分子筛对重金属废水吸附性能的实验研究

为验证分子筛对重金属废水的处理效果,以实际含锰废水为研究对象,采用13X分子筛,通过实验研究了吸附材料用量、吸附时间、搅拌转速和溶液pH对Ca²⁺、Mn²⁺、Mg²⁺吸附效果的影响。结果表明：吸附材料用量增加对Mn²⁺、Mg²⁺的吸附影响较大;随着吸附时间增长,各金属离子去除率增加;适当的转速有利于金属离子的吸附,但各金属离子对应的最佳转速各不相同;pH提高,能够促进分子筛对金属离子的吸附。13X分子筛对金属离子的吸附机理为离子交换吸附和表面吸附。研究表明,13X分子筛在处理低浓度含锰重金属废水方面表现出良好的应用前景。     

氧化铈-二氧化硅介孔材料制备及对铜离子的吸附性能

采用共沉淀法和沉淀浸渍法制备了纳米氧化铈-二氧化硅（CeO₂-SiO₂）介孔材料吸附剂,主要考察了其对水中铜离子（Cu²⁺）的吸附行为。通过X射线衍射（XRD）、扫描电镜（SEM）和氮吸附（BET）等手段对合成的介孔材料进行了性能表征,并通过静态吸附实验分析了溶液pH、溶液初始金属离子质量浓度、吸附剂用量、吸附时间等条件对介孔材料吸附Cu²⁺性能的影响。结果表明：共沉淀法制备的纳米CeO₂-SiO₂介孔材料对Cu²⁺的去除效果较沉淀浸渍法要好;当溶液pH=7.0时CeO₂-SiO₂介孔材料对Cu²⁺的吸附效果最好,20 min时基本达到吸附平衡;溶液初始Cu²⁺浓度增大Cu²⁺去除率降低,Cu²⁺累计吸附量增大;随着吸附剂用量增加Cu²⁺去除率增大,当CeO₂-SiO₂吸附剂用量为0.15 g/L时对Cu²⁺的去除率趋于稳定;CeO₂-SiO₂吸附剂对不同金属离子吸附性能由大到小的顺序为Cu²⁺、Fe²⁺、Mn²⁺,该吸附过程均符合准二级动力学模型。     

多胺型聚苯乙烯树脂的合成及对Cu2+的吸附性能

以聚苯乙烯树脂为起始原料,经氯乙酰化后与四乙烯五胺反应,合成了一种含四乙烯五胺功能基的多胺型聚苯乙烯树脂。考察了溶剂、物料比、时间和温度等反应条件对树脂合成的影响,研究了树脂对Cu²⁺的吸附性能。结果表明,合成反应在THF溶剂中室温即可顺利进行,所得树脂全交换容量为7.45mmol/g。树脂对Cu²⁺的吸附可以用准二级动力学方程来描述,液膜扩散为吸附主要控制步骤,吸附符合Langmuir等温方程,为单分子层吸附,饱和吸附量为46.15 mg/mL。对于Cu²⁺、Ni²⁺混合溶液,该树脂可以选择性吸附其中Cu²⁺。     

离子交换树脂脱除高盐废水中Ca2+的特性研究

采用螯合型离子交换树脂处理氟化工脱氟后的高盐废水中钙离子(Ca²⁺)。考察了树脂对Ca²⁺在静态吸附和动态吸附过程中的主要影响因素和吸附性能，并对多次吸附-再生后的树脂吸附性能进行测试。研究结果表明：树脂对Ca²⁺最大静态吸附量为35.1 mg/g；当废水NaCl浓度为150.0 g/L时，树脂Ca²⁺吸附量仅降低5.2%，树脂耐盐性较好；pH对树脂吸附Ca²⁺的静态和动态吸附量影响较小；动态吸附过程中，随着流量增大，工作吸附容量逐渐减少，适宜的流速应在4～9 BV/h；饱和吸附后树脂充分再生情况下，工作吸附容量基本保持不变。     

