交联壳聚糖树脂的微波合成及其对亚甲基蓝吸附性能的研究

以壳聚糖(CTS)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酸(AA)为原料,N,N-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸钾(KPS)为引发剂,采用微波辐射法,通过交联接枝共聚合成了CTS-g-PAMPS/AA交联CTS树脂。探讨了微波功率、反应时间,树脂用量、溶液pH、染料浓度、吸附时间对亚甲基蓝(MB)吸附性能的影响。结果显示该树脂在MB浓度为500mg/L,吸附剂为0.3g时,吸附量和吸附率分别达1776mg/g和95.4%。该树脂具有很强的pH敏感性和高吸附性能,其对染料的吸附行为满足Langmuir吸附等温模型。     

AMPS/AA/MA/St共聚吸附剂的合成及性能研究

在交联剂N,N′-亚甲基双丙烯酰胺(NMBA)的作用下,单体2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酸(AA)、顺丁烯二酸酐(MA)和淀粉(St)以溶液热聚合的方式合成四元共聚吸附剂。采用单因素法探究了反应条件对树脂吸附亚甲基蓝染料性能的影响,得到最佳的树脂合成工艺条件。实验结果表明:n(AMPS)∶n(AA)∶n(MA)∶W(St)=1∶0.5∶0.1∶1.98(wt,质量分数,下同),pH=2,W(NMBA)=0.1%,固含量为31%时,该树脂的吸附量最大,为106.35mg/g。     

互穿网络水凝胶的前端聚合制备及吸附性能研究

采用前端聚合方法,以丙烯酸(AA)和丙烯酰胺(AM)为单体,在4种线性高分子水溶液中制备了半互穿网络结构(semi-IPN)的水凝胶,其中的线性高分子分别为:聚乙烯醇(PVA)、聚乙二醇(PEG)、聚丙烯酰胺(PAM)、聚乙烯吡咯烷酮(PVP)。用扫描电镜(SEM)、吸水率和吸附量对互穿网络水凝胶的结构和性能进行了表征,结果表明:水解对水凝胶的吸水性能影响显著,使吸水率平均提高9.1倍,但对吸附性能影响较小,使亚甲基蓝吸附量提高不足1倍;在4种互穿网络水凝胶中,P(AM-AA)/PEG的吸水率最大,高达627.9g/g,P(AM-AA)/PAM互穿网络水凝胶对亚甲基蓝有最大的吸附能力,吸附量为91.6mg/g。     

水葫芦/丙烯酸/2-丙烯酰胺-2-甲基丙磺酸高吸水性树脂的制备及性能研究

以水葫芦为原料制备水葫芦羧甲基纤维素(CMC),以制得的水葫芦CMC为原料,采用反相悬浮法制备水葫芦CMC/丙烯酸(AA)/2-丙烯酰胺-2-甲基丙磺酸(AMPS)高吸水性树脂。其中,以硫酸钾为引发剂,N,N′-亚甲基双丙烯酰胺为交联剂,采用红外光谱,热重分析对产物结构进行表征,对水葫芦CMC/AA/AMPS高吸水性树脂的吸附性能进行测试。测试表明:该树脂吸水率为1239.7g/g,对氯化钠(NaCl,浓度为0.9%)溶液吸率为105.5g/g,对浓度为50mg/L的磷酸根离子(PO_4~(3-))溶液和硝酸根(NO~(3-))溶液的吸取率分别是66.3%,44.7%。     

新型吸附剂的制备及其对亚甲基蓝吸附的研究

以N,N'-亚甲基双丙烯酰胺(MBA)为交联剂,过硫酸钾(KPS)为引发剂,以丙烯酸(AA)、壳聚糖(CTS)及坡缕石黏土(PGS)作为原料,通过自由基聚合制备的PAA/CTS/PGS复合吸附材料。运用扫描电子显微镜(SEM),傅里叶变换红外光谱仪(FT-IR),热重分析(TG)对复合材料进行了形貌和结构表征。结果表明:聚合物复合材料的表面光滑,聚合物均匀复合,其中部分高分子聚合链进入了坡缕石黏土土层间,扩大了缝隙。吸附结果表明:当pH=10、染料浓度为200mg/L、振荡时间为60min、温度为30℃、吸附剂用量为0.025g时,该复合材料对亚甲基蓝的吸附率可达98%以上。     

