海藻酸钠接枝丙烯酸-丙烯酰胺共聚物/凹凸棒石复合材料的制备与表征

以凹凸棒石(AT)为原料、过硫酸钾为引发剂、N,N-亚甲基双丙烯酰胺为交联剂、丙烯酰胺(AM)、丙烯酸(AA)两种单体同时对海藻酸钠(SA)进行接枝改性,采用水溶液聚合法制备了海藻酸钠接枝丙烯酸-丙烯酰胺共聚物/凹凸棒石复合材料。考察了各合成因素对复合材料吸液倍率的影响,并采用FTIR、SEM对复合材料进行了表征。结果表明,当丙烯酰胺与丙烯酸的质量比为5 1∶、海藻酸钠质量分数为15%(占单体丙烯酸质量,下同)、凹凸棒石用量为25%、交联剂用量为0.095%、引发剂用量为0.55%和反应温度为80℃时,制备的复合材料的吸蒸馏水倍率最高,达到1 693.3 g/g。FTIR表明,海藻酸钠、丙烯酸、丙烯酰胺和凹凸棒石共同参与了接枝聚合反应。SEM表明,凹凸棒石的引入,复合材料的表面致密但存在大小不一的孔隙,有利于提高复合材料的吸液倍率。     

魔芋接枝丙烯酰胺-丙烯酸/凹凸棒石高吸水性树脂的制备与性能

以凹凸棒石(AT)为无机填料,丙烯酰胺(AM)、丙烯酸(AA)两种单体同时对魔芋(KGM)进行接枝改性,采用水溶液聚合法制备了标题化合物。考察了各合成因素对树脂吸液倍率的影响,并采用FT-IR,SEM对树脂进行了表征。结果表明,当魔芋用量为15%(占单体丙烯酸质量百分比,下同)、凹凸棒石用量为30%、交联剂用量为0.08%、引发剂用量为0.4%和丙烯酰胺与丙烯酸的质量比为5∶1时,制备的树脂的吸蒸馏水倍率最高,达到978.47 g/g。红外光谱(FTIR)测试分析表明魔芋葡甘聚糖、丙烯酸、丙烯酰胺和凹凸棒石共同参与了接枝聚合反应。扫描电子显微镜(SEM)测试分析表明凹凸棒石的引入,树脂的表面变得粗糙并存在大小不一的孔隙。     

壳聚糖碳化改性凹凸棒石对Cr(Ⅵ)的吸附性能

以壳聚糖为生物质碳源,通过一步水热碳化法对凹凸棒石进行亲有机改性,对改性凹凸棒石进行表征,研究了其对Cr(Ⅵ)的静态和动态吸附性能,对其除Cr(Ⅵ)机制进行了初步探讨.结果表明,改性凹凸棒石表面有丰富的羟基、氨基和羧基等有机官能团,壳聚糖碳化产物成功负载于凹凸棒石表面.在实验的pH值范围内,总铬去除率随pH值增加先增大后减小,pH为1和2时总铬去除率分别为11.7%和80.8%,pH为3时总铬去除率降至10.2%.总铬吸附量随Na~+浓度增加而降低.对总铬的吸附等温线符合Langmuir模型,最大吸附量高达204.1 mg/g.改性凹凸棒石对总铬的动态吸附主要受颗粒内扩散控制,在强酸性条件下(pH=2),去除Cr(Ⅵ)是吸附-还原-再吸附的耦合过程.     