一种巯基胺型羧酸螯合树脂的制备及其吸附性能

以环硫氯丙烷和多乙烯多胺为原料,通过交联反应合成了巯基胺型树脂(PA树脂)。然后对PA树脂进行氯乙酸化反应,合成了巯基胺型羧酸螯合树脂(PAC树脂),并通过傅立叶变换红外光谱仪(FTIR)对其结构进行了表征。研究了PAC树脂对模拟含Cu2+电镀废水的吸附性能,探讨了树脂用量、吸附时间和pH对Cu2+吸附性能的影响。实验结果表明,在常温常压下,取25 mL浓度为10 mmol/L的废水溶液,PAC树脂吸附Cu2+的最佳用量为0.40 g/mmol Cu2+,最佳吸附时间为150 min,最佳pH为6~10,最大吸附量和最大吸附率分别达到2.53mmol/g和94.7%。PAC树脂对Cu2+的吸附过程符合Langmiur和Freundlich等温吸附方程。     

阳离子交换树脂改性研究进展

强酸性阳离子交换树脂含有大量的强酸性基团,具有选择、交换、吸收和催化等功能,但其存在耐高温性能差、酸强度低等问题,故需要对其进行改性。改性的阳离子交换树脂广泛应用于水处理、有机合成、分离处理、环境保护及生物制药等领域。本文简要介绍了近年来强酸性阳离子交换树脂的改性方法,主要包含:金属离子改性(Al³⁺、Sn⁴⁺、Zn²⁺、Ti⁴⁺、Fe³⁺和Fe²⁺、Ce⁴⁺和Ga³⁺、Ni²⁺、Zr⁴⁺、Pd²⁺等)、磺化改性、巯基改性、胺化改性及其他类改性等方法;指出了其存在的问题,分析了改性阳离子交换树脂的未来发展方向,开发和研制具有耐高热和化学稳定性的树脂载体材料成为其研究的关键。除此之外,对树脂进行各种改性处理也是改善树脂综合性能、扩大其应用范围的重要方法。     

一种高吸水树脂对电镀废水中铜离子的吸附研究

以废弃聚乙烯(PE)塑料与具有亲水性基团的丙烯酸(AA)及其盐接枝共聚合成一种高吸水性树脂,并将所得高吸水树脂用于溶液中Cu2+的吸附。通过分光光度法研究了树脂去除水溶液中Cu2+的情况,考察了起始pH、树脂用量、金属离子起始浓度和吸附时间对金属离子去除率的影响。结果表明,该树脂对Cu2+具有较强的吸附性能。树脂初期吸附速率大,吸附达到平衡时的接触时间为30 min。当溶液pH为7.0,Cu2+初始浓度为25 mg/L,树脂用量在8 g/L时,树脂对Cu2+的去除率可达95.0%以上。     

复合水凝胶SA/AAm-Lgs的制备及其对Fe3+的静/动态吸附

将木质素磺酸钠(Lgs)引入到以海藻酸钠(SA)和丙烯酰胺(AAm)为基体的溶液中,通过自由基聚合法制备得到多孔三维的复合水凝胶(SA/AAm-Lgs),使用扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)和力学性能测试仪等对其结构和性能进行分析,并将其应用于去除废水中的Fe³⁺。研究结果表明：实验成功制备了多孔三维网状结构的复合水凝胶SA/AAm-Lgs。当Lgs用量增加时,水凝胶的断裂伸长率和抗拉强度相应增加,溶胀性能也有一定程度提高。SA/AAm-Lgs(含Lgs 7 mg)静态吸附Fe³⁺的较佳工艺为：水凝胶用量0.5 g、温度25℃、Fe³⁺初始质量浓度2 g/L,该条件下水凝胶对Fe³⁺的吸附量可以达到143 mg/g,吸附性良好且具有循环使用性能。吸附动力学和吸附等温线模拟结果表明该水凝胶对Fe³⁺的吸附过程符合准二级动力学和Langmuir模型。此外,通过固定床工艺对Fe³⁺进行动态吸附实验证明了SA/AAm-Lgs具有良好的工业...     

钠基蒙脱土改性聚丙烯酸树脂基吸附剂的制备与性能

以丙烯酸(AA)、丙烯酰胺(AM)为共聚单体,钠基蒙脱土(Na-MMT)为改性剂,采用反相悬浮聚合法,制备钠基蒙脱土改性聚丙烯酸树脂基吸附剂。在钠基蒙脱土用量为单体总质量的6%,温度75℃,单体比例AA∶AM为4∶1(质量比),搅拌速度350 rpm,引发剂(APS)用量为单体总质量的1%和交联剂(MBA)用量为单体总质量的0.25%的优化条件下,所制备的钠基蒙脱土改性聚丙烯酸树脂基吸附剂对重金属离子Pb²⁺、Cu²⁺的吸附量分别为292.6 mg/g和178.9 mg/g。     

