Adsorption Process Of Pb Research Articles

Use of unmodified orange peel for the adsorption of Cd(II), Pb(II) and Hg(II) ions in aqueous solutions

Ground orange peel (GOP) was used as adsorbent for Cd(II), Pb(II) and Hg(II) ions in aqueous solutions. Several experiments with variation of some factors namely: initial concentration of the heavy metal ions, contact time, temperature and pH were carried out. FT-IR spectrum of GOP showed the presence of different functional groups on its surface. Equilibrium data were analysed by Langmuir, Freundlich, and Temkin isotherms. Hg (II) and Cd (II) adsorptions were better described by Temkin isotherm while that of Pub (II) was best described Freundlich isotherm. Pseudo second order kinetics with higher R2 values described adsorption in all cases. Adsorption of Hg (II) was maximum at pH 4, while those of Cd (II) and Pub (II) ions were maximum at pH 6. Thermodynamics study showed that the adsorption processes of Pb(II) and Hg(II) ions were endothermic while that of Cd(II) ions was exothermic in nature.

Facile Synthesis and Characterization of Chrysotile Nanotubes and Their Application for Lead(II) Removal from Aqueous Solution

Chrysotile nanotubes (ChNTs) were synthesized using the hydrothermal method and characterized by XRD, XPS, SEM, TEM, and N2 adsorption-desorption. The results of XRD analysis confirm that the synthetic samples own the pure monoclinic chrysotile. The morphology images show that ChNTs have a hollow nanotubular structure. A batch experiment was employed to evaluate the adsorption efficiency of ChNTs toward Pb(II). The kinetic adsorption of Pb(II) on ChNTs can be described by a pseudo-second-order model very well. The adsorption of Pb(II) on ChNTs are strongly dependent on pH and ionic strength. The adsorption isotherms are fitted well by the Langmuir model, having a maximum adsorption capacity of 25.08 mg·g−1 at 298 ± 1 K. The thermodynamic parameters of the adsorption for Pb(II) indicate that the adsorption process of Pb(II) on ChNTs is spontaneous and endothermic. Herein, this finding suggests that ChNTs can be applied on the preconcentration of Pb(II) in the field of water treatment.

Chemical modification of silica gel with multidentate ligands for heavy metals removal

Two kinds of silica-gel supported chelating adsorbents with different multidentate ligands were synthesized for heavy metals removal. The obtained adsorbents were named as SG-AD and SG-ASD. SG-AD was the silica-gel supported dithiocarbamate ligand adsorbent; SG-ASD was the silica gel-supported dithiocarbamate and Schiff’s bases adsorbent. FT-IR analysis and thermogravimetry analysis were used to characterize the prepared adsorbents. Their adsorption properties of Pb(II), Hg(II), Cu(II), Zn(II), and Cd(II) were also investigated. The results showed that SG-AD and SG-ASD showed high performance toward Pb(II) and Hg(II) removal, especially toward Hg(II) removal. Adsorption kinetics suggested that the adsorption processes of Pb(II) and Hg(II) on SG-AD and SG-ASD were governed by film diffusion and followed a pseudo-second-order model. The Langmuir model and Scatchard model were applied to fit the experimental equilibrium data for SG-AD and SG-ASD. With increasing temperature, the adsorption capacities and affinity constants of SG-AD and SG-ASD for Pb(II) and Hg(II) were increased. SG-ASD which contained two kinds of multidentate ligands showed strong chelating affinity to Hg(II). Langmuir model and Scatchard model can be integrated in describing the processes of heavy metal adsorption.

Optimizing adsorption of Pb(II) by modified litchi pericarp using the response surface methodology

Litchi pericarp was chemically modified as a novel bioadsorbent (MLP) for Pb(II) adsorption in this study. Operating parameters such as contact time, adsorbent dosage, and initial pH of solution were investigated using batch assays and further optimized using response surface methodology (RSM). The results showed that the MLP exhibited a high adsorption efficiency of 99.97% for Pb(II), which was optimal at a contact time of 71.56min, a initial pH of 6.81, and an adsorbent dose of 3.80g/L. Adsorption processes of Pb(II) by MLP could be well described with Langmuir or Freundlich isotherms and a pseudo-second-order kinetic model. The maximum adsorption capacity of Pb(II) by MLP was determined as 163.93mg/g, suggesting a highly promising potential for MLP to be used as a new bioadsorbent. Additionally, the thermodynamic study indicated that the adsorption process of Pb(II) by MLP was spontaneously and exothermic.

A novel smart microsphere with magnetic core and ion-recognizable shell for Pb2+ adsorption and separation.

