Heavy Metals In Aqueous Solutions Research Articles

Highly nanocrystalline Mg doped ZnFe2O4 powders for rapid and simultaneous adsorption of Lead, Copper, and Cadmium heavy metals ions in synthetic / sea waters

This research aims to investigate the effect of Mg doping on individual and simultaneous adsorption of Pb+2, Cu+2, and Cd+2 heavy metals in aqueous solution and in seawater samples, by Zinc ferrite nanoparticles. The Mg-doped Zinc ferrite nanoparticles are synthesized successfully by the sol-gel route and varying Mg concentrations. TEM, XRD, FTIR, Raman, and XPS characterizations confirm the cubic spinel structure of Zinc ferrite with a semi-spherical shaped nanosized particles (10-15nm) irrespective of Mg doping content. The BET surface area manifests a significant increase within Mg doping (39.3 m2/g) compared with the pure zinc ferrite (28.4 m2/g). Accordingly, Mg-doped Zinc ferrite powders demonstrate considerable adsorption capacities for Pb+2 (143.5mg/g), Cu+2 (117mg/g), and Cd+2 (77mg/g) within 2h under optimized experimental conditions. The prepared nanopowders exhibit high selectivity towards Pb+2 in simultaneous adsorption in aqueous solutions (85mg/g) and real seawater samples. Nonetheless, the selectivity of Pb+2 ions drops dramatically to 25mg/g within real seawater samples due to the strong ionic strength of high-salinity seawater. This study provides insights into the importance of doped spinel ferrite nanoparticles in highly efficient, rapid, and simultaneous adsorption of heavy metals. Besides, it reveals the challenge of performing the adsorption process in real seawater.

Performances Study of Polyvinylidene Fluoride (PVDF)/Waste Eggshell (WES) Mixed-Matrix Membrane for Copper Removal

The presence of heavy metals in water resources brings hazard to health and the environment considering that most of these cannot be degraded and may result in bioaccumulation in the food chain. This study investigated the applicability and efficiency of waste eggshells for the removal of Copper (Cu) heavy metal in aqueous solution. The mixed-matrix membrane with polyvinylidene fluoride (PVDF) as membrane material, N-Methyl-2-pyrrolidone (NMP) as solvent and waste eggshell as additive with ratio of (a) 15:85:0, (b) 14.9:85:0.1, (c) 14.7:85:0.3, (d) 14.5:85:0.5 and (e) 14:85:1 is fabricated using phase inversion method. Phase inversion is a well-studied immersion precipitation technique for membrane synthesis. Using this common method, polymer is dissolved in an organic solvent and the solution cast upon a glass surface with 0.40 knife gap. The resulting membrane morphologies were analysed by using Scanning Electron Microscopy (SEM) and the significant functional group of the resulting membranes were identified using Fourier Transform Infrared Spectroscopy (FTIR). The addition of waste eggshell to the casting solution improved the morphology and structure of the membrane significantly. The appearance of waste eggshell on membrane surface demonstrated in SEM and FTIR analysis. Furthermore, the result of the study showed that the waste eggshells as an adsorbent could remove Cu in an aqueous solution up to 99% with water permeability of 56.52 Lm-2h-1bar-1. Overall, the study demonstrated that the waste eggshell that is generally considered as wastes in large quantities could become an economically advantageous for Cu removal.

Efficient extraction performance and mechanisms of Cd2+ and Pb2+ in water by novel dicationic ionic liquids

Ten novel hydrophobic dicationic ionic liquids (DILs) were synthesized and applied for the extraction of heavy metals in aqueous solutions. Their physicochemical properties were measured at ambient temperature, and the leaching behaviors of the as-prepared DILs in water were assessed by TOC analysis. Metal extraction experiments were carried out to evaluate the extraction performances of the DILs. It was found that the extraction rates of up to 0.45 and 0.53 mg·(g·min)−1 were achieved with 100 mg DILs for 5 mL of 5 mg/L Cd2+ and Pb2+ solutions. Besides, the extraction efficiencies of Cd2+ and Pb2+ were respectively up to 95.48% and 98.46%, when the volumes of the simulated wastewater were expanded by a factor of 20 at a constant extraction phase ratio (1000 mg DILs for 50 mL of 5 mg/L Cd2+ or Pb2+ solutions). The reusability of the novel DILs was successfully proved by the back-extraction experiments with 0.5 M HNO3. Finally, taking Cd2+ extraction as an example, the extraction mechanism based on FTIR analysis and quantum chemical calculations showed that both S and O atoms in the anions of DILs had physical and quasi-chemical interactions with Cd2+, which were stronger than the electrostatic attraction.

