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1.
Competitive adsorption of Ag +, Pb 2+, Ni 2+, and Cd 2 ions on vermiuculite in a binary, ternary, and quaternary mixture was investigated in batch experiments. The effects of the presence of Ag +, Ni 2+, and Cd 2+ ions on the adsorption of Pb 2+ ions were investigated in terms of the equilibrium isotherm. Experimental results indicated that Pb 2+ ions always favorably adsorbed on vermiculite over Ag +, Ni 2+, and Cd 2+ ions. The adsorption equilibrium data of Pb 2+ 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 + > Pb 2+ > Ni 2+ > Cd 2+. The desorption and regenration study indicated that vermiculite can be used repeatedly and be suitable for the design of a continuous process. 相似文献
2.
Abstract The aim of this work is to study the effectiveness of regional, low-cost natural clinoptilolitic zeolite tuff in heavy metal ions removal from aqueous solution, through comparative study with commercial granulated activated carbon. The equilibrium of adsorption of Cd 2+, Pb 2+, and Zn 2+ on both adsorbents have been determined at 25, 35, and 45°C in batch mode. The granulated activated carbon has shown around three times higher adsorption capacity for Cd 2+ and Zn 2+ than natural zeolite, and almost the same adsorption capacity for Pb 2+ as the natural zeolite. The metal ion selectivity series Pb 2+ > Cd 2+ > Zn 2+, on a mass basis, has been obtained on both adsorbents. The Langmuir and Freundlich model have been used to describe the adsorption equilibrium. The thermodynamic parameters were calculated from the adsorption isotherm data obtained at different temperatures. The study of the influence of the acidity of the metal ion aqueous solution has shown an increase of metal ion uptake with increase of the pH. The sorption mechanism of Cd 2+, Pb 2+, and Zn 2+ on natural zeolite changes from ion-exchange to ion-exchange and adsorption of metal-hydroxide with increase of the pH from 2 to 6 (and 7 for Zn 2+). The preliminary cost calculation, based on adsorbents maximum adsorption capacity and their price, have revealed the potential of natural zeolite as an economic alternative to the granulated activated carbon in the treatment of heavy metal polluted wastewater. 相似文献
3.
In this work, Fe 3O 4@SiO 2-(-NH 2/-COOH) nanoparticles were synthesized for the removal of Cd 2+, Pb 2+ and Zn 2+ ions from wastewater. The results of characterization showed that Fe 3O 4@SiO 2-(-NH 2/-COOH) was superparamagnetic with a core–shell structure. The surface of Fe3O4 was successfully coated with silica and modified with amino groups and carboxyl groups through the use of a silane coupling agent, polyacrylamide and polyacrylic acid. The dispersion of the particles was improved, and the surface area of the Fe3O4@SiO2-(-NH2/-COOH) nanoparticles was 67.8 m 2/g. The capacity of Fe 3O 4@SiO 2-(-NH 2/-COOH) to adsorb the three heavy metals was in the order Pb 2+ > Cd 2+ > Zn 2+, and the optimal adsorption conditions were an adsorption dose of 0.8 g/L, a temperature of 30°C and concentrations of Pb 2+, Cd 2+ and Zn 2+ below 120, 80 and 20 mg/L, respectively. The maximum adsorption capacities for Pb 2+, Cd 2+ and Zn 2+ were 166.67, 84.03 and 80.43 mg/g. The adsorption kinetics followed a pseudo-second-order model and Langmuir isotherm model adequately depicted the isotherm adsorption process. Thermodynamic analysis showed that the adsorption of the three metal ions was an endothermic process and that increasing the temperature was conducive to this adsorption. 相似文献
4.
Experimental studies on the retention of cadmium (Cd 2+), copper (Cu 2+), nickel (Ni 2+), and lead (Pb 2+) by bentonite samples from Iran were conducted using single- and multiple-component solutions. Based on the sorption capacity of bentonite the following order was obtained for single- and multiple-component solutions: Pb 2+ > Cd 2+ > Ni 2+ > Cu 2+. The maximum adsorption capacities of bentonite with metals in single- and multiple-component solutions were 29.5%, 22.5%, 19.2%, and 17.1% and 13.5%, 13.4%, 12.1%, and 9.1% for Pb 2+, Cd 2+, Ni 2+, and Cu 2+, respectively. Desorption isotherms of Cd 2+, Cu 2+, Ni 2+, and Pb 2+ deviated significantly from the sorption isotherms, thereby indicating irreversible or very slowly reversible sorption. Finally, soil solution saturation indices and metal speciation were assessed using the Visual MINTEQ 2.6 program and the probability of mineral precipitation was supported by scanning electron microscopy. 相似文献
5.
