共查询到20条相似文献,搜索用时 15 毫秒
1.
A poly(vinyl alcohol) membrane (PVA) was modified by radiation graft copolymerization of acrylic acid/styrene (AAc/Sty) comonomers. The Cu and Fe ion‐transport properties of these membranes were investigated using a diaphragm dialysis cell. In the feed solution containing CuCl2 or a mixture of CuCl2 and FeCl3, the PVA‐g‐P(AAc/Sty) membranes showed high degrees of permselectivity toward Cu2+ rather than toward Fe3+. The permeation of Cu2+ ions through the membranes was found to increase with decrease in the grafting yield. However, as the content of Cu2+ ions in the Cu/Fe binary mixture feed solutions decreased, the rate and the amount of transported Cu2+ through the grafted membrane decreased, with no appreciable permselectivity toward Fe3+. When Fe2+ ions were used instead of Fe3+ ions in the feed solution containing Cu2+, the transport of both Cu2+ and Fe2+ through the membrane was observed. The rate of transport of Fe2+ was higher than that of Cu2+. In addition, it was found that the selective transport of ions was significantly influenced by the pH difference between both sides of the membranes. As the pH of the feed or the received solution decreased, both Cu2+ and Fe3+ passed through the membrane and were transported to the received solution. The role of carboxylic acid and the hydroxyl groups of the grafted membranes in the transportation process of ions is discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 125–132, 2000 相似文献
2.
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 Pb2+, Cu2+, Cr3+, and Ni2+ were studied. Experimental results showed that the two crosslinked chitosan derivatives had not only good adsorption capacities for Pb2+, Cu2+, but also high selectivity for Pb2+, Cu2+ in the coexistence of Ni2+. For aqueous systems containing Pb2+, Ni2+, or Cu2+, Ni2+, CCTS‐1 only adsorbed Pb2+ or Cu2+. For aqueous systems containing Pb2+, Cr2+ and Ni2+, CCTS‐2 had high adsorption and selectivity properties for Pb2+. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2069–2074, 1999 相似文献
3.
《分离科学与技术》2012,47(15):3071-3091
Abstract NH4Y zeolite‐filled chitosan membranes were developed for the separation of water‐isopropanol mixture using pervaporation process. The NH4Y zeolite‐filled chitosan membranes were prepared using a solution technique with the variation of NH4Y zeolite loading (0, 0.1, 0.2, 0.3, 0.4, 0.5 wt.%). The membranes morphologies were studied using Scanning Electron Microscopy (SEM) and the membranes mechanical strength were tested using the parameter of tensile strength and percent strain at maximum. The effects of NH4Y zeolite loading on the liquid sorption characteristics and pervaporation performance were also evaluated. The diffusion coefficient of water and isopropanol for the chitosan membranes at different NH4Y zeolite loading is estimated. The presence of NH4Y zeolite in the chitosan membranes caused non‐homogeneous dispersion of NH4Y zeolite crystals and membrane swelling due to its hydrophilic properties. However, the presence of NH4Y zeolite was able to improve both tensile strength and percent strain at maximum of chitosan membranes. The presence of NH4Y zeolite also increased the total permeation flux and separation factor simultaneously. The Pervaporation Separation Index shows that 0.2 wt.% of NH4Y zeolite‐filled membrane gave the optimum performance in the pervaporation process. The diffusion coefficient estimated proves that the membranes were highly water selective. 相似文献
4.
《Ceramics International》2022,48(22):32798-32803
In this paper, copper-loaded antibacterial glasses were prepared by an ion-exchange method with CuSO4 or CuCl as copper sources. The effects of different molten salts and ion exchange duration on the antibacterial properties of copper-loaded glasses were investigated. The experimental results show that the glasses exchanged with CuSO4/Na2SO4 mixed molten salts have a higher surface copper loading than that with CuCl/KCl mixed molten salts. The sample color results from the reduced Cu0. The equilibrium between Cu+ and Cu0 is related to the Sn2+ ions existed in the lower surface of float glass. Finally, the antibacterial function of glass samples was found to be related to the charge transfer between Cu++e??Cu0, and has a proportional correlation with the content of Cu+ ions on the glass surface. 相似文献
5.
