Removal Efficiency Of Pb Research Articles

Green preparation of carbon materials from biomass slag and steam as byproducts of power plants for efficient treatment of lead-containing wastewater

Green preparation of high-performance and cost-effective carbon materials using biomass slag and steam, which were the byproducts of power plants, for efficient treatment of lead (Pb(II))-containing wastewater was investigated. The optimum carbon material CH500-800 (SBET=818.8 m2/g and Vt=0.46 cm3/g) was produced by one-step steam activation at 800 ℃ for 1h under a 500mL/min stream with a heating rate of 5°C/min. The obtained CH500-800 greatly enhanced the efficiency of Pb(II) removal, achieving the maximum adsorption capacity of 191.1mg/g. The removal of Pb(II) from wastewater was well described by the Pseudo-second-order, Elovich and Freundlich model, suggesting that it was predominantly governed by chemical adsorption and diffusion on heterogeneous surfaces. The adsorption process demonstrated a synergistic mechanism involving pore and surface adsorption, chemical interactions between oxygen-containing groups (C-O and -OH) and Pb(II), as well as Pb(II)-π interactions, which was responsible for the efficient removal of Pb(II) from wastewater. Moreover, CH500-800 retained a potential for reusability with a high adsorption stability (only 2.5% Pb(II) desorption after 48h) and ion selectivity (>93.0%) in the presence of K(I), Na(I) or Ca(II). Additionally, a circular economic model was proposed to valorize biomass slag and steam in situ for treating Pb(II)-containing wastewater effectively in biomass power plants. This approach provided an innovative solution for utilizing waste to treat hazardous substances within practical engineering applications.

Hybrid electrocoagulation/adsorption system using aluminum electrodes and novel GO@ZIF-7 nanocomposite for the effective removal of Pb(II) from wastewater

Water pollution resulting from heavy metals including lead [Pb(II)] is a major health concern for humans, animals, and aquatic life. Pb(II) is a highly hazardous contaminant that must be effectively removed from water before reuse or discharge. In this study, a hybrid electrocoagulation/adsorption system (EC/A) using aluminum electrodes integrated with a novel adsorbent GO@ZIF-7 nanocomposite, was studied for aqueous phase Pb(II) removal. The hybrid EC/A system yielded a near complete Pb(II) removal. The system was optimized using the Response Surface Methodology (RSM) based design of experiments (DOE) technique; specifically using the central composite design (CCD) the study analyzed the impacts of four primary process variables (i.e., current density, Pb(II) initial concentration, dosage of GO@ZIF-7 nanocomposite, and conductivity) on the Pb(II) removal. Notably, the findings show the significant role of current density in the Pb(II) removal process, particularly at a current density of 1.5 mA/cm2. The above-mentioned RSM design along with the analysis of variance (ANOVA) based statistical analysis and optimization, confirmed the suitability of the proposed RSM-based equations for Pb(II) removal modeling. Collectively, the findings of this study indicate that the proposed hybrid EC/A system using aluminum electrodes integrated with a novel GO@ZIF-7 nanocomposite has a significant practical viability as suggested by the remarkably high Pb(II) removal efficiency. Furthermore, this study also presents the effectiveness of three advanced machine learning (ML) based models, i.e., artificial neural network (ANN), eXtreme Gradient Boosting (XGBoost), and Random Forest Regression, for predictingthe Pb(II) removal using the EC/A process.

Fabrication of CaCO3 Microcubes and Mechanistic Study for Efficient Removal of Pb from Aqueous Solution

