Removal Efficiency Of Heavy Metals Research Articles

Pectin-nano zero valent iron nanocomposites for efficient heavy metal removal and bactericidal action against waterborne pathogens — Innovative green solution towards environmental sustainability

This study investigated the effectiveness of a pectin-nano zero-valent iron-based nanocomposite in adsorbing heavy metals in bimetallic form (chromium‑lead mixture), along with assessing its antibacterial properties. The nanocomposite was synthesized using a straightforward dispersion method, employing eco-friendly components like biocompatible pectin sourced from banana peels and nano-scale zero-valent iron. Analytical characterization confirmed the formation of stable, nano-crystalline particles with active interactions between the functional groups of pectin and nano iron. Batch adsorption experiments optimized various parameters such as pH, adsorbent dosage, contact time, metal ion concentration, and temperature to enhance bimetal removal from water. The optimal conditions were determined as pH 8.0, a temperature of 40 °C, 1.0 g/L adsorbent dosage, 75 mg/l initial bimetal concentration, and a contact time of 30 min. Further assessments revealed that the nanocomposite did not induce phytotoxic or ecotoxic effects, confirming its non-toxicity and environmental safety. Biocompatibility studies conducted using zebrafish models showed no adverse effects on hatching, survival, or heart rate. These findings underscore the potential of the nanocomposite as a sustainable and efficient solution for heavy metal remediation in water treatment process.

Magnetic Mesoporous Silica Functionalized with Amine Groups for Efficient Removal of Heavy Metals and Bacterial Inhibition

Magnetic Mesoporous Silica Functionalized with Amine Groups for Efficient Removal of Heavy Metals and Bacterial Inhibition

Fabrication and catalytic activity of TiO2/Fe3O4 and Fe3O4/β-cyclodextrin nanocatalysts for safe treatment of industrial wastewater

The rapid industrial growth has led to increased production of wastewater containing pollutants like heavy metals and organic compounds. These pollutants pose risks to human health and the environment if not properly treated. Engineered nanocatalyst materials (ENMs) are a burgeoning technology that show promise for treating industrial wastewater. Metal oxide ENMs, such as Fe3O4@β-cyclodextrin and Fe3O4@TiO2, have demonstrated efficient removal of heavy metals and methylene blue from wastewater. Fe3O4@TiO2 was found to be more effective than Fe3O4@β-cyclodextrin in removing these pollutants. The highest removal efficiencies were observed at a concentration of 40 mg/g and pH 8. Copper showed the highest removal efficiency (160.5 mg/g), followed by nickel (77.09 mg/g), lead (56.0 mg/g), and cadmium (46.05 mg/g). For methylene blue, the highest removal efficiency was also observed at a concentration of 40 mg/g and pH 8 (91.16 %). Lead (90.5 %), copper (90.48 %), nickel (83.34 %), and cadmium (77.58 %) were also efficiently removed. These findings highlight the potential of Fe3O4@TiO2 as a promising material for industrial wastewater treatment, offering cleaner and safer water for human health and the environment. ENMs have the potential to revolutionize wastewater treatment processes.

Effects of N, N-bis (carboxymethyl)-L-glutamic acid and polyaspartic acid on the phytoremediation of cadmium in contaminated soil at the presence of pyrene: Biochemical properties and transcriptome analysis

