Lead Sorption Research Articles

Removal of lead(II) ions from aqueous solutions using diatomite nanoparticles

In the present study, the performance of diatomite nanoparticles was investigated for the lead(II) ions sorption in a batch mode. The diatomite nanoparticles were characterized using X-ray fluorescence, scanning electron microscopy, dynamic light scattering, and Brunauer–Emmet–Teller analysis. The influence of sorption parameters including pH, contact time, initial concentration, and temperature on the lead ions sorption was evaluated. The maximum adsorption capacity of lead ions onto the diatomite nanoparticles was found to be 103.1 mg g−1 at equilibrium time of 90 min and temperature of 45°C. The kinetic data were analyzed by pseudo-first-order and pseudo-second-order kinetic models. The Freundlich and Langmuir isotherm models were applied to describe the equilibrium data. The kinetic data of lead ions were found to follow the pseudo-first-order kinetic model and the equilibrium data of lead ions sorption were well described by Langmuir isotherm model. Evaluation of thermodynamic parameters indicated that the lead adsorption onto the diatomite nanoparticles was endothermic and spontaneous process. The reusability studies indicated that the lead adsorption capacity did not change remarkably after five sorption–desorption cycles.

Kinetic And Equilibrium Studies On The Adsorption Of Pb2+ And Zn2+ From Aqueous Solution Using Coco-Peat By Batch Experiment

The presence of heavy metals in surface water, which is common in mining area pose harmful effect to human health and the environment. Recently, cocopeat has been studied as an effective sorbent material for removing heavy metals from wastewater. In this study, kinetic was done by analyzing the distribution of the heavy metal in sorbent material and liquid phase after mixing 50 mg/L solution of lead (Pb2+) and zinc (Zn2+)in single solute system with 0.1 g of coco-peat, that were consequently shaken at 5, 10, 15, 30, 60, 120, 180 and 360 minutes. To determine the equilibrium adsorption isotherm for each heavy metal, the solutions of 10, 20, 30,40 and 50 mg/L of Pb2+ and Zn2+ were prepared separately. Two different pH levels (natural pH, and pH 4) were setto describe the sorption behavior of Pb2+ and Zn2+ of each heavy metal.Using data from batch experiments, appropriate kinetic (time dependency) and equilibrium (isotherm) models were fitted on the sorbent material and liquid phase concentrations to determine adsorption parameters. Pseudo second-order kinetic model fitted well to the kinetic data due to chemisorption that happened during experiments. In other hand, Langmuir model fitted well to the equilibrium, this indicates that the sorption of lead and zinc on coco peat is monolayer and that the adsorbent’s surface is homogenous. The increase of heavy metals adsorption following the increase of pH might be due to negative charge of coco peat surface. Pb2+ adsorbed more than Zn2+ because ion with high hydration enthalpy will have smaller amount of ion adsorbed. The hydration enthalpies for Pb2+ and Zn2+ are 23 kJ/kg and 113 kJ/kg, receptively. Considering all the factors that we have discussed, cocopeat has high efficiency to remove the heavy metals from wastewater. Keywords: Coco-peat, adsorption, batch experiment, kinetic, equilibrium.

New Route to the Charged Functional Assisted Nano-Lanthanum Hydroxide Composite with Superior Lead Sorption Capacities

New Route to the Charged Functional Assisted Nano-Lanthanum Hydroxide Composite with Superior Lead Sorption Capacities

The Elovich equation as a predictor of lead and cadmium sorption rates on contaminant barrier minerals

Contaminant sorption reactions in soils are generally heterogeneous, multi-steps solid–liquid reactions that compliment transport processes. For contaminant barrier materials, reaction heterogeneity is promoted by variability in the mineralogy and grain size distribution of materials required in mix proportions to satisfy various design functions. The adsorption/desorption of contaminants in barrier systems is necessary for performance assessments. In this paper, the sorption/desorption rates of Pb2+ and Cd2+ on Na-montmorillonite ((OH)4Si8Al4O20nH2ONa) and kaolinite ((OH)8Si4Al4O10) were investigated by varying nature of aqueous contaminants and clay. Heavy metals including Pb2+ and Cd2+ were adsorbed/desorbed on the clays at pH levels of 2, 3, 4, and 7 for 48h. Sorption/desorption of these heavy metals was found to be influenced by point of zero charge, cation exchange capacity, particle size, pH of the system, complexation of metals, and hydrated ionic radius of metals. As a result, Elovich equation was found to adequately explain the kinetics of Pb2+ and Cd2+ on two clay minerals with the squared correlation coefficients (R2) that range from 0.70 to 0.99. At pH 2, removal rate were 36.3% for Pb2+ and 64.5% for Cd2+ from Na-montmorillonite while 67.1% for Pb2+ and 75.0% Cd2+ from kaolinite, respectively. The results obtained from the Elovich equation could be useful for assessing the sorption equilibrium for the metals potentially attained in soil barrier systems.

