Pb Sorption Research Articles

Facile preparation of magnetic Zr-MOF for adsorption of Pb(II) and Cr(VI) from water: Adsorption characteristics and mechanisms

A novel magnetic Zr-MOF named Ni0.6Fe2.4O4-UiO-66-PEI was synthesized by modifying UiO-66-NH2 with Ni0.6Fe2.4O4 and polyethyleneimine and its sorption characteristics for two representing heavy metals Pb(II) and Cr(VI) in water were examined. This material showed good thermal stability and was sufficiently magnetic to allow effective solid-liquid separation. The material had a maximum adsorption capacity of 273.2 mg/g for Pb(II) at pH 4.0 and 428.6 mg/g for Cr(VI) at pH 3.0, as obtained from the model fitting by the Hill equation. The sorption kinetics for both heavy metals on the material was fast, with adsorption equilibrium established in 60 min and 30 min for Pb(II) and Cr(VI), respectively. Model fitting of the kinetic data showed that Pb(II) and Cr(VI) sorption on Ni0.6Fe2.4O4-UiO-66-PEI followed the pseudo-second-order model. This material had good selectivity for competing ions, and still hold fairly good binding capacities after 5 times of regeneration. Adsorption mechanisms for Pb(II) and Cr(VI) by Ni0.6Fe2.4O4-UiO-66-PEI were proposed by analyzing FTIR, XPS and the electrokinetic property of the material. Specifically, Pb(II) adsorption on Ni0.6Fe2.4O4-UiO-66-PEI could be attributed to chelation of Pb(II) with the imine/amine functional groups in the material’s matrix, while Cr(VI) adsorption might stem from a combination of electrostatic attraction, chelation and redox reaction. It seems that Ni0.6Fe2.4O4-UiO-66-PEI could be used as a green and environmental-friendly material for heavy metals removal, particularly from acidic water streams.

Adsorption Characteristics of Cd and Pb on Microplastic Films Generated in Agricultural Environment

Objectives:Plastics are widely used in daily life and in various industrial fields due to their convenience and thermal insulation, and the use of plastics is continuing to increase. In agricultural environments, plastics are largely used for vinyl houses and mulching vinyl. Used plastics are degraded into small fragments through physical, chemical, and biological processes. Among these, plastics with a particle size of 5 mm or less are defined as microplastics. Since microplastics have a relatively large surface area, various pollutants including heavy metals can potentially be adsorbed and affect the agricultural ecosystem. The purpose of this study is to evaluate the Pb and Cd adsorption characteristics on microplastic films frequently generated in agricultural environments.Methods:The Pb and Cd adsorption characteristics on microplastic films were studied with 3 different plastic films. Microplastic samples were prepared by cutting PVC (polyvinyl chloride) and PE (polyethylene) films to have the sizes of < 5 mm×5 mm. The prepared microplastic samples were placed in Pb or Cd solutions having a range of concentrations and shaken for 72 h for sorption tests. The experimental results were fitted to the Langmuir, Freundlich, and Temkin isothermal adsorption models.Results and Discussion:The isothermal adsorption test results obtained fitted well to the Langmuir and Freundlich models (R<sup>2</sup>>0.9), but not the Temkin model. Regardless of the plastic type, the values of Langmuir constant (KL) and Temkin constant (AT) for Pb were larger than those for Cd, and the Freundlich constant (nF) showed a tendency of Pb>Cd>1, indicating the greater Pb sorption strength or affinity than Cd on PVC and PE.Conclusions:This study shows that the microplastics in soil adsorb heavy metals like Cd and Pb affecting the heavy metal fate in the soil environment. With an increasing attention on the environmental problems due to plastic wastes, this study provides the basis for the need of management of soil environment. Therefore, further research on microplastics in soil environment is required.