凹凸棒石/氢氧化物纳米复合材料对磷的吸附热力学

用铁/铝盐水解法制备了凹凸棒石/铝氢氧化物(PNCM Ⅰ)、凹凸棒石,铁氢氧化物(PNCM Ⅱ)和凹凸棒石/铁-铝氢氧化物(PNCM Ⅲ)3种凹凸棒石黏土纳米复合材料,对比研究了这3种复合材料和纯凹凸棒石黏士对水中磷的吸附净化能力,通过等温吸附实验探讨了3种纳米复合材料对磷的吸附机理.结果表明:PNCM Ⅰ和PNCMⅢ凹凸棒石黏十纳米复合材料对磷具有良好的吸附净化能力,而且温度对其影响很小;当初始浓度为1,2mg/L和5mg/L(以磷计)时,100mL水中加入0.1 g的PNCMⅠ和PNCM Ⅲ对磷的去除率可达到99%以上,对磷的吸附容量分别约为8mg/g和15mg/g;这3种凹凸棒石复合材料吸附过程均属于Langmuir吸附;PNCMⅠ和PNCMⅢ对磷的吸附是吸热的化学吸附和物理吸附并存的过程,PNCMⅡ对磷的吸附是吸热的物理吸附过程,且都为熵增加的吸附过程.     

改性腐植酸钠对Hg~(2+)吸附性能的研究

用腐植酸钠与丙烯酰胺按一定比例进行接枝聚合反应,制备腐植酸钠-聚丙烯酰胺接枝聚合物。通过正交试验,确定改性腐植酸钠的最佳工艺:反应时间5 h,过硫酸铵所占总质量的5%,丙烯酰胺与腐植酸钠物料比为1∶15,反应温度确定为60℃。红外光谱分析表明,腐植酸钠与丙烯酰胺发生接枝共聚反应。腐植酸钠-聚丙烯酰胺吸附Hg~(2+)效果随pH的增大而减小;随吸附时间的延长而增大,90 min左右时达到吸附平衡;但受腐植酸钠-聚丙烯酰胺质量和温度的影响较小。     

新型包埋吸附剂的制备及其除磷效果研究

为了吸附去除富营养化水体中的磷,利用碱酸改性凹凸棒石(ATP),经包埋成型技术制备一种新型吸附剂,考察其对水中磷酸根的吸附性能。结果表明,利用质量分数为8%的PVA包埋成型的Zr-ATP复合吸附剂在常温、常压下进行静态除磷试验,除磷效率为99%,吸附容量为7.8 mg/g,该富营养化修复剂值得进一步深化研究。     

不同改性处理玉米秸秆对氨氮吸附性能研究

对比了酸改性、碱改性和接枝共聚改性对玉米秸秆吸附氨氮性能的影响。结果表明,当初始氨氮质量浓度为200 mg/L时,玉米秸秆经酸改性、碱改性和接枝共聚改性的最大氨氮平衡吸附量分别达到23.4、26.4、33.8 mg/g,较未改性时分别提高55.0%、74.8%和123.8%,改性吸附效果为接枝共聚改性碱改性酸改性。玉米秸秆对氨氮的吸附过程可用Langmuir和Freundlich吸附等温模型描述,符合伪二级动力学方程。经过改性处理后△G降低,对氨氮的吸附变得更加容易。     

氧化铁改性埃洛石纳米管对磷的去除效果及其影响因素

为研究氧化铁改性埃洛石纳米管(HNTs)除磷效果,系统分析了氧化铁负载量、吸附剂用量、接触时间、p H、初始磷浓度和共存离子(SO42-、NO3-、Cl-)对其影响。通过响应曲面法分析得出三种最佳反应条件确定了各影响因素权重。磷吸附过程符合Langmuir等温吸附模型及准二级动力学模型,氧化铁改性HNTs既能应用于酸性含磷废水处理,又能服务于磷污染地下水、地表水修复。结果表明,三种最佳反应条件下氧化铁改性HNTs吸附容量分别为6.279、5.664、5.634 mg/g。反应240 min达到平衡。共存离子(SO42-、NO3-、Cl-)对吸附材料除磷无明显抑制作用。吸附材料再生循环利用5次,磷去除率从72.58%降到69.20%。可见本研究对磷污染水的处理与修复具有重要参考意义。     

