Industrial Wastewater Treatment Research Articles

Developments and Advances in Electrode Materials for Electrochemical Treatment of Industrial Wastewater

Developments and Advances in Electrode Materials for Electrochemical Treatment of Industrial Wastewater

A hybrid system based on the combination of adsorption, electrocoagulation, and wetland treatment for the effective remediation of industrial wastewater from underground coal gasification (UCG)

The study verified the effectiveness of treating post-process underground coal gasification (UCG) wastewater, containing high loads of inorganic and organic pollutants, using constructed wetlands (CW) enhanced by hybrid adsorption and electrocoagulation (EC) techniques. Four different system configurations were tested: wetland, EC/wetland, adsorbent/wetland, and EC/adsorbent/wetland. Each experiment lasted 60 days. The feed and effluents from each treatment step were analysed for their basic physicochemical parameters such as metals and trace elements, phenols, sulphides, cyanides, total organic carbon (TOC), chemical oxygen demand (COD), biological oxygen demand (BOD), benzene, toluene, ethylene, xylene (BTEX), and polyaromatic hydrocarbons (PAHs).Systems with electrocoagulation proved to be effective in the case of metal removal. The best results were obtained for Fe, Ni, Sb and As (up to 96%, 98%, 94% and 82% respectively). The systems were ineffective in removing Mn. All tested systems showed the greatest effectiveness in the treatment of wastewater from phenols, BTEX and CN (almost 100% removal). CWs without preliminary electrocoagulation showed practically 100% effectiveness in removing BTEX after 14 days of treatment. Electrocoagulation was particularly effective in reduction of large quantity of PAH compounds (from 1228 μg/l to below 0.050 μg/l). Effective toxicity reduction from V class to II class after 60 days in comparison with meeting the requirements contained in the Best Available Techniques (BAT) document, showed that all tested systems were favorable in terms of UCG wastewater treatment. A significant decrease in toxicity was observed in just 14 days (around 90% reduction of toxicity measured in TU values for systems without adsorbent and around 75% for systems with adsorbent). The wastewater were still toxic due to the formation of degradation intermediates of organic compounds (BTEX, PAHs, phenol compounds), despite a significant decrease in the concentration of contaminants, therefore toxicity assessment should be one of the evaluation criteria for industrial wastewater treatment.

Monitoring and Studying the Behavior of Metals in an Industrial Wastewater Treatment Plant in Italy

Heavy metals represent a significant hazard in textile wastewater, posing a considerable risk to both the ecosystem and human health. The objective of this study was to analyze the removal efficiency of specific heavy metals in a large wastewater treatment plant (WWTP) located in Prato (Tuscany, Italy), where the main Italian textile district is based. To achieve this, the mass balance calculation approach was employed. Therefore, two monitoring campaigns were conducted, collecting wastewater and sludge samples in some specific sections of the WWTP. The concentrations of Pb, Cd, Ni, As, and Sn were consistently below the detection limits. A good removal efficiency was determined for Zn, Cu, Ba, Crtot, and Sb, in the range of 37–79%. These metals are predominantly present in particulate form, facilitating their removal through sedimentation. Conversely, boron is largely present in the dissolved phase, resulting in its complete release through the treated effluent. Subsequently, an excellent linear correlation was identified between the input load and the contaminant load removed. This demonstrated that the plant’s efficiency remains unaffected by an increase in the input load at the observed contaminant concentrations. Finally, a probability law was identified that demonstrates an excellent degree of approximation in representing inlet metal concentrations. The findings of this study indicate that the treatment systems employed by the WWTP are capable of effectively removing heavy metals.