Lead (Pb) sorption and co-precipitation on natural sulfide, sulfate and oxide minerals under environmental conditions

Even low levels of lead (Pb) contamination result in significant disruption to the surrounding ecology as Pb accumulates in soils and water and can be taken up by plants, which are then consumed by higher order animals. Understanding how Pb partitions between solids and the aqueous phase underpins prediction of bioavailability and locales of high toxicity, and the development of effective treatment options. This paper aims to unify our empirical understanding of the interaction between Pb(aq) and various common minerals associated with many large sulfide ore-bodies mined for their base- and precious metal contents, by measuring the sorption of Pb onto hematite (Fe2O3), pyrite (FeS2), chalcopyrite (CuFeS2), bornite (Cu5FeS4) and barite (BaSO4) as a function of solution pH and Pb(aq) concentration. In general, all minerals displayed a linear relation on a log–log plot of sorbed portion versus Pb concentration in the coexisting solution (Freundlich isotherm) over a wide range of Pb concentrations at pH 6. Hematite had two different domains (dual Freundlich behaviour), with Pb(aq) showing higher affinity for sorption at low Pb(aq) concentrations compared to high Pb(aq) concentrations. For the sulfide minerals (pyrite, chalcopyrite, bornite), Pb sorption/precipitation on the oxidised surface is favoured at low pH, while Pb sorption to Fe(oxyhydr)oxide and/or co-precipitation as anglesite is favoured at high pH. Isotherm modelling highlights the dual roles of Pb(aq) concentration and pH in controlling Pb scavenging in these natural minerals, and it is important to consider these parameters when predicting the Pb-geochemical cycle and its dynamic uptake in natural and engineered systems.

Ultratrace determination of metal ions using graphene oxide/carbon nanotubes loaded cellulose membranes and total-reflection X-ray fluorescence spectrometry: A green chemistry approach

In this paper, the determination of ultratrace heavy metal ions was developed by combining a preconcentration method using graphene oxide/carbon nanotubes membranes (GO/CNTs) and total-reflection X-ray fluorescence spectrometry (TXRF). Due to the excellent adsorptive properties of the GO, the foregoing membranes are suitable for effective simultaneous sorption of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) from aqueous solutions. In this method, the aqueous solution is passed through the GO/CNTs membrane. The analytes are eluted from the GO and afterward transferred onto a siliconized quartz reflector for further TXRF analysis using W and Mo target X-ray tubes. The maximum recoveries for all the elements were obtained at pH 5; thus it was chosen for all further experiments. The face centered central composite design was performed to study the influence of the flow-rate and volume of the solution on the recovery of the determined metal ions. Recovery values higher than 96% for all studied metals allow performing efficient preconcentration with an enrichment factor of 133, achieving the limits of detection (LODs) in the range of 0.08–0.21 ng mL−1 for W target X-ray tube with a measurement time of 2000 s, and much lower LODs for Mo target X-ray tube: 0.001–0.002 ng mL−1 with the exception for Cd (0.11 ng mL−1) with a very short measurement time of 600 s. Certified reference materials of spring water and seawater were examined to verify the reliability of the method. The evaluated procedure does not require toxic reagents or organic solvents, thus minimizes the portion of the sample for TXRF measurement, and stands in good accordance with green analytical chemistry basic principles.

Sorption of Pb(Ii) Onto Biochar is Enhanced Through Co-Sorption of Dissolved Organic Matter

Sorption of Pb(Ii) Onto Biochar is Enhanced Through Co-Sorption of Dissolved Organic Matter

Sorption of Cd(II), Cr(VI), Ni(II) and Pb(II) Onto Unmodified Sludge from a Pond Treating Woolen Processing Industry Wastewater

Sorption of Cd(II), Cr(VI), Ni(II) and Pb(II) Onto Unmodified Sludge from a Pond Treating Woolen Processing Industry Wastewater

Application of chitosan for the removal of heavy metals from drilling fluids wastewaters

