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1.
Water-soluble chitin was successfully crosslinked to varying extents with glutaraldehyde in homogeneous aqueous solutions to improve the properties as an adsorbent for metal cations, and the effects of crosslinking were discussed. Complete insolubilization was achieved with the fivefold excess aldehyde, but, in terms of adsorptivity of Cu 2+, the chitin crosslinked at an aldehyde/amino group ratio of 1.0 was found to exhibit remarkable capacity and was much superior to others. The desorption of Cu 2+ from the adsorption complex was also attained effectively at pH 2.0. These results indicated that the loose crosslinking was quite simple and efficient to produce high capacity adsorbents for practical use. Thermal behavior of the crosslinked chitin was examined by TMA and TGA; a softening phenomenon was observed at 145°C. 相似文献
2.
The novel azacrown ether chitosan derivatives (CCAE‐I, CCAE‐II) were prepared by reaction between crosslinked chitosan with epoxy‐activated azacrown ethers. Their structures were confirmed by elemental FTIR spectra analysis and X‐ray diffraction analysis. The adsorption and selectivity properties of the crosslinked chitosan azacrown ethers for Pb 2+, Cu 2+, Cr 3+, Cd 2+, and Hg 2+ were also investigated. The experimental results showed that they have high adsorption capacity for Cu 2+, Cd 2+, and Hg 2+. The adsorption capacity of CCAE‐II is higher than CCAE‐I for Cd 2+ and Hg 2+. The selectivity properties of CCAE are better than chitosan and crosslinked chitosan. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3053–3058, 1999 相似文献
3.
A novel activated carbon‐chitosan complex adsorbent (ACCA) was prepared via the crosslinking of glutaraldehyde and activated carbon‐(NH 2‐protected) chitosan complex under microwave irradiation. The surface morphology of this adsorbent was characterized. The adsorption of ACCA for Pb 2+ and Cd 2+ was investigated. The results demonstrate that ACCA has higher adsorption capacity than chitosan. The adsorption follows pseudo first‐order kinetics. The isotherm adsorption equilibria are better described by Freundlich and Dubinin‐Radushkevich isotherms than by the Langmuir isotherm. The adsorbent can be recycled. These results have important implications for the design of low‐cost and effective adsorbents in the removal of heavy metal ions from wastewaters. 相似文献
4.
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
5.
In this study, bentonite originating from Turkey (Eski?ehir province) and activated carbon obtained from grapeseed were used as adsorbents for the removal of lead (Pb 2+) and copper (Cu 2+) ions from aqueous solutions. Experiments were performed in single- and binary-ion systems at constant temperature of 298 K and pH value of 5. In order to describe the adsorption mechanism Langmuir, Freundlich and Temkin isotherms were used. The total adsorption capacity values of adsorbents were compared. It was observed that the total adsorption capacity values were changed depending on the type of adsorbent used, type of metal ion and interaction between metal ions. 相似文献
6.
Two novel chitosan derivatives—crosslinked chitosan dibenzo‐16‐ c‐5 acetate crown ether (CCTS‐1) and crosslinked chitosan 3,5‐di‐ tert‐butyl dibenzo‐14‐ c‐4 diacetate crown ether (CCTS‐2)—were synthesized by the reaction of crosslinked chitosan with dibenzo‐16‐ c‐5 chloracetate crown ether and 3,5‐di‐ tert‐butyl dibenzo‐14‐ c‐4 dichloracetate crown ether with the intent of forming polymers that could be used in hazardous waste remediation as toxic metal‐binding agents in aqueous environments. Their structures were confirmed with elemental analysis, infrared spectral analysis, and X‐ray diffraction analysis. In the infrared spectra of CCTS‐1 and CCTS‐2, the characteristic peaks of aromatic backbone vibration appeared at 1595 cm −1 and 1500 cm −1; the intensity of the N H and O H stretching vibration in the region of 3150–3200 cm −1 decreased greatly. The X‐ray diffraction analysis showed that the peak at 2θ = 20° decreased greatly in CCTS‐1 and CCTS‐2. The adsorption and selectivity properties of CCTS‐1 and CCTS‐2 for Pb 2+, Cu 2+, Cr 3+, and Ni 2+ were studied. Experimental results showed that the two crosslinked chitosan derivatives had not only good adsorption capacities for Pb 2+, Cu 2+, but also high selectivity for Pb 2+, Cu 2+ in the coexistence of Ni 2+. For aqueous systems containing Pb 2+, Ni 2+, or Cu 2+, Ni 2+, CCTS‐1 only adsorbed Pb 2+ or Cu 2+. For aqueous systems containing Pb 2+, Cr 2+ and Ni 2+, CCTS‐2 had high adsorption and selectivity properties for Pb 2+. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2069–2074, 1999 相似文献
7.
