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1.
Various composite adsorbents based on sulfonated poly(ether ether ketone)/manganese dioxide were prepared for the removal of stable and radioactive ions from contaminated aqueous solution. Batch adsorption experiments revealed superior adsorption capacities of the composite using very low initial concentration of studied elements. Starting with 1000 µg L−1 contaminated solution, the maximum equilibrium metal uptake capacity reached 2.0 mg g−1 for Pb2+, 1.9 mg g−1 for Cd2+, Cu2+ and Zn2+, and 3.7 mg g−1 for Co2+. In addition, the distribution coefficient reached 11,600 mL g−1 for 137Cs and 70,000 mL g−1 for 210Pb. 相似文献
2.
Sulfonated ion irradiated (H+ and He2+) PEEK films were synthesized with a range of cross-linking density and a variety of sulfonation degrees. Batch adsorption experiments were carried out at an initial pH of 6.0 ± 0.2, initial concentrations of Pb2+ and 137Cs ions of 10.0 mg L−1 and 5500 Bq L−1, respectively. The maximum adsorption capacity was 60 mg g−1 for Pb2+, and the distribution coefficient reached 6200 cm3 g−1 for 137Cs. The results indicated that sulfonation could be used to recycle low cross-linked PEEK and prepare efficient adsorbents to remove toxic Pb2+ and 137Cs from polluted aqueous solutions. 相似文献
3.
Nanomaterials play a significant role in adsorption treatment of dye wastewater, but irreversible aggregation of nanoparticles poses a significant problem. In this work, nanomesoporous zinc-doped silicate (NMSZ) was prepared by an in situ method. To prevent agglomeration, NMSZ was covalently bonded to graphene oxide (GO) sheets to form a nano-silica/zinc/graphene oxide composite (GO-NMSZ), aimed at removal of cationic dye methylene blue (MB). For comparison, undoped mesoporous silica (MS) was also synthesized and modified to obtain a silica/graphene oxide composite (GO-MS). The materials were characterized by powder XRD, SEM, FTIR spectroscopy, TEM, nitrogen sorption, and X-ray photoelectron spectroscopy (XPS). Preservation of the oxygen-containing groups of GO in the composites led to higher adsorption capacities. The best GO-NMSZ composite exhibited an enhanced adsorption capacity of 100.4 mg g −1 for MB compared to those of undoped GO-MS (80.1 mg g −1) and nongrafted NMSZ (55.7 mg g −1). The nonselective character of GO-NMSZ is demonstrated by effective adsorption of anionic dye Congo red (127.4 mg g −1) and neutral dye isatin (289.0 mg g −1). The adsorption kinetics, adsorption isotherms, and a thermodynamic study suggested that MB adsorption occurs by chemisorption and is endothermic in nature. 相似文献
4.
In this study, the ion-imprinting method has been integrated to develop a novel composite material for the selective separation of Pb 2+ ions. Also, Pb 2+ ion binding ability of the organosmectite based inorganic-organic composite incorporation of bicyclic C18 organic compound into smectite layers was conducted to draw a projection its potential use as a solid phase exchanger which is quite selective toward Pb 2+ ions. The ion-imprinted nanocomposites were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), swelling tests, and elemental analyses. After that, maximum binding capacity, pH, and equilibrium binding time were also been optimized. In order to show the selectivity of the composite synthesized, non-imprinted composites were also synthesized in absence of Pb 2+ ions during polymerization. In this step, Ni 2+, Co 2+, Al 3+, Zn 2+, and Cu 2+ ions were used as competitors under batch adsorption conditions. The relative selectivity coefficients of imprinted composite were calculated as 28.5, 156.5, 69.3, 24.8 and 131.6 for Pb 2+/Co 2+, Pb 2+/Cu 2+, Pb 2+/Al 3+, Pb 2+/Zn 2+, Pb 2+/Ni 2+ binary solutions, respectively. Finally, reusability of the composites was evaluated to show its cost-efficiency by repeating adsorption-desorption experiments ten-times. The adsorption capacity of the imprinted composites did not change significantly whereas that of non-imprinted version reduced dramatically. 相似文献
5.
