GO/GA-g-PAMPS复合水凝胶的制备及其对阳离子染料的吸附性能

以自制氧化石墨烯(GO)、阿拉伯胶(GA)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为原料,采用一步水热法制备了GO/GA-g-PAMPS复合水凝胶,利用FTIR、XRD、SEM对复合水凝胶结构进行了表征。考察了水凝胶对阳离子染料亚甲基蓝(MB)和结晶紫(CV)的吸附性能。结果显示:在GO质量浓度为0.3 g/L、凝胶用量为0.05 g、溶液pH为7、温度为50℃、染料初始质量浓度为200 mg/L时,凝胶对MB和CV的吸附量和吸附率分别为395.68、381.70mg/g和98%、96%。经5次循环后,凝胶对MB和CV的吸附率仍能达到82.6%和81.2%。吸附等温线和动力学研究表明,凝胶对MB吸附更符合Freundlich模型,对CV的吸附更符合Langmuir模型,准二级动力学模型能更好地描述两种阳离子染料的吸附过程。热力学研究表明,水凝胶对两种染料吸附是自发、吸热和混乱度增加的过程。     

GO/GA-g-PAMPS复合水凝胶的制备及阳离子染料吸附性能

以自制氧化石墨烯（GO）和阿拉伯胶（GA）、2-丙烯酰胺基-2-甲基丙磺酸（AMPS)为原料,采用一步水热反应法制备了GO/GA-g-PAMPS新型复合水凝胶,利用FTIR、XRD、SEM对复合水凝胶结构进行了表征。研究了GO浓度、溶液pH、染料初始浓度、吸附时间、吸附温度对阳离子染料亚甲基蓝（MB）和结晶紫（CV）吸附性能的影响。结果显示：水凝胶对阳离子染料具有较好的吸附效果,在GO浓度为0.3mol/mL,凝胶用量为0.05g,溶液pH为7,温度为50℃,染料初始浓度为200mg/L时,凝胶对MB和CV的吸附量和吸附率分别为395.68、381.70mg/g和98%、96%。凝胶经过5次循环使用后,对MB和CV的吸附率仍能达到82.6%和81.2%。吸附等温线和动力学研究表明,凝胶对MB吸附更符合Freundlich模型,对CV的吸附更符合Langmuir模型,准二级动力学模型能更好地描述两种阳离子染料的吸附过程。热力学研究表明水凝胶对两种染料吸附是自发、吸热和混乱度增加的过程。     

N-异丙基丙烯酰胺/甲基丙烯酸/氧化石墨烯复合水凝胶研究

以N-异丙基丙烯酰胺(NIPAM)和甲基丙烯酸(MAA)为单体,N,N-亚甲基双丙烯酰胺(BIS)为交联剂,过硫酸铵(APS)为引发剂,在氧化石墨烯(GO)水溶液中进行自由基原位聚合,制备了聚N-异丙基丙烯酰胺/聚甲基丙烯酸/氧化石墨烯(PNIPAM/PMAA/GO)复合水凝胶,研究了GO的含量变化对复合水凝胶性能的影响。结果表明,GO的加入能明显提高水凝胶的力学性能,复合水凝胶的平衡溶胀比随着GO含量的增加而降低,并且也具有优异的pH敏感性。     

氧化石墨烯/海藻酸钠复合材料的制备及其对Ni2+吸附工艺研究

采用改进Hummers法制备了氧化石墨烯(GO)。以海藻酸钠(SA)为载体,采用溶液共混法制备氧化石墨烯/海藻酸钠(GO/SA)凝胶球。以GO/SA凝胶球作为吸附材料,对含镍废水进行吸附性能研究。实验结果表明:以质量浓度为7%Ca Cl2为交联剂,m(GO)∶m(SA)为1∶9,Ni~(2+)质量浓度为80g/L,GO/SA凝胶球投加量为40g/L,吸附温度为30℃,Ni~(2+)吸附率为17.15%。含镍废水p H值大于6时,出现大量白色沉淀,pH值对含镍废水中Ni~(2+)吸附率有显著影响。     