Cation-exchange adsorbents were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polypropylene (PP)
fabric and polyethylene (PE) hollow fiber and subsequent phosphonation of epoxy groups of poly(GMA) graft chains. The adsorption
characteristics of Pb 2+, Cu 2+ and Co 2+ for the two cation-exchange adsorbents were studied. In the grafting of GMA onto PP fabric, the degree of grafting (%) increased
with an increase in reaction time, reaction temperature, and pre-irradiation dose. The maximum grafting yield was observed
around 60% GMA concentration. In 50, 130 and 250% GMA-grafted PP fabric, the content of phosphoric acid was 1.52, 3.40 and
4.50 mmol/g at 80 °C in the 85 % phosphoric acid aqueous solution for 24 h, respectively. The adsorption of Pb 2+, Cu 2+ and Co 2+ by PP fabric adsorbent was enhanced with an increased phosphoric acid content The order of adsorption capacity of the PP
fabric adsorbent was Pb 2+>Co 2+>Cu 2+. In adsorption of Pb 2+, Cu 2+ and Co 2+ by PE hollow fiber, the amount of Pb 2+ adsorbed by the PE hollow fiber adsorbent containing 1.21 mmol/g of -PO 3H was ca. 54.4 g per kg. The adsorption amount of Cu 2+ and Co 2+ in the same PE hollow fiber was ca. 21.0 g per kg and ca. 32.1 g per kg, respectively. The order of adsorption of the PE hollow fiber adsorbent was Pb 2+>Co 2+>Cu 2+. 相似文献
6.
A novel chelating resin was synthesized and characterized by elemental, physico-chemical, GPC, NMR, and SEM analyses. Batch separation was adopted to study the recovery of selected metal ions with respect to the pH, time, concentrations, and electrolytes. From the results, it was observed that the order of the rate of metal ion uptake by the resin was Fe 3+ > Cu 2+ > Zn 2+ > Ni 2+ > Co 2+ > Pb 2+ ions. The adsorption kinetics follows first order, and isotherm models were also found to fit each other. The resin showed three-step thermal degradation, and its kinetic and thermodynamic parameters were also evaluated. 相似文献
7.
Abstract The aqueous-insoluble thia macrocycles tetrathia-14-crown-4 (TT14C4) and tetrathia-16-crown-4 (TT16C4) strongly and selectively synergize the extraction of Cu 2+ and Ag + ions from aqueous sulfuric acid solutions by the organophilic cation exchanger didodecylnaphthalene sulfonlc acid (HDDNS) in toluene diluent. Over a range of sulfuric acid concentrations, the selectivity is given by the order Ag 2 > Cu 2+ > Mn 2+, Fe 2+, Fe 3+, Co 2+, Ni 2+, and Zn 2+, where synergism occurs only for Ag + and Cu 2+. Selectivity factors greater than 300 have been achieved for Cu 2+ over ubiquitous Fe 3+. The synergistic extraction of Cu 2+ and Ag + was explored as a function of sulfuric acid concentration, relative concentration of macrocycle vs. HDDNS, and loading. 相似文献
8.
Sodium tripolyphosphate crosslinked chitosan was prepared and immobilized with pentamine moieties. The samples obtained were characterized by elemental analysis and FT-IR. The adsorption behavior of the samples was studied towards Hg 2+ using batch and column methods. The adsorption depended on the pH of the medium and was explained to proceed via complex formation and/or ion exchange mechanisms. The uptake capacity was found to be 4.7 mmol/g at pH = 2. Selective separation of Hg 2+ from a solution containing Pb 2+, Cu 2+, Ca 2+, Zn 2+, Fe 3+, and Mg 2+ was achieved at pH = 1. The values of the kinetics and the thermodynamic parameters of the uptake process were reported. The flow rate of 3 mL/min in column experiments was found to be the most preferable rate. The regeneration of the loaded resin was performed using 0.5 M potassium iodide. 相似文献
9.
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 Cu 2+ > Pb 2+ > Cd 2+. The optimum pH for adsorption of Cu 2+ and Cd 2+ was observed at 5 while for Pb 2+ it was pH 6. Based on the Langmuir model, the maximum adsorption capacity of Cu 2+, Pb 2+, and Cd 2+ 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. 相似文献
10.