生物基吸附材料在金堤河水体生态污染治理中的应用

针对金堤河水体存在较为严重的重金属离子污染的现象，以玉米秸秆为原料，通过添加氯甲烷、环氧氯丙烷、四乙烯五胺、三丙胺和叔丁醇钾等处理剂，制备了一种新型生物基吸附材料SXF-1，并评价了其对重金属离子Cr⁶⁺和Pb²⁺的吸附效果。实验结果表明，当生物基吸附材料SXF-1的加量为0.5%、水样pH值为5、水样中重金属离子的浓度为50mg·L^-1、吸附时间为12h、实验温度为20℃、干扰离子浓度为5000mg·L^-1时，Cr⁶⁺和Pb²⁺的去除率分别能够达到96.15%和90.04%。研究结果认为，生物基吸附材料SXF-1对重金属离子Cr⁶⁺和Pb²⁺的吸附处理效果较好，能够满足金堤河水体生态污染治理的要求。     

以N-乙烯基吡咯烷酮聚合物为助分散剂制备的PVC树脂的颗粒结构和加工性能

分别在使用聚乙烯醇(PVA)分散剂、PVA/N-乙烯基吡咯烷酮(NVP)复合分散剂及PVA/[NVP/醋酸乙烯酯(VAc)]复合分散剂的条件下合成悬浮PVC树脂,比较了得到的PVC树脂的颗粒结构和加工性能。结果表明:添加NVP均聚物或不同组成的NVP/VAc共聚物作为助分散剂,均可使PVC树脂的汞总浸入体积、孔隙率和总孔比表面积增加,初级粒子聚集体之间的孔隙尺寸分布基本不变,而孔隙率增加;PVC树脂的加工塑化时间缩短,加工性能提高。     

Preparation and characterization of high loading porous crosslinked poly(vinyl alcohol) resins

Porous crosslinked poly(vinyl alcohol) resin beads have been prepared by a two-step pathway involving a pre-crosslinking reaction followed by a reverse suspension crosslinking reaction with epichlorohydrin as crosslinker. The reaction conditions have been optimized for the two steps in order to obtain resins with various pores sizes. The crosslinking density of these resins was calculated from their swelling properties by a modified Flory equation. High loading of hydroxyl groups is one of the important characteristics of these resins (attaining ca. 17 mmol/g). The porosity, pore volume, pore structure and the swelling behavior in water of these resins have been studied.     

Porous maleic anhydride–styrene–divinylbenzene copolymer beads

The formation of the porosity and the pore stability in maleic anhydride–styrene–divinylbenzene (MAn–St–DVB) copolymer beads were investigated using the apparent density measurements of the samples dried from methanol (maximum porosity) and from dioxane (stable porosity). The copolymer beads were prepared by the suspension polymerization method in glycerol instead of water as the dispersing medium. A toluene–dioxane (1:1) mixture was used as the diluent at a fixed volume fraction of the organic phase (0.47). Compared to St–DVB copolymers prepared in the presence of nonsolvating diluents, porous MAn–St–DVB copolymers are obtained at relatively low DVB concentration, i.e., at 1–3% DVB. The porosity of the copolymers increases with decreasing MAn concentration in the feed due to the decrease in the copolymer yield. The results of the elemental analyses and titrimetric methods indicate that approximately only half of the MAn units in the copolymer are able to react with amine or with water. A possible rearrangement of the MAn units into the cyclopentanone structures was suggested.     

极性后交联吸附树脂的制备及其对水杨酸的吸附

将GMA与DVB悬浮聚合得到了初始共聚物PDG,再通过悬挂双键后交联反应制备出极性后交联树脂PDGpc,并研究了合成树脂对水杨酸的吸附性能。结果表明,后交联后,树脂的BET比表面积和孔容都显著增加,且对水杨酸拥有更高的吸附量。     

Studies of selective adsorption resins. XVIII. The influence of porosity of macroreticular chelating resin on adsorption of heavy metal ions in an aqueous solution

In order to choose the most practical macroreticular chelating resins for the removal and recovery of heavy metal ion from industrial waste solution, the influence of the porosity of macroreticular chelating resins on the adsorption for metal ion was studied. The four macroreticular chelating resins (RST) containing triethylenetetramine side chain with different porosity were used. It was found that the adsorption of zinc ion at its low concentration solution was affected by the porosity of the RST. Among the four resins with average pore radius of 21.0, 24.5, 28.0, and 66.5 nm, a resin with that of 66.5 nm gave the highest initial adsorption rate and the largest breakthrough capacity for zinc ion at a space velocity of 15 h^?1.     