离子液体中阳离子纤维素的制备及对酸性蓝40的吸附性能

以离子液体1-丁基-3-甲基咪唑氯盐(BMIMCl)为溶剂、丙烯酰氧乙基三甲基氯化铵(AETAC)为阳离子单体合成了高效的阳离子改性纤维素材料。将纤维素溶解于BMIMCl中,在溶液状态通过自由基聚合接枝阳离子单体,采用相分离法制得产物。红外光谱和元素分析表明单体已成功接枝到纤维素上,扫描电镜和X射线衍射仪分析表明阳离子纤维素的样品呈多孔结构,晶型从纤维素Ⅰ型变为纤维素Ⅱ型,结晶指数从80.33%降至53.81%。阳离子纤维素对酸性蓝40具有优良的吸附能力,在中性、无盐条件下吸附效果最好,理论平衡吸附量可达到448.43 mg/g。吸附类型属于化学吸附,吸附过程符合Langmuir吸附等温线模型和伪二阶吸附动力学方程。吸附剂可循环使用,NaOH溶液可作为解吸溶液。     

AA/SiO2/CTS复合材料制备及其吸附铬离子研究

通过浸渍法分别用丙烯酸(AA)和纳米二氧化硅(SiO₂)改性壳聚糖(CTS),制备AA/SiO₂/CTS复合材料。通过红外光谱表征了复合材料的结构，并以复合材料为吸附剂吸附铬离子，研究了复合材料吸附铬离子的吸附性能。结果表明：当吸附剂用量为2.0g, pH为6左右，铬离子浓度为20mg/L,温度为25℃,吸附70min时，吸附效果最好，改性后的复合吸附剂AA/SiO₂/CTS的吸附率最高可达96%,明显高于未改性CTS的85%和AA/CTS的92%。吸附热力学和动力学研究表明，Freundlich等温模型和拟二级动力学模型更加符合吸附过程。     

β-环糊精改性磁性壳聚糖微球对亚甲基蓝吸附性能研究

以壳聚糖、四氧化三铁(Fe_3O_4)和β-环糊精为原料,三聚磷酸钠和环氧氯丙烷为交联剂,采用离子交联法制备β-环糊精改性磁性壳聚糖微球,考察了改性微球对亚甲基蓝的吸附性能及吸附机理。结果表明:改性微球对亚甲基蓝的吸附量随着pH值的升高而增加,随着温度的升高而降低;亚甲基蓝在改性微球上的吸附等温线可用Langmuir方程模拟,吸附动力学符合拟二级动力学方程。在吸附温度为20℃,吸附时间为100min,pH值为8时,改性微球对亚甲基蓝吸附量和脱色率分别达到123.70mg/g和98.96%。用0.01mol/L硝酸(HNO_3)溶液对吸附饱和的改性微球进行解吸,经过3次重复试验后,对亚甲基蓝的吸附量和脱色率是首次的93.69%,再生效果较好,可重复使用。     

互穿网络高吸水性树脂的合成及性能

以聚乙烯醇、丙烯酰胺和丙烯酸为原料,过硫酸铵(APS)为引发剂,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂,采用溶液共聚法制备了聚乙烯醇-聚(丙烯酰胺/丙烯酸)(PVA-P(AM-co-AA))互穿网络高吸水性树脂。研究了MBA浓度、AA含量、PVA交联时间、溶液的离子强度对互穿网络高吸水树脂吸水倍率的影响。     

胶原/纤维素/壳聚糖凝胶珠对水溶液中Ni~(2+)的吸附

在以离子液体1-丁基-3-甲基咪唑氯盐([C4mim]Cl)为溶剂,制备胶原和纤维素复合凝胶珠吸附剂过程中,加入少量壳聚糖对凝胶珠进行改性。吸附实验结果显示,胶原/纤维素/壳聚糖凝胶珠(CCHB-CS,质量比2/3/1)能有效吸附水溶液中的Ni 2+,相较于胶原/纤维素凝胶珠(CCHB,质量比1/1)和壳聚糖/纤维素凝胶珠(CCSHB,质量比1/1),CCHBCS对Ni 2+离子的吸附能力有所降低;溶液pH值会影响CCHB-CS对Ni 2+的吸附,pH7.0为最佳条件;Langmuir单分子吸附模型适用于描述CCHB-CS吸附行为。     