Green Synthesis of Stable and Reusable Zinc Nanoparticle Adsorbents for the Removal of Carcinogenic Heavy Metals in Aqueous Solution

industrial applications led to an alarming rise in their presence, heightening the potential for contamination in various environmental mediums. In order to mitigate the adverse impacts of these heavy metals, it is imperative to reduce their concentrations in environmental samples. Therefore, this study aimed to produce zinc nanoparticles employing Diospyros chloroxylon (Roxb.) to effectively eliminate carcinogenic metals from water. The produced nanoparticles were subjected to comprehensive characterization using FT-IR, XRD, SEM, and EDX techniques. The XRD data indicated the emergence of a hexagonal wurtzite structure. SEM images illustrated the spherical morphology of the synthesized particles, with an average diameter measuring 53 nm and having elemental zinc accounting for 69.4% of the composition. The subsequent heavy metal sorption experiments encompassed a range of variables, remarkably, the nanoparticles displayed exceptional adsorption capabilities, achieving maximum removal rates of 95.81%, 90.13%, and 91.25% within an equilibrium time of 90 minutes for Cr, Pb, and Cd, respectively. The adsorption process adhered to a pseudo-first-order reaction kinetics model, with high correlation coefficients of 0.9561, 0.99058, and 0.98481, along with respective rate constants (K) of 0.483, 0.233, and 0.328 for Cr, Pb, and Cd. The outcomes highlight that the synthesized zinc nanoparticles exhibit biocompatibility, stability, and reusability, making them a promising tool for effectively removing carcinogenic heavy metals from polluted water sources.

A novel approach to modify Stenotrophomonas sp. D6 by regulating the salt composition in the growth medium: Enhanced removal performance of Cr(VI)

In this study, a novel and effective modified microbial reducing agent was developed to detoxify Cr(VI) from aqueous solutions. This was achieved by carefully controlling specific salt components in the growth medium. Based on the single-salt modification, several effective modified salts were selected and added to the medium for synergistic modification. The results showed that the synergistic modification with NH4Cl and KH2PO4 had the best detoxification effect on Cr(VI), reaching 98.5% at 100 mg/L Cr(VI), which was much higher than the 43.7% of the control (original Luria-Bertani medium). This enhancement was ascribed to the ability of NH4Cl and KH2PO4 to stimulate the growth of Stenotrophomonas sp. D6 promoted chromate reductase secretion. The protein content of the modified medium supernatant was significantly increased by 10.76% compared to that before modification. Based on the micro-characterization, the main process for the elimination of Cr(VI) is microbial reduction rather than biosorption. Most of the reduced Cr was found in the extracellular suspension, thereby suggesting that the primary reduction occurred outside the cells, whereas only a small fraction was detected intracellularly. Overall, this study provides a simple and effective method for microbial treatment of heavy metals in aqueous solutions.

Combination of magnetic activated carbon and activated sludge for methylene blue and nickel(II) ions removal in aerobic biological treatment

AbstractThe treatment of dyes and heavy metals in aqueous solutions is a major environmental concern, and many methods have been developed to address this problem. However, most of these methods focus on treating either dyes or heavy metals and have their own limitations. Therefore, treatment process that can simultaneously remove both dyes and heavy metals on large scale is essentially required. In this study, we synthesized magnetic activated carbon (MAC) derived from Litsea glutinosa seeds, which was applied to eliminate methylene blue and nickel ions in the aeration tank of the biological treatment system. Structural characteristics and adsorption properties of MAC were studied. The obtained results revealed that the removal efficiency of these pollutants significantly improved as a combination of MAC and activated sludge, especially in the case of nickel ions removal. Furthermore, using MAC in the biological treatment system markedly enhanced the COD removal in compared with that treated without MAC or activated sludge. The advantage of treatment process with MAC addition was also clearly observed by accelerating the settling of activated sludge. Moreover, the obtained results confirmed that wastewater after being treated was assessed as non‐toxic to living organisms by using bioassay.