Pb(II) contamination in aquatic environments has adverse effects on humans even at a low concentration, so the efficient removal of Pb at a low cost is vital for achieving an environmentally friendly, sustainable, and healthy society. A variety of CaCO3-based functional adsorbents have been synthesized to remove Pb, but the adsorption capacity is still unsatisfactory. Herein, calcite CaCO3 microcubes/parallelepipeds are synthesized via simple precipitation and a hydrothermal approach and found to outperform previously reported nano-adsorbents considerably. The CaCO3 achieves a high removal efficiency for Pb(II) (>99%) at a very low dosage (0.04–0.1 g/L) and an initial Pb(II) concentration of 100 mg/L. The CaCO3 presents an excellent adsorption capacity of 4018 mg/g for Pb(II) removal and depicts good stability over a wide range of pH 6–11. The maximum adsorption kinetics are fitted well by the pseudo-second-order kinetic model, whereas the Freundlich isotherm delineates the adsorption data at equilibrium well, indicating a multilayer adsorption process. The ex situ study confirms that the Pb(II) adsorption mechanism by CaCO3 can be attributed to the rapid metal-ion-exchange reaction between Pb(II) and Ca2+. Furthermore, a red shift in the Fourier Transform Infrared (FTIR) spectroscopy peak from 1386 cm−1 to 1374 cm−1 of CaCO3 after Pb removal indicates the adsorption of Pb onto the surface. This adsorbent provides an opportunity to treat wastewater and can be extended to remove other toxic heavy metals.

Sugarcane Bagasse Based Adsorbents and their Adsorption Efficacy on Removal of Heavy Metals from Nakuru Industrial Wastewater: Optimization, Kinetic and Thermodynamic Aspects

Currently, researchers are seeking to reduce heavy metal contamination from the environment, using agricultural waste materials like rice husk, groundnuts shells among others. The study focused on the removal of Cu(II), Pb(II), Cd(II), Ni(II), and Cr(III) ions from aqueous solutions and Nakuru industrial wastewater using sugarcane bagasse (NSCB) and valorised bagasse ash (VSCB), as alternative low-cost agricultural waste bio-sorbents. To achieve this goal, sugarcane bagasse was collected from Nzoia sugar industry in western Kenya, while the valorised bagasse was obtained by heating sugarcane bagasse sample in a muffle furnace at 300°C for three hours. Furthermore, batch adsorption studies were performed, and the effects of several factors, i.e. adsorbent particle size, pH, contact time, initial heavy metal ions concentration and temperature were investigated to optimise the removal efficiency of Pb, Cu, Cd, Ni, and Cr. The optimal adsorption conditions were pH of 5.0, adsorbent dosage of 0.1 g and ≤ 150µm particle size, equilibrium time of 60 minutes and at 25 degrees Celcius. The removal kinetics of the metal ions onto both adsorbents fitted well with the pseudo-second-order model. The removal kinetics of the metal ions onto both adsorbents fitted well with the pseudo-second-order model. The adsorption of Pb2+ and Ni2+ onto NSCB fitted better with the Freundlich isotherm model, while Cd2+, Cu2+ and Cr3+ showed better fit for the Langmuir isotherm model. As for VSCB adsorbent, Cr3+ has a better fit with the Langmuir isotherm model whereas Pb2+, Ni2+, Cd2+, and Cu2+ fitted well on the Freundlich isotherm model. Freundlich constant’s (1/n) values and the separation factor (RL) from the Langmuir isotherm model indicate that the metal ions were favourably adsorbed onto the adsorbents. Langmuir isotherm model was used to estimate the maximum adsorption capacities (qmax) for Cu(II), Pb(II), Ni(II), Cd(II), and Cr(III). The negative free energy change (∆G) values revealed that adsorption process of the metal ions onto NSCB and VSCB was spontaneous. Fourier Transform Infrared Spectroscopy (FTIR) was used for characterization studies. Interactions with metal ions caused the frequencies of the active functional groups, –OH, C=O and C=C, on the bio-sorbent surfaces to shift to higher values. Therefore, sugarcane bagasse and valorised bagasse have demonstrated higher potential to remove relatively all selected heavy metals in the industrial wastewater at controlled pH.