Sustainable natural adsorbents for heavy metal removal from wastewater: lead sorption on pine bark (Pinus radiataD.Don)

Aqueous Pb(II) adsorption on pine bark (Pinus Radiata D.Don), an inexpensive and sustainable natural sorbent material, has been evaluated and the mechanism of metal retention characterized by scanning electron microscopy (SEM), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and X-ray photoelectron spectroscopy (XPS). Bark pulp densities >1.5 g l−1 achieve near 100% Pb(II) removal from aqueous solutions containing 100 mg l−1 Pb(II). Adsorption rates increased with pulp density, although adsorption capacity diminished at high densities because of blockage of adsorption sites. The effects of washing and sulfuric acid activation were assessed and found to be less important than in previous metal sorption studies. Pb(II) sorption takes place mainly at the lignocellulosic C―O groups, with adsorption at phenolic sites appearing to be most significant. © 2016 The Authors. Surface and Interface Analysis published by John Wiley & Sons, Ltd.

Removal of Pb2+, Cd2+, and Cu2+ from phosphoric acid solution using the chitosan‐modified natural zeolite

AbstractSorption ability of the chitosan‐modified natural zeolite for Pb2+, Cd2+, and Cu2+ cations was investigated. The influence of time and concentration of heavy metals on their sorption from concentrated (85% H3PO4) phosphoric acid was determined. At 20 and 40 min of sorption curves, there are a number of maxima probably due to desorption of cations from the sorbent into the acid. According to the results, sorption of the modified zeolite for lead cation is the least in the whole interval of time. In the case of equal concentrations of all cations (CPb = CCd = CCu), sorption of lead, cadmium, and copper was 94.81–95.09%, 96.55–97.50%, and 97.53–98.14%, respectively. Sorption curves in the case of equal Pb2+ and Cd2+, but higher concentrations of Cu2+, are the same for all cations. Sorption of cadmium varies from 95.48% to 97.55%. Copper and lead sorbed in a less amount, in the case of (СРb = СCd < СCu), their sorption in 10 min was 95.42% and 97.55%, respectively. As in the case of equal concentrations of all cations (CPb = CCd = CCu), the sorptions of copper, cadmium, and lead were (92.09–96.93%), (92.13–95.37%), and (91.35–94.45%), respectively, in the case of (СРb = СCu < СCd).Physico‐chemical methods of analysis are as follows: Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray powder diffraction patterns, and Brunauer–Emmett–Teller have shown that natural zeolite is activated without destroying the structure and adsorbs lead, as well as cadmium and copper cations. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.

Sorption and Desorption of Lead and Cadmium in Calcareous Soils Treated with Used Engines oils

This study includes adsorption and desorption of Cadmium and lead and its relationship with soil polluted by used oils engines. The experiment carried out using soil samples from ten different locations in addition to the soils treated with used engine oils. Different concentrations of cadmium and lead were added in the levels of( 0, 1, 2 and 4) mmol L -1 with three replicates to achieve sorption and desorption process. Langmuir and Freundlich equations were used to describe the sorption and desorption of cadmium and lead from soil samples. Desorption index (DI), The study found That the amount adsorbed increases with increased of added Cd and Pb and variation of different soils chemical and physical properties study of the soils and the amount of calcium carbonate, organic matter, the quantity and quality of clay, pH and ionic strength and the Values of desorption Index (DI) gave a good indication for the detection of the potential risk of pollution of Cadmium and Lead in calcareous soils, which can be transmitted to the surface and groundwater as the desorption index (DI) was calculated for soils contaminated with different levels of used engine oil (0, 5, 10, 20%), Sulaymaniyah and Aldorah soils were treated with different concentrations of cadmium and lead (0, 1, 2, 4) mmol L-1. It was observed that desorption Index increased with increasing the proportion of used engine oils. Highest DI was recorded at 20% addition of oil for each of the soils

Sorption of lead by Salisbury biochar produced from British broadleaf hardwood

In this study, the physicochemical properties of Salisbury biochar produced from British broadleaf hardwood and its adsorption characteristics towards lead were investigated. The biochar particle size has a significant effect on its BET surface area, cation exchange capacity and sorption of lead. The kinetics data were well fitted by the Pseudo second order model. The increase of biochar dosage increased the percentage of lead removal in solutions. The increase of initial solution pH increased the percentage of lead removal across the pH range of 2–10. The calculated maximum adsorption capacities of lead by Langmuir model were 47.66 and 30.04mg/g for 0.15mm and 2mm samples. The adsorption capacities of different metals decreased in the order of lead>nickel>copper>zinc calculated in mmol/g. This study suggests a great potential of biochars derived from British broadleaf hardwood to be applied in soil remediation.

