Effective Removal Of Pb Research Articles

Effective removal of Pb (II) from wastewater by zinc-iron bimetallic oxide-modified walnut shell biochar: A combined experimental and DFT calculation approach

The modified walnut shell biochar (WBC) was prepared through zinc-iron bimetallic oxide modification (ZF@WBC) at 600 °C under oxygen-limited conditions in this study. Through adsorption experiments, characterization analyses, and density functional theory (DFT) calculations, the adsorption properties of ZF@WBC to Pb (II) were investigated and the mechanism underlying such adsorption was elucidated. Characterization results showed that the surface area (375.9709 m2/g) and total pore volume (0.205319 cm3/g) of ZF@WBC were significantly greater than those of walnut shell biochar. The maximum adsorption capacity of ZF@WBC for Pb (II) was found to be 104.26 mg/g, which is 2.57 times higher than that of WBC according to the adsorption experiments conducted. The observed adsorption behavior followed both the pseudo-second-order (PSO) kinetic model and Langmuir isothermal adsorption model, suggesting that chemisorption plays a major role in the absorption process. Based on SEM, XRD, XPS, FTIR characterizations along with DFT calculations performed in this study, it can be concluded that surface complexation, ion exchange, electrostatic attraction, physical absorption are among the main mechanisms responsible for absorption of Pb (II) by ZF@WBC. Furthermore, even in the presence of interfering ions at different concentrations, ZF@WBC exhibited a removal rate above 70% for Pb (II). Therefore, ZF@WBC has great potential as an effective absorbent for removing Pb (II) from wastewater, while also offering opportunities for biomass waste resource utilization.

Fluorescence detection and effective adsorption of trace Pb(II) based on nanofibrous metal-organic gel

Water pollution has become a global environmental problem, such as that caused by Pb(II). Therefore, there is an urgent need to develop multifunctional materials for Pb(II) monitoring and removal. Yet, developing bifunctional materials for sensitive detection and efficient removal of Pb(II) remain challenging. Here, a metal-organic gel (HNU-G4) was constructed for sensible responsive detection and efficient adsorption of Pb(II). The dry gel was obtained through the freeze-dried process and can be used for the Pb(II) detection via fluorescence quenching; the lowest limit of detection for Pb(II) is 0.766 ppb. Furthermore, HNU-G4 has an effective maximum adsorption capacity of 480.00 mg·g-1 for Pb(II) in water. Additionally, the gel demonstrates excellent recoverability and interference resistance, which can be used in the detection and recovery of actual reclaimed water samples to prevent secondary contamination. This study developed a bifunctional gel material for sensitive detection and effective removal of Pb(II) from water, providing a suggested strategy to tackle the heavy metal contamination problem.

Effective Removal of Pb(II) from Multiple Cationic Heavy Metals—An Inexpensive Lignin-Modified Attapulgite

To develop cost-effective heavy metal adsorbents, we employed water-soluble lignin from black liquor to modify activated attapulgite, resulting in the creation of a novel adsorbent called Lignin-modified attapulgite (LATP). In this study, scanning electron microscopy and Fourier transform infrared spectrometer techniques were utilized to characterize the structural details of LATP. The results revealed that lignin occupies the micropores of attapulgite, while additional functional groups are present on the attapulgite surface. We conducted adsorption tests using LATP to remove five types of heavy metal ions (Cd2+, Pb2+, Zn2+, Mn2+, Cu2+), and it was found that LATP exhibited greater removal mass and binding strength for Pb(II) compared to the other ions. For further investigation, batch experiments were performed to evaluate the adsorptive kinetics, isotherms, and thermodynamics of Pb2+ removal from aqueous solutions using LATP. The results indicated that the adsorption capacity of Pb(II) on LATP decreased with decreasing pH, while the presence of Na+ had no effect on adsorption. The adsorption process reached equilibrium rapidly, and the Langmuir adsorption capacities increased with temperature, measuring 286.40 mg/g, 315.51 mg/g, and 349.70 mg/g at 298 K, 308 K, and 318 K, respectively. Thermodynamic analysis revealed positive values for ΔH0 and ΔS0, indicating an endothermic and spontaneous adsorption process. Furthermore, ΔG0 exhibited negative values, confirming the spontaneous nature of the adsorption. Consequently, LATP demonstrates great potential as an effective adsorbent for the removal of Pb(II). Therefore, LATP shows great potential as an effective adsorbent for the removal of Pb(II) from natural water environments, contributing to the sustainable development of man and nature.