Treating waste with waste: Treatment of textile wastewater using upcycled food waste as a pore-forming agent in the fabrication of ceramic membranes employing DOE/FFD design

This study investigates a novel method for food waste management by using it as a sustainable replacement for conventional pore-forming agents in ceramic membrane production. The membranes were analyzed using various techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and a universal testing machine. The morphologies of the membranes were observed using scan electron microscopy (SEM). The effects of particle size (45–125 μm), pore-forming agent (5–20 wt%), and sintering temperature (900–1150 °C) on the porosity and mechanical strength of the membranes were investigated using the Design of Experiments (DoE) and Response Surface Methodology (RSM). The optimized membrane was evaluated for its performance in filtering industrial textile wastewater. It achieved impressive results, with approximately 98.4 % removal of turbidity and 71.3 % removal of chemical oxygen demand. This research paves the way for optimizing ceramic membrane fabrication using upcycled food waste, promoting sustainability and offering potential solutions for both food waste management and industrial wastewater treatment challenges.

Numerical Approximation Tool Prediction on Potential Broad Application of Subsurface Vertical Flow Constructed Wetland (SSVF CW) Using Chromium and Arsenic Removal Efficiency Study on Pilot Scale

\noindent {\bf Abstract:} This study investigates the potential broad application of Subsurface Vertical Flow Constructed Wetlands (SSVF CWs) for heavy metal remediation, focusing on Chromium (Cr) and Arsenic (As) removal efficiency. A pilot-scale experimental setup was employed, utilizing a SSVF CW filled with 12 mm gravel and 2 mm coarse sand, planted with Phragmites Australis. The research, conducted over 366 days, aimed to develop a numerical approximation tool to predict the performance and applicability of SSVF CWs in various environmental conditions. The experimental system operated at a hydraulic loading rate of $98-111 \mathrm{~mm} / \mathrm{d}$ and a hydraulic retention time of 6 days. Results showed average removal efficiencies of $44.87 \pm 9.52 \%$ for Cr and $43.16 \pm 9.43 \%$ for As. A mass balance analysis revealed that substrate accumulation was the primary mechanism for heavy metal removal, accounting for $29 \%$ of Cr and $26 \%$ of As removal. Plant uptake contributed to $3.5-9.9 \%$ of Cr and $0.3-$ $8.8 \%$ of As removal. Based on these findings, a numerical model was developed to simulate SSVF CW performance under varying environmental and operational parameters. The model incorporated factors such as influent concentrations, hydraulic loading rates, substrate composition, and plant species. Validation against experimental data showed good agreement, with an $\mathrm{R}^{2}$ value of 0.89 . The numerical tool was then used to predict SSVF CW performance across a range of scenarios, indicating potential broad applications in industrial wastewater treatment, mine drainage remediation, and contaminated groundwater cleanup. This study provides valuable insights into the scalability and versatility of SSVF CWs for heavy metal removal, offering a sustainable and cost-effective solution for water treatment challenges.\\

Enrichment of Methanothrix species via riboflavin-loaded granular activated carbon in anaerobic digestion of high-concentration brewery wastewater amidst continuous inoculation of Methanosarcina barkeri

Effective treatment of high-concentration brewery wastewater through anaerobic digestion (AD) has always been a challenging issue. Enhancing direct interspecies electron transfer (DIET) was demonstrated to increase methane production during AD under high organic loading rate (OLR). Herein, the feasibility of enhancing DIET with the addition of riboflavin-loaded granular activated carbon (RF-GAC) as well as co-addition with Methanosarcina barkeri (Rf-GAC+M.barkeri) was investigated (M.barkeri is well-known to be capable of DIET with electroactive bacteria). During the whole process, the Rf-GAC and the Rf-GAC+M.barkeri group both achieved average COD removal rates above 97 %, which was 14 % higher than that of the control. The average methane production in the Rf-GAC group and the Rf-GAC+M.barkeri group respectively reached 0.334 ± 0.02 L(stp)/g COD and 0.345 ± 0.02 L(stp)/g COD, 1.35 and 1.39 times higher than the 0.247 ± 0.03 L(stp)/g COD reached by the control. The control reactor deteriorated at an OLR of 12 kg COD/(m3·d), whereas the Rf-GAC and the Rf-GAC+M.barkeri group maintained stable as the OLR reached as high as 17.5 kg COD/(m3·d) and the volatile fatty acids concentration was consistently below 10 mM. The RF-GAC performed better than Rf-GAC+M.barkeri in enriching Methanothrix, whose relative abundance was 60.6 % in the former group. Metabolic pathway analysis revealed the addition of RF-GAC upregulated genes related to DIET in Methanothrix species, including hdrA and fpoD. Furthermore, Methanothrix remained the dominant archaea even continuously inoculating pure strains of M.barkeri during the entire operational period. Pure culture experiments proved that GAC inhibited M.barkeri growth. The results of this study can be optimized for practical application of AD treating high-concentration brewery wastewater.