Removal of lead and phosphate ions from aqueous solutions by organo-smectite

Smectite has been modified using hexadecyltrimethyl ammonium bromide in an amount of double cationic exchange capacity. This alteration makes it possible to use organo-smectite as a sorbent to remove anionic forms. The experiment consisted of the interchangeable sorption of phosphate(V) and lead(II) by organo-smectite. Research was carried out with varying pH (2–5) and various concentrations (0.1–5 mmol/L). Organo-smectite with previously adsorbed lead ions removed more phosphate than the untreated organo-smectite. Experimental data show that lead is more likely to absorb on the organo-smectite than on the organo-smectite with previously adsorbed phosphate ions. It follows that the most effective use of the organo-smectite is through the sorption of first – Pb cations and then PO4 anions. With an increasing concentration of Pb(II) or P(V), the sorption efficiency increases. The maximum sorption efficiency of lead and phosphate ions is observed at pH 5. This enables the removal of harmful lead and phosphorus compounds from waste water and immobilizes them on the sorbent's surface. The alternating reactions of lead and phosphorus ions result in the crystallization of brompyromorphite Pb5(PO4)3Br.

Efficient lead sorption from wastewater by carbon nanofibers

Wastewater from many industries contains toxic metal ions, which should be removed before water is released into the environment. Many adsorbents have been developed to remove metals, but their efficiency should be improved by, e.g., increasing surface area. Here, we tested the use of carbon nanofibers synthesized on the surface of activated carbon, to remove lead ions (Pb2+). We studied the effect of carbon nanofiber dose, pH, contact time and agitation speed on the sorption capacity. The best conditions were with nanofiber dose of 0.25 g/L, pH of 5.5, contact time of 60 min and agitation speed of 200 rpm. The nanocomposite product was also used for the removal of lead from industrial wastewater. We also found a successful removal of 67 % of lead ions from semiconductor wastewater sample.

Systematic evaluation of dissolved lead sorption losses to particulate syringe filter materials.

Distinguishing between soluble and particulate lead in drinking water is useful in understanding the mechanism of lead release and identifying remedial action. Typically, particulate lead is defined as the amount of lead removed by a 0.45-μm filter. Unfortunately, there is little guidance regarding selection of filter membrane material and little consideration to the possibility of the sorption of dissolved lead to the filter. The objective of this work was to examine the tendency of 0.45-μm syringe filter materials to adsorb lead. Tests were performed with water containing 40 and 24 μg/L soluble lead at pH 7 buffered with 50 mg C/L dissolved inorganic concentration (DIC). The amounts of lead sorbed greatly varied by filter, and only two filter types, polypropylene and mixed cellulose esters, performed well and are recommended. Great care must be taken in choosing a filter when filtering soluble lead and interpreting filter results.

Biosorptive removal of lead by lentil husk

Lentil husk an agricultural waste was found to be a promising low cost adsorbent for removal of lead and showed maximum adsorption potential among all other agricultural wastes tested. Different physico-chemical parameters were found to influence the adsorption process. Lead uptake capacity of lentil husk (qmax) was 81.43mgg−1 at optimized pH (5.0) and temperature (30°C) with an initial metal ion concentration of 250mgL−1. Adsorption process was well interpreted by Langmuir isotherm model. Kinetic study showed sorption was very fast at initial stage and equilibrium was reached within 60min following pseudo second order rate model. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and Fourier transform infrared spectroscopy (FTIR) further confirmed the sorption of lead. Chemical modification of functional groups revealed both hydroxyl and carboxyl groups played crucial role in binding process. The concerned biomass was capable of removing lead from actual industrial effluent.