Abstract The transport of cadmium ions from hydrochloric acid solutions across a bulk liquid membrane by using dicyclohexyl‐18‐crown‐6 (DC18C6) dissolved in dichloromethane has been studied at 25°C. The effect of the fundamental parameters influencing the transport, e.g., hydrochloric acid concentration in the feed phase, DC18C6 concentration and the type of diluent used in the membrane and time of transport have been investigated. The transported amount of the cadmium ions (initial concentration 0.001 M) from a 6 M hydrochloric acid solution across a dichloromethane solution of DC18C6 (0.05 M) into distilled water (receiving phase) was found to be 98.3 (±1.8) percent after 6 h. The selectivity and efficiency of the method toward cadmium ions were tested by performing the competitive transport experiments on the mixtures containing Cd 2+, Ni 2+, Mn 2+, Co 2+, Zn 2+, Pb 2+, and Fe 2+ ions. The best selectivity was found for the recovery of the cadmium ions from its mixture with Ni 2+, Mn 2+, Co 2+, and Pb 2+ ions. Thus, the method can be proposed for the application in cadmium recovery from the sources containing these ions such as spent rechargeable nickel‐cadmium batteries. 相似文献
11.
A novel terpolymer acts as an effective chelating ion exchanger which was synthesized using 2-amino-6-nitro-benzothiazole and semicarbazide with formaldehyde (BSF) by solution condensation technique. Its ion exchange properties was determined against certain metal ions viz. Fe 3+, Co 2+, Ni 2+, Cu 2+, Zn 2+ and Pb 2+ using batch equilibrium technique with different electrolyte concentrations, pH ranges and time intervals. The results of batch studies revealed that the separation of the selected metal ions from the aqueous solution by the terpolymer is found to be excellent compared to the available commercial resins and earlier reported resins. The order of metal ion uptake at higher concentrations by the BSF terpolymer at lower pH is Cu 2+ > Ni 2+ > Fe 3+ and at lower concentration at higher pH is Zn 2+ > Co 2+ > Pb 2+. The reusability of the resin was also reported for its effective ion-exchange behaviour for several cycles. The adsorption isotherm model was evaluated and the results are in good agreement with each other. The order of kinetics was also determined and the resin follows pseudo-second-order kinetics. Moreover, the physico-chemical analysis gives strong evidence for the effective metal ion removal compared with the earlier reported and commercial resins. Earlier, the structure and the properties of the synthesized novel chelating resin were clearly elucidated by elemental, FTIR, UV–Vis, 1H & 13C NMR spectra, GPC, SEM and XRD. 相似文献
12.
A total of six washed French and Algerian kaolins were studied. Kaolinite, halloysite, muscovite, feldspars, anatase, rutile, gibbsite, goethite, and todorokite were present. The thermal behavior of the samples was studied and the transformation heats were determined and quantified by differential thermal analysis. Calcined samples from 900°C to 1400°C are studied by X‐ray diffraction, the results show that the crystallite sizes of mullite rises as the temperature rises. The calcined samples showed an inverse correlation of L* and the crystallite sizes of mullite due to the incorporation of chromophore elements (Fe 3+, Ti 4+, and Mn 2+) in its structure. Muscovite and rutile phases decreased lightness and increased chromaticity. The reduction state of Fe 3+/Fe 2+ and Mn 4+/Mn 2+ at 1400°C enhanced lightness leading to the diminution of the b* parameter. The CIELAB color parameters were significantly affected with mineralogy and chemical compositions of the samples. Lightness of the natural kaolins is decreased (L* < 59) when organic matters beside manganese and iron oxides are present. L* was not affected when only iron (Fe 2+) is present in the kaolin; however, the chromaticity is increased (b* > 22). Whiteness and tint indices (W 10, T w,10) revealed that only one kaolin could be considered white (limits of CIE Colorimetry, 1986), though upon calcination, this number is enhanced to two. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 499–505, 2014 相似文献
13.
In a multicomponent systems, the adsorption of Pb 2+, Cu 2+, and Ni 2+ by date seed biochar exhibited competitive behavior. Compared to single component systems, the adsorption capacities of each ion were reduced by 48–75% in both batch and column experiments. Surface complexation with carboxyl and hydroxyl functional groups played a major role in the removal mechanism. Ion exchange mechanism accounted for 37–40% of the total adsorption compared to 57–72% in single component systems. Modified Langmuir isotherm best described the systems. Adsorption capacities and selectivity follow the order: Pb 2+> Cu 2+> Ni 2+. Multi-stage sequences system is recommended to avoid premature exhaustion of biochar. 相似文献
14.