Three types of high molecular weight polyarylether adsorbents with different molar ratios of carboxyl and phenylene were designed and synthesized through direct polycondensation in mixture solvents. The as‐prepared polymers were characterized by FTIR, 1H‐NMR, TGA, DSC, SEM, EDS, and GPC in order to study the regularity of polymeric adsorption/thermostability performances. Because of the highest molar ratio of carboxyl and phenylene, PAES‐C‐Na presented the highest adsorption capacity of Cu 2+ compared to PAESK‐C‐Na and PAES; therefore, PAES‐C‐Na was opted to study the impacts of adsorbent dosage, pH, contact time, and initial concentration on the adsorption of Pb 2+ and Cd 2+. Moreover, a kinetic analysis revealed that the adsorption process followed pseudo‐second‐order model, while the thermodynamic experimental data properly fitted with the Freundlich model. The multi‐component competitive adsorption capacity followed the order Pb 2+ > Cu 2+ > Cd 2+. Additionally, the regeneration tests indicated that PAES‐C‐Na still possessed the excellent adsorption capacity after several recycles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41984. 相似文献
8.
This study examined the sorption and desorption behaviors of Cu 2+ and Pb 2+ ions, which were adsorbed on the vinyl benzene chloride divinylbenzene (VBC-DVB-OH) polymer and magnetic hybrid adsorbent (VBC-DVB-OH-Fe) at pH 5. Batch and fixed bed column experiments were performed to study practical applicability and the breakthrough curves were obtained. The experimental equilibrium data, suitably fitted by the Langmuir and Freundlich isotherms, have shown that ferric oxide loaded magnetic hybrid sorbent (VBC-DVB-OH-Fe) exhibits higher adsorption capacity than vinyl benzene chloride divinylbenzene (VBC-DVB-OH) polymer. The results indicate the following order to fit the isotherms for both metal ions: Langmuir > Freundlich for polymeric sorbent and Freundlich > Langmuir for VBC-DVB-OH-Fe. The maximum adsorption capacity of VBC-DVB-OH adsorbent is 26.39 mg/g for Pb 2+ and 7.93 mg/g for Cu 2+ whereas it is increased to 45.81 mg/g for Pb 2+and 25.64 mg/g for Cu 2+ by using VBC-DVB-OH-Fe adsorbent. A series of column experiments were carried out to determine the breakthrough curves. The regeneration efficiency of the column runs was determined using HCl (10% v/v). The elution efficiency was 90% for each adsorbent. 相似文献
9.
BACKGROUND: The adsorption of Cu 2+ from aqueous solution using crosslinked chitosan hydrogels impregnated with Congo Red (CR) by ion‐imprint technology was systematically investigated with particular reference to the effects of contact time, pH, and initial concentration on adsorption. RESULTS: The adsorption capacity of the crosslinked chitosan without impregnation was only 68.68 mg g ?1 for Cu 2+. However, the adsorption capacity increased from 77.42 (without imprint ion) to 84.54 mg g ?1 (imprint ion content 0.5 mmol) after the chitosan was impregnated with a ratio of 1/12 of CR to chitosan. The as‐prepared adsorbents were found to be pH‐dependent and the process of adsorption agreed well with the Freundlich isotherm. The loaded adsorbents could be regenerated and reused without the appreciable loss of capacity. CONCLUSION: Chitosan hydrogels impregnated with CR showed higher Cu 2+ adsorption capacities compared with those prepared conventionally without imprint ion, and thus developed a good approach to increase Cu 2+ adsorption efficiency in the treatment of waste‐water. Copyright © 2012 Society of Chemical Industry 相似文献
10.