Chelator-assisted phytoremediation is an efficacious method for promoting the removal efficiency of heavy metals (HMs). The effects of N, N-bis(carboxymethyl)-L-glutamic acid (GLDA) and polyaspartic acid (PASP) on Cd uptake and pyrene removal by Solanum nigrum L. (S. nigrum) were compared in this study. Using GLDA or PASP, the removal efficiency of pyrene was over 98%. And PASP observably raised the accumulation and transport of Cd by S. nigrum compared with GLDA. Meanwhile, both GLDA and PASP markedly increased soil dehydrogenase activities (DHA) and microbial activities. DHA and microbial activities in the PASP treatment group were 1.05 and 1.06 folds of those in the GLDA treatment group, respectively. Transcriptome analysis revealed that 1206 and 1684 differentially expressed genes (DEGs) were recognized in the GLDA treatment group and PASP treatment group, respectively. Most of the DEGs found in the PASP treatment group were involved in the metabolism of carbohydrates, the biosynthesis of brassinosteroid and flavonoid, and they were up-regulated. The DEGs related to Cd transport were screened, and ABCG3, ABCC4, ABCG9 and Nramp5 were found to be relevant with the reduction of Cd stress in S. nigrum by PASP. Furthermore, with PASP treated, transcription factors (TFs) related to HMs such as WRKY, bHLH, AP2/ERF, MYB were down-regulated, while more MYB and bZIP TFs were up-regulated. These TFs associated with plant stress resistance would work together to induce oxidative stress. The above results indicated that PASP was more conducive for phytoremediation of Cd-pyrene co-contaminated soil than GLDA.

A Systematic Review on Removal Efficiency of Heavy Metals from Yamuna Water

A Systematic Review on Removal Efficiency of Heavy Metals from Yamuna Water

Removal of Chromium ions (Cr6+) and Nickel ions (Ni2+) from Simulated Industrial Wastewater Using Flow-by-Porous Electrode

The quality of water is significantly impacted by the presence of Cr6+ and Ni2+ ions. This study investigates the effectiveness of a flow-by porous graphite electrode cell in removing these contaminants from simulated industrial wastewater. We explore the impact of various factors on the removal process, demonstrating the method's potential for efficient removal. The initial concentration of nickel and chromium ions (20 to 80 mg/l and 20 to 100 mg/l, respectively), the feed flow rate (0.28 to 1.11 ml/s), current density (0.2 to 2.25 mA/cm2) and pH all influence the removal rate and efficiency. A higher feed flow rate negatively affects the removal efficiency of both Ni2+ and Cr6+ ions. Nickel removal efficiency decreased by 34.9% at 20 ppm and 26% at 80 ppm, representing the highest and lowest reductions in efficiency, respectively. Chromium removal efficiency decreased by 19% at 100 ppm and 6.5% at 50 ppm, indicating the highest and lowest reductions in efficiency, respectively, under the same flow rate change. Under optimal conditions, the removal efficiency for Ni2+ was 99.47% after 15 min of operation at a current density of 1.96 mA/cm2, a flow rate of 0.28 ml/s, and a pH of 8 and the removal efficiency for Cr6+ was 99.97% after 10 min of operation at a current density of 2.25 mA/cm2, a flow rate of 0.28 ml/s, and a pH of 2. The flow-through porous electrode system achieves efficient heavy metal removal with operating costs of 0.24 USD/m3 for nickel and 0.38 USD/m3 for chromium at optimal conditions.

Optimal growth conditions and heavy metal removal of Coelastrella sp. CORE-3 isolated from wastewater

This study was investigated to optimize growth conditions of native microalgae (Coelastrella sp. CORE-3) from wastewater, evaluate the removal of Cu2+, Zn2+, Cd2+ and Ni2+ and compare both isolated microalgae and Ankistrodesmus bibraianus, and describe their sorption mechanisms on the cell surface. The effects of the pH, light: dark cycle and temperature on the growth of the isolated Coelastrella sp. CORE-3 was optimized. The optimal L:D cycle, temperature, and pH conditions were 14:10 hr, 25℃, pH 7. The growth of isolated microalgae, Coelastrella sp. CORE-3. was compared with A. bibraianus. The removal efficiency of heavy metals by Coelastrella sp. CORE-3 and A. bibraianus were found as follows, respectively: (live cell) Zn2+ > Cd2+ > Cu2+ > Ni2+, (dead cell) Cu2+ > Cd2+ > Zn2+ > Ni2+. SEM analysis indicated that more cell surface deformation occurred in A. bibraianus compared to Coelastrella sp. after exposure to heavy metals. This result suggests that Coelastrella sp. CORE-3 has more resistant to heavy metal toxicity. In addition, based on the FT-IR analysis, the live cells of Coelastrella sp. CORE-3 and A. bibraianus showed the interactions of heavy metals with the functional groups: alcohol, alkane, amide, amine on their cell surfaces.