PE/PP fibrous adsorbents with bifunctional groups of tertiary amine and phosphate prepared by electron beam induced co-grafting for heavy metal adsorption of both cationic and anionic forms in acidic conditions.

A novel fabric adsorbent having bifunctional groups of tertiary amine and phosphate was prepared by co-graft polymerization of 2-diethylaminoethyl methacrylate (NMA) and 2-hydroxyethyl methacrylate phosphate (PMA) onto a polyethylene/polypropylene nonwoven fabric (PE/PP NF) under low-energy electron beam acceleration. The process involved pre-irradiating the fabric and immersing it in the comonomer solution for grafting. The kinetics of radiation-induced graft polymerization at a total dose of 100 kGy was investigated. For pre-irradiation at 100 kGy, the optimum condition offering highest degree of grafting was at 12 wt% of NMA, 8 wt% of PMA and 4 h of reaction time. The adsorption of anions using hydrogen chromate (HCrO4−) or Cr(VI) and cations using lead (Pb(II)), cadmium (Cd(II)) and copper (Cu(II)) in aqueous solution was carried out. The results demonstrated that the bifunctional adsorbent was able to adsorb both heavy metal anionic and cationic ions from water. The co-grafted adsorbents with tertiary amine and phosphate were able to adsorb 85% Cr(VI) anion and 29% Pb(II) cations from mixed Cr(VI) and Pb(II) solution at pH 3.0 and 71% Pb(II), 13% Cd(II) and 31 % Cu(II) from mixed Pb(II), Cd(II) and Cu(II) solution at pH 5.0. The unique achievement of this study is its hypothesis that a bifunctional adsorbent can be prepared from radiation-induced graft polymerization of two different monomers onto NF, along with proof that the prepared bifunctional adsorbent can actually absorb both cationic or anionic heavy metals forms. Additionally, the adsorbent's preparation offers a rapid and straightforward one-step grafting technique. Therefore, the new bifunctional adsorbents can remove heavy metal ions in aqueous solution, either in the cation or anion form, thus offering highly promising applications in industrial wastewater treatment.

Design of 3D printing superhydrophilic pyramid-shaped porous materials for oil-in-water emulsion separation and visualization of separation mechanism

This study focuses on the design and fabrication of a superhydrophilic pyramid-shaped porous material using high-precision 3D printing technology for effective oil-in-water emulsion separation. The unique pyramid-shaped structure enhances droplet interception, significantly improving separation efficiency. The material’s surface was modified with a self-polymerized dopamine (DA) and polyethyleneimine (PEI) coating, resulting in superhydrophilic and underwater superoleophobicity. This porous material achieved a separation flux of 3098 L/m2h with a separation purity of 99.3 %. Computational Fluid Dynamics (CFD) simulations were employed to visualize the emulsion separation mechanism, providing insights into the dynamic process of droplet behavior within the funnel structure. The material also demonstrated excellent corrosion resistance, maintaining its performance after prolonged exposure to acidic, alkaline, and saline environments. These results suggest that the developed material offers a promising solution for high-efficiency oil–water separation with potential applications in environmental remediation and industrial wastewater treatment.