The purpose of this study was to present a possibility of application of chitosan, covalently cross-linked by treating with glutaraldehyde as an effective sorbent of heavy metals ions from drilling wastewaters. The influence of the concentration and pH on the sorption capacity of the modified chitosan was determined in relation to Cr(II), Zn(II), Pb(II) and Cd(II) ions. Sorption parameters were defined. The greatest affinity to the modified chitosan was observed from ions of Zn(II), Pb(II). The effectiveness of the studied process is pH-depended. Processes of sorption of Cr(II), Zn(II), Pb(II) and Cd(II) ions in the presence of cross-linked with glutaraldehyde chitosan are well-described by Langmuir and Freundlich isotherms, which may be confirmed by high values of correlation coefficients (R>0.91). High values of the maximal sorption capacity (q0) have been reached for zinc ions (q0=3.67 mg/g) and lead ions (q0=3.31 mg/g), calculated on the basis of Langmuir isotherm equation which proves their great affinity to chitosan cross-linked with glutaraldehyde. Obtained results confirm good sorption properties of cross-linked chitosan towards heavy metals and a possibility of application of this sorbent in a wide range of the pH. Even small doses of sorbent, such as 5 g/L, facilitate the effective reduction of Cd, Cr, Pb, Zn content in drilling wastewaters, even from 75 to 90 %. Application of chitosan may be one of alternative and all the same effective methods leading to reduction of the inconvenience of fluid drilling waste.

Synthesis of Polyaminophosphonated-Functionalized Hydrochar for Efficient Sorption of Pb(II)

Synthesis of Polyaminophosphonated-Functionalized Hydrochar for Efficient Sorption of Pb(II)

Application of diatomite for sorption of Pb, Cu, Cd and Zn from aqueous solutions: kinetic, thermodynamic studies and application of response surface methodology (RSM).

Contamination of water and soil with toxic metals is a serious environmental issue. To study the Pb, Cu, Cd, and Zn sorption behavior by diatomite, batch experiments were carried out with increasing levels of initial concentration (0-200mg/L) under different contact times (0-360min) and temperatures (283, 293, 303, and 313K). The effects of concentration (0-200mg/L), pH (3-6), and ionic strength (0.01-0.06mol/L) on the sorption were modeled using response surface methodology (RSM). Results showed that adsorption data were well-fitted by the Langmuir equation. The sorption of metals intensified by increasing initial concentration and pH but ionic strength had inverse effect. High value for R2 (0.99) and adjusted R2 (0.99) showed that the removal of ions can be described by response surface method. One-way ANOVA showed (p-value<0.0001) that quadratic model is the best model for determining the interaction of variables. The values of the sorption energy parameter from Dubinin-Radushkevich model (E<8kJK-1 mol-1 ) and negative values of ∆G showed that the sorption of the metals was physical and spontaneous. The positive values of enthalpy (ΔH) indicated that the sorption reaction of metals was endothermic at 283-313K. PRACTITIONER POINTS: Applications of diatomite increased the sorption of Pb, Cd, Zn, and Cu from aqueous solutions. Diatomite, as low-cost adsorbent, had significant potential to sorption of ions. The sorption of heavy metals by adsorbent intensified by increasing initial concentration and pH but ionic strength had inverse effect. High value for R2 (0.99) and adj-R2 (0.99) showed that removal of metals can be described by response surface method (RSM) and the initial concentration of metal was the most significant factor.

Zero valent nickel nanoparticles decorated polyaniline nanotubes for the efficient removal of Pb(II) from aqueous solution: Synthesis, characterization and mechanism investigation

