Removal of Cd2+, Cu2+, Ni2+, and Pb2+ ions from aqueous solutions using tururi fibers as an adsorbent

This work investigates the removal of Cd²⁺, Cu²⁺, Ni²⁺, and Pb²⁺ ions from aqueous solutions using tururi fibers as an adsorbent under both batchwise and fixed‐bed conditions. It was found that modification of the tururi fibers with sodium hydroxide increased the adsorption efficiencies of all metal ions studied. The fractional factorial design showed that pH, adsorbent mass, agitation rate, and initial metal concentration influenced each metal adsorption differently. The kinetics showed that multi‐element adsorption equilibria were reached after 15 min following pseudo‐second‐order kinetics. The Langmuir, Freundlich, and Redlich–Peterson models were used to evaluate the adsorption capacities by tururi fibers. The Langmuir model was found to be suitable for all metal ions. Breakthrough curves revealed that saturation of the bed was reached in 160.0 mL with Cd²⁺ and Cu²⁺, and 52.0 mL with Ni²⁺ and Pb²⁺. The Thomas model was applied to the experimental data of breakthrough curves and represented the data well. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40883.     

Comparison of different sorbents (inorganic and biological) for the removal of Pb2+ from aqueous solutions

In an attempt to evaluate the suitability of activated sludge for Pb²⁺ removal, a comparative study was carried out using several chemical adsorbents and three types of biomass. The order of Pb²⁺ removal capacities for chemical adsorbents was found to be: ion exchange resin > zeolite > granular activated carbon (GAC) > powdered activated carbon (PAC), while for biomass the order was Aureobasidium pullulans > Saccharomyces cerevisiae > activated sludge. Although Pb²⁺ removal capacity (mg Pb²⁺ g⁻¹) of the activated sludge (30.9) was lower than those of the ion exchange resin (167.7) and other pure cultures of A pullulans (170.4) and S cerevisiae (95.3), it was higher than those of other chemical adsorbents such as GAC (26.0), PAC (2.1), and zeolite (30.2). The initial Pb²⁺ removal rates for the chemical adsorbents were in the order of PAC > GAC > zeolite > ion exchange resin, while for the biomass samples it was A pullulans > activated sludge > S cerevisiae. The initial Pb²⁺ removal rate of activated sludge was higher than those of GAC, zeolite, ion exchange resin and S. cerevisiae cells. Therefore, it was concluded that activated sludge that has been used in a municipal wastewater facility can be effectively used in heavy metal removal processes, in situ. © 2000 Society of Chemical Industry     

废啤酒酵母同步吸附水中Pb2+、Zn2+、Cd2+的研究

利用废啤酒酵母同步吸附处理含Pb2+、Zn2+、Cd2+废水,考察了初始pH、反应时间和初始浓度等因素对去除率的影响,并对吸附动力学进行探讨.结果表明:废啤酒酵母对Pb2+、Zn2+、Cd2+同步吸附去除率大小依次为Pb2+＞Cd2+＞Zn2+;三者之间存在竞争吸附;拟二级动力学方程相关系数R2＞0.99,对Pb2+和在低浓度条件下拟合情况更好,内扩散和液膜扩散联合控制吸附速率.     

L-cystein modified bentonite-cellulose nanocomposite (cellu/cys-bent) for adsorption of Cu2+, Pb2+, and Cd2+ ions from aqueous solution

In this study, L-cystein modified bentonite-cellulose (cellu/cys-bent) nanocomposite was synthesized and characterized by XRD, FTIR, SEM with EDS, TGA, and TEM techniques. In order to optimize the process the effect of various operational parameters such as pH, adsorbent dosage, contact time, and temperature were also investigated. The adsorption experiments were carried out in initial concentrations range of 20-100 mg L^?1and the adsorbent affinity for metal ions was found to be in order of Cu²⁺ > Pb²⁺ > Cd²⁺. The optimum pH for adsorption of Cu²⁺ and Cd²⁺ was observed at 5 while for Pb²⁺ it was pH 6. Based on the Langmuir model, the maximum adsorption capacity of Cu²⁺, Pb²⁺, and Cd²⁺ at 50^?C was found to be 32.36, 18.52, and 16.12 mg g^?1, respectively. The Langmuir isotherm and pseudo-second order model were found to be better fitted than the other isotherms and kinetic models. The results of thermodynamic parameters confirmed the process to be endothermic and spontaneous in nature.     