The competitive removal of Pb 2+, Cu 2+, and Cd 2+ ions from aqueous solutions by the copolymer of 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (AMPS) and itaconic acid (IA), P(AMPS‐ co‐IA), was investigated. Homopolymer of AMPS (PAMPS) was also used to remove these ions from their aqueous solution. In the preparation of AMPS–IA copolymer, the molar percentages of AMPS and IA were 80 and 20, respectively. In order to observe the changes in the structures of polymers due to metal adsorption, FTIR spectra by attenuated total reflectancetechnique and scanning electron microscopy (SEM) pictures of the polymers were taken both before and after adsorption experiments. Total metal ion removal capacities of PAMPS and P(AMPS‐ co‐IA) were 1.685 and 1.722 mmol Me 2+/g polymer, respectively. Experimental data were evaluated to determine the kinetic characteristics of the adsorption process. Competitive adsorption of Pb 2+, Cu 2+, and Cd 2+ ions onto both PAMPS and P(AMPS‐ co‐IA) was found to fit pseudo‐second‐order type kinetics. In addition, the removal orders in the competitive adsorption of these metal ions onto PAMPS and P(AMPS‐ co‐IA) were found to be Cd 2+ > Pb 2+ > Cu 2+ and Pb 2+ > Cd 2+ > Cu 2+, respectively. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
6.
The adsorption of Pb(II) ions from aqueous solutions by chitosan flakes and beads was studied. The chitosan beads were prepared by casting an acidic chitosan solution into alkaline solution. Experiments were carried out as a function of pH, agitation period and initial concentration of Pb 2+ ions. The uptake of Pb 2+ ions from aqueous solution was determined from changes in concentration as measured by atomic absorption spectroscopy. The maximum uptake of Pb 2+ ions on chitosan beads was greater than that on chitosan flakes. Adsorption isothermal data could be interpreted by the Langmuir equation. The experimental data of the adsorption equilibrium from Pb 2+ ion solutions correlated well with the Langmuir isotherm equation. SEM analyses were also conducted for visual examination of the chitosan flakes and beads. Physical properties including surface area and average pore diameter were characterized by N 2 adsorption experiment. 相似文献
7.
3‐Hydroxy‐ N, N‐diethylaniline (HDEA) as a tertiary aromatic amine was introduced onto the surface of chloromethylated polysulfone (CMPSF) microfiltration membrane through modification reaction, resulting in the modified membrane PSF‐DEA. A redox surface‐initiating system (DEA/APS) was constituted by the bonded tertiary aromatic amine group DEA and ammonium persulfate (APS) in aqueous solution, and so, the free radicals formed on the membrane initiated sodium p‐styrenesulfonate (SSS) as an anionic monomer to produce graft polymerization, getting the grafting‐type composite microfiltration membrane, PSF‐ g‐PSSS membrane. Subsequently, the adsorption property of PSF ‐g‐PSSS membrane for three heavy metal ions, Pb 2+, Zn 2+, and Hg 2+ ions, was fully examined, and the rejection performance of PSF ‐g‐PSSS membrane towards the three heavy metal ions was emphatically evaluated via permeation experiments. The experimental results show that by the initiating of the surface‐initiating system of DEA/APS, the graft polymerization can smoothly be carried out under mild conditions. PSF ‐g‐PSSS membrane as a functional microfiltration membrane has strong adsorption ability for heavy metal ions by right of strong electrostatic interaction (or ion exchange action) between the anionic sulfonate ions on the membrane and heavy metal ions. The order of adsorption capacity is Pb 2+ > Zn 2+ > Hg 2+, and the adsorption capacity of Pb 2+ ion gets up to 2.18 μmol/cm 2. As the volume of permeation solutions, in which the concentrations of the three metal ions are 0.2 mmol/L, are in a range of 50 to 70 mL, the rejection rate of PSF ‐g‐PSSS membrane for the three heavy metal ions can reach a level of 95%, displaying a fine rejection and removing performance towards heavy metal ions. 相似文献
8.