Hindered diffusion of heavy metal cations in the adsorption rate on activated carbon fiber

Water resource pollution caused by heavy metals represents a risk to the environment because of their toxicity. Adsorption on activated carbon materials can be applied to remove heavy metals in aqueous solutions. Activated carbon fiber (ACF) is a microporous material successfully used for adsorbing heavy metals from water solutions; however, the adsorption rate on ACF has yet to be investigated in detail. The adsorption equilibrium and rate of Cd(II), Ni(II) and Zn(II) on ACF were analyzed in this study, and the experimental data were procured in a differential packed bed batch adsorber. The Radke-Prausnitz isotherm successfully interpreted the experimental adsorption equilibrium data. The adsorption rate was analyzed employing a diffusional model, supposing that the external mass transfer along with intraparticle or intrafiber diffusion affect the overall adsorption rate. Besides, the metal intrafiber diffusion was attributed exclusively to diffusion in the pores volume, excluding surface diffusion. The results revealed that intrafiber diffusion is significantly affected by hindered diffusion caused by frictional effects on pore walls (Kr), steric exclusion (Kp), and blocking provoked by metal cations adsorbed onto pore walls (Ka). The hindrance factors Kr and Kp were estimated using literature correlations, and Ka was related to the mass of metal adsorbed.

Experimental investigation of fibroin content in polymethyl methacrylate‐based membranes for removal of heavy metals in aqueous solutions

AbstractMembrane technology has recently been given extensive consideration for the treatment of effluent to remove suspended solids, organic compounds and inorganic contaminants such as heavy metals. The aim of this study was to prepare, characterize, and test membranes made of silk fibroin (SF) and polymethyl methacrylate (PMMA) blend with different wt% ratios (5%, 10%, and 15%), respectively. The membranes were prepared by phase inversion scheme using water as non‐solvent. Fourier transform infrared spectroscopy (FTIR) was performed to find chemical interactions between polymer matrix and fibroin. The mechanical property of synthesized membranes was also carried out. The surface roughness, and finger‐like pore geometry developed by impregnation of fibroin filler in membrane matrix were depicted by atomic force microscopy (AFM) and scanning electron microscope (SEM), respectively. Surface porosity improved from 4.5% ± 1.9% to 30.0% ± 2.8%, water contact angle reduced from 68° ± 3.0° to 38° ± 1.2°, and highest pure water permeation value (31 L m−2 h−1) was obtained with the addition of fibroin loading. The membrane showed a greater affinity for Cr(VI) in comparison with Pb(II). The highest % rejection was evaluated to be 83% and 56% for Cr(VI), and Pb(II) by utilizing 1.70 wt% fibroin filler in membrane composition, respectively.

An investigation of Pseudomonas marincola to determine Pb(II) biosensor potential

Biosensors are strong alternatives to conventional analytical techniques such as HPLC and spectroscopic techniques for water quality and heavy metal detection. Heavy metal contaminated waters can monitor by microbial biosensors efficiently. For this purpose, newly isolated Pseudomonas sp. is used to develop a highly sensitive low-cost microbial biosensor for water quality monitoring. The objective of the study is the invention of new high sensitive low-cost microbial biosensors to determine heavy metals in aqueous solutions and optimise the working conditions Pseudomonas marincola cells were embedded onto the Screen Printed Electrode (SPE) carbon surface and dried for 30 minutes at laminar flow cabinet. Developed microbial sensors were immersed into the Pb(II) solution for electrochemical analysis. After the exposure time, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) analyses were carried out. The study shows that the sensor was found in a linear range between 1x10−8 M and 8x10−8 M, with the lowest detection limit 10−9 M. The optimum pre-concentration time and scan rate were measured as 10 minutes and 10 mV/s, respectively. The results support that the new isolated Pseudomonas sp. has significant potential to determine the trace amount of lead in aqueous solutions.