One-pot fabrication of highly permeable P84/UiO-66-NH2-PEI membrane for the efficient removal of heavy metals from wastewater

Heavy metal pollution threatens water bodies and public health, necessitating the exploration of advanced technologies to effectively remove heavy metals from wastewater. In this study, a one-pot approach was employed to fabricate a positively charged membrane using P84 as the substrate, and UiO-66-NH2 nanoparticles and PEI as crosslinkers. Introducing UiO-66-NH2 with inherent porous structures can create nanopores and gaps within the PA layer, providing extra pathways for water molecules to permeate the membrane. Moreover, the UiO-66-NH2 nanoparticles imparted hydrophilicity and a positive charge to the resulting membrane. Compared to the blank membrane without UiO-66-NH2 nanoparticles, the optimal membrane demonstrated a significant increase of 44 % in water flux (52.4 L m−2h−1) while maintaining a remarkable removal performance for CuCl2 (99.5 %), PbCl2 (99.4 %), Ni(NO3)2 (98.6 %), and ZnCl2 (98.4 %) at 4 bar. Furthermore, the UiO-66-NH2 nanoparticles can cross-link with the P84 polymer, ensuring a stable attachment between the polyamide (PA) layer and the P84 substrate by covalent bonds, preventing the potential conventional nanoparticle leakage. Additionally, three different fabrication methods were employed to explore the optimal approach for incorporating UiO-66-NH2 nanoparticles, with each method resulting in a distinct distribution of nanoparticles within the membrane. This study highlights the potential of the resultant membranes in addressing the challenges of wastewater treatment, offering a facile and promising avenue for heavy metal removal.

Evaluation of Heavy Metal Removal Efficiency in Artificial Acidic Drainage Using Calcite and Aragonite

Evaluation of Heavy Metal Removal Efficiency in Artificial Acidic Drainage Using Calcite and Aragonite

A comparative study on the efficacy of conventional and green chelating agents for soil heavy metal remediation

Soil heavy metal contamination poses significant risks to ecological balance, vegetation, agricultural productivity, and human health due to the toxicity, persistence, and resistance to degradation of heavy metal ions. Chelation presents a widely employed method for heavy metal ion removal. While conventional chelating agents exhibit high removal efficiencies, they are associated with ecological hazards. In contrast, green chelating agents have gained prominence for their environmentally friendly attributes. This paper meticulously examines the heavy metal removal efficiencies, mechanisms, application advantages and limitations, as well as optimal pH ranges of both the traditional chelating agent Ethylenediaminetetraacetic acid (EDTA) and the green chelating agents Tetrasodium glutamate diacetate (GLDA), Methylglycine diacetic acid (MGDA), and [S, S]-ethylenediaminedisuccinic acid (EDDS). A comprehensive comparison reveals that EDDS exhibits superior performance followed by MGDA, GLDA, and EDTA, with MGDA displaying the broadest pH range spanning from 2 to 13.5. EDDS emerges as the most biodegradable option. Moreover, in terms of elimination rates, both MGDA and EDDS demonstrate comparable efficacy to EDTA. In conclusion, the green chelating agents scrutinized herein hold promise to potentially supplant conventional EDTA in large-scale practical applications.