Effective Removal of Pb(II), Cr(VI), and Cd(II) Ions from Water Using Environmentally Friendly Cerium Oxide Nanoparticles Synthesized from Pods of Pisum sativum

Effective Removal of Pb(II), Cr(VI), and Cd(II) Ions from Water Using Environmentally Friendly Cerium Oxide Nanoparticles Synthesized from Pods of Pisum sativum

Aminated Spherical SiO2 Synthesized from Fly Ash and Its Application for Pb2+ and Cu2+ Sorption

Fly ash was utilized as raw material for the preparation of spherical SiO2 (SS), which was subsequently ammonified using APTES (H2NCH2CH2CH2Si(OC2H5)3) to obtain aminated spherical SiO2 (SSN). The physicochemical properties of SS and SSN were systematically characterized. Notably, SS exhibited a remarkable specific surface area and pore volume, enabling it to accommodate abundant nitrogen-containing groups. These functional groups served as crucial active sorption sites, significantly enhancing the sorption capacity of SiO2 for Pb2+ and Cu2+ ions. Thus, the removal efficiency was above 99.9% when using dosages of 4 and 6 g/L SSN in solutions containing 200 mg/L of Pb2+ and Cu2+, respectively. Additionally, SSN showed a higher theoretical maximum sorption capacity for Pb2+ and Cu2+ ions, as determined by the Langmuir isotherm model, with values of 185.2 mg/g and 86.2 mg/g, respectively. These results surpass those reported in previous studies on adsorbents derived from fly ash. The chemical reactions that occurred between the aqueous cations and nitrogen-containing groups were identified as the pivotal factors governing the sorption of Pb2+ and Cu2+. This study presents a practical approach to fly ash utilization, along with the effective removal of Pb2+ and Cu2+ from water.

Effective removal of Pb(II) and Congo red by polyrhodanine-modified sepiolite

Heavy metals and dyes present in industrial wastewater pose a significant threat to both the ecological environment and human health. In this study, we have developed a multifunctional adsorbent, SEP/PR, which is obtained by modifying sepiolite with polyrhodanine. The purpose of this adsorbent is to effectively remove Pb2+ ions and Congo red (CR) dye from contaminated water sources. The adsorbents were systematically characterized using SEM, EDS, XRD, BET, FT-IR and XPS. Compared with raw sepiolite, SEP/PR exhibited better adsorption performance due to its abundant adsorption sites. The adsorption of Pb2+ and CR on SEP/PR can be described by pseudo-second-order and Langmuir models, and the preferential adsorption capacities were still satisfactory even in the presence of interference. The maximum adsorption of Pb2+ and CR was 423.29 mg/g and 894.76 mg/g, respectively, at 298 K. It is noteworthy that the removal rates of both Pb2+ and CR were increased in the binary Pb2+-CR system. These observed increases can be attributed to the introduction of additional adsorption sites, as well as the electrostatic attractions that occur between the adsorbed Pb2+ (+) and CR (−) ions. The adsorption mechanism for Pb2+ primarily involves complexation, while for CR, it involves a combination of electrostatic interactions, hydrogen bonding, and π-π interactions. Finally, SEP/PR has good reusability and practical application capabilities. This study shows that SEP/PR is simple to synthesize and can be used for the synergistic removal of heavy metals and dyes in complex systems.

Effective removal of Pb(II) and Cu(II) from aqueous solutions using a hybrid composite of fuller's earth, aluminum silicate and chitosan

In this study, a highly effective hybrid adsorbent composite based on low-cost fuller’s earth (FE), aluminum silicate (AS) and chitosan (CS) was prepared using a facile method. The prepared composite was applied to adsorb lead (Pb2+) and copper (Cu2+) ions from aqueous solutions. Several analyses such as Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the composite. The adsorption efficiency of the prepared composite was investigated at different operating conditions. Moreover, the adsorption isotherm/kinetic models and adsorption thermodynamics of the composite were examined. The results showed that the pseudo-second-order kinetic model described well with the obtained data and the adsorption equilibrium can be better described by Langmuir isotherm model with maximum adsorption capacities of 305.5 and 284.2 mg/g for Pb2+ and Cu2+, respectively. The obtained data demonstrated that the prepared composite is an efficient and kinetically fast metal ion removal with high adsorption capacity and recovery efficiency.Graphical abstract

Structural and adsorptive properties of boron- and phosphorous-doped graphene oxide: Insight into effective removal of Pb(II) and As(III)