CMS-g-PAA高吸水性复合材料的制备及性能研究

以废弃全棉面膜基布(CMS)和丙烯酸(AA)为原料,采用自由基溶液聚合法制备CMS-g-PAA复合高吸水性材料,并用红外光谱(FTIR)进行表征。研究了吸水性、保水性及反复吸放液性能,采用准一级、二级动力学模型对其吸水溶胀过程进行模拟研究。结果表明,全棉面膜基布和丙烯酸单体之间发生了接枝共聚反应,所合成的CMS-g-PAA复合材料在去离子水和0.9%(质量分数)NaCl溶液的吸水倍率分别可达211.3g/g和45.5g/g,且溶胀过程符合准二级动力学吸附模型。在较高温度和一定压力下,CMS-g-PAA均具有良好的保水性能。反复吸放液性能测试表明循环8次后,去离子水和0.9%(质量分数)NaCl溶液的吸水倍率分别保持了最大吸水倍率的64.9%和44.4%。     

力学性能可控的CMC/AA/CB[8]/BET凝胶的制备及其吸附性

以八元瓜环、膨润土为双交联剂制备了力学性能可控的羧甲基纤维素/丙烯酸/八元瓜环/膨润土水凝胶(CMC/AA/CB[8]/BET gel)。采用FT-IR、SEM技术表征其结构和形貌,研究了这种凝胶的力学性能和吸附性能以及溶胀和吸附动力学。结果表明：CB[8]和BET通过氢键与接枝到CMC上的AA形成致密的网络结构,使凝胶的力学性能增强；这种凝胶的溶胀符合准二级动力学模型,并与应力松弛溶胀半结晶聚合物理论相符；这种凝胶在酸中浸泡后酸中的游离H⁺与CB[8]、BET生成的氢键使凝胶的断裂强度从0.52 MPa显著提高到3.0 MPa；这种凝胶对亚甲基蓝有良好的吸附效果,符合准二级动力学模型。     

The synthesis,activation and characterization of charcoal powder for the removal of methylene blue and cadmium from wastewater

Charcoal prepared from biomass, wastes of the local forest (tree branches), activated with NaOH solution and with Degussa P25 (TiO₂) was used as adsorbent and photocatalyst for the removal of cadmium cations and methylene blue from wastewater. These materials were characterized by using atomic force microscopy for roughness surface. The energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) analysis indicate the existence of nano TiO₂ on the charcoal surface. Additionally, the FT-IR spectroscopy measurements indicate that the alkali treatment develops hydroxyl groups on charcoal surface which could adsorb methylene blue, heavy metals and other pollutants via the synergistic effect. The activities of the charcoal (BC), activated charcoal (BCA) and BCA/TiO₂ mixture (BCA-D) depend on the contact time, adsorbent dosage and pH. The adsorption kinetic data were tested using pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The kinetic studies showed that the adsorption is followed by the pseudo-second-order reaction with regard to the intraparticle diffusion rate kinetics.     

A novel agricultural waste adsorbent for the removal of cationic dye from aqueous solutions

In this paper, pineapple stem (PS) waste, an agricultural waste available in large quantity in Malaysia, was utilized as low-cost adsorbent to remove basic dye (methylene blue, MB) from aqueous solution by adsorption. Batch mode experiments were conducted at 30 degrees C to study the effects of initial concentration of methylene blue, contact time and pH on dye adsorption. Equilibrium adsorption isotherms and kinetic were investigated. The experimental data were analyzed by the Langmuir and Freundlich models and the isotherm data fitted well to the Langmuir isotherm with monolayer adsorption capacity of 119.05mg/g. The kinetic data obtained at different concentrations were analyzed using a pseudo-first-order and pseudo-second-order equation and intraparticle diffusion equation. The experimental data fitted very well the pseudo-second-order kinetic model. The PS was found to be very effective adsorbent for MB adsorption.     

丝胶蛋白/丙烯酸/丙烯酰胺复合吸水材料的制备与吸水性能

以丝胶蛋白（SS）、丙烯酸（AA）和丙烯酰胺（AM）为主要原料,N,N′-亚甲基双丙烯酰胺（MBA）为交联剂,过硫酸铵（APS）为引发剂,采用水溶液聚合法制备了丝胶蛋白/丙烯酸/丙烯酰胺复合吸水材料,并考察了其在不同条件下的吸水性能。结果表明,SS/AA/AM复合吸水材料在去离子水、自来水、0.9%NaCl溶液中的吸水...     

