Removal Efficiency Of Heavy Metals Research Articles

Novel flow-electrode capacitive deionization system employing modified MOF-derived carbon electrodes for metal ion removal

Activated carbon (AC) as an electrode for capacitive deionization (CDI) is constrained by its low specific surface area and specific capacitance, leading to electrical double layer overlap (EDL). To address this issue, a flow electrode capacitive deionization system (MDC-FCDI) was developed, which used modified MOFs-derived carbon (MDC) as the electrode. The MDC electrode exhibited enhanced specific capacitance (145.78 F/g) and specific surface area (2458.44 m2/g). Compared to conventional FCDI, the MDC-FCDI system demonstrated a 35–39 % improvement in heavy metal removal efficiency from wastewater containing Pb2+, Cu2+, Cd2+, and Zn2+. The selectivity of MDC-FCDI for heavy metals exhibited a unique “two-step phenomenon” that differed from what was observed in conventional CDI systems. In the MDC-FCDI system, high-valent ions experienced stronger electric field forces and preferentially occupied active sites on the electrode surface prior to the adsorption of ions with lower valence. The selectivity of the MDC-FCDI system for heavy metal ions is determined by three factors in the following order of priority: ionic charge, hydration radius, and ion feed concentration. This study offers a practical approach for expanding the range of MDC-FCDI applications.

Utilization of Qihuang residue-derived hydrogels for efficient removal of heavy metals and dyes from aqueous solutions

Utilization of Qihuang residue-derived hydrogels for efficient removal of heavy metals and dyes from aqueous solutions

Utilization of efficient Al2O3@g-C3N4 nano sorbent for eliminated Ni (II) ions from polluted water

Toxic metals in water systems pose a global health risk. Thus, multifunctional water monitoring and treatment materials are indispensable. Nickel ions, a frequent heavy metal pollutant, affect ecosystem function. However, developing affordable, functional materials for efficient heavy metal removal remains problematic. This study investigates the utilization of Al2O3@g-C3N4 (AlCN) nanosorbent for adsorbing Ni (II) ions from aqueous solutions. The physicochemical analyses verify the creation of an AlCN nanosorbent with a mean size of 31.25 nm crystals and a specific surface area of 58 m2/g. Batch adsorption experiments were conducted to examine the impact of pH, initial Ni (II) concentration, and adsorbent dose on the efficiency of Ni (II) removal using the synthesized (AlCN) nanosorbent. Adding Al2O3 to g-C3N4 nanosheets increased the adsorption capacity to a maximum of 410 mg/g under ideal conditions, as demonstrated by the results. Ni (II) ions adsorption kinetics on AlCN nanosorbents follow the pseudo-second-order kinetic model with an R2 value of 0.99, surpassing the Elovich pseudo-first model. The adsorption isotherm results show that the Langmuir model fits the experimental data better than the Freundlich and Temkin models, indicating a monolayer adsorption process for the AlCN nanosorbent. In addition, the AlCN exhibited multi-elemental adsorption ability and good recyclability. These findings can nominate the fabricated composite as a candidate for water treatment.

High-efficient stabilization and solidification of municipal solid waste incineration fly ash by synergy of alkali treatment and supersulfated cement

Municipal solid waste incineration fly ash (IFA) designated as hazardous waste poses risks to environment and human health. This study introduces a novel approach for the stabilization and solidification (S/S) of IFA: a combined approach involving alkali treatment and immobilization in low-carbon supersulfated cement (SSC). The impact of varying temperatures of alkali solution on the chemical and mineralogical compositions, as well as the pozzolanic reactivity of IFA, and the removal efficiency of heavy metals and metallic aluminum (Al) were examined. The physical characteristics, hydration kinetics and effectiveness of SSC in immobilizing IFA were also analyzed. Results showed that alkali treatment at 25 °C effectively eliminated heavy metals like manganese (Mn), barium (Ba), nickel (Ni), and chromium (Cr) to safe levels and totally removed the metallic Al, while enhancing the pozzolanic reactivity of IFA. By incorporating the alkali-treated IFA and filtrate, the density, compressive strength and hydration reaction of SSC were improved, resulting in higher hydration degree, finer pore structure, and denser microstructure compared to untreated IFA. The rich presence of calcium-aluminosilicate-hydrate (C-(A)-S-H) and ettringite (AFt) in SSC facilitated the efficient stabilization and solidification of heavy metals, leading to a significant decrease in their leaching potential. The use of SSC for treating Ca(OH)2- and 25°C-treated IFA could achieve high strength and high-efficient immobilization.