Zero valent nickel nanoparticles (Ni0 NPs) have exhibited potential applicability in various fields including, chemical cells, fuel cells and catalysis. Alike zero valent iron NPs, Ni0 NPs and their composite nanostructures would have great prospect in remediating heavy metal pollutants from water bodies. To establish this fact composite nanotubes (CNs) of naphthalene sulfonic acid doped polyaniline (PANI-NSA) and Ni0 NPs ([email protected]0 CNs) were synthesized by immobilization of Ni0 NPs onto the PANI-NSA surface and effectively used for the removal of Pb(II) ions from aqueous solution. Morphological and structural characterization established that aggregation of ferromagnetic Ni0 NPs was greatly diminished by immobilization onto the matrix of PANI-NSA. Improved specific surface area and greater reactivity of the [email protected]0 CNs enabled superior removal performance towards Pb(II) ions in comparison with its constituents. The highest removal efficiency (90.9%) was observed using 0.5 g/L CNs at pH 5.0. Pb(II) sorption kinetics was very rapid and equilibrium was reached within 30–90 min for 50–150 mg/L concentrations at pH 5.0. The Langmuir isotherm model provided the best description of the isotherm data, with a deduced maximum Pb(II) removal capacity of 414.6 mg/g at 25 °C. Thermodynamic analysis revealed exothermic and spontaneous adsorption onto the adsorbent surface. Co-existing heavy metal ions had slight impacts on Pb(II) removal performance of the [email protected]0 with associated implications for the treatment of industrial wastewater. XRD and XPS analyses allude that Pb(II) adsorption onto deprotonated surface sites followed by reduction to Pb0 were the leading removal mechanism associated with the current CNs structure.

Clay-assisted protection of Enterobacter sp. from Pb (II) stress

Clay minerals can adsorb both microorganisms and heavy metals. In this study, typical soil bacterium, Enterobacter sp. was applied to investigate the potential protection of the bacterial cells from Pb2+ stress by clay minerals. The sorption by two representative types of montmorillonite (Mt) were contrasted, i.e., Mts/Mtw with strong/weak CEC. There was no significant difference between the two clay minerals regarding their adsorption of Pb2+ cations in water (i.e., ~55 mg L-1). However, the sorption of bacterial cells on the two clay minerals showed evident contrasts, which resulted in the different capacity of Pb sorption. Mts with high CEC preferentially adsorbed abundant bacterial cells (rather than Pb2+) on its surface. The residual Pb2+ concentration in solution actually raised by 7.5% after the addition of Enterobacter sp. In addition, both the Pb-contaminated cells and “healthy” cells (with low Pb contamination) could be adsorbed onto Mt surface, whereas the latter dominated the adsorbents on Mts. This was due to that the Mts with high CEC could provide more exchangeable cations, building more cation bridging ligands between the microbial cells (whatever the types of cells) and clay surface. Furthermore, the adsorbed “healthy” bacterial cells might escape from clay surface via “self-liberating” mechanism, i.e., increasing electrostatic repulsion between the bacteria and clay during microbial decomposition of the medium. This study hence elucidated the protection of microorganisms from Pb2+ stress by Mt.

Calligonum Crinitum as a Novel Sorbent for Sorption of Pb(II) from Aqueous Solutions: Thermodynamics, Kinetics, and Isotherms

Calligonum crinitum, a desert plant, was used as a natural adsorbent for the removal of Pb(II) ions from aqueous solutions. The sorption capacity of the sorbent was investigated through batch adsorption, as a function of contact time, metal ion concentration, and pH. The surface chemistry of the sorbent was probed using Fourier transform infrared spectroscopy, allowing an understanding of the key functionalities involved in binding the Pb(II) ions to the sorbent. Textural characteristics, including surface area and pore volume, showed higher surface areas relative to other natural adsorbents previously reported. Surface morphological analysis, observed via Scanning Electron Microscopy images and Energy-Dispersive X-Ray analysis, confirmed adsorption of Pb(II) ions, up to 71% on the surface of calligonum crinitum. Isothermal analysis, using Langmuir, Freundlich and Temkin models with nonlinear regression, showedthe Langmuir model to best represent adsorption within this system, yielding a maximum adsorption capacity of 337 mg g−1 (pH 5.5, 30 °C). The optimum conditions of adsorption was pH, 5.5; adsorbent concentration, 0.3 g/l, contact time, 20 min at 30 °C. The Freundlich constant of < 10 indicates that adsorption of Pb(II) ions is favourable onto calligonum crinitum. Adsorption kinetics were modelled using pseudo-first-order, pseudo-second-order and intra-particle diffusion models; the results indicate that the kinetics are pseudo-second-order, suggesting a degree of chemical influence in the adsorption process. While thermodynamic analysis shows the process to be exothermic in nature with an ordering of solute within the adsorption process. Calligonum crinitum has, therefore, been proven as an effective sorbent for the removal of Pb(II) ions from aqueous solutions, with potential in water remediation processes.