二乙基二硫代氨基甲酸钠与Cu2+、Pb2+、Cd2+、Ni2+的络合性研究

在0.01 mol/L硼砂缓冲溶液中,以二乙基二硫代氨基甲酸钠(DDTC)为配体,与Cu2 、Pb2 、Cd2 、Ni2 络合,用紫外可见分光光度法测定了金属络合物的吸收光谱,并计算出它们的稳定常数.实验结果表明,DDTC分别在257、282 nm处出现两个最大吸收峰,而Cu2 、Pb2 、Cd2 、Ni2 配合物分别在紫外区的304、305、303、321 nm处有最大吸收峰;DDTC与Cu2 、Pb2 、Cd2 、Ni2 形成的配合物的稳定常数分别为4.05×1011,2.67×1011,2.14×1011,4.01×1010,其稳定性顺序为:Cu(DDTC)2＞Pb(DDTC)2＞Cd(DDTC)2＞Ni(DDTC)2.     

Polyethyleneimine-containing sol-gels as novel sorbents for the removal of cadmium from aqueous solutions

The removal of cadmium ions from aqueous solutions is described using polyethyleneimine (PEI) entrapped in sol-gel matrices. The process is optimized with respect to operating conditions and both sorption and desorption are considered. The sorption process followed the Langmuir isotherm, and the corresponding Langmuir constants q_max and K_dwere found to be 80.64 mg Cd2⁺/g PEI and 236.36 mg/L, respectively, using the immobilized PEI polymer. More than 90% of the cadmium could be recovered in 2 h using 2 M NaCl solutions. This technique has potential applications in the recovery of cadmium in aqueous waste streams.     

Modification of chitosan with cellulose and gelatin for the removal of Cu2+, Fe2+, and Pb2+ from oily wastewater

In this study, chitosan was modified with cellulose and gelatin for the removal of Cu²⁺, Fe²⁺, and Pb²⁺ from oily wastewater. Chitosan was characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Carbon (77.54%), hydrogen (10.30%), oxygen (8.89%), nitrogen (2.74%), and sulphur (0.53%) were found in the organic constitution of the oil utilized, according to elemental analysis. Despite the presence of other metal ions in the used oil and effluent, this study focused solely on Cu²⁺, Fe²⁺, and Pb²⁺. Studies on the removal of Cu²⁺, Fe²⁺, and Pb²⁺ from oily wastewater were conducted, and multiple effect factors such as temperature and pH, time and pH, solvent and pH, temperature and time, temperature and solvent, and time and solvent were evaluated. An adsorption study was performed to remove the heavy metals. The results revealed that the highest percentage removal of Cu²⁺ was 96.62 (pH = 7.52 and conductivity = −12 mV), of Fe²⁺ was 97.95 (pH = 6.30 and conductivity = +68 mV), and of Pb²⁺ was 98.86 (pH = 10.58 and conductivity = −170 mV). To analyze the impacts of experimental factors, experiments were developed using central composite design (CCD) based on response surface methodology (RSM).     

小球藻吸附水体中Cd~(2+)、Pb~(2+)和Cu~(2+)的试验研究

为了研究小球藻藻体吸附水体中Cd2+、Pb2+和Cu2+的情况,在检测了典型电子垃圾处理区水体中重金属Cd、Pb和Cu浓度的基础上,采用冷冻干燥的小球藻藻体在模拟重金属离子溶液中进行吸附试验。结果表明,水体中重金属Cu的浓度较高,Cd和Pb的污染程度较严重。藻体对于Pb2+的去除效果较好,去除率和去除量分别达到88.42%和13.262 4 mg/g;Cu2+的去除率较低,但去除量高达17.480 6 mg/g;Cd2+去除率较高,但去除量仅有0.433 7 mg/g。     

Poly (methacrylic acid) modified biomass for enhancement adsorption of Pb2+, Cd2+ and Cu2+