Graphene oxide (GO) doped with heteroatoms are gaining interest in depollution of water because of their large surface area. This paper presents for the first time the comparative adsorptive properties of boron- and phosphorous- doped GO (B-GO and P-GO) to remove Pb(II) and As(III) ions from water. The doped GO were synthesized by two-step approach and fully characterized using various analytical techniques to demonstrate their distinct structural and adsorptive features. The Brunauer-Emmett-Teller (BET) surface areas of B-GO (127.4 m2g−1) and P-GO (144.4 m2g−1) were higher than that of pristine GO (77.4 m2g−1) due to insertion of dopants during synthesis. The defects in the doped GO were higher, which were seen in measurements of band intensity ratio of defect band to graphene band in the Raman spectra of B-GO, P-GO, and pristine GO as 1.02, 1.17, and 0.84, respectively. The XPS studies revealed that 96.9 % PO and 3.1 % of PC moieties were present in P-GO. Whereas in B-GO, 93.4 % C2BO/CBO2 and 6.3 % BC moieties were present. Thermodynamic and kinetic measurements of adsorption of Pb(II) and As(III) onto doped GO and pristine GO were determined under different experimental conditions of pH, adsorbent dose, and co-existing ions. Results were interpreted using linear and non-linear isotherms and kinetic modelling. The Langmuir binding capacities of P-GO were 388.1 mgg−1 and 157.4 mgg−1 for Pb(II) and As(III) ions, respectively, which were higher than B-GO and pristine GO. Higher adsorption capacity of P-GO was delineated on the basis of functional moieties, surface defects, smaller particle size, and larger surface area. The renewability experiment showed a negligible decrease in adsorption capacity of P-GO even after five repeated cycles. Column studies supported the applicability of P-GO as an effective adsorbent for removing metal ions in the continuous system.

Effective Removal of Pb2+ from Aqueous Solution Using Magnetic Mesoporous Silica Prepared by Rubidium-Containing Biotite Leaching Residues and Wastewater

The rubidium leaching process from biotite generates a large amount of waste materials that should ideally be reused for heavy metal ion adsorption so as not to create environmental problems. Ferric oxide/mesoporous silica (FO/MS) is a novel adsorbent used for heavy metal ion removal with a high removal capacity of Pb2+ (143.47 mg/g within 60 min) that was prepared for the first time by comprehensively utilizing both rubidium-containing biotite leaching residues and wastewater. The incorporation of mesoporous silica prepared by leaching residues could provide a porous framework and channel for depositing ferric oxide. Mesoporous channels have a high specific surface area that improves the adsorption activity and capacity of the material. Additionally, in a pH study, the adsorptive thermodynamic and dynamic analyses, as well as XPS and FTIR analyses, verified the adsorption properties involved in surface complexing and electrostatic binding. The surface complexation process mainly was the interaction of Pb2+ with surface hydroxyl groups. This work provided a novel and effective strategy for preparing waste solid-based heavy metal ion adsorption and expanded technologies for treating acid leaching wastewater. The adsorbents of FO/MS with a high Pb2+ adsorption capacity suggested that, compared with other materials, it is a suitable remediation material for Pb2+ contaminated water.

Revalorizing a Pyrolytic Char Residue from Post-Consumer Plastics into Activated Carbon for the Adsorption of Lead in Water

This work focuses on the use of a char produced during the pyrolysis of a mixture of non-recyclable plastics as a precursor for the preparation of porous activated carbon with high developed adsorption uptake of lead in water. Physical and chemical activation was used to enhance the porosity, surface area, and surface chemistry of char. The final activated carbon materials were deeply characterized through N2 adsorption isotherms, scanning electron microscopy, Fourier transformed infrared spectroscopy, analysis of the metal content by inductively coupled plasma mass spectroscopy, and pH of point zero charge. The native char displayed a Pb adsorption uptake of 348 mg Pb·g−1 and considerably high leaching of carbon, mainly organic, ca. 12%. After stabilization with HCl washing and activation with basic character activators, i.e., CO2, NaOH, and KOH, more stable adsorbents were obtained, with no organic leaching and a porous developed structure, the order of activation effectiveness being KOH (487 m2·g−1) > NaOH (247 m2·g−1) > CO2 (68 m2·g−1). The activation with KOH resulted in the most effective removal of Pb in water with a saturation adsorption uptake of 747 mg Pb·g−1.