The present study investigated the pervaporation performance of novel hydroxypropylated chitosan (HPCS) membranes to separate water from an aqueous alcohol solution. Hydroxypropylated chitosan was prepared from the reaction of chitosan and propylene oxide. The results show that the separation factor decreases and the flux increases with increasing of the substitution degree of the hydroxypropylated chitosan membrane. Crosslinking with glutaraldehyde or treatment with Cu2+ can improve the pervaporation performance of modified chitosan membrane grately. The performance data indicate that the crosslinking hydroxypropylated chitosan membrane treated with Cu2+ is an excellent pervaporation membrane for the separation of alcohol–water mixtures, and one-stage separation is attainable for some alcohol–water mixtures such as an n-propanol–water and an isopropanol–water system, which has a good separation factor of 220 for the n-PrOH/water system and 240 for the i-PrOH/water system using 85 wt % alcohol concentration at 60°C. The flux for both cases is around 0.5 kg m−2 h−1. At the same time, the structure of the chemically modified chitosan membranes and their separation characteristics for aqueous alcohol solutions are also discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2035–2041, 1998 相似文献
6.
Abdul Latif Ahmad Boon Seng Ooi 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2010,156(2):257-263
In this study, nanofiltration membrane is used to separate proton (H+) and copper ions from a ternary ions mixture (H+, Cu2+, SO42?). The performance of membrane in separating Cu2+ and H+ was tested under the effect of pressure, concentration and different acid strength (pH). It was found that the H+ rejection is independent of the applied pressure. Permeability of solution decreased linearly with the increase of CuSO4 concentration. In terms of H+ rejection, there is a continuous drop in rejection from 0.1 mM CuSO4 to 10 mM CuSO4 solution. H+ was poorly retained and concentrated in the permeate stream in corresponding to the electro-neutrality requirements, on the other hand, the rejection of copper ion was almost constant with pH. In overall, optimum acid reclamation and copper recovery can be achieved at higher volume flux. A Three Parameters-Combined Film-Extended Nernst-Planck Equation (CF-ENP) model is successfully applied to predict the performance of nanofiltration membrane in separating the ternary ions. 相似文献
7.
Based on the structural characteristics of chitosan (CTS) and carboxymethyl starch (CMS), CTS–CMS composites were prepared by crosslinking. The composites had a plurality of reactive functional groups such as NH2, NH3+, COOH, and OH and are applied to the adsorption of Cu2+ in aqueous solution. The adsorption capacity and stability in acidic solution of the composites were preferable to that of raw material. The effects of temperature, contact time, initial concentration, and pH on the adsorption of Cu2+ were investigated. Infrared spectroscopy, scanning electron microscope–energy dispersive spectrometer, X-ray diffraction, and X-ray photoelectron spectroscopy were used to explore the adsorption mechanism. The experiment showed that chemisorption and physisorption coexisted in the adsorption process. It is promising to apply this adsorbent to remove the metal ions in wastewater. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48636. 相似文献
8.
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 Pb2+, Cu2+, Cr3+, Cd2+, and Hg2+ were also investigated. The experimental results showed that they have high adsorption capacity for Cu2+, Cd2+, and Hg2+. The adsorption capacity of CCAE‐II is higher than CCAE‐I for Cd2+ and Hg2+. 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
9.
The blend membranes were satisfactorily prepared by coagulating a mixture of O‐carboxymethylated chitosan (CM‐chitosan) and alginate in aqueous solution with 5 wt % CaCl2, and then by treating with 1 wt % HCl aqueous solution. Their structure and miscibility were characterized by scanning electron micrograph, X‐ray diffraction, infrared spectra, differential thermal analysis, and atomic absorption spectrophotometer. The results indicated that the blends were miscible, when the weight ratio of CM‐chitosan to alginate was in the range from 1 : 1 to 1 : 5. The polymers interpenetration including a Ca2+ crosslinked bridge occurred in the blend membrane, and leads to high separation factor for pervaporation separation of alcohol/water and low permeation. The tensile strength in the wet state (σb = 192 kg cm−2 for CM‐chitosan/alginate 1 : 1) and thermostability of the blend membranes were significantly superior to that of alginic acid membrane, and cellulose/alginate blend membranes, owing to a strong electrostatic interaction caused by —NH2 groups of CM‐chitosan with —COOH groups of algic acid. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 610–616, 2000 相似文献
10.
