates under the same conditions. As a result, we advocate for further investigations to devise strategies that can enhance denitrification in MABR systems. In conclusion, this study advances our knowledge of biofilm dynamics by introducing a comprehensive model and illuminating the key factors driving nitrification and denitrification performance in MABRs. These findings pave the way for improved biofilm engineering and wastewater treatment strategies, opening new horizons for sustainable environmental practices.

Hyphenated Fenton-column packed nMnO-modified wood biochar for tannery effluent treatment: Adsorption mechanism and reusability study

Industrial wastewater contains a wide range of pollutants that, if released directly into natural ecosystems, have the potential to pose serious risks to the environment.This study aims to investigate sustainable and efficient approaches for treating tannery wastewater, employing a combination of hyphenated Fenton oxidation and adsorption processes. Rigorous analyses were conducted on wastewater samples, evaluating parameters like COD, sulphide, NH3–N, PO43−, NO3−, and Cr(VI). The performance of this adsorbent material was gauged through column adsorption experiments. A comprehensive characterization of the adsorbent was undertaken using techniques such as SEM, EDX, BET, FTIR, XRD, and LIBS. The study delved into varying operational parameters like bed depth (ranging from 3.5 to 9.5 cm) diameter (2.5 cm) and influent flow rate (ranging from 5 to 15mLmin-1). The experimental outcomes revealed that increasing the bed depth and decreasing the influent flow rate significantly bolstered the adsorption column's effectiveness. Breakthrough curves obtained were fitted with different models, including the Thomas and Yoon-Nelson models. The most optimal column performance was achieved with a bed height of 10.5 cm and a flow rate of 5mLmin-1. The combined process achieved removal efficiencies of 94.5% for COD, 97.4% for sulphide, 96.2% for NH3–N, 83.1% for NO3−, 79.3% for PO43−, and 96.9% for Cr(VI) in tannery effluent. This research presents a notable stride toward the development of sustainable and efficient strategies for tannery wastewater treatment.