Mill scale scrap, which contains vast amounts of valuable metals, is a solid waste produced in the iron and steel industry. Conventional mill scale scrap treatment methods for metal extraction are characterized by high energy consumption and low value addition. In this study, co-treatment of mill scale scrap and manganese ore via the oxidization roasting-magnetic separation process was investigated for the synchronous preparation of higher-value materials and recovery of valuable metals. Thermodynamic and magnetism analyses indicated that a higher temperature (>1100 °C) and a MnO 2/Fe 2O 3 molar ratio of 0.75–1 are essential for the preparation of manganese ferrite. The experimental validation revealed that soft magnetic manganese ferrite powders with a purity of 97.5 wt% were obtained when the test was conducted at 1300 °C for 120 min, followed by a two-stage grinding and magnetic separation process; the corresponding yield and the Mn and Fe recoveries were 78.99 wt%, 86.14 wt%, and 84.60 wt%, respectively. During the oxidization process, [Fe 2+]O was initially oxidized to the anti-form spinel-type structure of [Fe 3+][Fe 2+Fe 3+]O 4, and thereafter, it reacted with the decomposition product of [Mn 3+][Mn 2+Mn 3+]O 4 to form a hybrid spinel-type structure [Me 2+xMe 3+l-x][Me 2+1-xMe 3+1+x]O 4 (Me refers to Mn and Fe) via the Mn 2+/Fe 2+/Mn 3+/Fe 3+ ions exchange at the tetrahedral and octahedral sites. Moreover, the as-purified ferrite can be used as an ingredient for the preparation of high-performance MnZn ferrite. 相似文献
15.
ABSTRACT The ion exchange of trace amounts of Cu 2+, Zn 2+ and Pb 2+ with the hydrogen-form of hydrated ferric oxide as a function of nitric acid concentration has been studied at 25, 30,35 and 60 °C. Ion exchange of these cations increases with increasing temperature in the investigated temperature range. From these results, equilibrium constants for the Cu 2+/H +, Zn 2+/H + and Pb 2+/H + ion exchange on hydrated ferric oxide and thermodynamic quantities for these reactions were calculated, and some predictions made for the exchange process taking place in this material. The selectivity series is Zn 2+ > Cu 2+ > Pb 2+. 相似文献
16.
In this paper, Methacrylic acid (MAA) and 4-vinyl pyridine (4-VP) as functional monomers, Ethylene glycol two methyl acrylate (EGDMA) as crosslinking agent, isopropyl alcohol as the solvent, prepared the Cu(II)- and Pb(II)- imprinted polymers (IIPs) submicron spheres by precipitation polymerization. The presence/absence of the template ion in the preparation of the imprinted polymer was confirmed by EDX spectroscopy, and the structure of the particles was investigated using IR, SEM and BET analysis. From different components of crosslinker/monomer (C/M) ratio analysis, C/M at 1:3 was the optimal ratio for preparing IIPs. Atomic absorption spectroscopy (AAS) was characterized the imprinted polymers absorption behavior. The results show that the maximum adsorption capacity of Cu2+ and Pb2+ -imprinted polymer were 26.9 mg g?1 and 25.3 mg g?1, respectively. They also have good adsorption capacity and superior selectivity property for Cu2+ and Pb2+ in water, respectively. The selectivity factors (α) for Ni2+, Zn2+, Co2+ and Fe2+ were 16.5 (Cu2+) and 12.1 (Pb2+), 13.8 (Cu2+) and 16.2 (Pb2+), 10.8 (Cu2+) and 10.1 (Pb2+), 20.4 (Cu2+) and 20.7 (Pb2+), respectively. The regeneration experiment result demonstrates an excellent re-utilization property of these two type IIPs, after ten uses, the adsorption capacity can maintain above 60%. 相似文献
17.
Abstract An electron beam grafted adsorbent was synthesized by post irradiation grafting of acrylonitrile (AN) on to a non‐woven thermally bonded polypropylene (PP) sheet using 2 MeV electron beam accelerator. The grafted poly(acrylonitrile) chains were chemically modified to convert a nitrile group to an amidoxime (AMO) group, a chelating group responsible for metal ion uptake from an aqueous solution. The effect of various experimental variables viz. dose, dose rate, temperature, and solvent composition on the grafting extent was investigated. PP grafted with the amidoxime group (AMO‐g‐PP) was tested for its suitability as an adsorbent for removal of heavy metal ions such as Co 2+, Ni 2+, Mn 2+, and Cd 2+ from aqueous solution. Langmuir and Freundlich adsorption models were used to investigate the type of adsorption of these ions. The adsorption capacities of the adsorbent for the metal ions were found to follow the order Cd 2+>Co 2+>Ni 2+>Mn 2+. The kinetics of adsorption of these ions indicated that the rate of adsorption of Cd 2+ was faster than that of other ions studied. 相似文献
18.