Optimizing Enhanced Heavy Metal Detoxification by Novel Hybrid Fungal Hyphae-Nano-Biocomposite Functionalized with Graphene Oxide: Unravelling Process Parameters & Adsorption Modelling

Heavy metal pollution poses significant environmental and health risks, demanding efficient novel remediation strategies. This paper presents a fungal hyphae-based nano-biocomposite integrated with graphene oxide (FHGO) for the efficient removal of heavy metals from aqueous solutions. The successful formation of nanoparticles was investigated by morphological characterization using Fourier Transform Infrared Spectroscopy (FTIR), Scanning electron microscopy (SEM) & X-ray diffraction (XRD). Through comprehensive exploration of process parameters, including pH, initial concentration, and contact time, the nano-biocomposite demonstrated exceptional removal efficiencies exceeding 90% for both heavy metals i.e. chromium (Cr6+) & nickel (Ni2+). The optimum pH conditions for Cr (VI) removal was 4,whereas it was 9 for Ni (II) removal. The equilibrium data were well-fitted to Langmuir isotherm models, suggesting monolayer adsorption onto a homogeneous surface with adsorption capacities of 38.89mg/g & 42.88mg/g for Ni (II) & Cr (VI), respectively, with value of R2=0.997. Additionally, biocompatibility assessments via (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) MTT assays on Henrietta Lacks (HeLa) cell line cultures revealed a low IC50 value of FHGO nano-biocomposite, affirming the efficiency of the composite for biomedical applications. Furthermore, seed germination assays indicated comparatively minimal hindrance to plant growth in the treated sample, highlighting the composite's potential for environmental remediation without compromising plant health. These findings underscore the promising potential of the fungal hyphae-based nano-biocomposite with GO as an effective and environmentally safe adsorbent for heavy metal removal, with implications for sustainable environmental management and public health protection.

An Overview of Heavy Metals Treatment & Management for Laboratory Waste Liquid (LWL)

The laboratory waste liquid (LWL) is the discarded liquid after the completion of analysis and is produced from environmental testing laboratories including regulatory institutions, colleges, universities and research organizations. This LWL is laden with a variety of heavy metals due to the use of heavy metal salts in analysis and the treatment and safe disposal of LWL is seldom given due consideration. Thus, the management of hazardous laboratory waste liquid (HLWL) containing heavy metals is essential at the source itself. Accordingly, this article presents systematic review of three processes for heavy metals removal viz. precipitation, adsorption, and membrane separation. The review covers various factors such as heavy metal removal efficiencies & concentration ranges, optimum pH, most frequently studied method, less studied aspects, its commercial availability, operational ease, and the potential of risk minimization with due concern to toxic heavy metals. The concentrations of heavy metals in LWL is also presented. Based on the review, activated carbon (AC) adsorption appears to be the best option for LWL having heavy metals concentration of less than 10mg/L. The heavy metals removal efficiency of more than 95% can be achieved at AC dose of 0.2 to 1g/L. The hydroxide precipitation was found to achieve more than 95% removal efficiencies at higher heavy metals concentrations. Thus, for concentrations higher than 10mg/L up to 3000mg/L, the hydroxide precipitation followed by activated carbon adsorption may prove beneficial.