Removal of copper(II) and lead(II) from aqueous solution by manganese oxide coated sand I. Characterization and kinetic study

The preparation, characterization, and sorption properties for Cu(II) and Pb(II) of manganese oxide coated sand (MOCS) were investigated. A scanning electron microscope (SEM), X-ray diffraction spectrum (XRD) and BET analyses were used to observe the surface properties of the coated layer. An energy dispersive analysis of X-ray (EDAX) and X-ray photoelectron spectroscopy (XPS) were used for characterizing metal adsorption sites on the surface of MOCS. The quantity of manganese on MOCS was determined by means of acid digestion analysis. The adsorption experiments were carried out as a function of solution pH, adsorbent dose, ionic strength, contact time and temperature. Binding of Cu(II) and Pb(II) ions with MOCS was highly pH dependent with an increase in the extent of adsorption with the pH of the media investigated. After the Cu(II) and Pb(II) adsorption by MOCS, the pH in solution was decreased. Cu(II) and Pb(II) uptake were found to increase with the temperature. Further, the removal efficiency of Cu(II) and Pb(II) increased with increasing adsorbent dose and decreased with ionic strength. The pseudo-first-order kinetic model, pseudo-second-order kinetic model, intraparticle diffusion model and Elovich equation model were used to describe the kinetic data and the data constants were evaluated. The pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior of Cu(II) and Pb(II) onto MOCS, suggesting that the adsorption mechanism might be a chemisorption process. The activation energy of adsorption (E(a)) was determined as Cu(II) 4.98 kJ mol(-1) and Pb(II) 2.10 kJ mol(-1), respectively. The low value of E(a) shows that Cu(II) and Pb(II) adsorption process by MOCS may involve a non-activated chemical adsorption and a physical sorption.     

Equilibrium, kinetic and sorber design studies on the adsorption of Aniline blue dye by sodium tetraborate-modified Kaolinite clay adsorbent

Raw Kaolinite clay obtained Ubulu-Ukwu, Delta State of Nigeria and its sodium tetraborate (NTB)-modified analogue was used to adsorb Aniline blue dye. Fourier transformed infrared spectra of NTB-modified Kaolinite suggests that modification was effective on the surface of the Kaolinite clay with the strong presence of inner -OH functional group. The modification of Kaolinite clay raised its adsorption capacity from 1666 to 2000 mg/kg. Modeling adsorption data obtained from both unmodified and NTB-modified Kaolinite clay reveals that the adsorption of Aniline blue dye on unmodified Kaolinite clay is on heterogeneous adsorption sites because it followed strongly the Freundlich isotherm equation model while adsorption data from NTB-modified Kaolinite clay followed strongly the Langmuir isotherm equation model which suggest that Aniline blue dye was adsorb homogeneous adsorption sites on the NTB-modified adsorbent surface. There was an observed increase in the amount of Aniline blue adsorbed as initial dye concentration was increased from 10 to 30 mg/L. It was observed that kinetic data obtained generally gave better robust fit to the second-order kinetic model (SOM). The initial sorption rate was found to increased with increasing initial dye concentration (from 10 to 20 mg/L) for data obtained from 909 to 1111 mg kg(-1)min(-1) for unmodified and 3325-5000 mg kg(-1) min(-1) for NTB-modified adsorbents. Thereafter there was a decrease in initial sorption rate with further increase in dye concentration. The linearity of the plots of the pseudo-second-order model with very high-correlation coefficients indicates that chemisorption is involved in the adsorption process. From the design of a single-batch adsorber it is predicted that the NTB-modified Kaolinite clay adsorbent will require 50% less of the adsorbent to treat certain volumes of wastewater containing 30 mg/L of Aniline blue dye when it is compared with the unmodified adsorbent. This will be cost effective in the use of NTB-modified adsorbent for the adsorption of Aniline blue dye from water and wastewater.     

微波辐射合成丙烯酸类耐盐性高吸水树脂及其性能

采用微波辐射方法合成了2-丙烯酰胺基-2-甲基丙磺酸(AMPS)/丙烯酰胺(AM)/丙烯酸(AA)耐盐性高吸水树脂。探讨了单体的组成、交联剂、引发剂用量、中和度和微波功率对待测液体吸液倍率的影响,并进行了树脂吸液速率和保水性能的研究,用红外光谱对树脂官能团进行了表征。实验结果表明,该树脂在蒸馏水中的吸水倍率为1509 g/g,在质量分数为0.9%的NaCl及相同离子强度的CaCl2、FeCl3溶液中吸液倍率分别为184g/g,165g/g,14g/g,树脂具有较强的耐盐性能;树脂的吸液倍率与电解质溶液阳离子的价态有关,价态越高,树脂的吸液倍率越低;该树脂具有较大的吸水速率和良好的保水性能。