In this study, the graft copolymerization of methacrylic acid onto the biomass of baker's yeast was carried out in aqueous medium using potassium persulfate (PPS) as initiator. The poly (methacrylic acid) modified biomass obtained was characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS) and microscopic analyses. The number of functional groups was determined by potentiometric titration. The adsorption capacity of the modified biomass for Pb²⁺, Cd²⁺ and Cu²⁺ showed a significant increase compared with the pristine biomass, due to the presence of a large number of functional groups. According to the Langmuir equation, the maximum uptake capacities (q_m) for Pb²⁺, Cd²⁺ and Cu²⁺ were 243.9, 108.7 and 73.5 mg g^?1, respectively. Adsorption kinetics study showed that completion of the adsorption process needed only 30 min. The loaded biosorbent was regenerated using EDTA solution and used repeatedly three times with little loss of uptake capacity. Good results were obtained when the modified biomass was used to treat simulated wastewater containing Pb²⁺, Cd²⁺ and Cu²⁺. Copyright © 2007 Society of Chemical Industry     

Bio‐sorbents from cassava waste biomass and its performance in removal of Pb2+ from aqueous solution

Cassava xanthogenate and their derivatives, as adsorbents to remove Pb²⁺ from aqueous solution, are studied based upon orthogonal factorial design. The structural and thermal properties, adsorption performance as well as equilibrium‐kinetics are comprehensively investigated with multiple tools, such as Fourier transform infrared spectroscopy, thermal gravimetric analysis (TGA), and UV–visible spectrum technique. The influence of multiple parameters, including initial Pb²⁺ concentrations, compositions, pH values, and temperatures, on the adsorption performance is emphasized. The crosslinked cassava xanthogenate serves as an effective bio‐sorbent to remove Pb ions from aqueous solution, allowing regeneration in dilute acid solution. The findings in this study are beneficial for the development of adsorbents from cassava waste biomass and may contribute to environment recovery in “nature‐to‐nature” manner. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39780.     

Concentration and separation of aqueous solutions of Cu2+, Ni2+, Fe3+ by dextran

The effects of water-soluble polymers on the concentration and separation of the aqueous solutions of the metal ions have been studied. The separation of metal ions can be possible by ultrafiltration-complexation process. The effect of Dextran, which is a water-soluble polymer, on the concentration and separation of metal ions (Cu²⁺, Ni²⁺, Fe³⁺) have been investigated by using EC-PEG 4000 alloy membranes. The permeability of these membranes for metal ions has been rrecorded at constant pressure but different pH values. It has been notices that the highest water-permeable membrane is also permeable towards Cu²⁺ and Ni²⁺, but has shown a considerable retention for Fe³⁺ as a result of the hydrolysis of Fe³⁺. The retentions of metallic ions and metallic-ion-Dextran couples have been determined at constant pressure but different pH and polymer concentration values. It has been shown that Fe³⁺/Ni²⁺ and Fe³⁺/Cu²⁺ couples can be separated by using Dextran. © 1995 John Wiley & Sons, Inc.     

Competitive Adsorption of Ag+, Pb2+, Ni2+, and Cd2+ Ions on Vermiculite

Competitive adsorption of Ag⁺, Pb²⁺, Ni²⁺, and Cd² ions on vermiuculite in a binary, ternary, and quaternary mixture was investigated in batch experiments. The effects of the presence of Ag⁺, Ni²⁺, and Cd²⁺ ions on the adsorption of Pb²⁺ ions were investigated in terms of the equilibrium isotherm. Experimental results indicated that Pb²⁺ ions always favorably adsorbed on vermiculite over Ag⁺, Ni²⁺, and Cd²⁺ ions. The adsorption equilibrium data of Pb²⁺ ions better fitted the Langmuir model than the Freundlich model. The results showed that the pseudo-second-order kinetics model was in good agreement with the experimental results for all metal ions, and the adsorption rate among the metal ions followed Ag⁺ > Pb²⁺ > Ni²⁺ > Cd²⁺. The desorption and regenration study indicated that vermiculite can be used repeatedly and be suitable for the design of a continuous process.     

Competitive adsorption of Pb, Cu and Cd ions from aqueous solutions by multiwalled carbon nanotubes

The individual and competitive adsorption capacities of Pb²⁺, Cu²⁺ and Cd²⁺ by nitric acid treated multiwalled carbon nanotubes (CNTs) were studied. The maximum sorption capacities calculated by applying the Langmuir equation to single ion adsorption isotherms were 97.08 mg/g for Pb²⁺, 24.49 mg/g for Cu²⁺ and 10.86 mg/g for Cd²⁺ at an equilibrium concentration of 10 mg/l. The competitive adsorption studies showed that the affinity order of three metal ions adsorbed by CNTs is Pb²⁺>Cu²⁺>Cd²⁺. The Langmuir adsorption model can represent experimental data of Pb²⁺ and Cu²⁺ well, but does not provide a good fit for Cd²⁺ adsorption data. The effects of solution pH, ionic strength and CNT dosage on the competitive adsorption of Pb²⁺, Cu²⁺ and Cd²⁺ ions were investigated. The comparison of CNTs with other adsorbents suggests that CNTs have great potential applications in environmental protection regardless of their higher cost at present.     