Spatial and temporal variations in environmental impacts of heavy metal emissions from China's non-ferrous industry: An enterprise-specific assessment

In China, the non-ferrous metal industry is the sector with the highest emissions of arsenic, cadmium, mercury and lead, causing serious impacts on human health and the ecosystem. However, current heavy metal emission inventories are inadequate for figuring out their exposures and associated environmental impacts due to the lack of detailed data. Here, we constructed a high-resolution, enterprise-specific, and long-term dataset detailing heavy metal emissions from the non-ferrous industry in China from 1981 to 2020, using comprehensive enterprise information. Furthermore, an environmental impact assessment was performed using the characterization factors of the IMPACT World + model. Results show that: (1) from 1981 to 2020, the total heavy metal emissions of China's non-ferrous industry reached 144,697 tons (t), with atmospheric emissions (104,524 t) exceeding aquatic ones (40,173 t). (2) The industry's emissions showed a rising and then declining trend, with significant spatial heterogeneity, where heavy metal emissions concentrated in the central and western parts of Yunnan, the southern part of Hunan, the northern part of Guangxi, Henan along the Yellow River, the intersection of Gansu and Shaanxi, the central and eastern parts of Liaoning, and the eastern part of Inner Mongolia. (3) The environmental impact on human health was 1.19 × 107 DALY, and the value of ecosystem quality was 7.26 × 109 species·yr. The top 10 % of enterprises with the largest environmental impacts contributed over 60 % of human health risks and 62 % of ecosystem quality impacts. Improving the removal efficiency of heavy metals by 10 % within the four major industry classes could lead to a 9.92 % reduction in human health impacts and a 9.77 % reduction in ecosystem quality impacts within the non-ferrous metals industry. The findings of this study can provide insights for pollution control, environmental risk reduction, and sustainable development in the non-ferrous metals industry.

Green synthesis of silver nanoparticles by waste of Murcott Mandarin peel as a sustainable approach for efficient heavy metal removal from metal industrial wastewater

This study introduces a sustainable and environmentally friendly method for synthesizing silver nanoparticles (Ag-NPs) using waste from Murcott Mandarin peel (Citrus reticulata Blanco × C. sinensis (L.) Obs.). By repurposing agricultural waste as a precursor for nanoparticle synthesis, the research not only reduces waste but also aligns with green chemistry principles. The synthesis process involved extracting bioactive compounds from Murcott Mandarin peel, which acted as both reducing and stabilizing agents during nanoparticle formation. Characterization techniques, including UV–Vis spectroscopy and X-ray diffraction (XRD), confirmed the successful formation of silver nanoparticles. These nanoparticles demonstrated exceptional efficiency in removing heavy metals from metal industrial wastewater, particularly lead ions. Batch experiments revealed significant adsorption capabilities, with lead ions being uptake by silver nanoparticles at a rate of 42.7 mg/g under optimal conditions of pH 5.5 and 60 min of stirring. Additionally, Murcott Mandarin Solid Residue (MM-SR) obtained from the filtration process during Ag-NP synthesis exhibited promising lead ion uptake, reaching 6.6 mg/g under the same optimal conditions. The eco-friendly synthesis route and the efficient heavy metal removal capabilities of silver nanoparticles underscore the potential of utilizing agricultural waste in nanomaterial synthesis for wastewater treatment. This approach not only tackles waste disposal challenges but also generates value-added materials with practical applications in environmental management. Overall, the study emphasizes the importance of exploring innovative and sustainable pathways for nanoparticle synthesis, highlighting the promising role of silver nanoparticles synthesized from Murcott Mandarin peel waste in cost-effective and environmentally benign strategies for heavy metal removal in metal industrial wastewater treatment.