The reaction of copper salts with AlPO4-5 or Vv-VAPO-5 under acidic (CuCl2, pH adjusted to 2) but especially basic conditions (Cu(NH3)
4
2+
, pH adjusted to 9) gives ion incorporations greater than expected by a simple ion exchange mechanism (both AlPO4-5 and Vv-VAPO-5 could be expected to have no cation exchange capacity). Ion incorporation is proposed to occur initially at defect sites, and examination of the ESR spectrum of a dehydrated, evacuated CuCl2-exchanged AlPO4-5 shows that these defect sites give rise to a number of unique environments upon CuII incorporation. The CuCl2-exchanged VAPO-5 retains a significant toluene accessibility to the Vv sites in the VAPO-5. However, the toluene accessibility in the Cu(NH3)
4
2+
-exchanged VAPO-5 is significantly reduced and we propose this is due to a combination of the presence of crystalline CuO and structural collapse from reaction with base (NH4OH). The ability of treatment with base (NH4OH, pH 13) to restrict access of toluene to the Vv sites of the original VAPO-5 was verified in a separate experiment. 相似文献
11.
The cross-linking microstructure formed by the metal-coordination bonds provides excellent properties for rubber materials. Copper sulfate (CuSO4) and tetramethylthiuram monosulfide (TMTM) are successfully compounded with nitrile–butadiene rubber (NBR) to fabricate vulcanizates by the coordination cross-linking. The curing characteristics, mobility of macromolecular segment, mechanical properties, morphology analysis, swelling properties, and dynamic features under cyclic compression of the vulcanizates are investigated systematically. The results indicate that the microstructure of 3D cross-linking is held together by the metal-coordination bonds between Cu2+ and CN. The torque during static vulcanization, tensile strength, and cross-linking density of the obtained NBR/CuSO4/TMTM vulcanizates are better than that of NBR/CuSO4 vulcanizates, which is attributed to the synergistic effect between the radicals formed by the splitting of TMTM under thermal activation and the Cu2+; moreover, the highly reactive [Cu(SnCNMe2)]•2+ complexes are formed by the synergistic effect and promote the coordination stability of NBR and CuSO4 effectively. The excellent tensile properties of the prepared NBR/CuSO4/TMTM vulcanizates via synergistic effect made the metal-coordination cross-linking attractive in the field of industrial application. 相似文献
12.
Three new chitosan crown ethers, N‐Schiff base‐type chitosan crown ethers (I, III), and N‐secondary amino type chitosan crown ether (II) were prepared. N‐Schiff base‐type chitosan crown ethers (I, III) were synthesized by the reaction of 4′‐formylbenzo‐21‐crown‐7 with chitosan or crosslinked chitosan. N‐Secondary amino type chitosan‐crown ether (II) was prepared through the reaction of N‐Schiff base type chitosan crown ether (I) with sodium brohydride. Their structures were characterized by elemental analysis, infrared spectra analysis, X‐ray diffraction analysis, and solid‐state 13C NMR analysis. In the infrared spectra, characteristic peaks of C?N stretch vibration appeared at 1636 cm?1 for I and 1652 cm?1 for II; characteristic peaks of N? H stretch vibration appeared at 1570 cm?1 in II. The X‐ray diffraction analysis showed that the peaks at 2θ = 10° and 28° disappeared in chitosan derivatives I and III, respectively; the peak at 2θ = 10° disappeared and the peak at 2θ = 28° decreased in chitosan‐crown ether II; and the peak at 2θ = 20° decreased in all chitosan derivatives. In the solid‐state 13C NMR, characteristic aromatic carbon appeared at 129 ppm in all chitosan derivatives, and the characteristic peaks of carbon in C?N groups appeared at 151 ppm in chitosan crown ethers I and III. The adsorption and selectivity properties of I, II, and III for Pd2+, Au3+, Pt4+, Ag+, Cu2+, and Hg2+ were studied. Experimental results showed these adsorbents not only had good adsorption capacities for noble metal ions Pd2+, Au3+, Pt4+, and Ag+, but also high selectivity for the adsorption of Pd2+ with the coexistence of Cu2+ and Hg2+. Chitosan‐crown ether II only adsorbs Hg2+ and does not adsorbs Cu2+ in an aqueous system containing Pd2+, Cu2+, and Hg2+. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1886–1891, 2002 相似文献
13.