Biosorbent materials represent an interesting alternative to classic methods of metal removal from industrial effluents. Acacia biomass showed a higher absorption capacity for heavy metals than living biomass. This study aimed to evaluate the bioadsorption of Lead and Cadmium onto Acacia Gummifera gum, using batch experiment. The structural characterization of the biosorbent was carried out using FT-IR, SEM, BET, TGA and DSC analysis. The adsorption equilibrium was reached within 15 min. A maximum uptake of 18.3 mg.g −1 Pb 2+ and 9.57 mg.g −1 Cd 2+ was achieved at pH 6.5. The metal ions seemed to be removed exclusively by ion exchange, physical sorption and chelation. The biomass of A. Gummifera powder was found to be effective for lead and cadmium removal with respectively 97% and 86% sorption efficiency at a concentration of 100 mg/L, in aqueous media. Parameters affecting adsorption capacities such as biosorbent dosage, initial metal concentration, temperature, and pH are discussed in detail. Furthermore, adsorption thermodynamics, kinetics, and equilibrium were studied and fitted by different models. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherms were used to compare adsorption data at equilibrium. The adsorption kinetics data were found to be best fitted by the pseudo-second-order model, and the adsorption isotherm was well fitted with the Langmuir model. The calculated thermodynamic parameters (ΔG 0, ΔS 0 and ΔH 0) indicated a spontaneous and exothermic biosorption of both metal ions onto Acacia Gummifera. Moreover, chromatograms obtained by size exclusion chromatography coupled with multi-angle laser light scattering detection system (SECMALLS) showed the formation of complexes between the arabinogalactan-peptide (AGP) and glycoprotein (GP) Acacia moieties and the two studied metal ions. The analysis of the FTIR spectra of dried Acacia and that of Acacia loaded with lead and cadmium in aqueous media suggests that the surface functional groups such as amides and carboxy groups might be involved in the metal removal process.The extent of adsorption for both metals increased along with an increase of the A. Gummifera biomass dosage. A. Gummifera biomass, which is safe, of low-cost, and highly selective, seems therefore to be a promising substrate for simultaneous trapping of Pd and Cd ions in aqueous solutions. 相似文献
9.
Kapok fiber, a natural hollow fiber with thin shell and large cavity, has rarely been used as adsorbent for heavy metal ions. In this paper, kapok fibers were modified with diethylenetriamine pentaacetic acid (DTPA) after hydrophilicity treatment. The adsorption behavior of the resultant kapok-DTPA influenced by pH, adsorption time and initial concentration of metal ion was investigated. The results demonstrate that adsorption equilibrium was reached within 2 min for Pb 2+ and Cd 2+. Adsorption kinetics showed that the adsorption rate was well fitted by pseudo-second-order rate model. The adsorption isotherms were studied, and the best fit was obtained in the Langmuir model. The maximum adsorption capacities of kapok-DTPA were 310.6 mg g ?1 for Pb 2+, 163.7 mg g ?1 for Cd 2+, 101.0 mg g ?1 for Cu 2+, respectively. After eight desorption and re-adsorption loops, the lost adsorption capacities for Pb 2+ and Cu 2+ were less than 10 %. Because of the large specific area derived from the hollow fiber structure, kapok-DTPA exhibited much better adsorption capacity compared with many other reported adsorbents based on natural materials. 相似文献
10.
以聚甲基含氧硅氧烷(PMHS)、正硅酸乙酯(TEOS)和氨丙基三甲氧基硅烷(APTMS)作为反应前驱体,在无需传统结构导向剂的溶胶-凝胶体系中制备了介孔结构发达的氮基功能化凝胶吸附剂,并采用元素分析、固体核磁共振、傅里叶红外光谱、低温氮气吸附/脱附、透射电镜和热重分析等手段对产物结构性能进行了表征.氮气吸附和透射电镜测... 相似文献
11.