Removal of Lead Ions from Waste Water Using Modified Jordanian Zeolite

In this study a Jordanian Zeolite was modified using anionic surfactant which is sodium dodecyl sulfate (sodium dodecyl sulfate). The sorption of Pb(II) from synthetic wastewater by surfactant modified Zeolite (SMZ) was investigated as a function of temperature. The experimental data was analysed using isotherm models namely Langmuir, Freundlich, Redlich-Peterson and Temkin and kinetic models such as the pseudo- second-order, intraparticle diffusion and the Elovich models in order to understand the mechanism of the interaction between this SMZ and the lead ions. All the isotherm models showed good correlation with the experimental results but Freundlich was the best. The calculated DH was obtained using Langmuir constant (aL), its value of 8.29kJ/mol revealed that the type of sorption is physical oneThe values of RL at all temperatures reflect the favorability of this interaction. The calculated activation energy was 21.126 kJ/mol using the pseudo-second order constant (k2), which indicates that the sorption is physisorption. The intraparticle diffusion model showed multilinearity which means multiple stages there occurred to achieve the removal of lead ions, the first linear curve is due to the boundary layer diffusion and the second linear curve isfor the intraparticle diffusion effect. The adsorption kinetics data fitted also Elovich model.

Potassium phosphate/magnesium oxide modified biochars: Interfacial chemical behaviours and Pb binding performance

Removal of lead (Pb) from aqueous solutions by biochar is a promising method. In this study, wheat straw biochar (WBC) was modified by phosphate/magnesium via pre-treatment of biomass and post-treatment of biochar, noting as WBC_PMA and WBC_PMB, respectively. Based on Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses, phosphate/magnesium chemically bound to the structures of biochar surface, increasing the contents of polar groups (i.e., -COOH and -OH) and phosphorus-containing compounds, mainly Mg3(PO4)2 and Mg2P2O7. Owing to pyrolysis process enhancing loading ability of phosphate/magnesium, WBC_PMA possessed more active functional groups than WBC_PMB. Results showed that maximum sorption capacity of Pb was improved by modifications, following the sequence of WBC_PMA (470.09 mg/g) > WBC_PMB (308.39 mg/g) > WBC (59.93 mg/g). Pseudo-second-order kinetics and thermodynamics study indicated that chemisorption was involved in sorption process. Precipitation, complexation and cation exchange dominated Pb sorption and the corresponding contributions accounted for 17.89–32.73%, 28.84–46.22%, and 21.05–53.27%, respectively. Additionally, desorption characteristics of Pb illustrated that WBC_PMA owned more prominent stabilization ability than that of WBC and WBC_PMB. The findings of this study suggested that pre-modification method increased the contents of active groups in biochar and strengthened the removal efficiency of Pb ultimately. Due to the complexity of the actual Pb-containing wastewater environment, it was necessary to evaluate the effects of various factors on the stabilization performance of the pre-modified biochar in further.

The relationship between properties of plant-based biochars and sorption of Cd(II), Pb(II) and Zn(II) in soil model systems