Sorption of Pb(II) on palygorskite and sepiolite in the presence of amino acids: Equilibria and kinetics

The environmental mobility and bioavailability of heavy metals in soil are greatly influenced by sorption reactions on soil minerals, which are, in turn, controlled by the presence of various organic ligands, such as amino acids, in soil solution. In this study, the effects of l-cysteine (Cys) and l-histidine (His) amino acids on lead (Pb) sorption by palygorskite and sepiolite, as the specific silicate clay minerals of arid and semiarid soils, were studied using the batch method. Experimental Pb sorption data were subsequently analyzed by various isothermal and kinetic models. The equilibrium data revealed that both Langmuir and Freundlich models can describe the Pb sorption on palygorskite and sepiolite minerals. The sorption capacities of the minerals for Pb were decreased in the presence of Cys, probably because of the formation of neutral stable complexes of Pb and Cys as [ML] in the solution. The His effects, however, were different for the two minerals. Histidine reduced the Pb sorption capacity of sepiolite, but its diminishing effect was much lower than that of Cys. This result may be because of the formation of cationic soluble His–Pb complexes as [ML2H]+, which can be slightly adsorbed by the clay surfaces via electrostatic attraction. l-Histidine increased the sorption of Pb by palygorskite, probably due to formation of highly charged complexes with Pb, in the form of [ML2H2]2+ and [ML2H3]3+, or ternary surface complexation processes. The kinetics of Pb sorption by the minerals were satisfactorily described by the power, pseudo-first order, pseudo-second order and parabolic diffusion equations, among which the power function provided the best fit. The kinetics of Pb sorption by the palygorskite was rapid, approaching equilibrium within 10h. Lead sorption on the sepiolite, however, was much slower and equilibrium condition was attained after 10h. The Pb sorption rate indices, such as the initial sorption rate and diffusion rate constant, were also considerably affected by the presence of amino acids. These findings emphasize the importance of amino acids in evaluating the fate of Pb in arid soils in which fibrous silicate clay minerals are dominated in the clay fraction.

Sorption of Pb(II), Cd(II), and Ni(II) From Single- and Multimetal Solutions by Recycled Waste Porous Glass

Selective sorption of lead, cadmium, and nickel ions on recycled waste porous glass beads was investigated. Single-metal equilibrations were carried out in demineralized water and ternary metal equilibrations were carried out in demi- and tap water. Freundlich isotherm gave a good correlation of the experimental data. Maximum metal retention (qmax) in single-ion solutions were 18.66 mg/gRPWG (0.090 mmol/gRPWG), 4.83 mg/gRPWG (0.043 mmol/gRPWG), 4.00 mg/gRPWG (0.068 mmol/gRPWG), respectively, for Pb+2, Cd+2, and Ni+2, and lower figures were in the case of ternary systems: 13.50 mg/gRPWG(0.065 mmol/gRPWG), 2.23 (0.020 mmol/gRPWG), 2.05 mg/gRPWG(0.034 mmol/gRPWG), respectively, for Pb+2, Cd+2, and Ni+2, with further drastic reduction in tap water. Metal exhausted beads were used as thermal insulators in cement mortars, minimizing their potential impact in the environment.

Role of iron and aluminum coagulant metal residuals and lead release from drinking water pipe materials

Bench-scale experiments investigated the role of iron and aluminum residuals in lead release in a low alkalinity and high (> 0.5) chloride-to-sulfate mass ratio (CSMR) in water. Lead leaching was examined for two lead-bearing plumbing materials, including harvested lead pipe and new lead: tin solder, after exposure to water with simulated aluminum sulfate, polyaluminum chloride and ferric sulfate coagulation treatments with 1-25-μM levels of iron or aluminum residuals in the water. The release of lead from systems with harvested lead pipe was highly correlated with levels of residual aluminum or iron present in samples (R2 = 0.66–0.88), consistent with sorption of lead onto the aluminum and iron hydroxides during stagnation. The results indicate that aluminum and iron coagulant residuals, at levels complying with recommended guidelines, can sometimes play a significant role in lead mobilization from premise plumbing.

Preparation of magnetic metal organic frameworks adsorbent modified with mercapto groups for the extraction and analysis of lead in food samples by flame atomic absorption spectrometry

A novel magnetic metal organic frameworks adsorbent modified with mercapto groups was synthesized and developed for extraction and spectrophotometric determination of trace lead. The adsorbent was characterized by Fourier transforms infrared spectrometer, X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry. The results indicated the adsorbents exhibited high adsorption capacities for lead due to the chelation mechanism between metal cations and mercapto groups. Meanwhile, the lead sorption onto the adsorbents could be easily separated from aqueous solution using a magnetic separation method. Under the optimal conditions, a linear calibration curve in the range from 1 to 20μgL−1 was achieved with an enrichment factor of 100. The limits of detection and quantitation for lead were found to be 0.29 and 0.97μgL−1, respectively. The developed method was successfully applied to the determination of trace amounts of lead in food samples and certified reference material with satisfactory results.