Novel chitosan‐based adsorbent materials were synthesized with a higher fatty diacid diglycidyl as a crosslinking agent, and the adsorption ability of the resulting polymers for several metal ions was evaluated. Selective adsorption for Cu 2+ in comparison with other divalent metal ions, such as Ni 2+, Pb 2+, Cd 2+, and Ca 2+, was observed with the crosslinked chitosan sorbent at pH 6; however, the adsorption power decreased abruptly as the pH value of the solution decreased. The addition of ethylenediamine tetraacetic acid (EDTA) residues to crosslinked chitosan significantly enhanced the adsorption power for metal ions, especially for Ca 2+. The adsorptivity of Ca 2+ was dramatically improved with the introduction of EDTA residues, and the value was greater than that obtained with a commercial chelate resin (CR11). Although the adsorption power of the EDTA‐derivatized sorbent for other metal ions was just comparable to that of the CR11 material, the newly synthesized adsorbent could be used for the recovery of metal ions from industrial waste solutions with a relatively wide range of pHs, from 4.0 to 6.0. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2758–2764, 2004 相似文献
11.
A series of gel resins were prepared by polymerizing glycidyl methacrylate (GMA) and 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and functionalizing with ammonia (NH 3) and tetraethylenepentamine (TEPA). The aminated gel resins were then used as an adsorbent for the removal of heavy metal ions (Cu 2+ and Pb 2+). These gel resins containing amino groups and chelating amino groups had excellent adsorptive properties for Cu 2+ and Pb 2+. The adsorption process reached equilibrium in 40 min, and the adsorption capacities of Cu 2+ and Pb 2+ were 75.0 mg g ?1 and 266.6 mg g ?1 for the NH 3‐aminated gel resins and 57.5 mg g ?1 and 330.6 mg g ?1 for the TEPA‐aminated gel resins, respectively. After five adsorption–desorption processes, the adsorption capacities only decreased slightly. Thus, these aminated gel resins can be used as effective adsorbents for aqueous heavy metal ions (Cu 2+ and Pb 2+). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44466. 相似文献
12.
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
13.
A novel chitosan-based adsorbent (CCTM) was prepared by the reaction of epichlorohydrin O-crosslinked chitosan with maleic anhydride under microwave irradiation. The chemical structure of this polymer was characterized by infrared spectroscopy and X-ray diffraction analyses. The effects of various variables such as degree of substitution, adsorption time, initial metal ion concentration, solution pH, and temperature, on the adsorption of Pb 2+ and Cu 2+ by CCTM were investigated. The results demonstrate that the microwave irradiation can remarkably enhance the reaction. CCTM has higher adsorption capacity than chitosan. The maximum adsorption capacities for Pb 2+ and Cu 2+, with initial concentrations of 0.02 mol L −1 at pH 5, are 246.3 and 132.5 mg g −1, respectively. The adsorbent can be recycled. These results have important implications for the design of effective chitosan-based adsorbents in the removal of heavy metal ions from wastewaters. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
14.
The work presented involved the fabrication and evaluation of an ion‐imprinted azo‐functionalized phenolic resin for selective extraction of Ni 2+ ions from aqueous media. The azo‐containing ligand was first synthesized by coupling of a p‐aminophenol diazonium salt with resorcinol. The ligand was coordinated with Ni 2+ ion template before condensation polymerization with formaldehyde and resorcinol was performed. The Ni 2+ ions were extracted from the crosslinked resin matrix to finally afford the Ni 2+ ion‐imprinted Ni‐PARF adsorbent. The synthetic steps were extensively investigated using elemental analysis and Fourier transform infrared, NMR and energy‐dispersive X‐ray spectroscopies. Also, the surface morphologies along with the surface areas of the adsorbent resin were evaluated using scanning electron microscopy and Brunauer–Emmett–Teller techniques, respectively. Batch experiments indicated that the pseudo‐second‐order kinetic equation provided the best fit with the experimentally obtained kinetic data and equilibrium was reached after 40 min. The isotherm studies were also in a good fit with the Langmuir model and the maximum adsorption capacities of Ni 2+ ions with respect to both Ni‐PARF and control non‐imprinted C‐PARF adsorbents were around 260 and 100 mg g ?1, respectively. In the presence of Co 2+, Cu 2+, Zn 2+ and Pb 2+ as competing coexisting ions, the relative selectivity coefficients of Ni‐PARF for Ni 2+ were, respectively, 84.91, 44.97, 30.41 and 32.20. Regeneration experiments indicated that after eight adsorption/desorption cycles, the Ni‐PARF adsorbent still maintained around 97% of its initial efficiency. © 2018 Society of Chemical Industry 相似文献
15.
This work investigates the removal of Cd 2+, Cu 2+, Ni 2+, and Pb 2+ 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 Cd 2+ and Cu 2+, and 52.0 mL with Ni 2+ and Pb 2+. 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. 相似文献
16.