Poly(acrylamide- co-itaconic acid) (AAm/IA) and poly(acrylamide- co-monomethoxyethyl itaconate) (AAm/MEI) hydrogels (HGs) synthesized at different molar ratios were used to study the adsorption of some metal ions as Cu 2+, Ni 2+, Pb 2+, Cd 2+, and Fe 3+ in aqueous solutions at different concentration: 10, 50, 100, 500, and 1000 mg L −1. Statistical analysis was performed and the effect of the metal ion, ion concentration, and hydrogel (HG) composition, on adsorption and adsorption efficiency, was evaluated for both HGs studied (AAm/IA and AAm/MEI) and each factor gave rise to significant differences ( P ≤ 0.05). The adsorption depends on the type of ion, its concentration, and also influenced by the type and composition of the HGs. For each system the adsorption efficiencies for all ions were similar with exception of Fe 3+, which showed the highest adsorption efficiency in AAm/MEI HG, but the less for the AAm/IA. For both systems, the maximum adsorption efficiency was observed when the molar ratio AAm/IA or AAm/MEI is 80/20. When the adsorption was carried out with individual ions, AAm/MEI HG was more efficient than AAm/IA. For a multielement sample of Cu 2+, Ni 2+, Pb 2+, and Cd 2+, both HGs could adsorb all the ions and their behavioral trend was the same in both cases, in which the adsorption efficiency was Pb 2+ > Cu 2+ > Cd 2+ > Ni 2+. The results of the statistical analysis evidence the advantage of its use in this type of studies. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46999 相似文献
19.
Six chelating hollow fiber membranes were prepared by radiation‐induced grafting of glycidyl methacrylate onto a polyethylene hollow fiber membrane and its subsequent amination. The adsorption characteristics of Pb 2+ and Pd 2+ for the chelating hollow fiber membranes were presented when the solution of Pb 2+ and Pd 2+ permeates across the chelating membrane, respectively. The degree of grafting for glycidyl methacrylate increases with increasing monomer concentration, reaction temperature, and preirradiation dose. The adsorption of Pd 2+ by chelating hollow fiber membranes modified with five kinds of amines was in the following order: diethylene triamine > hexamethyl diamine > ethylene diamine > dimethyl amine > trimethyl amine. The chelating hollow fiber membrane modified with iminodiacetic acid adsorbed Pb 2+ ions much more than Pd 2+. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 643–650, 1999 相似文献
20.
Reusability and selective adsorption toward Pb 2+ with the coexistence of Cd 2+, Co 2+, Cu 2+ and Ni 2+ ions on chitosan/P(2-acrylamido-2-methyl-1-propanesulfonic acid- co-acrylic acid) [CS/P(AMPS- co-AA)] hydrogel, a multi-functionalized adsorbent containing –NH 2, –OH, –COOH and –SO 3H groups was studied. The CS/P(AMPS- co-AA) was prepared in aqueous solution by a simple one-step procedure using glow discharge electrolysis plasma technique. The reusability of adsorbent in HNO 3, EDTA-2Na and EDTA-4Na was investigated in detail. The competitive adsorption of the metal ions at the initial stage was compared between their equal mass concentration and equal molar concentration. In addition, the adsorption mechanism of the adsorbent for adsorption of Pb 2+ was also analyzed by XPS. The results showed that the optimum pH of adsorption was 4.8, and time of adsorption equilibrium was about 180 min. Adsorption kinetics fitted well in the pseudo second-order model. The equilibrium adsorption capacities of Pb 2+, Cd 2+, Co 2+, Cu 2+, and Ni 2+ at pH 4.8 were obtained as 673.3, 358.3, 176.7, 235.0 and 171.7 mg g ?1, in their given order. The adsorbent displayed an excellent reusability using 0.015 mol L ?1 EDTA-4Na solution as the eluent, and the desorption ratio could not correctly reflect the true characteristics of adsorption/desorption process. Moreover, the adsorbent showed good adsorption selectivity for Pb 2+. The molar adsorption capacity at the initial stage with equal molar concentration was more reliable than the mass adsorption capacity during the study of selective adsorption. According to the XPS results, the adsorption of Pb 2+ ions by the CS/P(AMPS- co-AA) absorbent could be attributed to the coordination between N atom and Pb 2+ and ion-exchange between Na + and Pb 2+. 相似文献
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