New approach to agro-industrial solid and liquid waste management: Performance of an EGSB reactor at different hydraulic retention times for methane production

This study investigated the removal of agro-industrial wastes (5 g COD L⁻1 from coffee and 0.5 g COD L⁻1 from brewery wastewater, plus 1 g L⁻1 of coffee pulp and husk) in a continuous Expanded Granular Sludge Bed (EGSB) reactor at 35 °C. The effect of Hydraulic Retention Times (HRTs) of 72h, 48h, and 24h on CH₄ yield was examined using a mixed culture of cattle manure and granular sludge. Methane yields were 201, 124.5, and 113.8 mL CH₄ g⁻1 COD for the 1st, 2nd, and 3rd phases, respectively. Volatile fatty acids, particularly acetic acid, increased at lower HRTs. Sequencing of the 16S rRNA gene on the Illumina HiSeq platform revealed a syntrophic relationship between Syntrophorhabdus, Syntrophobacter, and Pseudomonas with methanogens Methanomassiliicoccus, Methanospirillum, and Methanobacterium, aiding in the removal of phenolic compounds. The study suggests that an HRT of 72h is optimal for maximizing CH₄ production in the EGSB reactor.

Dual application of lotus stem in fabricating a bioreactor for the remediation of nitrate, plumbum, and carbamazepine in industrial wastewater

Addressing the treatment of complex industrial wastewater continues to be a substantial challenge within the realm of water treatment. A biofilm reactor was engineered, integrating lotus stem biochar, lotus stem biological filler, and the ZW5 strain for enhanced wastewater treatment. The removal efficiencies of nitrate (NO3--N), calcium (Ca2+), chemical oxygen demand (COD), phosphorus (PO43--P), plumbum (Pb2+), and carbamazepine (CBZ) were 98.46, 81.08, 91.79, 96.63, 97.75, and 99.26% when HRT was 3 h, pH was 7.0, Pb2+, CBZ, and influent salinity contents were 15.0, 3.0, and 1500 mg L-1. The reactor effectively fixed the microorganisms and provided a good microenvironment and niche, which was conducive to the adsorption of Pb2+ and CBZ by microorganisms and biominerals. Furthermore, the modified biochar in the reactor filler facilitated microbial metabolism and enabled indirect electron transfer. Microorganisms altered their dominant community structure in response to Pb2+ and CBZ exposure. Microorganisms maintained efficient activity through synergy and direct electron transfer through nanowires. The reactor serves as a model for pollutant removal from complex industrial wastewater, leveraging the multifaceted use of lotus stems and microbial-induced calcium precipitation.

Enhanced anaerobic reduction of nitrobenzene under hypersaline fluctuation: Glycine betaine metabolism and microbial osmoadaptation mechanisms

High salinity, particularly large fluctuations in salinity, poses a significant threat to the biological treatment of high-salt industrial wastewater, while glycine betaine (GB) is commonly used for osmotic pressure balance. However, the GB metabolism mechanism and the effect of GB addition on microbial osmoadaptation responding to salt perturbations are still unclear. This study investigated the effect of GB on the stability of anaerobic process in nitrobenzene reduction under various salt perturbations and further explored the microbial osmoadaptation and metabolism mechanism. The nitrobenzene reduction was observably improved with GB addition (R+), and the microbial resilience increased due to repeated salt shocks. The generation of acetic acid showed a 46.21 % decrease in R+ compared to that without GB addition (R-) at 3 % salinity. Meanwhile, the intracellular GB concentration reached 10.76 mg L−1 to 54.76 mg L−1 with salinity increasing from 1.5 % to 6 %. 16S rRNA analysis revealed that the osmoadaptation period was shortened in R+ through the rapid osmoadaptation of salt-intolerant microorganisms (such as Propionibacteriaceae and SBR1031) and the massive enrichment of salt-tolerant microorganisms (such as Glutamicibacter). Besides, the resistance to hypersaline disturbance improved by the increasing size and complexity of the microbial community network. Moreover, the metagenomic analysis revealed that the abundance of genes involved in microbial metabolism was significantly enhanced in R+, indicating a more efficient metabolic efficiency and electrons transfer with GB addition under high-salt environments. This study provides vital insights into GB metabolism and microbial osmoadaptation responding to salt perturbations in long-term high-salt wastewater biotreatment.