《分离科学与技术》2012,47(4):517-535
ABSTRACT The pervaporation transport process of H2O-EtOH solution was studied on a chitosan membrane and on a H2SO4 crosslinked chitosan membrane. The influence of concentration, temperature, and crosslinking was also studied. The dependence of permeation fluxes on feed concentration showed strong coupling effects existed in the permeation process. That the thermodynamic swelling—distribution relationship changed with the feed concentration also showed that a strong coupling effect existed in the thermodynamic swelling process. The permeation fluxes and thermodynamic swelling processes showed analogous relationships versus the concentration in the feed. The high swelling ratio and the high selectivity of the membrane in the thermodynamic swelling distribution process was the basis ofhigh flux and high permselectivity of pervaporation. With an increase of temperature, the permeation fluxes increased quickly, but the swelling ratio of water and EtOH in the membrane scarcely changed. This showed that an increase of temperature promoted the diffusion process but had little influence on permselectivity. The permselectivity of pervaporation depended strongly on the thermodynamic swelling process. 相似文献
14.
The ability of dimethylaniline (DMA)/Cu2+ ion initiator to induce grafting of methyl methacrylate (MMA) onto nylon 6 was investigated under a variety of conditions. It was found that the graft yield is dependent on the concentration of the Cu2+ ion, of DMA, and of MMA. While the graft yield increases as the monomer concentration increases, there are optimal concentrations of DMA and Cu2+ ion. Below or above these concentrations, lower grafting occurred. The type of cupric salt also affects grafting to varying degrees. While the presence of CuSO4 and Cu(NO3)2 accelerates grafting, the presence of CuCl2 offsets the reaction. Increasing the reaction temperature and reaction time favorably influences grafting. Addition of acetic acid enhances grafting, whereas formic acid decreases grafting. Preswelling of nylon with formic acid leaves the susceptibility of nylon toward grafting practically unaltered. Studies of the copolymerization reaction was not confined to the graft yield but was extended to homopolymer formation and total conversion. 相似文献
15.
Poly(1‐trimethylsilyl‐1‐propyne) (PTMSP) is known to show preferential permeation of ethanol in the pervaporation of ethanol–water mixture. Although this polymer presents good characteristics for the separation of organic–water solutions, operation conditions and membrane characteristics, such as thickness, affect its pervaporation performance. The effect of temperature and feed concentration on pervaporation was studied. During pervaporation of 10 wt % ethanol–water solution, the separation factor (αH2OEtOH) remains almost constant, whereas the permeation flux (F) increases exponentially with operation temperature. On the other hand, the separation factor decreases, whereas the permeation flux increases with ethanol content in the feed mixture. The membrane thickness also affects the performance of PTMSP polymer films: selectivity increases sharply with membrane thickness up to 50 μm, whereas it remains constant for thicker membranes. The permeation flux decreases with membrane thickness in the whole range studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94:1395–1403, 2004 相似文献
16.
Metal complexes of copolymers based on polyacrylic acid radiation grafted onto films of low density polyethene were prepared by complex‐forming with solutions of salts of FeCl3.6H2O, CuCl2.2H2O, CoCl2.6H2O, NiCl2.6H2O, VOSO4.5H2O, Na2MoO4.2H2O, Na2WO4.2H2O, and NH4VO3. The introduction of metal ions was found to depend mainly on the degree of grafting of acrylic acid and was from 0.5 to 5.0 mass%. These complexes were characterized by IR, UV spectroscopy, and EPR. The moisture content of the materials obtained changed linearly with the degree of grafting of acrylic acid and was from 9.0 to 80.0%. The introduction of the MoO22+ and WO22+ towards carboxylic groups lead to increasing the thermal stability of the metal complexes of the copolymers compared to the initial grafted films. The modified acrylate copolymers were studied in reactions of catalytic oxidation of cyclohexene. The activities of the complexes obtained towards cyclohexene epoxidation can be arranged in the following order: PAA–MoO22+ > PAA–VO2+ > PAA–VO > PAA–WO22+, while for the reaction of cyclohexene hydroxylation the order was—PAA–Co2+ > PAA–Cu2+ > PAA–Fe3+ > PAA–Ni2+. The contents of cyclohexene oxide and 2‐cyclohexene‐1‐ol reached 38.5% and 7.5%, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1658–1665, 2006 相似文献
17.
Synthesis,characterization, metal sorption,and biological activity of poly(N‐heterocylic acrylamide)
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N‐heterocyclic acrylamide monomers were prepared and then transferred to the corresponding polymers to be used as an efficient chelating agent. Polymers reacted with metal nitrate salts (Cu2+, Pb2+, Mg2+, Cd2+, Ni2+, Co2+, Fe2+) at 150°C to give metal‐polymer complexes. The selectivity of the metal ions using prepared polymers from an aqueous mixture containing different metal ion sreflected that the polymer having thiazolyl moiety more selective than that containing imidazolyl or pyridinyl moieties. Ion selectivity of poly[N‐(benzo[d]thiazol‐2‐yl)acrylamide] showed higher selectivity to many ions e.g. Fe3+, Pb2+, Cd2+, Ni2+, and Cu2+. While, that of poly[N‐(pyridin‐4‐yl)acrylamide] is found to be high selective to Fe3+ and Cu2+ only. Energy dispersive spectroscopy measurements, morphology of the polymers and their metallopolymer complexes, thermal analysis and antimicrobial activity were studied. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42712. 相似文献
18.