Plant based biochars are proposed as soil amendments to immobilize potentially toxic trace elements (PTEs), such as Cd(II), Pb(II) and Zn(II) and aid in soil restoration. However, the sorption capacity of biochar for these elements can vary widely depending on biochar nature and metal properties. Currently, there is no clear methodology to pre-screen biochars for their suitability as adsorbents for these elements. Therefore, to facilitate biochar selection for application in soil restoration, this study explored the relationships between the physico-chemical properties of five plant-based biochars and their capacity to immobilize Cd(II), Pb(II) and Zn(II). Batch experiments using synthetic soil pore water were used to assess the sorption of these elements. The sorption isotherms described by the Hill model indicated that PTE sorption capacity followed the order Pb(II) > Cd(II) >Zn(II) regardless of biochar type in mono-element systems. Preferential sorption of Pb(II) limited the immobilization of Cd(II) and Zn(II) in multi-element systems. ATR-FTIR and SEM-EDX spectroscopy studies indicated that Cd(II) and Pb(II) sorption was mediated by complexation with carboxylic groups, cation–π interactions and precipitation with phosphates and silicates, while Zn(II) sorption occurred mainly by complexation with phenolic groups and precipitation with phosphates. A high correlation (>0.8) between Electrical Conductivity, Cation Exchange Capacity, pH and sorption capacity was identified for all metals tested, highlighting the electrostatic nature of the sorption mechanisms involved. Biochars derived from herbaceous feedstock were better candidates for remediation of soil polluted with Cd(II), Pb(II) and Zn(II), rather than wood-derived biochar. Overall, this study provides evidence of the direct relationship between specific properties of plant-based biochars (pH and EC) and their suitability as adsorbents for some PTEs in soil systems.

Wood vinegar enhances humic acid-based remediation material to solidify Pb(II) for metal-contaminated soil.

Heavy metal lead is a typical widespread potentially toxic element (PET) contamination due to their extensive and wide applications in industrial processes. The development of cost-effective methods for preventing potentially toxic element lead residues from soil into food is thus highly desirable. A new type of humic acid-based remediation material (HA/WV) incorporating humic acid salt (HA), biochar powder (BC), and wood vinegar (WV), which is a cheap and environmentally friendly industrial by-product from charcoal processing, was prepared and evaluated. The results showed that 0.10 g remediation material HA/WV with a mass ratio of 1:1 was added to 1 kg surface soil of 0-20 cm from agricultural land contaminated by 300 mg Pb2+, the reduction ratio of available Pb in soil can reach 61.4%. Especially, wood vinegar can enhance the reduction ratio of available Pb by at least 14.7% over without wood vinegar. Furthermore, according to the analysis of adsorption interaction and the electrostatic attraction between Pb(II) and oxygen-containing functional groups on HA/WV are the dominant mechanisms responsible for Pb(II) sorption. The wood vinegar liquid can improve the oxygen-containing group in HA/WV, which can enhance the complexation of remediation materials and Pb(II) ion.

Comparative analysis of kinetics and mechanisms for Pb(II) sorption onto three kinds of microplastics

Microplastics (MPs), a kind of novel contaminant, have potential to concentrate and transport heavy metals in the aquatic environment. This feature may affect the distribution and bioavailability of heavy metals. In order to determine the sorption behaviors of heavy metals onto the MPs, the sorption kinetics and mechanisms were investigated between the MPs (polyvinylchloride PVC, polyethylene PE, polystyrene PS) and Pb(II). The results suggested that the Pb(II) sorption onto the MPs were pH- and ionic strength-dependent. The sorption processes were best fitted by the pseudo-second-order model, and the rate-limiting steps were the intraparticle diffusion and final equilibrium process. The maximum sorption capacities of PVC, PE and PS were 483.1 μg/g, 416.7 μg/g and 128.5 μg/g under the condition of 0.01 M NaCl, pH 6.0, T = 298 K. The sorption rate constants were in the following order: PVC<PE<PS. According to the Fourier transformed infrared and X-ray photoelectron spectroscopy, no new bonds were formed between the MPs and Pb(II). Physisorption was the main driven force for Pb(II) sorption. In summary, the investigation reveals the Pb(II) sorption kinetics and mechanisms onto the MPs, which will improve the understanding of the interactions between the MPs and heavy metals.