Highly efficient and sustainable polyacrylic acid-polyacrylamide double-network hydrogels prepared by cross-linking of waste residues for heavy metals ions removal

In this paper, an adsorbent composite called S-PEMR, which consists of electrolytic manganese residues (EMR)- silicate minerals-based polyacrylic acid-polyacrylamide double-network hydrogels, has been developed. The successful synthesis was confirmed by the characteristic peaks of COO, amide I, CO, -CH2, C-N group vibration in FTIR spectra as well as amorphous carbon in XRD patterns. This composite tackles the issue of harnessing EMR, which consists of layered silicate minerals and additional elements. These elements have potential value but are difficult to be effectively and safely utilized. It was observed that the adsorption process agreed with the quasi-secondary model and the Langmuir isotherm, the adsorption process is controlled by a chemisorption mechanism with the occurrence of electron sharing or electron transfer (establishment of covalent bonds) between the S-PEMR and the adsorbate. The S-PEMR was found to be recyclable up to four times. In the initial experiment, the concentrations of Ni, Cu, Cd, and Pb in a natural wastewater were recorded as 645.84, 906.21, 378.15, and 8.29 μg/L, respectively. The composites used in the study exhibited high removal efficiency for Ni (42.06 %), Cu (93.14 %), Cd (89.68 %), and Pb (77.02 %). The S-PEMR can be recycled up to four times with only a moderate reduction in adsorption performance. The removal mechanism primarily involved chelation or coordination, ion exchange, functional groups containing elements such as O and N, as well as the interaction of Si-O and Al-O with the heavy metal ions. This research establishes S-PEMR as a highly effective adsorbent for removing harmful contaminants from water.

Selective Single-Atom Adsorption for Precision Separation of Lead Ions in Tap Water via Capacitive Deionization

Capacitive deionization (CDI) offers a cost-effective and low-energy method for selective removal of Pb2+ from drinking water. Modifying CDI electrode surfaces with functional groups presents a versatile approach to enhancing selective ion adsorption capacity. However, a comprehensive understanding of the selectivity and removal efficiency of Pb2+ among diverse functional groups remains unexplored. Here, we investigated the effects of different functional groups (-SH, -COOH, and -NH2) attached to the graphene oxide (GO) electrode surfaces on Pb2+ selectivity and removal efficiency. Surprisingly, GO-COOH demonstrated single-atom adsorption of Pb2+, displaying superior removal efficiency and selectivity compared with -SH and -NH2, although -SH possesses significant chelation capability for Pb2+. Both density functional theory (DFT) calculations and X-ray pair distribution function (PDF) analyses confirmed that Pb2+ exhibits a theoretically higher affinity to -COOH. This research deepens our understanding of the interactions between functional groups and heavy metal ions, enabling selective and rapid separation of target cations for water purification.

Modification of polysulfone membranes using magnetite nanoparticles containing sulfonic acid and heteropoly acid groups to improve permeability and antifouling properties

To increase the performance of ultrafiltration membranes, it is necessary to develop new materials. In this study, membrane production was carried out using magnetite nanoparticles functionalized by sulfonic acid and phosphotungstic acid (HPW) to increase permeability and improve antifouling properties. Firstly, Fe3O4@SiO2@NH2-SO3H (FSNS) and Fe3O4@SiO2@NH2-SO3H-HPW (FSNSPW) materials were synthesized. Then, different amounts of the nanoparticles were added to the membrane solutions. While the pure water flux was 164.2 LMH in the bare membranes, it was observed as 202.8 LMH and 195 LMH as a result of adding 0.5 % FSNSPW and FSNS. While Pb removal efficiency was 90 % in the bare membrane, it was measured as 97 % for 0.1 % FSNSPW and 89.6 % for 0.5 % FSNS. Maximum flux recovery ratio is 65.3 % for 0.5 % FSNSPW and 63.4 % for 1 % FSNS. Additionally, the highest Reactive Red 120 dye permeation flux was 72.2 LMH for 0.1 % FSNSPW and 71.9 LMH for 0.1 % FSNS membrane. Additionally, the highest permeation flux of Reactive Black 5 dye solution is 83.3 LMH for 0.5 % FSNSPW and 95 LMH for 0.5 % FSNS membrane. It could be concluded that the presence of the HPW group can improve the performance of the membranes.

Enhanced Pollutant Removal and Antifouling in an Aerobic Ceramic Membrane Bioreactor with Bentonite for Pharmaceutical Wastewater Treatment.