Tommy Hawkins Leslie Hall Kerri Tollison Adam Brand Milton McKay GregoryW. Drake 《Propellants, Explosives, Pyrotechnics》2006,31(3):196-204
The synthesis, characterization, theoretical calculations, and safety studies of energetic salts based on 1,2‐bis(oxyamino)ethane, (H2N O CH2 CH2 O NH2), were carried out. The salts were characterized by vibrational (infrared, Raman), multinuclear NMR studies (1H, 13C), differential scanning calorimetry (DSC), elemental analysis, and initial safety testing (impact and friction sensitivity). Single crystal X‐ray diffraction studies were carried out on the mono‐perchlorate and the double nitrate salts, revealing the expected structures. 相似文献
19.
We first synthesized N‐benzylidene chitosan (CTB) by the reaction of benzaldehyde with chitosan (CTS). Chitosan‐dibenzo‐18‐crown‐6 crown ether bearing Schiff‐base group (CTBD) and chitosan‐dibenzo‐18‐crown‐6 crown ether (CTSD) were prepared by the reaction of 4,4′‐dibromodibenzo‐18‐crown‐6 crown ether with CTB and CTS, respectively. Their structures were confirmed by Fourier transform infrared spectral analysis and X‐ray powder diffraction analysis. These novel crown ether crosslinked CTSs have space net structures with embedded crown ethers and contain the double structures and properties of CTS and crown ethers. They have stronger complexation with and better selectivity for metal ions than corresponding crown ethers and CTS. Moreover, these novel CTS derivatives can be used to separate and preconcentrate heavy or precious metal ions in aqueous environments. From this practical viewpoint, we studied the adsorption and selectivity properties of CTB, CTBD, and CTSD for Ag+, Cu2+, Pb2+, and Ni2+. The experimental results showed that CTBD had better adsorption properties and higher selectivity for metal ions than CTSD. For aqueous systems containing Pb2+–Ni2+ and Pb2+–Cu2+, the selectivity coefficients of CTSD and CTBD were K/Ni2+ = 24.4 and K/Cu2+ = 41.4 and K/Ni2+ = 35.5 and K/Cu2+ = 55.3, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 29–34, 2002; DOI 10.1002/app.10180 相似文献
20.
N‐carboxyethylation of chitosan by β‐halopropionic acids in the presence of various proton and halogen ion acceptors was investigated. It has been observed that carboxyethylation of chitosan in aqueous medium is accompanied by the by‐processes of hydrolysis and dehydrohalogenation of the β‐halopropionic acids yielding β‐hydroxypropionic acid, bis(2‐carboxyethyl) ether, and acrylic acid. Degree of carboxyethyl substitution (DS) of chitosan and the relative rates of the by‐processes varied significantly depending on the conditions used and nature of the proton or halogen ion acceptor. At carboxyethylation of chitosan with the alkaline β‐bromopropionates, the DS increased in the order Cs+ < Rb+ < K+ ~ Na+ < Li+. For alkaline earth salts BrCH2CH2COOM0.5 (M = Be2+, Mg2+, Ca2+, Sr2+, Ba2+), the highest DS was obtained with strontium and barium salts, which could be subsequently removed from the reaction mixture by precipitation as sulfates. Among the organic bases applied (tetrabutylammonium hydroxide, triethylamine, trimethylamine, pyridine, 4‐N,N‐dimethylaminopyridine, 2,6‐lutidine, and 1,5‐diazabicyclo[4.3.0] non‐5‐ene), the highest DS was obtained using a moderately strong base triethylamine. For the halogen acceptors (Pb2+, Ag+, Tl+), the stoichiometrically highest DS was achieved in a system comprising iodopropionic acid plus Tl+ and a comparable conversion rate was obtained using also a combination of chloropropionic acid and Ag+. A novel alternative preparative approach—gel‐state synthesis—was suggested that provides for the highest DS at the optimum reaction conditions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献