改性钢渣陶粒对低浓度磷的吸附特征

为了阐明改性钢渣陶粒应用于水体除磷的可行性,通过吸附实验研究了镧铁复合氧化物改性钢渣陶粒对低浓度磷的吸附特性,考察了投加量、pH、共存离子等因素对除磷率的影响,并研究其吸附动力学特性。采用NaOH作为再生剂,比较了吸附饱和的改性钢渣陶粒经不同条件再生处理后的除磷效果。结果表明,对于初始磷浓度1 mg/L的溶液,吸附剂投加量5 g/L,pH为7时,除磷率高达99.07%;HCO_3^-和SO_4-和SO_4^(2-)对除磷的抑制作用较强。吸附动力学过程符合准二级动力学模型。使用1.5 mol/L NaOH浸泡60 min是较为合理的再生条件,一次再生后的除磷率仍可达98.51%。     

水热法改性凹凸棒石及其吸附性能的研究

分别以葡萄糖和淀粉为碳前驱体,凹凸棒石为原料,水热法制备有机改性凹凸棒石。通过扫描电镜(SEM)、红外吸收光谱(FTIR)、X射线衍射(XRD)以及吸附性能,考察葡萄糖和淀粉对凹凸棒石的形貌和性能的影响。结果表明,在制备改性凹凸棒石的过程中,碳前驱体对产物形貌和吸附性能有着明显的影响。葡萄糖分子在水热条件下碳化为直径50 nm碳颗粒,均匀负载在凹凸棒石表面,复合材料中含有─CH有机官能团;淀粉碳化为直径40~80 nm的碳球,不均匀的负载在凹凸棒石的表面,且表面含有─CH有机官能团。采用葡萄糖和淀粉为碳源的有机改性凹凸棒石对苯酚的去除率分别为70%和46%,分别是纯凹凸棒石对苯酚去除率的4倍和2.5倍。     

草酸改性凹凸棒土吸附偏二甲肼实验研究

通过草酸对凹凸棒土进行改性处理,以提高对偏二甲肼的吸附性能,分别考察了草酸浓度、固液比、分散剂、温度和活化时间对草酸处理后凹凸棒土吸附性能的影响,并通过正交实验对草酸改性凹凸棒土的最佳工艺进行了选择。结果表明:草酸为饱和溶液,固液比为1 g∶10 mL,分散剂质量分数为5%,温度为30℃,活化时间为60 min,上述工艺条件下,偏二甲肼吸附率可达95%。     

凹凸棒黏土/黄原胶接枝改性高吸水性树脂的制备

以丙烯酸(AA)、丙烯酰胺(AM)为单体对黄原胶(XG)进行接枝改性,再以N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸铵(APS)为引发剂,加入凹凸棒黏土,采用溶液聚合法合成了一种新型复合高吸水性树脂。通过单因素试验研究了AA中和度、交联剂用量、引发剂用量、反应温度和凹凸棒黏土用量等因素对该树脂吸水(吸盐水)性能的影响,利用傅里叶红外光谱(FT-IR)仪、热重分析(TGA)仪对其结构和热性能进行了表征。结果表明:制备高吸水性树脂的最佳工艺条件为AA中和度70%,反应温度70℃,w(交联剂)=0.06%,w(APS)=1.0%,w(凹凸棒黏土)=5%;在最佳工艺条件下制备的高吸水性树脂,其最大吸水倍率、吸盐水倍率分别为827、109 g/g。     

盐交换凹凸棒黏土的理化性质及其对双氯芬酸钠吸附性能的影响

将凹凸棒黏土采用不同价态的硫酸盐和相同价态不同用量硫酸盐交换后,通过红外光谱、扫描电镜、比表面积和ζ电位的测定,考察了盐交换处理对凹凸棒黏土微结构和理化性能的影响。在此基础上,考察了处理凹凸棒黏土对双氯芬酸钠的吸附影响。结果表明,金属盐交换凹凸棒黏土对双氯芬酸钠的吸附量不仅与所交换金属离子的价态有关,更与凹凸棒黏土的微孔比表面积和微孔体积有关。当硫酸铝用量为凹凸棒黏土量的0.5%时,其交换凹凸棒黏土对双氯芬酸钠的吸附量最大,达到了126 mg/g,与凹凸棒黏土原矿相比,吸附量提高了近4倍。     