This study examined the impact of adding bentonite clay (concentration of 1.5 to 10 g/L) to a pilot-scale aerobic ceramic membrane bioreactor (AeCMBR) for treating pharmaceutical wastewater (PhWW). The hydraulic retention time (HRT) was maintained at 24 h; the dissolved oxygen was between 2 mg/L (on) and 4 mg/L (off) throughout operation. Organic and nitrogen pollution removal rates and heavy metal (Cu, Ni, Pb, Zn) reduction rates were assessed. The chemical oxygen demand (COD) removal efficiency exceeded 82%. Adsorption improved ammonia (NH4+) removal to 78%; the addition of 5 g of bentonite resulted in a 38% improvement compared with the process without bentonite. The average nitrate concentration decreased from 169.69 mg/L to 43.72 mg/L. The average removal efficiencies for Cu, Ni, Pb and Zn were 86%, 68.52%, 46.90% and 56.76%, respectively. Bentonite at 5 g/L significantly reduced membrane fouling. The cost-benefit analysis enabled us to predict that the process will meet the multiple objectives of durability, treatment performance and economic viability. The combination of an AeCMBR and bentonite adsorption has proven to be a valuable solution for treating highly polluted wastewater.

Enhanced removal of lead ions from wastewaters by electrochemical adsorption using nitrogen-doped Ti3C2Tx MXene

As a two-dimensional material containing transition metal carbides and nitrides, MXene is often used in capacitive deionization for its excellent hydrophilic and pseudocapacitive properties. Nitrogen doping is widely used to improve the adsorption properties of certain materials. However, the effect of nitrogen doping on the electrochemical adsorption properties of MXene remains unclear. In this work, nitrogen-doped Ti3C2Tx MXene was synthesized using a simple hydrothermal method to achieve highly selective and efficient removal of Pb(II) at a constant cell voltage. The concentration of Pb(II) decreased from 4.95 to 0.02 mg L−1 in a 100 mg L−1 NaCl supporting electrolyte after electrosorption. The removal efficiency of Pb(II) reached 99.5%, whereas it was only 15.2% for Na+. The introduction of nitrogen functional groups increased the electrical conductivity and layer spacing of MXene, thereby improving the pseudocapacitive adsorption performance in the presence of Pb(II). The complexation function of the Ti-OH group on nitrogen-doped Ti3C2Tx surface increased and contributed to the selective adsorption of Pb(II). The removal efficiency of Pb(II) increased with increasing solution pH and cell voltage, reaching the maximum value at pH 5.0 and 1.5 V, respectively. The effect of supporting electrolyte type on the removal of Pb(II) was negligible. In addition, the removal efficiency for mixed heavy metal ion solutions, including Cu(II), Ni(II), and Pb(II), exceeded 79.0%. It exhibited the highest removal efficiency for Pb(II) at 97.9%. After five cycles of electrochemical adsorption–desorption, the nitrogen-doped Ti3C2Tx maintained a stable Pb(II) removal efficiency of 97.0%. This work provides a promising material for the electrochemical removal of low-concentration heavy metal ions from wastewaters.

Removal of lead and cadmium from aqueous solution by using cashew gum polysaccharide (Arabinogalactan) - Acrylamide hydrogel

There is an increasing need for clean water for human health and the environment, so the removal of toxic metals from wastewater with low-cost adsorbents plays an essential role. In this research, the synthesis of cashew gum (CG) polysaccharide (arabinogalactan)-acrylamide (Am) (CG-AM) hydrogel was carried out with three independent variables: Hydration ratio (ml/g), amount of monomer (acrylamide, Am) (g) and concentration of crosslinker (methylene-bisacrylamide, MBA) (%) by radical polymerisation. The removal efficiency of Pb2+ and Cd2+ from the stock solution of lead nitrate and cadmium sulphate by adsorption technique was also studied by optimisation using BBD of RSM. Furthermore, the functional and structural properties of all types of hydrogels were analysed by characterisation with FTIR, (XRD), (SEM) with EDS and swelling capacity analysis. An optimum hydrogel yield of 4.527 g was obtained at a hydration ratio of 10 ml/g, monomer amount of 2.5 g and crosslinker concentration of 3% w/v of one gram of extracted arabinogalactan. For Pb2+ removal, 86.985 % removal efficiency was obtained at a hydration ratio of 25 ml/g, monomer amount of 1g and crosslinker concentration of 1%, while for Cd2+ removal, 18.875 % removal efficiency was obtained at a hydration ratio of 10 ml/g, monomer amount of 4g and crosslinker concentration of 2%. (CG-AM)H Pb2+ had the highest swelling capacity of 11.072 g H2O/g polymer hydrogel but (CG-AM)H had the lowest of 5.322 g H2O/g polymer hydrogel due to crosslinking capacity. The FTIR result, the (CG-AM)H Pb2+ showed a significant peak of C-O stretching of the S-glycosidic bond of hydrogel to absorb the Pb2+ ions. From XRD and SEM results, (CG-AM)H Pb2+ showed an amorphous nature of hygroscopic properties and a three-dimensional network structure with open pores.