Abstract A comparative study of the adsorbents prepared from several industrial wastes for the removal of Pb 2+ has been carried out. Fertilizer industry waste viz. carbon slurry and steel plant wastes viz. blast furnace (B.F.) slag, dust, and sludge were investigated as low‐cost adsorbents after proper treatment in the present study. The adsorption of Pb 2+ on different adsorbents has been found in the order: B.F. sludge>B.F. dust>B.F. slag>carbonaceous adsorbent. The least adsorption of Pb 2+ on carbonaceous adsorbent even having high porosity and consequently greater surface area as compared to other three adsorbents, indicates that surface area and porosity are not important factors for Pb 2+ removal from aqueous solutions. The adsorption of Pb 2+ has been studied as a function of contact time, concentration, and temperature. The adsorption has been found to be exothermic, and the data conform to the Langmuir equation. The kinetic results reveal that the present adsorption system follows Lagergren's first order rate equation. Since all three waste products from the steel industry show higher potential to remove lead from water, therefore, it is suggested that these metallurgical wastes can be fruitfully employed as low‐cost adsorbents for effluent treatment containing toxic metal ions. 相似文献
17.
Amidoximated bacterial cellulose (Am‐BC) was prepared through successive polymer analogous reactions of bacterial cellulose with acrylonitrile in an alkaline medium followed by reaction with aqueous hydroxylamine. It was used as an adsorbent to remove Cu 2+ and Pb 2+ from aqueous solutions. The adsorption behaviors of Cu 2+ and Pb 2+ onto Am‐BC were observed to be pH‐dependent. The maximum adsorption capacity of 84 and 67 mg g –1 was observed, respectively, for Cu 2+ and Pb 2+ at pH 5. Scanning electronic microscopy (SEM) indicated that the microporous network structure of Am‐BC was maintained even after the modifacation. The adsorption mechanisms for Cu 2+ and Pb 2+ onto Am‐BC were investigated by fourier transform infrared spectroscopy (FTIR), ζ potential measurement and X‐ray photoelectron spectroscopy (XPS). The results revealed that the mechanism for the adsorption of Cu 2+ onto Am‐BC could be mainly described as between metal ions and nitrogen atom in the amidoxime groups or oxygen atom in the hydroxyl groups. However, in the adsorption process for Pb 2+, precipitation played the important role along with electrostatic interactions, although chelation action also existed in the process accounted for the adsorption process. The regeneration of Am‐BC was studied by treatment with a strong complexing agent, ethylenediaminetetracetic acid (EDTA). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
18.
Amidoximated chitosan‐ g‐poly(acrylonitrile) (PAN) copolymer was prepared by a reaction between hydroxylamine and cyano group in chitosan‐ g‐PAN copolymer prepared by grafting PAN onto crosslinked chitosan with epychlorohydrine. The adsorption and desorption capacities for heavy metal ions were measured under various conditions. The adsorption capacity of amidoximated chitosan‐ g‐PAN copolymer increased with increasing pH values, and was increased for Cu 2+ and Pb 2+ but a little decreased for Zn 2+ and Cd 2+ with increasing PAN grafting percentage in amidoximated chitosan‐ g‐PAN copolymer. In addition, desorption capacity for all metal ions was increased with increasing pH values in contrast to the adsorption results. Stability constants of amidoximated chitosan‐ g‐PAN copolymer were higher for Cu 2+ and Pb 2+ but lower for Zn 2+ and Cd 2+ than those of crosslinked chitosan. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 469–476, 1999 相似文献
19.
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
20.
Various alginate gel‐based adsorbents were investigated for the removal of heavy metals: alginate beads, alginate capsules, and alginate gel‐coated adsorbent. Of these, alginate capsules showed the greatest Pb 2+ uptake capacity of 1560 mg g ?1 of dry sodium alginate, and the alginate gel‐coated adsorbent, prepared simply by forming a thin alginate film on an inert matrix, achieved rapid adsorption equilibrium within 10 min. Adsorbed metals were readily removed from the alginate gel‐based adsorbents using eluents such as HNO 3 and could be reused for up to 10 adsorption–desorption cycles without marked loss of metal uptake capacity. Alginate gel‐coated adsorbents could be prepared in a dried state and have great application potential for the removal of heavy metals from contaminated water. Copyright © 2004 Society of Chemical Industry 相似文献
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