壳聚糖接枝聚丙烯酸/石墨烯复合水凝胶的制备及表征

首先采用改进的Hummers法制备氧化石墨烯,将壳聚糖溶解在乙酸溶液中,后加入引发剂过硫酸钾和单体丙烯酸,引发丙烯酸发生接枝聚合,将丙烯酸接枝聚合到壳聚糖上得到壳聚糖接枝聚丙烯酸（CS-g-PAA）。将CS-g-PAA分散在蒸馏水中,加入石墨烯（GO）形成分散液,最后采用戊二醛交联得到CS-g-PAA/GO复合水凝胶。水凝胶呈现纤维状,直径为723±125 nm。CS-g-PAA:GO从3:1降低到1:1,水凝胶的孔隙率和比表面积分别为从94.33%和55.31 m2/g增加至96.12%和60.90 m2/g。体外凝血实验表明,CS-g-PAA和CS-g-PAA/GO水凝胶均可促进血液凝结,相比较纯的CS-g-PAA,复合水凝胶中引入GO后,水凝胶的血液凝固指数（BCI）从65.12%降低到40.19%。主要归因于GO促进血小板聚集和CS-g-PAA/GO具有更强的物理吸收能力的结合作用。CS-g-PAA/GO复合水凝胶有望成为理想的止血材料。     

活性炭对聚丙烯酸水凝胶pH敏感性的影响

以丙烯酸(AA)为单体、活性炭(AC)为惰性致孔剂、N,N-亚甲基双丙烯酰胺为交联剂、过硫酸铵为引发剂,采用自由基溶液聚合法制备了聚丙烯酸(PAA)/AC复合水凝胶,并研究了AC的引入对PAA水凝胶pH敏感性的影响以及不同pH值的缓冲液中水凝胶的溶胀动力学。结果表明:AC的引入并未影响PAA水凝胶的化学组成和热稳定性,但增大了其孔隙尺寸;AC的引入提高了PAA水凝胶的pH敏感性;冻干的PAA/AC复合水凝胶比烘干的PAA/AC复合水凝胶达到溶胀平衡的速率更快、平衡溶胀比更大。     

改性再生纤维素/nano-La (OH)3复合水凝胶的制备及除磷性能

以马来酸酐接枝改性的再生纤维素水凝胶为载体(MAH-RC),以硝酸镧为前驱液、氢氧化钠为沉淀剂,通过原位合成的方法成功制备了MAH-RC/nano-La(OH)3复合水凝胶。探讨了马来酸酐(MAH)接枝改性最佳工艺条件,并着重考察了前驱液镧离子(La3+)浓度对复合水凝胶结构性能影响。研究发现,接枝温度为65℃,时间为3 h,MAH与再生纤维素(RC)质量比为5:1,吡啶用量为7.5%时接枝效果最佳,改性纤维素取代度高达0.69;负载La(OH)3后,复合水凝胶仍保持多孔结构,但前驱液La3+浓度增加,原位生成La(OH)3逐渐团聚。当前驱液La3+浓度0.2 mol/L时,纳米La(OH)3均匀分散在纤维素凝胶骨架中,其具有较高吸附容量(30.0 mgP/g)且La(OH)3利用率高。该复合水凝胶能在pH值=3~9范围内有效吸附磷酸盐,且抗干扰离子(Cl-、NO3-、SO42-)能力强。     

胶束模板法制备海藻酸复合水凝胶及性能研究

以海藻酸钠(Na-Alg)为原料、丙烯酸(AA)为单体、过硫酸铵(APS)为引发剂、N,N-亚甲基双丙烯酰胺(BIS)为交联剂,控制表面活性剂正十二烷基硫酸钠(SDS)的加入量,制备了具有多孔结构的pH敏感型海藻酸/聚丙烯酸复合水凝胶(alginate/PAA composite hydrogels,简写为T-APCGs)。采用傅里叶变换红外光谱(FTIR)和扫描电子显微镜(SEM)对其进行了表征,结果显示加入0.96 g SDS的复合水凝胶孔洞数量最多且分布最均匀。在水中测其溶胀度,发现加入1.96 g SDS的复合水凝胶溶胀度最大为165 g/g。在不同pH条件下测试T-APCGs的溶胀性能,证明其具备良好的pH敏感性.探究了T-APCGs对牛血清白蛋白(BSA)负载及释放能力,测得其对BSA最大负载量为0.184 g/g,在pH=1.2的模拟胃液环境下累计释放率为10%,在pH=7.5的模拟肠液环境下累积释放率为95%。这种复合材料有望作为一种新型药物载体被用于医疗行业。     