Plant-based synthesis of Selenium-doped Silver/Magnesium Oxide/Zinc Oxide nanocomposite using Mentha pulegium to investigate their photocatalytic and biological properties

In this study, the photocatalytic test and biological effects of Selenium-doped Silver/ Magnesium Oxide/ Zinc Oxide nanocomposite (Se-doped Ag/MgO/ZnO) have been studied. The samples were synthesized by a green method with Mentha pulegium plant extract and investigated by different analyses. The outcomes of X-ray and FESEM display crystal nature and flower-like morphology. According to the ICP results, the removal efficiency of Pb+2 ions was equal to 72 %. The photocatalytic test of the nanocomposite investigated to degradation of organic dyes, and the results show that the degradation percentage of RhB (Rhodamine B), EBT (Eriochrome Black T), MO (Methyl Orange), and MB (Methylene Blue) dyes were about 73 %, 96 %, 99 %, and 97 % respectively. Also, the toxicity of the Se-doped Ag/MgO/ZnO) was studied against the cancer B16F0 cell line and the IC50 value was reported as 269.6 μg/mL.

Adsorption of heavy metal ions by carbon-based adsorbent using magnetic nitrogen-doped carbon and graphene oxide

ABSTRACT The adsorption of weighty metal particles from contaminated water sources has garnered significant attention due to its critical role in environmental remediation and ensuring safe drinking water. Heavy metal ions can be removed from water using conventional adsorbents such as activated zeolites; however, these materials have low absorption and slow kinetics. To solve these issues, carbon-based adsorbents that exhibit easy synthesis, high porosity, design ability, and stability have been proposed. In this review, a carbon-based adsorbent, named M-NC, and graphene oxide were created for the particular evacuation of weighty metal particles. To increase the potential for Heavy Metals (HM) immobilization, sulfide-modified biochar was created via a process called synchronous carbon layer epitome. A hypothetical physicochemical and thermodynamic examination of the adsorption of weighty metals Zn2+, Cd2+, Ni2+, Ag2+, Pb2+ and Cu2+ on carbon-based adsorbents was done with factual material science fundaments. The biochar with large surface areas is utilized to eliminate weighty metal particles, quite possibly the most significant heavy metal pollutants, from aqueous solutions. The limit of the adsorbent for eliminating weighty metal ions was concentrated on utilizing Langmuir adsorption isotherm under ultrasound-helped conditions. The Mesoporous Silica Nanoparticles (MNCs) can be applied to the Langmuir model and pseudo-second-order kinetics. It is possible to use the Langmuir and second-order kinetic equations to accurately explain the adsorption method. Thermodynamic limitations were also envisioned because sorption is exothermic when it happens spontaneously. A homogeneous measurable physical science adsorption typically was utilized to describe and analyze the experimental heavy metal removal isotherms at 30°C and pH5 utilizing adsorbents produced by pyrolysis of biomasses (broccoli stalks). The experimental results were investigated in terms of Langmuir and pseudo-2nd-order kinetic equations, Freundlich and isotherm models. The outcome of pH, initial heavy metal ion concentration, contact time, and adsorbent dosage regarding the adsorption capacity and removal efficiency of Pb2+ and Cd2+ on the hydrogel was examined. This study contributes to the advancement of information in the ground of environmentally friendly heavy metal removal techniques, specifically focusing on the usage of biomass-based adsorbents. These findings have the potential to address the need for effective solutions in water purification and environmental cleanup efforts.