Highly efficient adsorption of aqueous heavy metals by Co-derived metal-organic framework. Synergistic mechanism for enhanced water purification

This study opens up exciting possibilities for the application of Co-MOF, a Metal-Organic Framework ([Co(5-NH2-bdc)(bpy)0.5(H2O)]3·2H2O), in the efficient removal of heavy metals (Pb2+, Hg2+, Cd2+, Cu2+) from water. The removal mechanism combines ion exchange and adsorption, influenced by the ionic radius of the metal ions. Langmuir's model determined maximum adsorption capacities (Qm), showing a proportional increase with the ionic radius of heavy metals: 75.47 mg/g (Cu2+), 344.82 mg/g (Cd2+), 485 mg/g (Hg2+), and 526.31 mg/g (Pb2+). Free Gibbs energy, inversely proportional to the metal's ionic radius, was determined as −36.43 kKj/mol (Cu2+), −28.67 Kj/mol (Cd2+), −24.13 Kj/mol (Pb2+), and −21.67 Kj/mol (Hg2+). The pseudo-second-order mechanism explained heavy metal removal, except for Cu2+, due to continuous ion exchange. Reutilization experiments showed a decrement in efficacy in the second cycle. Filtration experiments demonstrated a lower removal percentage (close to 60 %) and confirmed the competitive activity of Co-MOF compared to other MOFs, particularly in Cd2+ removal, with superior rate constants and maximum adsorption capacities.

Syzygium aromaticum-mediated green synthesis of iron oxide nanoparticles for efficient heavy metal removal from aqueous solutions

The current study focused on the environmentally friendly synthesis of iron oxide nanoparticles (IONPs) using ferric nitrate Fe(NO3)3 9H2O as a precursor and aqueous Syzygium aromaticum (clove) extract as a reducing agent. Several analytical methods, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and ultraviolet–visible (UV–Vis.) spectroscopy, were used to confirm the synthesized iron oxide nanoparticles. These procedures were carried out to learn more about the surface shape and chemical composition of the produced iron oxide nanoparticles. The mean size of iron nanoparticles was determined by TEM examination to be 4.7 nm. The characterization revealed that the primary component of iron nanoparticles was magnetite when the Syzygium aromaticum extract was utilized as a reducing agent for Fe3+. For application, synthesized material was used to remove the harmful Cr (VI) ions from an aqueous solution. The batch adsorption approach was utilized to maximize the effects of significant elements such as pH, adsorbent dose, treatment duration, and initial Cr (VI) ions concentration to achieve the highest removal of Cr (VI) ions. The experimental adsorption data were fitted using various isotherm and kinetic adsorption models.

Development of a composite MoS2/PEI nanofiltration membrane for radionuclides efficient removal from aquatic environments

The simultaneously efficient removal of radionuclides and heavy metals is an important and challenging topic for aquatic environmental protection. In this work, molybdenum disulfide (MoS2) with heavy metal ion adsorption capacity and positively charged polyethyleneimine (PEI) were used to fabricate a novel layer-by-layer (LbL) self-assembly composite membrane by a simple alternating immersion method. The unique structure with positive charge ensures high removal for toxic metals (RCs(I) = 99.83 %, RSr(II) = 100 %, RHg(II) = 99.2 %, RPb(II) = 98.13 %, RAs(III) = 98.5 %). The inherent low resistance channels in MoS2 provided the optimized composite membrane an elevated water flux. Long-term experiments and membrane regeneration also demonstrated that the membrane possesses exceptional stability and reusability in removing low levels of radionuclides Cs(I) and Sr(II) from water. This study confirms the feasibility of the MoS2-PEI composite membrane for the treatment of contaminated waters containing radionuclides and heavy metals.

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.

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

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 38.89 mg/g & 42.88 mg/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.

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.

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 the 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 methods, 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 10 mg/L. The heavy metals removal efficiency of more than 95% can be achieved at an AC dose of 0.2–1 g/L. The hydroxide precipitation was found to achieve more than 95% removal efficiencies at higher heavy metals concentrations. Thus, for concentrations higher than 10 mg/L up to 3000 mg/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.