Construction of a novel hydrogel composite with polylactic acid nonwoven fibers: rapid and effective removal of Pb(II) and Ni(II)

In this study, a hydrogel composite adsorbent structure was reported and showed satisfactory adsorption performance. The study uses polylactic acid melt-blown nonwoven fabric to optimize and improve the adsorption performance of the hydrogel. The results show that the nonwoven fabric structure enables the composite material to reach the swelling equilibrium faster than the hydrogel. The adsorption-isotherm model found that the adsorption capacity of composite materials Pb(II) and Ni(II) reached 416.07 and 243.10 mg/g, respectively, and still had high removal efficiency at low pH. The composite material has low cost and can be reused, which solves the problems of difficulty in recovery of the hydrogel adsorbent, low strength, and easy damage, and promotes the industrialization of the hydrogel as an adsorbent.

Effective removal of Pb(II) ions using piperazine-modified magnetic graphene oxide nanocomposite; optimization by response surface methodology

In this research, the piperazine-modified magnetic graphene oxide (Pip@MGO) nanocomposite was synthesized and utilized as a nano-adsorbent for the removal of Pb(II) ions from environmental water and wastewater samples. The physicochemical properties of Pip@MGO nanocomposite was characterized by X-ray diffraction analysis (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDAX), Thermo-gravimetric analysis (TGA), Vibrating Sample Magnetometery (VSM) and Fourier-transform infrared spectroscopy (FT-IR) analysis. In this method, the batch removal process were designed by response surface methodology (RSM) based on a central composite design (CCD) model. The results indicated that the highest efficiency of Pb(II) removal was obtained from the quadratic model under optimum conditions of prominent parameters (initial pH 6.0, adsorbent dosage 7 mg, initial concentration of lead 15 mg L−1 and contact time 27.5 min). Adsorption data showed that lead ions uptake on Pip@MGO nanocomposite followed the Langmuir isotherm model equation and pseudo-second order kinetic model. High adsorption capacity (558.2 mg g−1) and easy magnetic separation capability showed that the synthesized Pip@MGO nanocomposite has great potential for the removal of Pb(II) ions from contaminated wastewaters.

Effective removal of Pb(II) and Ni(II) ions by Bacillus cereus and Bacillus pumilus: An experimental and mechanistic approach

Herein, we report a bacteria-based strategy as an efficient, reasonable, benign, and promising methodology for remediating heavy metals fed waterbodies. The contemporary study deals with isolating, screening, and characterizing heavy metal resistive bacteria from metal-rich sites. The transcriptome analysis reveals the identity of the isolated species as Bacillus pumilus and Bacillus cereus. Batch studies put forth the bioremoval results in designed conditions of different pH, concentration, dose, and time. The mechanistic actions are drawn using complementary techniques such as Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The theory of surface adsorption of lead (Pb(II)) and nickel (Ni(II)) is further fostered by the application of adsorption isotherms. The conducted studies establish the bacterial morphological stratagems and multifarious biochemical approaches for countering metallic ions of Pb(II) and Ni(II). The exhibition of significant removal results by the isolated bacterial strains in simulated water samples with remarkable proliferation rates has opened up its favorability for industrial platforms.

Enhancement of TiO2 activity under visible light by N,S codoping for Pb(II) removal from water

This paper deals with a systematic study on the co-doping N,S on TiO2 photocatalyst to improve its activity under visible light on the removal of Pb(II) from the aqueous media. The co-doping TiO2 by N,S atoms was conducted in an autoclave by one-step hydrothermal of TiO2 mixed with nitric and sulfuric acids as the sources of N and S, respectively. The mole ratio of TiO2:nitric acid:sulfuric acid was varied as 1:1:0.5, 1:1:1, and 1:1:1.5 to find the best ratio toward the activity. The co-doped photocatalysts obtained were characterized by specular reflectance UV/Vis (SRUV), X-ray diffraction (XRD), and fourier transform infrared (FTIR) instruments. A batch experiment was carried out for oxidation of Pb(II), driven by a combination of visible light and TiO2-N,S photocatalyst. The research results attribute that co-doping N,S into TiO2 has remarkably narrowed the gap in the TiO2 structure, emerging in the visible region. It was also proven that the co-doped in TiO2 can considerably enhance its activity in the removal of Pb(II) under visible light, and the highest activity was owned by TiO2-N,S (1:1:1). Furthermore, the most effective removal of Pb(II) 10 mg/L (98%) could be reached by employing 500 mg L-1 of the TiO2-N,S (1:1:1) dose, 45 min of the time, and the solution pH at 7. The Pb(II) removed is due to the photo-oxidation induced by OH radicals to form the handleable PbO2.