Waste materials from industries such as food processing may act as cost effective and efficient biosorbents to remove toxic contaminants from wastewater. This study aimed to establish an optimized condition and closed loop application of processed orange peel for metals removal. A comparative study of the adsorption capacity of the chemically modified orange peel was performed against environmentally problematic metal ions, namely, Cd 2+, Cu 2+ and Pb 2+, from aqueous solutions. Chemically modified orange peel (MOP) showed a significantly higher metal uptake capacity compared to original orange peel (OP). Fourier Transform Infrared (FTIR) Spectra of peel showed that the carboxylic group peak shifted from 1637 to 1644 cm −1 after Pb (II) ions binding, indicated the involvement of carboxyl groups in Pb(II) ions binding. The metals uptake by MOP was rapid and the equilibrium time was 30 min at constant temperature and pH. Sorption kinetics followed a second-order model. The mechanism of metal sorption by MOP gave good fits for Freundlich and Langmuir models. Desorption of metals and regeneration of the biosorbent was attained simultaneously by acid elution. Even after four cycles of adsorption-elution, the adsorption capacity was regained completely and adsorption efficiency of metal was maintained at around 90%. 相似文献
12.
Mesoporous materials have exceptional properties for application owing to their ability to absorb and interact with guest species. A novel MgO/OMC composite with mesoporous structure was successfully synthesized via in situ magnesiothermic reduction. The structure was confirmed by N 2 sorption isotherms, X‐ray diffraction pattern (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). By using nafion and bismuth films as co‐modifiers, the MgO/OMC composite material shows high sensitivity of 0.113 μA ? L μg ?1 and lower background current for electrochemical determination of lead ion (Pb 2+) by using anodic stripping voltammetry. The high specific surface area and good mass transfer on the proposed mesoporous material, as well as the outstanding adsorption abilities of MgO to metal ions and the excellent conductivity of the carbon skeleton contribute to the enhanced electrochemical response of Pb 2+. As the stripping response of Bi/MgO/OMC‐Nafion/PGE is highly linear (R 2=0.998) over a Pb 2+ concentration range of 2 to 300 μg/L, it was successfully used to analyse Pb 2+ in real tap‐water samples with good recoveries. 相似文献
13.
The preparation of malonic acid‐catalyzed carbon xerogels modified with nitric acid and their high performance for adsorption of Cu 2+ were investigated. The treated and untreated carbon xerogels (nitrogen‐doped carbon xerogel and carbon xerogel) are mainly microporous with high surface areas (1150.18 and 1201.46 m 2 g ?1) based on the analysis of N 2 adsorption isotherm. Fourier transform infrared spectroscopy study demonstrates that modification process generates a number of functional groups such as carboxyl, carbonyl, and nitrate groups. X‐ray photoelectron spectra analysis shows an increase in the content of O and N after oxidation. The adsorption performance for Cu 2+ using different process parameters like initial concentration, contact time, and temperature was investigated. The result indicates that the pseudo‐second order correlates with the experimental data, and the activation energy of Cu 2+ adsorption onto nitrogen‐doped carbon xerogel and carbon xerogel is calculated as 15.62 kJ mol ?1 and 2.79 kJ mol ?1, respectively, indicating the coexistence of chemisorption and ion‐exchange. Langmuir and Freundlich isotherms were used to describe the adsorption behavior of Cu 2+. The adsorption of Cu 2+ by carbon xerogels modified with nitric acid was fast and had noticeable adsorption capacity, with a higher adsorption capacity than the original carbon xerogels (299.41 vs 260.42 mg g ?1). Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
14.