Smart core-shell microspheres for selective Pb(2+) adsorption and separation have been developed. Each microsphere is composed of a Pb(2+) recognizable poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (PNB) shell and a magnetic Fe3O4 core. The magnetic PNB core-shell microspheres show excellent Pb(2+) adsorption selectivity among the coexisting Cd(2+), Co(2+), Cr(3+), Cu(2+), Ni(2+), Zn(2+), K(+), and Ca(2+) ions by forming stable B18C6Am/Pb(2+) host-guest complexes and exhibit an interesting temperature-dependent Pb(2+) adsorption. The inner independent magnetic Fe3O4 cores enable the Pb(2+)-adsorbed microspheres with a magnetically guided aggregation to be separated from the treated solution using a remotely controlled manner. The isothermal Pb(2+) adsorption result fits well with the Freundlich isotherm. The magnetic PNB core-shell microspheres show very fast adsorption of Pb(2+), and the adsorption process of Pb(2+) onto magnetic PNB core-shell microspheres fits well with the pseudo-second-order model. Moreover, Pb(2+)-adsorbed microspheres can be regenerated by simply increasing the operation temperature and washing with deionized water. The proposed magnetic PNB core-shell microspheres provide a promising candidate for Pb(2+) adsorbents with selectively separable and efficiently reusable abilities.

Preparation of Reduced Graphene Oxide/Poly(acrylamide) Nanocomposite and Its Adsorption of Pb(II) and Methylene Blue

Carboxyl groups at the periphery of reduced graphene oxide (RGO) sheets are converted to amine groups by reaction with N-hydroxysuccinimide and 1,3-diaminopropane, and a free-radical polymerization initiator is anchored to the RGO sheets. Poly(acrylamide) (PAM) polymer brushes on RGO sheets (RGO/PAM) are synthesized by in situ free-radical polymerization. The heavy metals, Pb(II), and the benzenoid compounds, methylene blue, (MB) were selected and adsorbed by RGO/PAM composites, and the adsorption capacity of RGO/PAM for Pb(II) and MB was measured. The experimental data of RGO/PAM isotherms for Pb(II) and MB followed the Langmuir isotherm model. The RGO/PAM displays adsorption capacities as high as 1000 and 1530 mg/g for Pb(II) and MB, respectively, indicating RGO/PAM is a good adsorbent for the adsorption of Pb(II) and MB. The adsorption kinetics of Pb(II) and MB onto RGO/PAM can be well fitted to the pseudo-second-order model. The adsorption processes of Pb(II) and MB onto RGO/PAM are spontaneous at 298, 308, and 318 K.

Sulfonated modification of cotton linter and its application as adsorbent for high-efficiency removal of lead(II) in effluent

Sulfonated modification of cotton linter and its novel application as adsorbent for Pb(2+) in effluent were investigated. Results show that sulfonated cotton linter (SCL) has strong adsorbability for Pb(2+), more than 85% of Pb(2+) can be removed at lower Pb(2+) concentration (<20 mg/L). Its adsorbability for Pb(2+) is related to effluent pH, temperature, and initial Pb(2+) concentration. The adsorption process can reach equilibrium within 8 min, which can be described through the pseudo-second-order kinetic model. The adsorption isotherm is closely fitted with the Temkin isotherm model, which suggests that the adsorption of Pb(2+) on SCL can be regarded as chemical adsorption. The adsorption process of Pb(2+) on SCL is non-spontaneous and endothermic, based on the value of Gibbs free energy and enthalpy. Compared with commercial activated carbon, SCL is simple to prepare and does not require any special technology.

Impacts of inorganic ions and temperature on lead adsorption onto variable charge soils

Abstract The effect of inorganic ions and temperature on lead (Pb2 +) adsorption was evaluated on three acidic soils: yellow-brown soil (YBS), latosol soil (LS), and lateritic red soil (LRS). The results showed that the adsorption of Pb2 + in the presence of anions decreased in the order: SO42 − > NO3− = Cl−, while in the presence of cations, it reduced in the order: K+ > Ca2 +. Accordingly, the contamination of YBS, LS and LRS soils with Pb2 + was more noticeable when they contained more NO3−, Cl− and Ca2 + than SO42 − and K+. The distribution coefficient (Kd) of Pb2 + declined in the order: YBS > LS > LRS in the presence of anions. Adsorption and Kd values of Pb2 + were mainly dependent on ion types and altered surface properties caused by the adsorption and/or the formation of ion complexes. The Kd values enhanced slightly with increasing temperature up to 35 °C and then decreased at 45 °C. Based on the thermodynamic parameters, including the heat of reaction (ΔH), entropy change (ΔS) and the free energy change (ΔG), the adsorption process of Pb2 + on YBS, LS and LRS soils was endothermic and impetuous at low temperatures, whereas it was exothermic and non-spontaneous at high temperatures.