葡萄糖响应GO/微凝胶复合水凝胶的制备及性能

为了实现胰岛素对糖尿病患者血糖浓度智能调控,提出以3-丙烯酰胺基苯硼酸(AAPBA)、N,N'-二甲基丙烯酰胺(DMAA)、丙烯酰胺(AAm)为单体,70℃下经乳液聚合制备Poly(AAPBA-DMAA-co-AAm)微凝胶。以微凝胶为交联点,氧化石墨烯(GO)为改进剂,制备了GO/微凝胶复合水凝胶。采用傅里叶红外光谱仪(FT-IR),X射线衍谢仪(XRD)和扫描电镜(SEM)对水凝胶的组成、表面形貌进行表征,粒径分析表明微凝胶的粒径分布均匀、分散性良好。通过称重法对水凝胶的葡萄糖响应性进行测试,结果表明在p H为7.3条件下,水凝胶的响应速率随着葡萄糖浓度的增加而增大。当葡萄糖浓度为40 mmol×L~(-1),GO/微凝胶复合水凝胶对葡萄糖最大响应溶胀度为18%,响应时间为30 min,载药水凝胶的体外释放结果表明,10 h胰岛素累计释放率可达到52.59%,GO/微凝胶复合水凝胶对胰岛素具有缓释控释作用。     

PAA/PEG复合水凝胶膜的制备及其性能

以丙烯酸(AA)为单体、聚乙二醇(PEG)为大分子模板、N,N-亚甲基双丙烯酰胺为交联剂、过硫酸铵为引发剂,通过自由基溶液聚合法原位聚合制备了聚丙烯酸(PAA)/PEG复合水凝胶膜,研究了PEG用量对复合水凝胶成膜性、热稳定性、溶胀性能和力学性能的影响。结果表明:成功制备了PAA/PEG复合水凝胶膜;适量PEG的引入有利于复合水凝胶成膜;PAA/PEG复合水凝胶膜的热稳定性良好;PEG的引入对水凝胶膜的吸水溶胀性能不利;适量PEG有利于提高凝胶的力学性能,复合水凝胶膜软而韧;PEG与AA质量比为0.4的PAA/PEG复合水凝胶的拉伸强度和断裂标称应变最大,分别为1.58 MPa,414%。     

Radiation synthesis of graphene oxide/composite hydrogels and their ability for potential dye adsorption from wastewater

A high yield of graphene oxide (GO) was chemically synthesized from graphite powder utilizing adjusted Hummer's method. The contents of acidic functional groups in GO were determined using potentiometric titration. Composite hydrogels dependent on graphene oxide/poly(2-acrylamido-2-methylpropanesulfonic acid)/polyvinyl alcohol (GO/PAMPS/PVA) were synthesized utilizing a ⁶⁰Co gamma irradiation source at different doses. The synthesized graphene oxide and composite hydrogels were portrayed via X-ray diffraction, thermogravimetric analysis, and Fourier transform infrared analysis. The morphology of composite hydrogels was characterized by scanning electron microscope. The gel % and swelling % for the prepared hydrogel demonstrated that the swelling % of hydrogel increased with raising AMPS content. Whereas the increment of GO and increasing the irradiation dose lead to a reduction in the swelling %. The influences of pH, GO percentage, initial dye concentration, the adsorbent dosage, contact time, and temperature on the adsorption of basic blue 3 dye were evaluated and the adsorption capacity was 194.6 mg/g at optimum conditions; pH = 6, GO/PAMPS/PVA composite hydrogels with 5 wt% of GO, initial dye concentration = 200 mg/L, adsorbent dose = 0.1 g, solution volume = 50 mL after 360 min at room temperature (25°C). The adsorption of dye onto the GO/PAMPS/PVA composite hydrogels follows Pseudo-second-order adsorption kinetics, fits the Freundlich adsorption isotherm model.     

Preparation of Sodium carboxymethylcellulose/poly(methyl acrylate) IPN hydrogels and their application for adsorption

Sodium carboxymethylcellulose/poly(methyl acrylate) (NaCMC/PMA) interpenetrating polymer networks (IPNs) were prepared by fractional step in 40 wt % ethanol solution with N,N′‐methylenebisacrylamide as a crosslinker. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimeter were used to characterize the NaCMC/PMA IPN hydrogels and confirm the IPN structure as well. Simultaneously, adsorption of the obtained IPN hydrogels to methylene blue (MB) was also investigated. It was observed that the adsorption of MB onto the hydrogels was mainly dependent on the initial concentration of MB and the pH of the solution. Adsorption rate of MB was much higher in the first 9 h than that in the following period and saturated adsorption amount of MB was 2370 mg/g at the initial MB concentration of 100 mg/L. Moreover, the adsorption capacity of the IPN hydrogels at the neutral pH condition is much higher than those at acid or alkaline pH conditions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41101.     