Effective Azo-functionalized metal-organic framework colorimetric and ratiometric sensor for detection of heavy metals in aqueous solution by the naked eye

In this work, azo-functionalized zirconium metal organic framework grafted on carboxymethlated cellulose membrane (UiO-66-Azo-Im@CCM) was synthesized by solvothermal method. The developed sensor was systematically characterized and their sensitivity, selectivity and ratiometric properties were investigated. The effect of pH on the sensing performance of the fabricated sensor was also studied. The findings show that developed sensor exhibited excellent sensitivity, selectivity and ratiometric property toward copper, cobalt and nickel heavy metal ions. The calculated limit of detection (LOD) these heavy metals ions were lower than the world health organization permissible concentration that reveals its potential candidacy in monitoring these heavy metals. This work confirms that the developed UiO-66-Azo-Im@CCM can used as powerful tool for the monitoring of Cu2+, Ni2+, and Co2+ without need of the sophisticated instrument. Therefore, we anticipate that it will play its role in environmental remediation in general wastewater treatment in particular.

Preparation of recycled poly s tyrene derivatives to remove heavy metal ions from contaminated water

In recent years, numerous researchers have concentrated on the process of turning waste into usable materials. Polystyrene and its modifications have received great attention over the past few decades due to their outstanding ion exchange behavior toward various toxic heavy metals in aqueous solutions. Therefore, this study is concerned with the preparation of three different cationic polymeric resins for the removal of Pb2+, Cd2+, and Fe3+ heavy metal ions from their contaminated water samples based on the sulfonated single-used polystyrene teacup waste (SPS), which was used to prepare sulfonated polystyrene-g-acrylamide monomer (SPS-g-Acryl) and sulfonated polystyrene-g-chitosan (SPS-g-Chit) using commercial chitosan (DD=85%) originally extracted from shrimp cortex. The concentrations of the selected heavy metal ions were measured before and after each experiment with a flame atomic absorption spectrometer (F-AAS). The analytical studies started by exploring the influence of pH (2, 4, 6, and 8) on removing the heavy metal ions Pb2+, Cd2+, and Fe3+ from their aqueous solutions. The obtained results revealed that as the pH of the analyzed ion solution is increased, the removal efficiency for ions increases. All three resins (SPS, SPS-g-Acryl, and SPS-g-Chit) had different removal efficiencies for the investigated ions, with SPS-g-Chit resin.

Low-cost modified adsorbents derived from the solid residue of Rosmarinus officinalis L. for heavy metal uptake

The current study investigates for the first time the potential of using solid residues collected from the hydrodistillation of R. officinalis, after their modification with Fe, as low-cost adsorbents to alleviate the heavy metals in aqueous solutions. Physicochemical properties and adsorptive performances of R. officinalis solid residue (RO-SR) and Fe-modified R. officinalis solid residue (Fe-RO-SR) were investigated. The Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) revealed that the iron was successfully fixed to the surface of RO-SR. Furthermore, after iron modification, the specific surface area of ROSR was increased from 36.2 to 50.4 m2/g. Kinetics and isotherms of adsorption of Co onto RO-SR and Fe-RO-SR were fitted by applying different models, though the pseudo-second-order (Adj. R2 > 0.9985) and Langmuir (Adj. R2 > 0.9532) models fitted the experimental results better, respectively. The adsorption performances of RO-SR and Fe-RO-SR for Co were 37.31 and 50.25 mg.g−1, respectively. The equilibrium adsorption capacity was reduced from 22.56 g/L to 10.67 g/L when the temperature was raised from 25 °C to 45 °C. Furthermore, after four successful cycles of adsorption-desorption, the adsorbent's adsorptive performance remained above 83.04%, and the adsorbent selectivity revealed interesting heavy metal uptake. Selectivity tests revealed that the adsorption capacities are different for the heavy metal species at the same concentrations, and the series is Fe2+ > Co2+> Cu2+ > Cr3+. Fe-RO-SR could be an interesting, inexpensive ($4.56/Kg), and attractive potential adsorbent for heavy metal removal from aqueous solutions.