The dynamic uptake of lead and its radionuclides by natural and synthetic aluminium-phosphate-sulfates

The ability of aluminium-phosphate-sulfate (APS) phases to preferentially sorb lead and its radionuclides, particularly 210Pb, from metallurgical processing streams has been recently recognised empirically. This suggests that APS minerals may be suitable for the removal of lead from environmental and anthropogenic processes. We investigated the Pb sorption capabilities of APS with different Ca:Sr and SO4:PO4 ratios over a range of aqueous Pb concentrations (10–1000 ppm) and pH (1.5–5.5) typical of metallurgical processes and acid drainage conditions. Through a combination of characterization techniques including electron probe microanalysis, (laser ablation-) inductively coupled plasma mass spectrometry and X-ray absorption spectroscopy, we confirm the rapid (< 8 h) incorporation of Pb into the crystal lattice of APS phases. We also provide a mechanistic pathway for the sorption mechanism, with Pb sorption favoured at pH 3.5–5.5 via the direct replacement of lattice-bound Ca by Pb within the APS crystal structure. The observed Pb-incorporation dynamics of APS minerals, along with their insolubility and high thermodynamic stabilities, support the use of APS minerals as a novel agent for the uptake of Pb, radiogenic and nonradiogenic, from process-, surface-, and groundwaters. Since Pb quickly enters the crystal structure of environmentally stable APS minerals, these phases have much potential for long-term storage of Pb waste, and in particular for sequestration of the highly radioactive 210Pb isotope enriched in U-bearing geological materials.

Modification of Adansonia digitata Cellulose by Hydroxamic Acid: a Promising Resource for Removing Pb (II) Ions from Water

Developing cheap and affordable materials for the removal of toxic heavy metal ions such as Pb (II) ions from water is a challenge. In response to this, this work evaluated the synthesis and use of hydroxamic acid modified Adansonia digitata cellulose (ADHX) as a useful resource for the removal of Pb (II) ions from water. ADHX was characterized using Fourier Transform Infrared spectrometry (FTIR), Thermogravimetric analysis (TGA), X-ray Diffraction analysis (XRD), zeta potential, Particle Size Dispersion (PSD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The sorption of Pb (II) ions on ADHX follows the pseudo-second order model, intra-particle diffusion and Liquid film diffusion kinetic models. The adsorption capacity of ADHX was found to be 18.00 mg g−1, which fitted well for Langmuir, Temkin and Freundlich isotherms. PSD revealed ADHX to be monomodal while Gibb’s free energy change (∆Go) suggests a non-spontaneous process. The negative nature of enthalpy change (∆Ho, −69.774 kJ mol−1) shows that the process is exothermic while entropy change (∆So, −0.214 kJ mol−1) suggests a stable configuration of Pb (II) ions on the surface of ADHX. However, the desorption studies revealed a possible regeneration of ADHX with a desorption capacity of 68.75% in 0.01 M NaNO3 while quantum chemical computation using Density Functional Theory (DFT) revealed the mechanism of sorption to be via ionic interaction. This study revealed ADHX to be a promising resource for removing Pb (II) ions from water. Graphical abstract

Synthesis, characterization, and lead (II) sorption performance of a new magnetic separable composite: MnFe2O4@wild plants-derived biochar

In present study, the magnetic separable biochar nacomposite (MWPC) was synthesized by using the facile chemical coprecipitation method of wild plants-derived biochar (WPC) and manganese ferrite nanoparticles (MnFe2O4). Its crystal structure, surface morphology and elemental composition, textural structure, surface chemistry and magnetic performance were illuminated. The magnetic nanoparticles of spinel manganese ferrite were observed to significantly affect the surface area and pore structure of the WPC. Its saturation magnetization value was measured as 19.7 emu/g. In addition, the optimum sorption conditions of the lead selected as a model for testing metal sorption performance from water were determined by considering the effects of important process parameters such as solution pH, metal concentration, interaction time and temperature. The kinetic and isotherm sorption data were found to be well compatible with Langmuir isotherm and pseudo-second order kinetic models, respectively. It was observed that the maximum Pb(II) sorption capacity of MWPC was approximately 2.6 times higher than that of WPC. Thermodynamic parameters such as ΔG°, ΔH°, ΔS° calculated to explain the nature of the interaction during the sorption showed that the process is endothermic and spontaneous. The findings show that MWPC has a high surface area and a wide porous sorbent that is effective in lead removal and can be magnetically separated without leaving a second pollution to the environment.