Removal of Cu2+ and Pb2+ ions from aqueous solutions by starch-graft-acrylic acid/montmorillonite superabsorbent nanocomposite hydrogels

In this study, the removal of copper(II) and lead(II) ions from aqueous solutions by Starch-graft-acrylic acid/montmorillonite (S-g-AA/MMT) nanocomposite hydrogels was investigated. For this purpose, various factors affecting the removal of heavy metal ions, such as treatment time with the solution, initial pH of the solution, initial metal ion concentration, and MMT content were investigated. The metal ion removal capacities of copolymers increased with increasing pH, and pH 4 was found to be the optimal pH value for maximum metal removal capacity. Adsorption data of the nanocomposite hydrogels were modeled by the pseudo-second-order kinetic equation in order to investigate heavy metal ions adsorption mechanism. The observed affinity order in competitive removal of heavy metals was found Cu²⁺ > Pb²⁺. The Freundlich equations were used to fit the equilibrium isotherms. The Freundlich adsorption law was applicable to be adsorption of metal ions onto nanocomposite hydrogel.     

改性泥炭对Pb2+、Ni2+、Cu2+的吸附性能研究

在静态条件下,研究了改性泥炭对重金属离子Pb2+、Ni2+、Cu2+的吸附性能,着重探讨了改性泥炭去除废水中重金属离子Pb2+、Ni2+、Cu2+的适宜条件,同时对改性泥炭的吸附及解吸再生机理进行了初步分析。结果表明:在25℃条件下,当pH值为5～7、吸附剂用量为2g/L、吸附时间为2h时,改性泥炭对Pb2+、Ni2+、Cu2+的去除率分别为98.0%、96.7%、95.5%。吸附了重金属离子的改性泥炭经酸解吸再生后,可循环使用,不会带来二次污染。     

Interaction of stevensite with Cd2+ and Pb2+ in aqueous dispersions

The experimental process of adsorption of Pb(II) and Cd(II) onto clay mineral is studied here in order to evaluate the capacity for removal for these two heavy metal ions. This study is performed under various conditions such as initial solution pH, chemical clay modification conditions, initial metal ion concentration and contact time. The experimental isotherm data are analysed using Temkin, Langmuir and Freundlich equations and it is shown that models produce comparable equilibrium correlation results. The isotherm curves show very clearly the selectivity of the clay for the lead ions but also significant amounts of cadmium are removed as well. Adsorption kinetics data were tested using pseudo-first-order and Intraparticle diffusion models. Adsorption mechanism studies revealed that the process was complex and followed both surface adsorption and particle diffusion. The rate-controlling parameters and diffusion coefficients were determined using the Crank and McKay diffusion models. It was found that the adsorption occurs through film diffusion and the particle diffusion becomes the rate-determining step for each metal ion.     

Removal of Pb2+, Cd2+, Fe3+, and Sr2+ from Aqueous Solution by Selected Activated Carbons Derived from Date Pits

Date pits (DP) are a huge solid waste in Egypt and are of little or no economic value and in fact present a disposal problem. The quantity of DP has been estimated at a million tons per year. DP have been used for the preparation of physically and chemically activated carbons. The raw materials were physically activated with steam or chemically by impregnation with 10% ferric chloride or calcium acetate. The present study deals with the factors affecting the uptake of (Pb²⁺, Cd²⁺, Fe³⁺, and Sr²⁺) as pollutants from aqueous solution using activated carbon developed from locally available material DP, by a one‐step steam pyrolysis in a batch mode. The effect of various factors—carbon type, carbon dosage, pH, initial concentration, and temperature on the adsorption capacity were quantitatively determined. The two equilibrium models, the Langmuir and Freundlich equations, were discussed. In this work, analyses and batch adsorption experiments have been carried out to characterize and understand the adsorption mechanism by modeling the adsorption kinetics. Concurrently removal of these cations from the aqueous medium were found to be affected by the presence of some anions, NO₃ ^?, CO₃ ^?2, SO₄ ^?2 and masking agents, oxalic acid, and EDTA in solution.