Polymeric Adsorbent for the Effective Removal of Toxic Dyes from Aqueous Solutions: Equilibrium, Kinetic, and Thermodynamic Modeling

AbstractThis study investigates the adsorption behavior of anionic (Congo red, Eosin yellow) and cationic (Malachite green) dyes on synthesized TD polymer particles, highlighting the material's potential as an effective adsorbent for industrial wastewater treatment. Key operational parameters, including initial solution's pH, contact time, initial dye concentration, and temperature, were systematically evaluated to determine their influence on adsorption efficiency. The experimental data demonstrated that the Langmuir isotherm provided the best fit for all three dyes, indicating monolayer adsorption with maximum adsorption capacities of 153.8 mg/g for Malachite green, 49.36 mg/g for Congo red, and 227.9 mg/g for Eosin yellow. Kinetic analysis revealed that the adsorption of Malachite green and Congo red followed pseudo‐second‐order kinetics, while Eosin yellow adsorption was better described by the intra‐particle diffusion model. Thermodynamic assessments, including Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°), confirmed the spontaneous and endothermic nature of the adsorption processes for Malachite green and Eosin yellow, contrasting with the exothermic behavior observed for Congo red. These findings underscore the versatility and effectiveness of TD polymer particles in removing both anionic and cationic dyes from aqueous solutions. Further research could explore material optimization and real‐world applications to broaden their utility in sustainable water treatment strategies.

Microalgae as potential agents for biochar production: Future of industrial wastewater treatment

Microalgae as potential agents for biochar production: Future of industrial wastewater treatment

Anchoring atomic Pd on molybdenum disulfide with state-of-the-art specific activity in the electrochemical dehalogenation of florfenicol

The widespread discharge of halogenated organic pollutants (HOPs) in wastewater brings significant risks to the environment and human health due to potent high toxicity, antibacterial activity, and strong biodegradation resistance. Adsorbed atomic hydrogen (H*ads)-mediated electrocatalytic hydrodehalogenation (EHDH) has been recognized as an efficient strategy for HOPs removal through selectively breaking carbon-halogen bonds. In this work atomic Pd uniformly anchored on molybdenum disulfide (denoted as Pd-MoS2) was synthesized through a facile hydrothermal method and found with state-of-the-art specific activity in florfenicol (FLO) removal via the H*ads-mediated EHDH process. Pd-MoS2 completely dehalogenated (∼100 %) FLO within 30 min at a rate constant of 0.15 min−1, which was 6.0, 6.5 and 33.1 times the value of MoS2, Pd/C and carbon paper samples, respectively. Notably, the toxicity of the wastewater was reduced to 1/6 of its original value after the treatment. Moreover, Pd-MoS2 presented superior catalytic stability in five successive cycles. Furthermore, Pd-MoS2 was also robust in complex water environment with practical applicability for industrial wastewater treatment. A dual-active-center mechanism with enhanced H*ads production capacity and the improved H*ads utilization efficiency was contributed to the increased EHDH activity on Pd-MoS2.