Synthesis, Characterization and Application of Karak Bentonite Clay-Graft-Poly (Acrylamide/Co- Acrylic Acid) Superabsorbent Composite and its Adsorption Study for Selected Heavy Metals

A novel superabsorbent composite (SAC) based on bentonite, acrylamide and acrylic acid was synthesized. The effects of bentonite quantity, initiator content on the grafting degree and on the water absorbency for the samples were studied. Synthesis mechanism, morphology and thermal properties of the SAC were characterized. FTIR results confirmed the presence of acrylamide/ acrylic acid onto bentonite backbone while TGA showed that introduction of 70 % bentonite to polymer increases thermal stability. The SAC was also tested in the removal of heavy metal in aqueous solution where kinetics analyses were performed using Langmuir adsorption isotherm. The optimum adsorption capability of heavy metal ions onto bentonite-based SAC from solution was 92, 48 and 91 % for Pb++, Ni++, and Cu++ respectively. The unique characteristics of these SAC such as its slow-release and water-retention capability, nontoxicity in soil, environmentally friendly and high capacity for the removal of heavy metals might be very valuable in agriculture and environmental studies

Development of a magnetic calcium-alginate hydrogel-sphere encapsulated with Fe–Mn–Zr ternary metal composite for heavy metal adsorption

Heavy metal contamination has become one of the greatest global environmental problems. In this study, a magnetic calcium-alginate hydrogel-sphere encapsulated with Fe–Mn–Zr ternary-metal composite (MCHETC) was prepared through a combined co-precipitation and extrusion approach and used for the adsorption of heavy metals in aqueous solutions. The active sites were dispersed in the MCHETC, which can be separated by the magnetic force for the ease in operation. Above 80% of ultimate adsorption was completed at a contact time of 5 h. The copper uptake history was well described by the intraparticle surface diffusion model, suggesting a multi-step process for the adsorption. The optimum pH for adsorption was 4; the maximum adsorption capacity was 103.1 mg-Cu/g. The adsorption capability well remained after the 5 adsorption–desorption cycles and the copper could be recovered. Furthermore, the adsorbent performed well in the nature water spiked with copper ions. The mechanism studies illustrated that the adsorption was mainly controlled by the ion-exchange reaction. This study demonstrated that the MCHETC adsorption technology may be used for heavy metal removal and recovery with higher efficacy.

N-Doped Biochar from Lignocellulosic Biomass for Preparation of Adsorbent: Characterization, Kinetics and Application.

Medulla tetrapanacis is composed of a lignocellulosic biopolymer and has a regular porous structure, which makes it a potential biomass material for preparing porous N-doped biochar. Herewith, N-doped Medulla tetrapanacis biochar (UBC) was successfully prepared by modification with urea and NaHCO3 under pyrolysis at 700 °C. The nitrogen-containing groups were efficiently introduced into biochar, and the micro-pore structures of the UBC were developed with sizeable specific surface area, which was loaded with massive adsorption sites. The adsorption kinetics and isotherms of the UBC conformed to pseudo-second-order and Langmuir model. The superior adsorption capacities of the UBC for methylene blue (MB) and congo red (CR) were 923.0 mg/g and 728.0 mg/g, and the capacities for Cu2+ and Pb2+ were 468.5 mg/g and 1466.5 mg/g, respectively. Moreover, the UBC had a stronger affinity for Cr3+ and Fe3+ in multiple metal ions and retained at a preferable adsorption performance for dyes and heavy metals after five cycles. Precipitation, complexation, and physical adsorption were the main mechanisms of the UBC-adsorbing metal ions and dyes. Thus, lignocellulosic biochar has great potential for removing dyes and heavy metals in aqueous solutions.

Effect of Pyrolysis Temperature on Removal Efficiency and Mechanisms of Hg(II), Cd(II), and Pb (II) by Maize Straw Biochar

Pyrolysis temperature significantly affects the properties of biochar, which in turn can affect the removal of heavy metal ions and the underlying mechanism. In this work, biochars from the pyrolysis of maize straw at 300, 400, and 500 °C (BC300, BC400, and BC500, respectively) and wheat straw at 400 °C (WBC400) were investigated. The influence of production temperature on the adsorption of Hg2+, Cd2+, and Pb2+ by maize straw biochar was investigated by the characterization of the biochars and by adsorption tests. The adsorption capacities of maize and wheat straw biochar were compared in an adsorption experiment. Biochar BC400 showed the best physical and chemical properties and had the largest number of surface functional groups. The pseudo-second-order kinetic model was more suitable for describing the adsorption behavior of metal ions to biochar. The Langmuir model better fit the experimental data. Biochar BC400 had a higher adsorption speed and a stronger adsorption capacity than WBC400. The sorption of Pb2+ and Hg2+ to maize straw biochar followed the mechanisms of surface precipitation of carbonates and phosphates and complexation with oxygenated functional groups and delocalized π electrons. The adsorption mechanism for Cd2+ was similar to those of Hg2+ and Pb2+, but precipitation mainly occurred through the formation of phosphate. In the multi-heavy-metal system, the adsorption of Cd2+ by BC400 was inhibited by Pb2+ and Hg2+. In summary, BC400 biochar was most suitable for the adsorption effect of heavy metals in aqueous solution.