硝酸改性凹凸棒石粘土及吸附Cu2+的工艺研究

将凹凸棒石粘土用硝酸进行改性处理,然后用于对含铜废水中铜离子的吸附,研究了硝酸浓度、改性凹凸棒石粘土用量、吸附时间、pH值等因素对吸附性能的影响。结果表明:经4mol/LHNO3改性处理后的凹凸棒石粘土吸附能力最好,凹凸棒石粘土加入量为30g/L,水样pH值为4,超声搅拌20min,废水中Cu2+的吸附率接近99%,同时吸附剂的再生实验表明,复用时吸附量下降平缓,可以重复使用。     

Study on superabsorbent composite. XI. Effect of thermal treatment and acid activation of attapulgite on water absorbency of poly(acrylic acid)/attapulgite superabsorbent composite

The effect of acid activation and thermal treatment of attapulgite on water absorbency of superabsorbent composite were investigated. Under the same preparation conditions, superabsorbent composite prepared with natural attapulgite exhibited a water absorbency of 639 g/g and it merely kept 71% of its initial water absorbency after 5 times of swelling–deswelling–reswelling test. However, superabsorbent composites prepared with 2–10 M hydrochloric acid acidified attapulgite and 100–400°C thermal treated attapulgite respectively exhibited the water absorbency of 884–1,241 g/g and 701–1,515 g/g. Also, those superabsorbent composites can keep 87% and 85% of their initial water absorbency after 5 times of swelling–deswelling–reswelling test, respectively. These results showed that, compared with superabsorbent composite prepared with natural attapulgite, the comprehensive water‐absorbing properties of poly(acrylic acid)/ attapulgite superabsorbent composites were improved effectively by acid activation and thermal treatment of attapulgite. This improvement of water absorbencies and gel strength of superabsorbent composite may be due to synthetical factors such as changes in the crystalline structure and the specific surface area and improvement of the number and the activity of hydroxyl groups of attapulgite, which in turn influence the grafting efficiency of monomer, crosslinking density, and the structure of superabsorbent composite network. POLYM. COMPOS., 28:397–404, 2007. © 2007 Society of Plastics Engineers     

Influence of grafting with acrylic acid on the dyeing properties of polyamide 6.6 fibres

Polyamide 6.6 fibres were modified for the improvement of dyeing affinity using a graft copolymerisation method. These fibres were grafted with acrylic acid as monomer. The influence of the chemical modification of polyamide 6.6 fibres on the dyeing properties was investigated using a cationic dye (Red Astrazon 5BL). It was shown that the dye uptake of the modified fibres was greater than that of the unmodified fibres. The kinetic study of the cationic dye used at various grafting percentages showed an improvement of the dye build‐up rate, such as its exhaustion. In addition, an increase in the adsorption of the dye quantity fixed on the surface layer of the fibre made up of the grafted molecules was announced. Colour fastness to washing was improved with the grafting percentage. The modelling of the adsorption isotherms using Langmuir, Freundlich and Jossen relations allows the determination of isotherm constants. The results obtained from this modelling study show the existence of several models corresponding to various percentages of grafting.     

Surface grafting of styrene on polypropylene by argon plasma and its adsorption and regeneration of BTX

Active macromolecular free radicals were generated on polypropylene (PP) fiber surfaces by argon plasma irradiation, and surface‐modified PP fibers (PP‐g‐St fibers) were prepared by in situ grafting reaction of styrene monomers (St). The prepared samples were characterized by Fourier transform infrared, NMR, X‐ray photoelectron spectroscopy, scanning electron microscopy, and thermogravimetric analysis. Effects of reaction parameters on grafting percentage were studied, and adsorption capacities of PP‐g‐St fibers for benzene, toluene, and xylene (BTX) were evaluated. Regeneration adsorption efficiencies after adsorption of pure BTX and BTX emulsion and solution in water were explored. The results indicated that, using pure St as the monomer, the optimum input power, irradiation time, and grafting reaction time are 90 W, 3 min, and 3 h, respectively, and the grafting percentage of St reached 5.7% when pure St was used. The characterization results demonstrated that St was grafted onto the surface of the PP fibers. Compared to pristine PP fibers, the adsorption capacities of PP‐g‐St fibers toward toluene and xylene emulsions and solutions in water increased. In addition, regeneration adsorption efficiencies of modified fibers remained >90% after six cycles of regeneration adsorption experiments, which showed excellent regeneration ability. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46171.     