Efficient removal of heavy metals from sewage sludge using a low-cost protic ionic liquid: Investigation of mechanism and ecological risk

Land utilization for the disposal of sewage sludge (SS) is an effective strategy, yet the existence of heavy metals (HMs) in the SS represents critical constraints to its implementation on a larger scale. By the principles of simple synthesis steps and low synthesis cost, a low-cost double cationic protic ionic liquid was produced in this study for HMs removal from SS. The influence of reaction time, protic ionic liquid to SS mass ratio, and reaction temperature on HM removal were thoroughly investigated. This result indicated that the integration of protic ionic liquid and heat treatment was efficacious in the efficient elimination of HMs. Under 60°C, 15 min, and protic ionic liquid: SS of 0.5, the removal efficiency of Zn, Fe, Ni, and Cd exceeded 80%, and Cr achieved a removal efficiency of up to 93%. The BCR sequential extraction procedure and calculation of the potential ecological risk index revealed a significant reduction in the ecological risk associated with the treated SS, transitioning from a high to a low-risk level. The alterations in elemental and chemical bonding within the solid phase of SS and changes in polysaccharide and fluorescence properties within the liquid phase of SS were investigated using redundancy analysis, two-dimensional correlation analysis, and parallel factor analysis. These findings suggest that dehydration, deamination, and decarboxylation reactions may be responsible for removing HMs within SS. These findings have a positive impact on further elucidating the effects of protic ionic liquid in SS pretreatment, thereby facilitating the efficient utilization of municipal SS resources.

High-efficiency combination washing agents with eco-friendliness simultaneously removing Cd, Cu and Ni from soil of e-waste recycling site: A lab-scale experiment

Soil washing technology plays an important role in the removal of heavy metals, and the efficacy of this process depends on the washing agent used. Due to the difficulty in treating soils contaminated by multiple heavy metals, there is still a need for further exploration of efficient washing agents with low environmental impact. Although single washing agents, such as chelators, can also effectively remove heavy metals from soil, combining efficient washing agents and determining their optimal washing conditions can effectively improve their removal efficiency for multiple heavy metals in soil simultaneously. Based on the previous research, the present study was carried out to combine different types of washing agents to remediate contaminated soils at a commonly e-waste recycling site. The objectives were to investigate their efficient washing conditions and assess the impact of the washing process on the speciation distribution and pollution level associated with heavy metals in soil. The results showed that the combination of HEDP (1-hydroxyethylidene-1,1-diphosphonic acid) and FeCl3 at a ratio of 6:4 exhibited the most effective removal of Cd, Cu and Ni from the contaminated soil at an e-waste recycling site. Under optimal washing conditions, with a soil-to-liquid ratio of 1:20 and a washing time of 48 h, the removal rates of Cd, Cu and Ni were 96.72%, 69.91% and 76.08%, respectively. It needed to be emphasized that the combination washing agents were able to remove most of the acid-soluble, reducible and oxidizable fractions of heavy metals, and even the removal rates of the stable residual fraction (e.g., of Cd) was at a relatively high level. In addition, the washing process significantly reduced the pollution level associated with heavy metals in soil. This study aid in the development of combined efficient washing agents and explores optimal washing strategies for the remediation of Cd, Cu, and Ni-contaminated soil at e-waste recycling sites. The findings may play a role in enhancing the remediation capabilities for soils contaminated with multiple heavy metals, due to its characteristics of and high-efficiency and environmental friendliness.

Nanoribbons as advanced nanomaterials for facile detection and efficient removal of heavy metals: a comprehensive review

Nanoribbons as advanced nanomaterials for facile detection and efficient removal of heavy metals: a comprehensive review

Efficient Removal of Heavy Metals from Crude Oil Using High Surface Area Adsorbent Media: Vanadium as a Case Study