Functionalization of polyvinyl alcohol hydrogels with graphene oxide for potential dye removal

Because of highly frozen macromolecule chains, polyvinyl alcohol (PVA) hydrogels have never been used for dye removal. This work focuses on improving the adsorption capacity of the PVA hydrogel by using amphiphilic graphene oxide to improve its macromolecular chain mobility in crystal domain and introduce new functional groups. To evaluate its effectiveness, crystal structure, swelling kinetics, and model dye methylene blue (MB) adsorption of the as‐prepared PVA hybrid hydrogels were systematically investigated. The results indicate that the hybrid PVA hydrogels have lower crystallinity and less crystal stability, demonstrating the improved macromolecular chain mobility. Moreover, improved swelling ratios of PVA/GO hydrogels also illustrate the enhanced macromolecular chain mobility. MB adsorption experiment indicates that GO introduced can result in great improvement in MB adsorption. And the adsorption process follows the second‐order kinetic model and Morris–Weber model, which is determined by the intraparticle diffusion. Furthermore, MB adsorption isotherm follows Freundlich model and the adsorption is heterogeneous. Desorption studies indicate that the interaction between PVA hydrogels and MB consists of both physisorption and chemisorption. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39872.     

CuO/腐植酸复合材料的制备及其吸附性能

采用水热法合成了CuO-腐植酸（HA）纳米复合材料,研究了其对亚甲基蓝的初始吸附性能及再生吸附性能。运用扫描电镜/能谱仪（SEM/EDS）、傅里叶变换红外光谱仪（FTIR）、X射线粉末衍射仪（XRD）、激光粒度分析仪和比表面积测定仪（BET）对其结构进行了表征。研究了pH、亚甲基蓝初始浓度和反应温度等因素对CuO/HA吸附亚甲基蓝的影响,采用多种模型研究了CuO/HA复合材料对亚甲基蓝的吸附动力学和热力学行为。结果表明：合成的CuO/HA平均粒径约为135.0nm,比表面积为188.15m²/g。CuO/HA对亚甲基蓝（MB）的吸附动力学行为符合拟一级动力学模型,在60min内达到吸附平衡,较好地符合Frendlich吸附模型。在室温下pH=7时,CuO/HA复合材料初始饱和吸附量达172.01mg/g;循环使用8次,可保持初始吸附能力的89.27%,表明有较好的吸附性能,可作为一种有效除去水体中亚甲基蓝污染物的高容量吸附材料。     

Comparative study of PEO and PVA hydrogels for removal of methylene blue dye from wastewater

In this study, poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO) hydrogels were synthesized and evaluated as adsorbent for dye removal from wastewater using methylene blue (MB) in aqueous solution as probe. PEO samples were photochemically prepared by varying irradiation time (1–16 h), while PVA samples were synthetized with different concentration of glutaraldehyde (GA) (0.03–0.48%). The obtained hydrogels were obtained through the analysis of a swelling test, scanning electron microscopy, and adsorption studies. PEO hydrogels adsorption capacity was dependent on the irradiation time, while the PVA hydrogel adsorption capacity reduces with GA concentration. Both hydrogels demonstrated a Langmuir isotherm adsorption model at the equilibrium and pseudo‐second order kinetic fits properly. pH studies showed that when pH reaches 12, the adsorbed MB amount is close to 8 and 2 times higher than pH = 2 both hydrogels. Photochemical preparation of hydrogels shows an easier way of tuning their properties in order to maximize dye removal. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45043.     

Removal of methylene blue dyes from wastewater using cellulose‐based superadsorbent hydrogels

Superadsorbent cellulose‐graft‐acrylic acid (C‐g‐AA) hydrogels were successfully prepared via free radical polymerization in phosphoric acid solution. Phosphoric acid solution provides a homogeneous reaction system. The C‐g‐AA hydrogels have a porous network inner structure with cellulose as the backbone. The introduced carboxyl groups enable the C‐g‐AA hydrogels with good swelling property (swelling ratio 7327%) and excellent MB adsorption capacity (equilibrium adsorption amount 2197 mg g^?1). The dynamic swelling behaviors of the hydrogels were tested, water intake of hydrogels followed a non‐Fickian type diffusion. The effects of mole ratio of AA to cellulose, the pH of adsorption medium and the initial MB concentration on dye adsorption capacity of hydrogels were investigated. The adsorption isotherm and kinetics fit the Langmuir model and the Pseudo‐second‐order model well, respectively. Desorption was carried out in weak acid solution and 70% MB could be removed, suggesting the C‐g‐AA hydrogels had the potential for reuse. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