Synthesis of functionalized PET fibers by grafting and modification and their application for Cr(VI) ion removal

A new fiber adsorbent for removing Cr(VI) ions from aqueous solution was prepared by grafting and modification. The grafted fiber and modified fiber were characterized by SEM, FTIR, and TGA. FTIR analysis indicated that acrylonitrile monomer was grafted onto the PET surface and that new groups were present on the surface after the modification. Scanning electron microscopy showed that the PET fiber was wider after grafting and especially modification. The TGA results showed that the degradation steps and the thermal behavior of the PET fiber changed after modification. The effects of the pH, ion concentration, and temperature on the amount of Cr(VI) adsorbed were investigated. The fiber showed its maximum adsorption capacity in acidic medium. Isotherm studies indicated that the experimental results were best fitted to the Langmuir isotherm. The adsorption capacity of the modified fiber was found to be 25.77, 38.17, and 44.84 mg/g fiber at 25, 35, and 45 °C, respectively. Kinetic results indicated that the adsorption of Cr(VI) onto the modified fiber followed a pseudo-second-order kinetic model. Calculated thermodynamic parameters demonstrated that the adsorption of Cr(VI) ions on the modified fiber is an endothermic, feasible, and spontaneous process.     

Comparison of two approaches to grafting hydrophilic polymer chains onto polysulfone films

To reduce the surface protein adsorption of polysulfone (PSf) film, we improved the hydrophilicity of this film by photochemical grafting of methoxypoly (ethylene glycol) (MPEG) derivatives on its surface. Grafting was achieved with both the simultaneous method and the sequential method. Surface analysis of the grafted film by X‐ray photoelectron spectroscopy (XPS) revealed that the PEG chains had successfully grafted onto the surface of the film. The grafting efficiencies by simultaneous and sequential methods were 20.8% and 10.2%, respectively. With an atomic force microscope (AFM), the surface topography of PEG‐grafted films by these two methods was compared. Static water contact angle measurement indicated that the surface hydrophilicity of the film had been improved. Protein adsorption measurement showed that the surface protein adsorption of the modified film was significantly reduced compared with that of the unmodified PSf film. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3818–3826, 2007     

马来酸酐接枝纤维素超细纤维制备高容量可再生吸附剂

在静电纺丝制备出纤维素超细纤维（CSF）的基础上,利用马来酸酐（MAH）改性制备了新型羧基化吸附剂,接枝温度为100℃,时间为3h,MAH与CSF质量比为5：1,过氧化二苯甲酰（BPO）用量为7.5%时接枝效果最佳,取代基含量可达2.304mmol/g。通过SEM观察了纤维素超细纤维改性前后的形态分布和微观结构,通过酸碱滴定定量地测定了改性纤维素超细纤维（MAH-CSF）中的取代基含量,FTIR图谱分析定性地表明马来酸酐成功地接枝在了纤维素超细纤维上。从XRD和DSC谱图中得知MAH-CSF的晶型未发生变化但结晶度有所下降,马来酸酐改性提高了纤维素超细纤维的热稳定性。研究了CSF和MAH-CSF对亚甲基蓝的吸附性能,经马来酸酐改性后纤维素超细纤维对亚甲基蓝的吸附量从210mg/g提高到了306mg/g,这表明羧基化可极大地提高其对亚甲基蓝的吸附量。在低pH下,H⁺与亚甲基蓝间的竞染作用使得吸附剂的吸附量较小;随着吸附剂的去质子化,吸附量明显迅速增大;在pH大于5.5时吸附量增加趋势减缓。MAH-CSF与MB之间的离子交换作用使其具有更优良的吸附效果,吸附过程更适合用准二级动力学模型来描述。在超声波作用下吸附剂再生5次的吸附率达89%以上,这表明吸附剂具有很好的再生性。