Biosorption of pb(II) from aqueous solution by citrus reticulate: adsorption studies, and modeling

Removing toxic Pb(II) ions from aqueous solution by the peels of citrus reticulate (mandarin orange), a fruit industry waste, presents suitable scale-up possibilities. The Scanning Electron Microscope (SEM) and Brunauer-Emmett-Teller (BET) studies reflected that the mandarin orange peel powder had a porous surface area (32.46 m2g−1), average pore size and pore volume was 38.6 Å and 0.402 cm3g−1, respectively, favorable for binding Pb(II) ions. Fourier-transform infrared spectroscopy (FTIR) showed C-Br stretching, primary alcohol (C-O), phenolic O-H, and carbodimide N = C = N bands primarily helped to bind Pb(II) ions. The study evaluated and optimized the parametric influences of pH, adsorbate and biosorbent concentration, contact time and temperature on the removal efficiency of Pb(II) ions. A maximum of 97.08% Pb(II) was removed from 20 mg L−1 solution when 2.5 g L−1 adsorbent was present. The reaction obeyed the pseudo-second-order kinetic model. The intra-particle diffusion was involved in lead sorption. The Langmuir isotherm model resulted in an adsorption capacity of 23.04 mg g−1. 35.28% Pb(II) was removed in the 3rd adsorption-desorption cycle with 0.4 M HCl. The adsorption process was natural, impulsive and endothermic. The statistical investigation used Multiple Polynomial Regression (MPR) and Genetic Algorithm (GA). The analysis effectively forecasted the percentage removal at the optimized condition.

Removal of lead in water by potassium hydroxide-activated biochar developed from Syzygium cumini stem

Lead (Pb) contamination in water poses a significant threat to public health across the globe which requires effective remediation strategies. The main objective of this study is to achieve a removal efficiency of Pb(II) ions from aqueous media using activated Syzygium cumini (java plum) stem biochar. It was prepared by slow pyrolysis at 400 °C after treating the biomass with potassium hydroxide for activation. These biochars were characterized thoroughly (SEM, SEM–EDX, TEM, FTIR, XRD, elemental analyses, and SBET) to conduct a set of batch experiments. The effect of several parameters such as pH, temperature, contact time, adsorbent dosage, initial lead concentrations, and co-existing ions were explored. The decrease in starting lead concentrations from 50 to 10 mg L−1 resulted in improved removal efficiency. The removal effectiveness of activated biochar was 97%, but non-activated biochar was just 19%. Lead adsorption increased considerably as pH increased from 3 to 5. Further, the activated biochar was optimized through various isotherms models, kinetic equations, and thermodynamic analysis. It was observed that the pseudo-second-order kinetic model and Temkin isotherms were the best-fitted models that identify the mechanism of chemisorption and monolayer sorption. According to this study, activated biochar is a promising biosorbent for removing lead from an aqueous solution.Graphical

A highly efficient adsorbent adapting to low pH condition for Pb(II) sequestration from aqueous solution − marine diatom: Laboratory and pilot scale tests

Highly efficient, economically feasible and environmentally friendly adsorbents have been a research hotspot for heavy metal sequestration. In the present study, dried marine diatom biomass (mainly composed of Chaetoceros sp.), which possessed high suface area and cumulative pore volume of 5.72 m2/g and 0.028 cm3/g, respectivly, were used to adsorb Pb(II) from aqueous solution. The immoblized marine diatom beads and an adsorption reactor filled with the beads were further investigated for continuous Pb(II) removal. The removal efficiency was evaluated as a function of contact time, initial concentration, pH and co-existing cations. Results indicated that the dried diatom biomass and the immobilized diatom beads effectively adsorbed Pb(II) under pH > 3.0 and pH > 4 0.0 conditions, respectively. The optimal conditions for the immobilized diatom beads preparation were: diatom powder dosage of 5.0 g / 100 mL sodium alginate solution, sodium alginate concentration of 20 g/L, CaCl2 concentration of 2 %, and cross linking time of 1 h. The Pb(II) adsorption on the marine diatom biomass and the immobilized beads were both well described by pseudo-second-order kinetic and Langmuir model. The maximumPb(II) adsorption capacities of the immobilized beads were 919.1 mg/g, which were much higher than that of the most of adsorbents reported elsewhere. Adsorption mechanism analysis demonstrated that Pb(II) was adsorbed onto the diatom biomass mainly through interaction with nitrogen bonds (mainly with pyrrolic nitrogen) and carboxylic groups, and ion exchange with light metals and hydrogen ions in quaternary nitrogen bonds. The diatom beads were used as adsorbents in a continuous Pb(II) treatment reactor, and the Pb(II) removal efficiency of the reactor reached to almost 100 % from the initial concentration of Pb(II) = 50 mg/L.