Vanadium, one of the heavy metals present in crude oil, harmfully affects the equipment of oil refineries and the quality of petroleum products. As a result, it is important to innovate effective methods for reducing or removing its concentration. This paper aims to study removing vanadium metal from Iraqi crude oil using activated carbon as an effective adsorbent material. Different experimental factors, i.e., the activated carbon dose, contact time, and agitation speed, were regulatory varied to evaluate their impact on vanadium adsorption efficiency. The outcomes revealed an exceptionally good efficacy of activated carbon to eliminate vanadium. The results exhibited that the maximum remediation was 86.33%, recorded at optimum factors, i.e., 0.5 g of activated carbon, 400 rpm of agitation speed, 75 °C temperature, and time of 400 minutes. According to these findings, activated carbon has a great ability to adsorb vanadium from crude oil. Thus, it can be considered a sustainable material for treating petroleum. Furthermore, this approach will help the refineries by reducing costs by eliminating the heavy metals that lead to corrosion or poisoning catalysts.

Enhanced heavy metal leaching from volcanic muds: Synergistic effects of citric acid and EDTA composite system

The soil leaching technology is a well-established technique commonly employed for the remediation of soils contaminated with heavy metals. Volcanic muds share similar properties to those of soil. This study utilizes soil leaching technology to tackle the presence of heavy metals in volcanic muds. It examines the leaching removal effect of the synergistic system of organic acid citric acid (CA) and chelating agent EDTA on heavy metals Pb, Cd, Cr, and Ni in volcanic muds. The leaching conditions were initially selected and subsequently optimized through the application of response surface methodology (RSM). The priority of leaching conditions can be ranked as follows: leaching duration is found to be more crucial than leaching agent concentration, which is noted to be more pivotal than the solid-liquid ratio. Following an in-depth evaluation of model predictions and experimental validation, it has been established that the optimal leaching concentration of EDTA is 0.15 mol·L−1, the optimal leaching duration is 9 h, and the optimal solid-liquid ratio is 1:10. For the compound CA, the most effective leaching concentration is 0.3 mol·L−1, the optimal leaching duration is 8 h, and the optimal ratio of solid to liquid is 1:10. The significance of the leaching conditions was further explored in conjunction with RSM. Furthermore, the integration of both leaching methods, namely combined leaching and stepwise leaching, has been demonstrated to amplify the removal efficiency of heavy metals, with stepwise leaching showing the highest removal rate. The experimental findings suggest that the leaching technique involving CA and EDTA composite system is an effective approach for the remediation of heavy metals such as Pb, Cd, Cr, and Ni in volcanic muds. This study provides theoretical rationale for the adoption of soil leaching technology in the remediation of heavy metals in volcanic muds. Additionally, the heavy metal content of the remediated volcanic muds substantially meets with the standards for cosmetic raw materials.

Factors affecting the performance of a pharmaceutical wastewater treatment plant: Characterization of effluent and environmental risk

Pharmaceutical industries produce a huge volume of emerging pollutants (EPs) that pose a threat to the aqueous environment. Biological processes have shown their inefficacy in treating many pharmaceutical products. The study assessed physicochemical parameters, EPs, heavy metals in pharmaceutical industrial wastewater, and the removal efficiency (RE) of an aerobic biological treatment plant. The study also assessed the contamination levels and risk using several indices, such as the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI), heavy metal pollution index (HPI), heavy metal evaluation index (HEI), and risk quotients index (RQs). The study found that the treated water quality was poor, having antibiotics, nonsteroidal anti-inflammatory drugs, and others, along with several transformation products (TPs) and heavy metals, which were unsafe for consumption with high environmental risk. The analysis results showed that the RE for TSS, BOD5, COD, TDS, and EC were found to be 91.80%, 86.81%, 72.29%, 72.20%, and 65.60%, respectively, where the values of BOD5, COD, NO3−, and PO43− in the effluent were still higher than the permissible limits of the ECR (2023). However, the RE for heavy metals was in the order of Cu (84.62%) > Fe (65.04%) > Mn (63.3%) > Zn (60.58%) > Cd (53.85%) > Ni (54.12%) > Pb (42.42%) > Cr (38%), where Cr and Cd concentrations were still higher than the permissible limit of DoE (2019). The Pearson correlation and PCA suggested that EC, TDS, TSS, DO, BOD5, and COD were the most correlating and contributing variables. This study argued that metal-ligand behaviors mainly affect the removal efficiency of the treatment plant by lowering the removal rate of heavy metals and pharmaceutical products.