Effect of High-Rate Aeration in the Electrocoagulation Treatment of Pharmaceutical and Synthetic Textile Industrial Wastewater Effluents

Despite the extensive literature on the effects of implementing aeration in the electrocoagulation (EC) treatment of industrial wastewater, few studies evaluate the performance of this technique at high aeration rates. In this work, we present the outcomes derived from EC treatment of pharmaceutical and synthetic textile wastewater effluents in two lab-scale reactors with and without aeration, each equipped with different electrode combinations of aluminium and iron (Al/Al, Al/Fe, and Fe/Fe). In the non-aerated EC reactor, maximum chemical oxygen demand (COD) reductions of 56% and 80% were achieved for the pharmaceutical and textile effluents, respectively, with up to 100% removal of turbidity and colour with the Al/Al combination. The installation of high-rate aeration to prevent sludge accumulation on the electrode surface markedly reduced residence times and enhanced the COD removal in the pharmaceutical effluent. However, this implementation potentially reduced the process efficiency for thesynthetic textile effluent as prolonged operation led to flocculation breakdown and subsequent re-dissolution of the contaminants in the water.

The trends of per-and polyfluoroalkyl substances (pfas) in drinking water systems in Maryland United States

Per- and polyfluoroalkyl substances (PFAS) have become a major concern in water quality management because of their persistence in the environment and associated health risks. In Maryland, the diverse water resources and densely populated areas, faces unique challenges culminating from PFAS contamination. This research paper presents a comprehensive overview of PFAS contamination trends in Maryland's drinking water systems across four distinct phases, spanning from 2019 to 2022, it highlights the trends of PFAS contamination, environmental and public health risks, and strategies for effective management. Utilizing data from extensive monitoring efforts conducted in the state, the study reveals a persistent and evolving environmental health challenge characterized by the dominance of different PFAS compounds, particularly PFOS and PFOA, found at concerning concentrations. Mean concentrations of total PFOA/PFOS across the sampling periods were at 18.78 ng/L, 7.28 ng/L, 14.60 ng/L, 12.46 ng/L, significantly surpassing the EPA's 2024 maximum contaminant levels of 4 ng/L for PFOA and PFOS. Despite fluctuations observed across sampling phases, PFAS levels consistently surpass EPA health advisory levels, indicating widespread contamination. Potential sources, such as industrial sites and wastewater treatment plants, underscore the need for robust regulatory enforcement and innovative remediation strategies to safeguard public health. The findings emphasize the necessity for continuous monitoring and multi-faceted mitigation approaches to address PFAS contamination effectively, ensuring the safety of Maryland's water resources and the health of its residents.

Design and Optimization of Microfluidic Vortex Diode

The performed research presents modeling results for designing microfluidic vortex diodes. These devices rectify fluid flow and can be used in many applications on micro and macro scales. The modeling, utilizing computational fluid dynamics (CFD) with the turbulence model RANS k-ε in COMSOL Multiphysics, has led to optimizing diodicity—the reversed-to-forward flow pressure drop ratio. The goal was to find the best flow-rectifying geometry within the 2D vortex-type design by changing the wall geometry, diode shape, and inflow velocities, identifying significant parameters and dependencies. Improving diodicity can be achieved by increasing the radius r1 of the central channel, increasing the entire diode radius r2, decreasing the width w of the rectangular channel, and reducing its length L. Additionally, changing the circular shape of the diode to an elliptical one can improve diodicity. The significance of this research is evident in the potential applications of these devices in microfluidic setups where fixed-geometry unidirectional flow is required, e.g., mixing, filtration, cell separation, and drug delivery, or on industrial scales, e.g., energy harvesting, wastewater treatment, and water sterilization.

Simplex-lattice design and decision tree optimization of endophytic Trichoderma-multi-walled carbon nanotube composite for enhanced methylene blue removal