Effective removal of Pb(II)/4-nitroaniline/E. faecalis and E. coli pollutants from water by a novel unique graphene quantum dots@gemifloxacin@ double-layered Fe/Al nanocomposite

Design and assembly of a novel sustainable unique nanocomposite with multi-purpose activities with efficient adsorptive removal behavior toward different organic, inorganic and biological pollutants is a challenging aspect. Therefore, the current work is directed to prepare graphene quantum dots (GQDs) from mango peels via a facile method. GQDs were coupled with FeAl double layered hydroxide (FA-DLH) and intercalated via co-precipitation with gemifloxacin antibiotic (Gem) for the formation of a 3D structure with multiple functional nanocomposite (GQDs@Gem@FA-DLH). This was utilized for various pollutants removal including lead (Pb(II)), 4-nitroaniline (4NA), Enterococcus faecalis (E. faecalis) and Escherichia coli (E. coli)). GQDs@Gem@FA-DLH was characterized from FT-IR, EDX, HR-TEM, BET, XRD and TGA techniques. The maximum removal of 4NA and Pb(II) were established as 90.7% (pH 2.0) and 98.8% (pH 6.0), respectively. The adsorption performance by GQDs@Gem@FA-DLH was favored according to Langmuir and pseudo-second order. Furthermore, the antibacterial removal activity against gram-positive (E. faecalis) and gram-negative (E. coli) by GQDs@Gem@FA-DLH was assessed using two different methods, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) and the removal percentages reached to 91.3% and 82.9%, respectively. Moreover, the removal of bacteria from wastewater based on the total plate count was established as 80%.

The effective removal of Pb2+ by activated carbon fibers modified by l-cysteine: exploration of kinetics, thermodynamics and mechanism.

Herein, we developed a low-cost fabrication route to prepare chemically grafted activated carbon fibers, which effectively removed Pb2+ from solution. Multiple characteristic results indicated that l-cyst-ACF had abundant nitrogen-containing and sulfur-containing functional groups. Based on the XPS and EDS analyses, the capture of Pb2+ was attributed to the abundant adsorption sites on the fiber surface. According to the analysis of the pseudo-second-order kinetic model and the Langmuir isotherm model, the adsorption process could be interpreted as monolayer adsorption and chemisorption, and the equilibrium adsorption capacity was determined to be 136.80 mg g−1 by fitting the pseudo-second-order kinetic model. The maximum adsorption capacity of l-cyst-ACF for Pb2+ was calculated to be 179.53 mg g−1 using the Langmuir model. In addition, the adsorption reaction was endothermic and spontaneous, as evidenced by the thermodynamic parameters. The outcomes of this study provide a low-cost and feasible strategy for the remediation of Pb2+ pollution in the environment.

Pengaruh sistem monokultur dan tumpangsari antara sayuran dan Crotalaria juncea L. terhadap akumulasi Pb, biomassa, dan hasil tanaman

Intercropping system that involves planting multispecies between accumulator plants and cultivated plants is a way to improve the phytoextraction of heavy metals in agricultural land simultaneously. However, how the effect of accumulator plants on the growth and yield of cultivated plants has not been widely studied. This study aims to determine the growth and yield of vegetables intercropped with accumulator plants from the legume group, namely Crotalaria juncea L. The study was carried out using a randomized block design with one factor, namely Chinese vegetable monoculture (P1), bean vegetable monoculture (P2), and accumulator plant monoculture. Crotalaria juncea L. (P3), an intercropping system between Chinese cabbage and Crotalaria juncea L. (P4; and an intercropping system of beans and Crotalaria juncea L (P5). The results showed that in Chinese cabbage, monoculture planting produced biomass and crop yields. per plant and per plot was higher than the crops grown by intercropping. In the bean crop, monoculture and intercropping systems did not provide differences in biomass yield and fruit yield per plant and per plot. Crotalaria juncea L, which was grown in monoculture produced plant biomass and the yield of the stove per square is higher gi compared to those planted by intercropping. Crotalaria juncea L. intercropped with Chinese cabbage was able to accumulate more Pb in the roots, while Crotalaria juncea intercropped with chickpeas accumulated higher Pb in the stems. Crotalaria juncea plants grown in monoculture accumulated higher Pb than those intercropped with vegetables, so further research is needed to test the effective removal of Pb using other cropping systems.