A zinc oxide-coated nanoporous carbon adsorbent for lead removal from water: Optimization, equilibrium modeling, and kinetics studies

A zinc oxide-coated nanoporous carbon sorbent was prepared by acid modification and ZnO functionalization of mesoporous carbon. The synthesized materials, such as mesoporous carbon, oxidized mesoporous carbon and zinc oxide-coated nanoporous carbon, were characterized by nitrogen adsorption–desorption analysis, Fourier transform infrared spectra, scanning electron microscopy, and transmission electron microscopy. ZnO on oxidized mesoporous carbon gradually increased with increase in the number of cycles. Furthermore, the effects of agitation time, initial metal ions concentration, adsorbent dose, temperature and pH on the efficiency of Pb(II) ion removal were investigated as the controllable factors by Taguchi method. The value of correlation coefficients showed that the equilibrium data fitted well to the Langmuir isotherm. Among the adsorbents, zinc oxide-coated nanoporous carbon showed the largest adsorption capacity of 522.8 mg/g (2.52 mmol/g) which was almost close to that of the zinc oxide-coated (2.38 mmol/g), indicating the monolayer spreading of ZnO onto the oxidized mesoporous carbon. The results of the present study suggest that ZnO-coated nanoporous carbon can be effectively used for Pb(II) adsorption from aqueous solution, whereas a part of acidic functional groups may be contributed to binding the Pb(II) for the oxidized mesoporous carbon and mesoporous carbon. Kinetic studies indicated that the overall adsorption process of Pb(II) followed the pseudo-second-order model. The ZnO-coated nanoporous carbon was regenerated and found to be suitable of reuse of the adsorbent for successive adsorption–desorption cycles without considerable loss of adsorption capacity.

Removal of Lead (II) from Aqueous Solution on Multiwalled Carbon Nanotube by Using Response Surface Methodology

ABSTRACT Heavy metals released into the environment continue to receive attention over with advances of technology, but with variations in concentration. Heavy metals released into the environment in various concentrations continue to receive attention, fostered by advances in technology. Lead, one of the best-known heavy metals, can be found at high levels in industrial wastewater, is nonbiodegradable, and is a neurotoxic metal. To remove Pb(II) ions from aqueous solutions, the adsorption process of Pb(II) ions was optimized by using response surface methodology (RSM). The effects of initial pH, initial concentration of lead, and temperature on the adsorption efficiency (E, %) were investigated. pH was the most significant factor that affected the removal of lead. Central composite design (CCD) can be successfully applied to the removal of Pb(II) ions from aqueous solutions.

The adsorption of Pb(II) on Mg 2Al layered double hydroxide

The adsorption behavior of Pb(II) by Mg 2Al layered double hydroxide (Mg 2Al LDH) was studied as a function of contact time, pH, ionic strength, foreign ions, humic substances and temperature under ambient conditions. The results showed that the kinetic adsorption could be described by a pseudo-second order model very well. The adsorption of Pb(II) on Mg 2Al LDH was strongly dependent on pH and ionic strength. The presence of HSs enhanced the adsorption of Pb(II) on Mg 2Al LDH at low pH, whereas reduced Pb(II) adsorption at high pH. The Langmuir model fitted the adsorption isotherms of Pb(II) better than the Freundlich model at three different temperatures of 303.15, 323.15 and 343.15 K. The thermodynamic parameters (Δ H°, Δ S° and Δ G°) calculated from the temperature dependent adsorption isotherms indicated that the adsorption process of Pb(II) on Mg 2Al LDH was endothermic and spontaneous. The results show that Mg 2Al LDH is a promising material for the preconcentration and separation of pollutants from large volumes of aqueous solutions.

Lead separation by sorption onto powdered marble waste

Batch adsorption experiments were carried out, aiming to remove lead ions from aqueous solutions and water samples using powdered marble wastes (PMW) as an effective inorganic sorbent, which is cheap, widespread, and may represent an environmental problem. The main parameters (i.e., solution pH, sorbent and lead concentration, shaking time, and temperature) influencing the sorption process, were investigated. The results obtained showed that the sorption of Pb2+ ions onto PMW was fitted well with the linear Freundlich and Langmuir models over the concentration range studied. From the Dubinin–Radushkevick (D–R) isotherm model it was found that the adsorption was chemical in nature. Thermodynamic parameters viz. the change in Gibbs free energy change (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) were also calculated. These parameters indicated that the adsorption process of Pb2+ ions on PMW was spontaneous and endothermic in nature. Under the optimum experimental conditions employed, the removal of about 100% of Pb2+ ions was attained. The procedure was successfully applied to remove lead ions from aqueous and different natural water samples. Moreover, the adsorption mechanism is suggested.