Heavy metals removal from synthetic and industrial wastewater using synthesized zinc oxide nanoparticles

With the advancement in wastewater treatment systems over conventional systems the application of nanotechnology has gained popularity in the past decade. The process can be applied by modifying the physico-chemical properties of metal oxides that increase their effectiveness in extracting heavy metals from wastewater. The present study has been carried out by synthesizing the Zinc oxide nanoparticles using green and chemical synthetic methods. Green-synthesized ZnO nanoparticles (GS-ZnO-NP) were discovered to exhibit a maximum removal effectiveness of 93% and 94% for heavy metals in industrial wastewater and synthetic wastewater, respectively. However, heavy metals removal efficiency from industrial and synthetic wastewater was observed to be 98% and 98% respectively using chemically synthesized ZnO nanoparticles (CS-ZnO-NP). The heavy metals removal efficiency for specific metal is observed to be Cr > Pb > Cu > Hg > As. The kinetics of adsorption was calculated using Freundlich and Langmuir isotherm models. Freundlich model is the best fit with the coefficient of correlation in the range of 0.71–1 for green synthesized and 0.82 to 0.95 for chemically synthesized ZnO nanoparticles.

Efficient removal of heavy metals from acid mine drainage by ε-MnO2 adsorption

The clean-up of acid mine drainage (AMD) is challenging, as classical treatment including a pH neutralization step produces large amounts of toxic sludge. Here we demonstrated that removal of heavy metals through adsorption at low pH was achievable with the use of ε-MnO2 adsorbent, which could be produced in a simple one-step process. The material, which was negatively charged even at pH 2, exhibited outstanding potential for the removal of heavy metals at strongly acidic pH. At pH 2, adsorption capacities were achieved of 172.14 mg/g towards Pb2+ (at an initial concentration of 400 mg/L), 65.64 mg/g for Fe3+ (at 300 mg/L) and 8.5 mg/g for Cd2+ (at 10 mg/L). Mechanistic studies revealed that ion exchange was the main adsorption mechanism for removal of Pb2+, while electrostatic interaction was dominant for Fe3+ and Cd2+ removal. In the case of Pb2+ adsorption, double corner sharing (DCS) complexes were formed at the edges, which promoted the dissolution of structural Mn(III), thereby generating Mn2+ and vacancies which promoted Pb2+ adsorption via an ion exchange process. In the case of Fe3+ and Cd2+ adsorption, along with electrostatic adsorption, triangle corner sharing (TCS) dominated complex formation at the intermediate vacancies, and less Mn2+ was released. Note that the Mn2+ was in dynamic equilibrium with structural Mn(Ⅲ) and Mn(Ⅳ). The actual AMD was retreated in 5 cycles by ε-MnO2, the removal rates of 100% were achieved for Pb2+, Fe(total) and Mn2+, together with 98% for Cu2+ and 95.1% for Cd2+, all of which reached the national emission standards. This approach is a highly suitable option for AMD treatment that avoids toxic sludge formation.

Efficient Removal of Heavy Metals, Dyes, and Contaminants from Industrial Wastewater Using Chitosan-Coated Fe3O4 Nanocomposites: Biosynthesis, Characterizations, and Performance Evaluation

Efficient Removal of Heavy Metals, Dyes, and Contaminants from Industrial Wastewater Using Chitosan-Coated Fe3O4 Nanocomposites: Biosynthesis, Characterizations, and Performance Evaluation

Eco-friendly nanoparticles: mechanisms and capacities for efficient removal of heavy metals and phosphate from water using definitive screening design approach.