Effective removal of Pb2+ from oral medical wastewater via an activated three-dimensional framework carbon (3D AFC)

Oral medical wastewater with heavy metal ions (such as plumbum, Pb2+) is regarded as the main pollutant produced in the oral cavity diagnosis, and the treatment process can pose a serious threat to human health. The removal of Pb2+ from oral medical wastewater facing major difficulties and challenges. Therefore, it is of great significance to take effective measures to remove Pb2+ by using effective methods. A new activated three-dimensional framework carbon (3D AFC), regarded as the main material to remove Pb2+ in the oral medical wastewater, has been fabricated successfully. In this experiment, the effects of 3D AFC absorbing Pb2+ under different conditions (including solid-to-liquid ratio, pH, ionic strength, contact time, and initial concentration, etc.) were discussed. And the result revealed that the adsorption kinetics process of Pb2+ on 3D AFC conformed to the pseudo-second-order model and the adsorption isotherm conformed to the Freundlich model. Under the condition that pH = 5.5 and T = 298 k, the calculated maximum adsorption capacity of 3D AFC for Pb2+ was 270.88 mg/g. In practical application, it has strong adsorption ability for Pb2+ in oral medical wastewater. Thus, 3D AFC shows promise for Pb2+ remove and recovery applications because of high adsorption capacity for Pb2+ in oral medical wastewater due to its high specific surface area, outstanding three-dimensional network structure.

Fast and effective removal of Pb(II), Cu(II) and Ni(II) ions from aqueous solutions with TiO2 nanofibers: Synthesis, adsorption-desorption process and kinetic studies

ABSTRACT In this study, titanium oxide (TiO2) nanofibers were synthesised and determined to be an effective adsorbent for efficient removal of Ni(II), Pb(II), Cu(II) ions from aqueous solutions. TiO2 nanofibers were synthesised by the electro-spinning method. TiO2 nanofibers were characterised with X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray spectrometer (EDX) and Fourier Transform Infrared Spectroscopy (FTIR). A series of batch adsorption experiments were done to research the influence of various parameters such as pH, adsorbent dosage, contact time, temperature, the concentration of metal ions, complexing agent on the metal ion removal capacity of TiO2 nanofibers. Adsorption equilibration time was 28 minutes and adsorption capacity was 834.56 mg g−1 for Cu(II) ions, 756.67 mg g−1 for Ni(II) ions and 685.56 mg g−1 for Pb(II) ions. The adsorption of Cu(II), Ni(II) and Pb(II) was observed maximally at pH = 6. The kinetic and isotherm model fitting studies confirmed that the data fit well with Langmuir isotherm and pseudo-second-order kinetic models. Thermodynamic studies show that the adsorption of Pb(II), Cu(II) and Ni(II) ions are endothermic, spontaneous in nature. The reusability of nanofibers for the adsorption of Ni(II), Cu(II) and Pb(II) was examined for five studies. Simultaneous adsorption of Ni(II), Cu(II) and Pb(II) from aqueous solutions was also investigated. The results showed that TiO2 nanofibers adsorbent can quickly and effectively remove heavy metals from aqueous solutions and also the adsorbent is eco-friendly, low cost, high stability and non-toxic. Also, the reusability of the material has confirmed that TiO2 nanofibers can be used many times to efficiently remove heavy metal ions from aqueous solutions.

One-step removal of lead from water using an electricity-free and sustainable membrane filtration

Lead (Pb) is a typical contaminant in water with adverse effects on human health. Hong Kong’s incident of drinking water contamination by Pb in 2015 caused severe public concerns regarding drinking water safety. Conventional treatment methods for Pb removal generally require electricity, chemical dosage, and considerable time and space, which significantly restrict their use for rapid water purification under emergency situations. In this study, a polyvinyl alcohol/polyacrylic acid (PVA/PAA) composite nanofibrous membrane was developed for the rapid and effective removal of Pb from water. The PVA/PAA membrane had a high water permeability of 550 L/m2/h/kPa - 710 L/m2/h/kPa, which allowed the filtration to be driven by gravity (e.g. with a water height of 10.0 cm). The membrane showed consistently high removal efficiency of Pb (> 95%) with a volumetric loading up to 3000 L/m2. This high removal efficiency was attributed to the combined effects of complexing and electrostatic attraction between Pb and PAA. An esculent citric acid was used to regenerate the exhausted PVA/PAA membrane. The regenerated membrane maintained its removal efficiency of Pb over a five-cycle filtration. These results imply that the PVA/PAA composite membrane can be repeatedly used in electricity-free filtration devices for rapid elimination of Pb under emergency situations.