Recovery of uranium from seawater. XII. Preparation and characterization of lightly crosslinked highly porous chelating resins containing amidoxime groups

A number of lightly cross-linked poly(acrylonitrile-co-divinylbenzene) beads (RN-5) have been synthesized by suspension polymerization. The use of solvating diluents such as chloroform, dichloroethane, and tetrachloroethane resulted in copolymer beads having highly porous structures. The chelating resins containing amidoxime as a functional group (RNH-5) have been prepared by the reaction of copolymer beads with 3% hydroxylamine in methanol. A detailed analysis is made of the pore structure of lightly cross-linked copolymers of acrylonitrile–divinylbenzene and their amidoxime derivatives in the anhydrous state including pore-size distribution, specific surface area, and pore structure in the aqueous media by means of gel permeation chromatography (GPC). A set of experiments have been performed to ascertain the potential of the resins for the adsorption of uranium from seawater. Because of their modified pore structures, the chelating resins exhibited a marked adsorption rate for uranium in seawater as high as 23 μg of U/cm³ of resin/day without alkaline treatment.     

A novel route for synthesis of cross-linked polystyrene copolymer beads with tunable porosity using guar and xanthan gums from bioresources as alternative synthetic suspension stabilizers

Cross-linked polymer beads with different cross-linking agent loading were prepared by carrying out cross-linking suspension copolymerization of styrene-divinylbenzene (St- DVB) monomers using guar gum (GG) and xanthan gum (XG) from bioresources as eco-friendly suspension biopolymer stabilizers in the presence of non reactive diluents. The effects of GG and XG as suspension biostabilizers on the characteristics of the styrene copolymer beads were investigated regarding thermal properties, porosity characteristics, solvent swelling ratio, and surface morphologies using TGA, DSC, XRD, SEM, BET analyses. Spherical and regular beads with smooth surface were produced and the average particle size was in the range 170–290 μm (50–80 mesh size). The porosity characteristics of the produced beads including surface area and pore volume were in range 0.45 m²/g and 32–45 ml/g, respectively. Overall, the present article provided a novel route to prepare cross-linked polystyrene copolymer beads with tunable porosity suitable for catalyst support.     

喷墨打印PVC证卡涂层研究

研究了不同规格二氧化硅和胶粘剂对喷墨打印PVC证卡涂层的影响,优选出一种二氧化硅和聚乙烯醇(PVA)胶粘剂,并通过在涂层中添加聚丙烯酸酯乳液和明胶解决了打印质量覆膜牢度低和涂层龟裂问题。     

Styrene-divinylbenzene copolymers,V. Inhomogeneity in the structure and the average degree of swelling

The compositional inhomogeneity and the average degree of swelling of heterogeneous styrene-divinylbenzene (S-DVB) copolymers were investigated using two morphological features of porous copolymers. At a fixed volume fraction of a nonsolvating diluent, the extent of inhomogeneous crosslinking increases with increasing DVB concentration. In addition, the crosslinking density of less crosslinked regions of the network decreases as the DVB concentration increases. The experimental results can be explained by the microgel-model of the network formation. The average degree of volume swelling can be predicted from the composition of the starting monomer mixture and from the porosity of the final copolymer dried from water. Depending on these parameters, the changes in the value of v₂, the volume fraction of copolymer in the swollen gel, and the conditions for the pore stability are discussed.     

Preparation and characterization of amidoxime resins based on poly(acrylonitrile-co-vinylidene chloride-co-divinylbenzene)

The poly(acrylonitrile-co-vinylidene chloride-co-divinylbenzene) beads with macroporous morphology were synthesized by suspension polymerization. The use of dichloroethane as a solvating diluent resulted in copolymer beads having highly porous structures. These have been reacted with hydroxylamine in methanol, which generates amidoxime groups. The precursory resins were readily functionalized within 0.5–1 h. A detailed analysis is made of the pore structure of resins in the anhydrous state including pore size distribution and specific surface area. © 1994 John Wiley & Sons, Inc.