Lead Sorption by Carbon Nanofibers Grown on Powdered Activated Carbon — Kinetics and Equilibrium

Carbon nanofibers (CNFs) were synthesized by using a safe and less hazardous method, compared to using floating catalysts in chemical vapor deposition (CVD) process. This process used C 2 H 2 as carbon source and oil palm kernel shell-based powdered activated carbon (PAC) as cheap solid substrate. Use of nickel ( Ni 2+) impregnated PAC as fixed substrate for the synthesis of CNF is one of the novelties of the research work accomplished by the authors. The PAC–CNFs porous nanocomposite product was used for the sorption of lead ions ( Pb 2+) from synthetic aqueous solution. Kinetics of Pb 2+ adsorption and isotherms were investigated by varying initial concentration of lead and contact time. PAC–CNFs were found to remove Pb 2+ better at acidic pH of about 5.5. Langmuir and Freundlich isotherms were applied to the sorption equilibrium data to find the best fitted model. Langmuir isotherm model with R2 = 0.965 fitted the adsorption data better than the Freundlich isotherm. The kinetic processes of Pb 2+ adsorption on CNFs were investigated by applying different kinetic models, namely zero-order, pseudo-first-order and pseudo-second-order. The pseudo-second-order rate equation exhibited the best results with R2 = 0.999, qe = 74.79 (mg/g) and K2 = 0.029 (min ⋅ g/mg). The novel nanocomposite product seemed to have the potential to remove Pb 2+ ions from aqueous solution.

Hydrochars derived from plant biomass under various conditions: Characterization and potential applications and impacts

Hydrothermally carbonized biomass (hydrochar) has received increased attention recently as a potential agent for contaminant remediation and soil improvement. There is a need to understand how the properties of hydrochar vary with production conditions. In this work, sugarcane bagasse, hickory, and peanut hull were converted into hydrochars at three different temperatures (200°C, 250°C, and 300°C). Basic physicochemical properties of the nine hydrochars were determined and batch aqueous sorption experiments were conducted to measure ability of the hydrochars to sorb methylene blue, lead, and phosphate. The yield, surface area, and pore volume of the hydrochars decreased with increasing conversion temperatures. Among all the hydrochars, the ones made at the lowest temperature (200°C) were the best for sorption of methylene blue and lead. However, none of the hydrochars were able to remove significant amounts of phosphate from solution. In addition, the hydrochars did not significantly affect seed germination rate, though some did have a significant effect on root development of seedlings. Findings from this work suggest that lower temperature hydrochars may be optimal for contaminant remediation because of their higher sorption ability and absence of negative effect on plants.

Manganese oxide-modified biochars: Preparation, characterization, and sorption of arsenate and lead

This work explored two modification methods to improve biochar’s ability to sorb arsenic (As) and lead (Pb). In one, pine wood feedstock was pyrolyzed in the presence of MnCl2·4H2O (MPB) and in the other it was impregnated with birnessite via precipitation following pyrolysis (BPB). The resulting biochars were characterized using thermogravimetry, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive X-ray analyses. The dominant crystalline forms of Mn oxides in the MPB and BPB were manganosite and birnessite, respectively. Batch sorption studies were carried out to determine the kinetics and magnitude of As(V) and Pb(II) onto the biochars. As(V) and Pb(II) sorption capacities of MPB (0.59 and 4.91g/kg) and BPB (0.91 and 47.05g/kg) were significantly higher than that of the unmodified biochar (0.20 and 2.35g/kg). BPB showed the highest sorption enhancement because of the strong As(V) and Pb(II) affinity of its birnessite particles.

Convenient Synthesis of Micron-sized Macro Porous Polymers with Silica on their Surfaces and Excellent Adsorption Performance for Pb(II) Ion

The phenol-formaldehyde/silicon dioxide resin (PFSR) adsorbent showed superior adsorption properties for Pb (II) ion. The aimed composite material was characterized by XRD, FT-IR, SEM and BET techniques. Sorption properties of the synthesized composite powder were evaluated through sorption of lead ions from their aqueous solutions. Batch sorption tests were carried out at different initial heavy metal ion concentrations revealing that the synthesized composite has great selectivity to lead ions. The experimentally obtained sorption results were analyzed using pseudofirst and second order kinetic models to stand on the possible sorption mechanisms indicating the sorption behavior of the studied ions onto PFSR composite belonged to the pseudo-second order kinetic model and the sorption process was a chemical process. Isotherm plots were constructed and analyzed using Langmuir, Freundlich, Temkin, D-R and Jovanoic isotherm models. The D-R and Temkin isotherm model provided the best fit for the Pb(II) ion, revealing the maximum adsorption capacity of 13.74 mg/g. Thermodynamic studies revealed that Pb(II) adsorption on the PFSR adsorbent is a favorable, spontaneous, and endothermic process.