Paper sludge as a feasible soil amendment for the immobilization of Pb 2+

The possibility of amending Pb 2+ contaminated soil (S) with paper sludge (P) was investigated through adsorption and desorption experiments. The adsorption process of Pb 2+ in soil containing paper sludge (SP) could be well described by pseudo second-order kinetic model and the Langmuir isotherm model. After P addition, the equilibrium time decreased greatly (from 28 to 8 hr) and the Pb 2+ maximum adsorbed amount ( Q max) increased by a factor of more than three to 102.04 mg/g. Q max reached its maximum as S:P was 9:1 ( m/ m) after 10 days contact between S and P. Moreover, Pb 2+ adsorbed amount increased with the rise of pH during the adsorption process. Desorption experiments indicated that Pb 2+ adsorption in SP was irreversible. The metal ion fraction was analyzed with Energy Dispersive Spectrometer and Environmental Scan Electron Microscope. As a result, the addition of P to soil was found to induce a decrease in the mobile forms. The Pb 2+ complexes formation in the presence of carbonates was the main adsorption mechanism. Overall, the paper sludge could be one of the promising soil amendments for the remediation of soil with Pb 2+ contamination.

Adsorption of Pb(II) on diatomite as affected via aqueous solution chemistry and temperature

To better understand the application of diatomite as an adsorbent for the removal of Pb(II) from heavy metal-contaminated water, in this paper, diatomite was used to adsorb Pb(II) from aqueous solution under various conditions. The results demonstrated that the adsorption of Pb(II) was strongly dependent on ionic strength at pH < 7.0, outer-sphere surface complexation or ion exchange may be the main adsorption mechanism of Pb(II) on diatomite at low pH values. No drastic difference of Pb(II) adsorption was observed at pH > 7.0, and the adsorption at high pH values was mainly dominated via inner-sphere surface complexation. The presence of HA/FA showed great influence on Pb(II) adsorption on diatomite. The adsorption of Pb(II) on diatomite was dependent on foreign ions (herein K +, Na +, ClO 4 −, NO 3 − and Cl −) in solution at pH < 8.0, and was independent of foreign ions at pH > 8.0. The thermodynamic parameters (i.e., Δ H°, Δ S°, Δ G°) were evaluated from the temperature dependent adsorption isotherms. The results indicated that the adsorption process of Pb(II) on diatomite was spontaneous and endothermic in nature.

The modified clay performance in adsorption process of Pb2+ ions from aqueous phase—Thermodynamic study

Smectite clay sample from Acre state, Amazon region, Brazil, was used for pillaring and organofunctionalization process in the present study. The pillaring ions were obtained through chemical reaction of AlCl3·6H2O/NaOH, Ti(OC2H5)4/HCl, Cr3(OH)44+/NaOH and ZrOCl2·8H2O solutions. The resulting materials were organofunctionalized with 3-Aminopropyltriethoxysilane (APS). The adsorption capacity was investigated with Pb2+, ions from aqueous solution in pH 5.0 and controlled temperature 298±0.20K. The Langmuir, Freundlich and Temkin adsorption isotherms models have been applied to fit the experimental data, linear regression. The energetic effect caused by metal cation adsorption was determined through calorimetric titration at the solid–liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant.

Removal of Pb(II) ions from aqueous solutions by sulphuric acid-treated wheat bran

Sulphuric acid-treated wheat bran (STWB) was used as an adsorbent to remove Pb(II) ions from aqueous solution. It was observed that the adsorption yield of Pb(II) ions was found to be pH dependent. The equilibrium time for the process was determined as 2 h. STWB gave the highest adsorption yield at around pH 6.0. At this pH, adsorption percentage for an initial Pb(II) ions concentration of 100 mg/L was found to be 82.8 at 25 °C for contact time of 2 h. The equilibrium data obtained at different temperatures fitted to the non-linear form of Langmuir, Freundlich and Redlich–Peterson and linear form of Langmuir and Freundlich models. Isotherm constants were calculated and compared for the models used. The maximum adsorption capacity ( q max) which was obtained linear form of Langmuir model increased from 55.56 to 79.37 mg/g with increasing temperature from 25 to 60 °C. Similar trend was observed for other isotherm constants related to the adsorption capacity. Linear form of Langmuir isotherm data was evaluated to determine the thermodynamic parameters for the process. Thermodynamic parameters show that adsorption process of Pb(II) ions is an endothermic and more effective process at high temperatures. The pseudo nth order kinetic model was successfully applied to the kinetic data and the order ( n) of adsorption reaction was calculated at the range from 1.711 to 1.929. The values of k ad were found to be 5.82 × 10 −4 and 21.81 × 10 −4 (min −1)(mg/g) 1− n at 25 and 60 °C, respectively. Activation energy was determined as 29.65 kJ/mol for the process. This suggest that the adsorption Pb(II) ions by STWB is chemically controlled.