AbstractAmino-functionalized mesoporous silica nanoparticles (AFMSN) were prepared based on the self-assembly process of the pre-fabricated template of anionic gemini surfactant. The perfect mass ration of the reactants for the synthesis of the AFMSN with high surface area and amino loading was optimized by orthogonal experiments. Adsorption capability of the optimized product for lead ion (Pb 2+) was investigated in detail. Specially, the effects of the amino content, solution pH, adsorbent dosage, temperature, and interference of other metal ions on the removal efficiency of Pb 2+ were studied. It is found that these factors can greatly affect the removal efficiency of Pb 2+ and the prepared adsorbent exhibits the high adsorption selectivity for Pb 2+. At an optimal condition, the AFMSN adsorbent presents an excellent adsorption capacity for Pb 2+ up to 211.42?mg/g. The adsorption kinetics study revealed that the pseudo-second-order model could well describe the Pb 2+ adsorption process, and the adsorption isotherm was fitted well with the Langmuir model. More importantly, the AFMSN adsorbent could be recycled 8 times and a high adsorption efficiency of Pb 2+ could still be maintained. Therefore, the prepared AFMSN adsorbent may find practical application in removing Pb 2+ from the polluted water. 相似文献
15.
Amino group-functionalized Fe 3O 4 is loaded on a coordination complex-modified polyoxometalate nanoparticle. In this composite material, Fe 3O 4 and coordination complex-modified polyoxometalate are connected with intense hydrogen bonds as suggested by FTIR. This composite material exhibits excellent methylene blue (MB) adsorption, with adsorption capacity of 175.5 mg g ?1. It also possesses selective separation ability between cationic and anionic dye molecules. In binary solution of MB and methyl orange (MO), MB adsorption efficiency reaches 75%, but it exhibits almost no effect on the adsorption of methyl orange. The saturation magnetization value of this composite material is 18.89 emu g ?1, allowing magnetic separation, which facilitates the recycle and reuse of this composite adsorbent. 相似文献
16.
The current study discusses application of the lanthanum ions (La 3+) as an activating agent incorporated /immobilized into coconut shell–based granular activated carbon (GAC) for porosity development; subsequently, the carbon material is used for the adsorption of phenol from aqueous solutions. The new carbons were characterized using FTIR, XRD, CHNO, burn off, and carbon yield. The surface functional groups were determined by Boehm titration. The Brunauer–Emmett–Teller (BET) surface area of the carbons is 953 m 2 g −1 (GACLa1073), 997 m 2 g −1 (GAC383), and 973 m 2 g −1 (GACO383). Langmuir, Freundlich, Dubinin–Radushkevich, and John–Sivanandan Achari (J-SA) isotherm models on the equilibrium isotherm data were examined for the new carbon-phenol system. It is found that the Langmuir isotherm fits better with a monolayer adsorption capacity, highest for GACLa1073 (387.59 mg g −1) followed by GAC383 (303.03 mg g −1) and GACO383 (197.62 mg g −1). Kinetic studies reveal that the adsorption system follows the pseudo–second-order kinetic model. Isotherm analysis by the phase change method of John-Sivanandan Achari (J-SA) isotherm gives a better insight into adsorption phenomena, which is accompanied by regeneration studies of carbon with >75% for GACLa1073 after three cycles. 相似文献
17.
Various polyoxometalates (POMs) were successfully immobilized to the mesoporous coordination polymer MIL‐101 resulting in a series of POM–MOF composite materials POM@MIL‐101 (POM=K 4PW 11VO 40, H 3PW 12O 40, K 4SiW 12O 40). These materials were synthesized by a simple one‐pot reaction of Keggin POMs, tetramethylammonium hydroxide (TMAH), terephthalic acid (H 2bdc), and Cr 3+ ions. XRD, FTIR, thermogravimetric analyses (TG), inductively coupled plasma (ICP) spectrometry, and energy‐dispersive X‐ray spectroscopy (EDX) collectively confirmed the successful combination of POMs and the porous framework. Further, these composites POM@MIL‐101 with different loading of POMs were achieved by variation of the POM dosage. Notably, the uptake capacity of MIL‐101 towards organic pollutants in aqueous solution was significantly improved by immobilization of hydrophilic POMs into cages of MIL‐101. An uptake capacity of 371 mg g ?1, comparable to that of the graphene oxide sponges, and much higher than that of the commercial activated carbon, was achieved at room temperature in 5 min when dipping 20 mg PW 11V@MIL‐101 in the methylene blue (MB) solution (100 mL of 100 mg L ?1 MB solution). Further study revealed that the POM@MIL‐101 composite materials not only exhibited a fast adsorption rate towards dye molecules, but also possessed of selective adsorption ability of the cationic dyes in wastewater. For example, the adsorption efficiency of PW 11V@MIL‐101 (10 mg) towards MB (100 mL of 10 mg L ?1) could reach 98 % in the initial 5 min, and it could capture MB dye molecules from the binary mixture of the MB and MO with similar size. Also, the POM@MIL‐101 materials could be readily recycled and reused, and no POM leached in the dye adsorption process. 相似文献
18.