This study investigates a novel approach for enhancing methylene blue (MB) removal from water using a composite of endophytic Trichoderma mate and multi-walled carbon nanotubes (MWCNTs). For the first time, a unique combination of simplex-lattice design and decision tree learning algorithm was employed to optimize MB removal. This innovative approach effectively identified the optimal composite ratio of hyphal mate (0.5354 g/L) and MWCNTs (0.4646 g/L) for maximizing MB removal, which achieved remarkable removal efficiency ranging from 63.50 to 95.78 % depending on the combination used. The DT model further demonstrated promising potential for predicting MB removal efficiency. SEM revealed a unique hybrid material formed by the intertwining or entrapment of MWCNTs within the hyphal network of Trichoderma mate. FT-IR analysis confirmed the presence of novel functional groups on the MWCNTs' surface at 2438.79 and 528.25 cm−1, likely due to interactions with the endophytic fungi's biomolecules. These functional groups presumably act as reducing and stabilizing agents, promoting efficient MB adsorption. This research paves the way for utilizing the combined biological and chemical approach (fungal biomass and MWCNTs) in bioremediation applications. The findings suggest significant potential for practical applications in wastewater treatment, providing an eco-friendly and cost-effective method for dye removal. Furthermore, the proposed method shows promise for scaling up to industrial wastewater treatment and applicability in resource-limited settings, offering a sustainable solution for global water pollution challenges. Further investigations with larger datasets incorporating additional influencing factors are necessary to refine the predictive power of the DT model for practical applications.

Electrocoagulation treatment of wastewater collected from Haldia industrial region: Performance evaluation and comparison of process optimization

This study investigates the treatment of oil-contaminated wastewater with high levels of inorganic substances, suspended solids and turbidity, collected from the Haldia industrial region of India in February 2023. The wastewater, originating from industries such as chemical, petrochemical, textile, and battery manufacturing, presents a complex pollutant load that challenges traditional treatment methods. Electrocoagulation was employed as the treatment technique, with process optimization conducted using Box-Behnken design (BBD) and central composite design (CCD) for key parameters: pH, initial oil concentration, current density, and electrolysis time. The study comprehensively examined the effects of these parameters on turbidity removal. The optimal conditions were determined to be a pH of 7.5, an initial oil concentration of 275 mg/L, a current density of 17.5 mA/cm², and an electrolysis time of 20 min. Under these conditions, CCD outperformed BBD, achieving a desirability score of 93 % compared to 80 % for BBD. The process successfully reduced turbidity from 450 NTU to 56 NTU and total suspended solids (TSS) from 300 mg/L to 102 mg/L. The operation cost of the process was found to range from ₹0.904/m³ to ₹2.71/m³ as the electrolysis time increased from 0.17 to 0.5 h. The study presents a viable solution for industrial wastewater treatment in this region, aligning with the United Nations Sustainable Development Goal (UN SDG) 2030. Additionally, combining electrocoagulation with membrane filtration may enhance comprehensive pollutant removal.

Simultaneous removal of Pb(II) and Cr(VI) from a steel company wastewater using various green adsorbents: Material characterization and numerical optimization

ABSTRACT This study focuses on the simultaneous uptake of Pb(II) and Cr(VI) from industrial wastewater by walnut shell (WS), almond shell (AS), peanut shell (PS), and coconut shell (CS) adsorbents. Among the used adsorbents, the CS adsorbent exhibited the greatest BET surface area of 18.97 m2/g and porosity of 63.17% and the WS adsorbent also had the highest pore volume of 0.3536 m3/g. Lead and chromium removal were optimized using response surface methodology via a central composite design (CCD) approach. The efficiency of lead and chromium uptake from the wastewater was enhanced by increasing the concentration of WS, AS, PS, and CS adsorbents (Cads.) and decreasing the flow rate (Q) of the wastewater. Under the optimal conditions (Cads. = 0.85 g/L and Q = 2.5 mL/min), the maximum lead and chromium uptake from steel company wastewater was achieved using CS (92%) and WS (97.2%) adsorbents, respectively. The actual lead and chromium removal values were well-fitted based on a high Rpred2, confirming the validity of the CCD model. The acceptable performance of these green adsorbents in the simultaneous removal of chromium and lead from the wastewater introduces the WS, AS, PS, and CS adsorbents as inexpensive and available candidates for industrial wastewater treatment containing heavy metals.