RSM versus ANN for modeling and optimization of magnetic adsorbent based on montmorillonite and CoFe2O4

A highly resourceful, environmentally benign, and recyclable magnetic montmorillonite composite (MMT/CF) was obtained through a simple one-step hydrothermal method and exhibited excellent Pb (II) removal. The as-synthesized adsorbent was then characterized by XRD, SEM–EDX, FTIR, BET, and TGA-DTA. The operating parameters including adsorbent dosage, initial Pb (II) concentration, solution pH, and time were studied. Also, a comparative approach was formed between response surface methodology (RSM) and artificial neural network (ANN) to optimize and model the removal efficiency of Pb (II) by MMT/CF. The results indicated that the ANN model was more precise and quite trusted optimization tool than RSM in consideration of its higher correlation coefficient (R2 = 0.998) and lower prediction errors (RMSE = 0.851 and ADD = 0.505). Langmuir isotherm provided the best fit to the experimental data, and the maximum adsorption capacity was 101.01 mg/g. Additionally, the kinetic studies showed that the pseudo-second-order model fitted well with the experimental data. The magnetic MMT/CF composite possesses high adsorption capacity and is suitable for reuse. Therefore, this study shows that MMT/CF composite can be a potential adsorbent in Pb (II) uptake from aqueous media.

Enhanced removal of Pb(II) from acid mine drainage using green reduced graphene oxide/silver nanoparticles

Mining activities can potentially release high levels of Pb(II) in acid mine drainage (AMD), which thereafter poses a significant threat to ecological security. In this study, green reduced graphene oxide/silver nanoparticles (rGO/Ag NPs) were successfully synthesized via a one-step approach using a green tea extract and subsequently used as a cost-effective absorbent to remove Pb(II) from AMD. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy indicated that organic functional groups in the green tea extracts, such as C=O-C, CO, and CC, acted both as reductants and stabilizers in the synthesis of rGO/Ag NPs. In addition, the removal efficiency of Pb(II) by rGO/Ag NPs (84.2 %) was much better than either rGO (75.4 %) or Ag NPs (12.3 %) alone. Also, in real AMD, the distribution coefficient (Kd) of Pb(II) (4528 mL/g), was much higher than other heavy metal indicating the adsorbent had a high selective affinity for Pb(II). Interestingly, after five cycles of use, the removal efficiency of Pb(II) by rGO/Ag NPs from AMD actually increased from 46.4 to 65.2 % due to iron oxides (i.e., Fe2O3 and Fe3O4) being generated when rGO/Ag NPs was exposed to AMD. The removal of Pb(II) via adsorption on the rGO/Ag NPs surface involved formation of hexagonal rod-like precipitates. This work demonstrated the potential of rGO/Ag NPs to be continuously used for the removal of Pb(II) from AMD.

Assessing the Lead Removal Potential of Pineapple Waste Hydrochar in Simulated Wastewater Treatment