Adsorption of Pb 2+ ions on the combustion derived nanosized γ-Fe 2O 3 and its thiourea complex composite is reported. The adsorbents upon adsorption of Pb 2+ ions are characterised by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray microanalysis and infrared spectroscopy techniques. The eluent is characterised by atomic absorption spectroscopy for the estimation of Pb 2+ ions. The reduction in the amount of lead after adsorption was estimated to be around 50% in case of complex composite adsorbent and around 15% in case of the γ-Fe 2O 3 adsorbents. Orthorhombic PbSO 4 precipitated out from the eluent and is reported with a model reaction. Adsorption of lead onto the complex composite is explained through the formation of a surface tertiary complex. The advantage of employing a thiourea-γ-Fe 2O 3 complex composite as solid adsorbent for the adsorption of heavy metal pollutants is envisaged in the present investigation. 相似文献
19.
A new chitosan imprinting adsorbent using diatomite as core material was prepared by using the surface molecular imprinting
technology with the Pb 2+ as imprinted ion. The preparation process conditions of the surface molecular imprinting adsorbent were studied. The adsorbent
was characterized by using Fourier transform infrared (FTIR) spectrum. FTIR spectrum indicated that it was cross-linked by
epichlorohydrin. The new imprinting adsorbent could provide a higher adsorption capacity for Pb 2+, which reached 139.6 mg/g increasing 32.3% compared with cross-linking chitosan adsorbent (the initial Pb 2+ concentration of 600 mg/L). The adsorption velocity was quick and the equilibration time of the imprinting adsorbent for
Pb 2+ was 3 h that shortened about 40% compared with cross-linking chitosan adsorbent. It had a more wide pH range of 5–7 than
that of cross-linking chitosan adsorbent. The new imprinting adsorbent can be reused for up to ten cycles without loss of
adsorption capacity. In the kinetics and isotherm study, the pseudosecond order model and Langmuir model could represent the
adsorption process. 相似文献
20.
Baker's yeast was cross‐linked by glutaraldehyde and then modified by grafting with poly(amic acid), which was prepared via reaction of pyromellitic dianhydride (PMDA) and arginine at 50°C. The morphology of the pristine, cross‐linked, and modified biomass was observed by microscope. The presence of poly(amic acid) on the biomass surface was verified by X‐ray photoelectron spectroscopy (XPS) analyses. Due to the high density of the functional groups on the modified biomass surface, the metal adsorption capacity for nickel and lead increased significantly, especially when the carboxylic acid groups were converted into carboxylate ions using NaOH. The adsorption process for nickel and lead adsorption followed the pseudo‐second‐order kinetics. The metal adsorption data were fitted with the Langmuir and Freundlich isotherms with the former having a better fit. Using the Langmuir adsorption isotherm, the maximum uptakes for nickel and lead were found to be 0.848 and 0.980 mmol g ?1 respectively which were about 15 and 11 times higher than the prisitine biomass. In the simulated wastewater containing 0.400 mmol l ?1 of Ni 2+ and Pb 2+, the metal adsorption capacity of Ni 2+ and Pb 2+ reached 0.365 mmol l ?1 and 0.390 mmol l ?1, respectively. The metal ions loaded biomass was regenerated using Ethylene Diamine Tetraacetic Acid (EDTA) solution and used repeatedly over four cycles with little loss of uptake capacity. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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