Detection of Cd2+ in Aqueous Solution by the Fluorescent Probe of CdSe/CdS QDs Based on OFF-ON Mode.

The detection of heavy metals in aqueous solutions has always attracted much attention from all over the world. A fluorescent probe of CdSe/CdS core-shell quantum dots (QDs) was designed to detect trace Cd2+ in aqueous solutions using the OFF–ON mode rapidly and efficiently, likely based on adsorption and desorption reactions between ethylenediaminetetraacetic acid disodium salt (EDTA) and CdSe/CdS QDs. In the OFF mode, the optical shielding function of EDTA results in fluorescence quenching owing to the strong adsorption ability of EDTA with Cd2+ on the sites of CdSe/CdS QDs surface. In the ON mode, the introduction of Cd2+ promotes the desorption of EDTA from the EDTA-CdSe/CdS QDs and restores the fluorescence intensity. There were two linear response ranges which were 0.1–20 µmol/L and 20–90 µmol/L for the EDTA-CdSe/CdS system to detect Cd2+. The detection limit was 6 nmol/L, and the standard deviation was below 4% for the detection of Cd2+ concentration in tap water.

Adsorption of ions of heavy metals in aqueous solutions utilizing montmorillonite

The adsorption process is an alternative treatment method used to remove heavy metals of industrials effluents. In the present paper, the sorption processes of the metals nickel (II), copper (II) and lead (II) in aqueous solutions, utilizing montmorillonite like substrates, including adsorption isotherms of single metal solutions were studied. According to X ray diffraction the principal constituent of montmorillonite is the quartz (SiO2) that in the surface area create the most likely group Si-OH. This group is probably going to absorb the cations of the solutions. On the other hand, the dissociated group (-S-O) is a weak Lewis acid because of the polarization, and the chemisorption process in this case is not favorable. The Langmuir adsorption model, in all cases, was found to present the highest regression values (R2), and therefore the best fit. The mineral showed the ability to take up the tested heavy metals in order Ni (II) > Pb (II) > Cu (II), and this could be related to the valence and the hydration radius (IR) of the cations. According to the presented results in this paper the montmorillonite can be used for removal a considerable amount of heavy metals present in aqueous effluent.

MoS2/Bentonite prepared by a facile method for efficient removal of Cd2+ from aqueous solution

The pollution of heavy metals in aqueous solution has been paid considerable attention in the past several decades. Many researches focused on developing new materials or methods for removing heavy metals. The two-dimensional lamellar structure of molybdenum disulfide (MoS 2 ) has attracted extensive interest and was regarded as a potential material due to it has a large number of active sites. In this paper, a novel one-step hydrothermal method was proposed to prepare the MoS 2 /Bentonite composite material. The MoS 2 composed of many nano petals grew successfully in the pores of bentonite to form flower spheres, and the addition of bentonite can effectively avoid the agglomeration phenomenon of MoS 2 prepared by the hydrothermal method. Pseudo-second-order model was applied to describe the adsorption process, revealing the adsorption dominated by chemical adsorption. The dynamic model was in accord with the Langmuir model and the maximum adsorption capacity of Cd 2+ was 89.45 mg/g. The excellent performance of MoS 2 /Bentonite made it have the tremendous application of removing heavy metal ions. • MoS 2 /Bentonite was prepared by a facile one-step hydrothermal method. • The addition of bentonite can avoid the agglomeration phenomenon of MoS 2 . • The performance of MoS 2 /Bentonite was superior to both pure MoS 2 and bentonite. • The adsorption characteristics were analyzed by kinetic model and isotherm model. • MoS 2 /Bentonite exhibited considerable adsorption capacity of Cd 2+ from water.

Oxidized regenerated cellulose nanofiber membranes for capturing heavy metals in aqueous solutions

Oxidized regenerated cellulose nanofiber membranes for capturing heavy metals in aqueous solutions