VMT/P(AMPS-co-AA)复合高吸水树脂的性能测试

研究了溶液pH、盐浓度对辉光放电电解等离子体引发合成的蛭石/聚(2-丙烯酰胺-2-甲基丙磺酸-co-丙烯酸) (VMT/P(AMPS-co-AA)) 复合高吸水树脂的溶胀行为的影响,考察了染料pH、吸附时间、染料浓度等因素对复合高吸水树脂吸附量的影响,同时对树脂的吸附-解吸性能进行了研究。结果表明, VMT/P(AMPS-co-AA)具有高吸水性、pH敏感性、盐敏感性以及高吸附性。该树脂在蒸馏水中的最大溶胀率达到822.4 g/g,对阳离子染料亚甲基蓝(MB)、结晶紫(CV)和孔雀石绿(MG)的吸附量分别可达2027.8, 2171.8和883.2 mg/g。在pH=6.5和25℃下,其对染料的吸附行为符合动力学准二级模型,该树脂还具有一定的吸附-解吸性能和重复利用性能。     

H6P2W18O62/MIL-101(Fe)材料的制备及其吸附性能

采用溶剂热合成法在制备MIL-101(Fe)的过程中引入杂多酸H_6P_2W_(18)O_(62),制备出吸附剂H_6P_2W_(18)O_(62)/MIL-101(Fe),并测试了其对亚甲基蓝(MB)的吸附性能。考察了H_6P_2W_(18)O_(62)的负载量、MB质量浓度、溶液pH、温度等对材料的吸附性能。通过XRD、SEM、FTIR、N2吸附-脱附等手段对材料进行表征。结果表明:吸附平衡前,吸附量随MB质量浓度的增加而增加,在溶液pH=4、H_6P_2W_(18)O_(62)负载量相对于复合物质量分数为35%的条件下,吸附剂H_6P_2W_(18)O_(62)/MIL-101(Fe)对亚甲基蓝溶液吸附效果最佳,在303K下H_6P_2W_(18)O_(62)/MIL-101(Fe)对MB的最大吸附量可达148.1 mg/g。通过动力学和热力学分析,该吸附过程符合拟二级动力学与Langmuir等温吸附模型,同时是一个吸热、自发的过程。     

Removal of methylene blue from aqueous solutions by poly(2-acrylamido-2-methylpropane sulfonic acid-co-itaconic acid) hydrogels

In this study, removal of methylene blue (MB) from aqueous solution by poly(AMPS-co-IA) hydrogels was examined by batch equilibration technique. The effects of monomer ratio, concentration of initiator and crosslinker, pH, adsorption time, initial dye concentration and adsorption temperature on the removal of MB were studied. The results show that the removal of MB was highly effected by preparation conditions of hydrogel. The maximum removal was observed at 10/90 IA/AMPS monomer ratio, 1.0% KPS, and 10.0% MBAAm concentrations. Removal of MB was strongly affected by pH. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were applied. It was concluded that adsorption of MB on hydrogel followed pseudo-second-order kinetics. It was found that the adsorption isotherm of the MB fit Langmuir-type isotherms. From the Langmuir equation, the adsorption capacity was found as 1,000 mg/g for MB dye. Thermodynamic parameters suggest that the adsorption is a typical physical process, spontaneous, and exothermic in nature. Ten adsorption—desorption cycles demonstrated that the hydrogels were suitable for repeated use without considerable change in adsorption capacity. The results revealed that this hydrogels have potential to be used as an adsorbent for the removal of MB from aqueous solution.     

Removal of methylene blue from aqueous solution by sorption on lignocellulose-g-poly(acrylic acid)/montmorillonite three-dimensional cross-linked polymeric network hydrogels

Batch lignocellulose-g-poly(acrylic acid)/montmorillonite (LNC-g-PAA/MMT) hydrogel nanocomposites were applied as adsorbents. The nanocomposites were characterized by FTIR, XRD, SEM, and TEM. The results showed that montmorillonite (MMT) could react with the monomers and change the structure of polymeric network of the traditional superabsorbent materials, an exfoliated structure was formed in the nanocomposites. The effect of process parameters such as MMT content (wt%), contact time (t), initial concentration of dye solution (C ₀), adsorption temperature (T), and pH value (pH) of the dye solution for the removal of methylene blue (MB) from aqueous solution were also studied. The results showed that the adsorption capacity for MB increased with increasing contact time, initial dye concentration, and pH value, but decreased with increasing MMT content and temperature. The adsorption kinetics were better described by the pseudo-second-order equation, and their adsorption isotherms were better fitted for the langmuir equation. By introducing 20 wt% MMT into LNC-g-PAA polymeric network, the obtaining hydrogel composite showed the high adsorption capacity 1994.38 mg/g and economic advantage for MB. The desorption studies revealed that the composite provided the potential for regeneration and reuse after MB dye adsorption, which implied that the composite could be regarded as a potential adsorbent for cationic dye MB removal in a wastewater treatment process.