This study explores the viability of utilizing biochar and hydrochar derived from pineapple waste as adsorbents for removing lead (Pb) from water. Pineapple residues, including stems, leaves, and fruit, were subjected to pyrolysis and Hydrothermal Treatment to produce biochar (PWB) and hydrochar (PWH) respectively. Fourier Transform Infrared (FT-IR) analysis was employed to characterize the surface properties of PWB and PWH, validating their potential as adsorbents. A series of adsorption experiments assessed the impact of pH (ranging from 2 to 6), contact time (ranging from 15 to 90 minutes), and temperature (ranging from 30 to 90°C) on the adsorption efficiency of both materials. Results indicate PWH to be markedly more effective, with an average Pb removal efficiency of 84.07% compared to PWB's 55.68%. The optimal contact time was determined to be 60 minutes for both materials. Moreover, pH 4.0 was identified as the optimal condition for Pb adsorption, showcasing a significant increase in biosorption capacity within this pH range. Additionally, higher temperatures corresponded to enhanced Pb2+ removal efficiency, rising from 75.02% to 87.58% as temperature increased from 30°C to 90°C. Overall, these findings underscore the potential of pineapple waste-derived biochar and hydrochar as promising, environmentally friendly adsorbents for addressing heavy metal contamination in water, particularly in wastewater treatment applications.

Self-powered sodium borohydride alkaline fuel cell for efficient removal of lead(II) and copper(II)

Heavy metals in industrial wastewater cause serious environmental pollution and they are easy to accumulate and difficult to degrade. Copper and lead are two typical heavy metals, and it is of great significance to remove them at the same time. This work shows a strategy of reducing and removing Pb(II) and Cu(II) by self-powered non-biological fuel cell (SP-nBFC) with dual-chamber reactor. Therein, sodium borohydride in alkaline solution as fuel (electron donor) was electrooxidized on nicke1 foam (NF) at anode and Pb(II) and Cu(II) ions (electron acceptors) in strong acidic solution were electro-reduced at Bi/MXene/GP cathode (bismuth nanoparticles and MXene modified graphite paper (GP)).Additionally, a proton exchange membrane, Nafion, was introduced into form complete circuit by offering ions channel. The results showed that Cu(II) and Pb(II) were reduced to Cu and Pb, and the SP-nBFC could produce electricity in this process without external energy consumption. The Bi/MXene/GP cathode could increase significantly removal efficiencies of Cu(II) and Pb(II), which were higher than about 37.0 %, 22.5 % for Cu(II) and 25.7 %, 16.3 % for Pb(II) than those of GP and MXene/GP cathode. This system could obtain a high Cu(II) removal efficiency (RE, 99.3 %) and moderate Pb(II) RE of 56.8 %, and acquire Cu and Pb sediments in cathode chamber. Furthermore, the proposed system could generate 923 mV of maximum potential and 1420 mW/m2 of maximum power density in 48 h. Thus, this SP-nBFC system provides a viable method for treatment of Cu(II) and Pb(II) pollution and generating electricity simultaneously, and also has prospective approach for other heavy metals remediation.

Characterization Analysis of Mudstone and Study of Its Pb (II) Adsorption Characteristics in Polluted Water Bodies

In order to explore a medium material for the efficient treatment of Pb(II) pollutants in groundwater, in this paper, mudstone is selected as the medium material, and the morphological structure of the mudstone is characterizes via X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analyses to study the feasibility of the mudstone adsorbing Pb(II) ions. Then, static adsorption experiments are carried out to investigate the removal effect of mudstone on Pb(II) in aqueous solutions under different conditions and to determine the optimal adsorption conditions. Finally, the results are fitted and analyzed using a thermodynamic model to explore the adsorption mechanism of the mudstone. The main results of this study are as follows. The main mineral composition of the mudstone used in the experiments includes CaCO3, SiO2, CaAl2O4·10H2O, and CaFe4O7. The specific surface area of the mudstone is as high as 23.027 m2·g−1, the pore size is 9.145 nm, and its surface structure is rough, with pores and fissures developed. The pore space and adsorption capacity of the mudstone were enhanced. When 1 g·L−1 of mudstone was added, the pH value of the solution was 6, the reaction time was 60 min, and the initial concentration of Pb(II) was 30 mg·L−1. The removal efficiency of Pb reached 84.5%, and the adsorption amount was 25.352 mg·g−1. For the removal of Pb(II) from the aqueous solution by the mudstone under different concentrations of Pb(II), the reaction was in accordance with the Langmuir adsorption isotherm model, and the maximum adsorption amount reached 54.975 mg·g−1. The relationship between the removal of Pb(II) and the reaction time was in accordance with the pseudo-second-order rate model. The results of this study suggest that mudstone can be used for the removal of Pb(II) from aqueous media.