Removal of Pb(II) from Aqueous Solution by Cross-linked Starch Phosphate Carbamate

The adsorption process of Pb(II) ions from aqueous solution by water-insoluble starch phosphate carbamates was investigated. The influences of adsorption conditions, such as adsorption time, adsorbent dose, pH, content of the substituent groups, initial Pb(II) concentration, and temperature, were thoroughly studied. It was shown that an adsorption time of 20 min is sufficient to reach the adsorption equilibrium, the adsorption equilibrium data follow well the Langmuir isotherm model, and the adsorption of Pb(II) ions on cross-linked starch phosphate carbamate is endothermic in nature. For the cross-linked starch phosphate carbamate (CSPC3) with a phosphate group content of 3.10 mmol/g and a carbamate group content of 1.40 mmol/g, the maximum adsorption capacity evaluated from the Langmuir isotherm towards Pb(II) is 2.01 mmol/g. In addition, repeated adsorption/desorption cycles were performed to examine the reusability of adsorbents and the recovery efficiency of Pb(II) ions. The adsorption capacity of Pb(II) ions by CSPC3 decreased from 1.85 to 1.47 mmol/g for three cycles.

Removal of Pb (II) by crosslinked amphoteric starch containing the carboxymethyl group

The adsorption process of Pb (II) ions from aqueous solution by crosslinked amphoteric starch with quaternary ammonium and carboxymethyl groups was investigated. The adsorption capacity is found to be dependent on the pH of the solution, the dose of the crosslinked amphoteric starch, and the initial concentration of Pb (II) ion. Moreover, the adsorption capacity increases with the increasing degree of substitution (DS) of carboxymethyl groups. The Langmuir adsorption isotherm gave a satisfactory fit of the equilibrium data. The adsorption process is endothermic, and thermodynamic parameters were calculated at different DS.

Adsorption of Pb 2+ in aqueous solution by SO 2-treated activated carbon

The adsorption of Pb 2+ in aqueous solution by SO 2-treated activated carbon was investigated from both kinetic and equilibrium standpoints. A commercial activated carbon (C–S) was used. It was treated at 30 °C in SO 2 (C–SO 2–N 2-30), at 30 °C in two successive steps: first in SO 2 and then in H 2S (C–SO 2–H 2S–N 2-30), and from room temperature to 900 °C in SO 2 (C–SO 2-900). The samples were characterized by N 2 adsorption at −196 °C and by helium and mercury density measurements. The adsorption process of Pb 2+ was studied using Pb 2+ solutions at pH 5.4 and 2.0 and at 25 and 45 °C. The amount of sulfur introduced in C–S is much larger for C–SO 2–H 2S–N 2-30 and C–SO 2-900 than for C–SO 2–N 2-30. For C–SO 2–H 2S–N 2-30 and C–SO 2-900, also, the loss of surface area and porosity is greater than for C–SO 2–N 2-30. The introduction of sulfur in C–S significantly slows down the adsorption rate of Pb 2+ but markedly enhances the extent to which it occurs, except at pH 2.0. The removal of sulfur from C–SO 2–H 2S–N 2-30 and C–SO 2-900 noticeably favors the kinetics and also the adsorption of metallic ion. The process may be then as fast as for C–S.

LEED investigation and analysis of Pb/Si(111)

The adsorption process of Pb onto clean Si(111)-7 × 7 substrates over a wide range of deposition doses and deposition/annealing temperature has been studied using LEED intensity (I(V)) spectra. Two √3×√3 R30° phases have been observed. For fixed substrate temperature only one of these phases is present independent of the adsorbed dose. There is an irreversible phase change between the two surfaces at ∼ 350°C. Using Tensor LEED the high temperature phase has been analysed and adsorption shown to occur at the t4) site for this phase with a saturation coverage of 13 ML.