Can nano-zero-valent iron, synthesized using oak leaf extract, be the key solution for water preservation, efficiently removing heavy metal ions and phosphate anions simultaneously? This research unveils how this technology not only promises high efficiency in the remediation of water resources, but also sets new standards for environmentally friendly processes. The high antioxidant capacity and high phenol content indicate suggest the possibility of oak-nZVI synthesis using oak leaf extract as a stable material with minimal agglomeration. The simultaneous removal of Cd and phosphates, as well as and Ni and phosphates was optimized by a statistically designed experiment with a definitive screening design approach. By defining the key factors with the most significant impact, a more efficient and faster method is achieved, improving the economic sustainability of the research by minimizing the number of experiments while maximizing precision. In terms of significance, four input parameters affecting process productivity were monitored: initial metal concentration (1-9mgL-1), initial ion concentration (1-9mgL-1), pH value (2-10), and oak-nZVI dosage (2-16mL). The process optimization resulted in the highest simultaneous removal efficiency of 98.99 and 87.30% for cadmium and phosphate ions, respectively. The highest efficiency for the simultaneous removal of nickel and phosphate ions was 93.44 and 96.75%, respectively. The optimization process fits within the confidence intervals, which confirms the assumption that the selected regression model well describes the process. In the context of e of the challenges and problems of environmental protection, this work has shown considerable potential and successful application for the simultaneous removal of Cd(II) and Ni(II) in the presence of phosphates from water.

Nanofiltration membrane with surface nanostructure induced by interfacial modification for heavy metal ions removal, salt selection and antibacterial

Positively charged nanofiltration membranes offer promising options for the removal of heavy metal ions. However, their electrical properties often lead to serious drawbacks such as impaired filtration performance and poor fouling resistance, thus further modification of these positively charged membranes are imperative. Herein, we report the interfacial manipulation of nanofiltration membranes using a hydroxyl monomer (β-cyclodextrin) in concert with the typical positively charged ammonia monomer (polyethyleneimine) to achieve efficient removal of heavy metals, improved perm-selectivity and fouling resistance. The results indicated that water flux of the modified membrane was increased by over 2-folds owing to structural modification compared with pristine membrane. The charge effects and enhanced cross-linking improve the rejection of salts ions, especially divalent ions. The topological and Turing-structured membranes reached 99.9% removal of heavy metal ions due to the combination of adsorption, complexation, Donnan and site resistance effects, and has excellent stability. Additionally, the functionalized membranes exhibited reduced adhesion and survival of bacteria on the surface based on the excellent bacteriostatic and hydrophilicity properties. These findings revealed the mechanism of interfacial modification induction on the nanostructure and properties of membranes and provided an efficient solution for the synthesis of multifunctional membranes.

The application of machine learning methods for prediction of heavy metal by activated carbons, biochars, and carbon nanotubes

Carbonaceous materials are commonly used as adsorbents for heavy metals. The determination of the adsorption capacity needs time and energy, and the key factors affecting the adsorption capacity have not been determined. Therefore, a new and efficient method is needed to predict the adsorption capacity and explore the decisive factors in the adsorption process. In this study, three tree-based machine learning models (i.e., random forest, gradient boosting decision tree, and extreme gradient boosting) were developed to predict the adsorption capacity of eight heavy metals (i.e., As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) on activated carbons, biochars, and carbon nanotubes using 3674 data points extracted from 151 journal articles. After a comprehensive comparison, the gradient boosting decision tree had the best performance for a combined model based on all data (R2 = 0.9707, RMSE = 0.1420). Moreover, independent models were developed for three datasets classified by the adsorbent and eight datasets classified by the heavy metals. In addition, a graphical user interface was built to predict the adsorption capacity of heavy metals. This study provides a novel strategy and convenient tool for the removal of heavy metals and can help to improve the removal efficiency of heavy metals to build a healthier world.