Removal of Mercury by an Aminated Fiber Prepared by Irradiation Grafting Copolymerization

A chelating fiber having amine functional group with high adsorption capacity for mercury ions was synthesized by grafting copolymerization of acrylic acid onto polypropylene fiber, consequently aminating with diethylenetriamine. The content of the amine groups of the chelating fiber and its adsorption capacity for mercury ion was evaluated. Isotherms were fitted by the Langmuir model, implying that the interaction between mercury and the adsorbent is mainly monolayer chelating adsorption. A comparison of the experimental adsorption capacity with the theoretical values of the chelating fibers indicated that the adsorption of the fiber for mercury ions in aqueous solution may involve ion exchange of carboxyl groups on the chelating fiber with mercury ions, besides the chelating adsorption of amine groups with mercury ions. The maximum adsorption capacity for mercury based on the Langmuir model is as high as 5.19 mmol/g. 99% removal efficiency would be achieved when feed concentration of mercury was 1 mg/L. The chelating fiber shows much higher adsorption capacity for mercury when pH value was higher than 3. The thermodynamic data indicated that the adsorption follows an endothermic and spontaneous process at solid/solution interface. Adsorption equilibrium was attained rapidly in 50 min. These results indicate that the chelating fiber is effective in practical treatment of mercury wastewater.     

蔗渣纤维丙烯酸高吸水树脂的制备

以蔗渣纤维为原料,丙烯酸为接枝单体,N,N-亚甲基双丙烯酰胺为交联剂,K2S2O8为引发剂,通过溶液聚合的方法合成了蔗渣纤维（sugarcanebagasse,SCB）与聚丙烯酸（polyacrylicacid,PAA）的接枝共聚高吸水树脂（scB—g—PAA）。研究了丙烯酸用量、引发剂用量、交联剂用量以及中和度对吸水树脂吸水倍率的影响,结果表明,该接枝共聚吸水树脂的最佳合成条件是以丙烯酸用量为标准,蔗渣纤维、K2S2O8、交联剂用量分别是10％、2％、0．1％,中和度为80％,共聚物吸水倍率最高为765．7g·g-1。     

胺化聚苯乙烯树脂的制备及吸附对硝基酚

以氯甲基化聚苯乙烯树脂(PS-Cl)和氯乙酰化聚苯乙烯树脂(PS-Acyl-Cl)为母体, 引入三乙烯四胺(TETA)制备两种胺化聚苯乙烯树脂PS-TETA与PS-Acyl-TETA。用红外光谱和表面孔径吸附仪对树脂进行表征, 并用于对硝基酚(PNP)的吸附研究。静态和动态吸附实验结果表明, 两种树脂对PNP的吸附过程都可以用准二级动力学方程来描述;液膜扩散为吸附PNP的主要控制步骤;吸附符合Freundlich等温方程, 为多分子层吸附;吸附为自发的放热过程, 属于以物理吸附为主的吸附过程;PS-TETA与PS-Acyl-TETA对PNP的饱和吸附量分别为157.87mg/mL、90.77mg/mL, 穿透体积为165BV、80BV, 动态脱附率为98.4% 、98.9%。     

A study on the recovery of xylitol by batch adsorption and crystallization from fermented sugarcane bagasse hydrolysate

Xylitol was recovered from fermented sugarcane bagasse hemicellulosic hydrolysate by adsorption and crystallization procedures. Silica gel adsorption was employed to purify the broth containing xylitol. In this step, different mixtures of the solvents ethyl acetate, ethanol and acetone were used as eluent, and different proportions of fermented broth volume incorporated per gram of silica gel (V_b/M_sg, varying from 1.0 to 2.0 cm³ g^?1) were used to pack the column employed as stationary phase bed. The xylitol purification efficiency varied for each mixture of solvent, and for each V_b/M_sg ratio used. The purified broth was submitted to different crystallization procedures (cooling, concentration and supplementation with commercial xylitol) aiming to recover xylitol crystals. The best result (60% crystallization yield and 33% total recovery of xylitol from fermented broth) was obtained when the column was packed with a V_b/M_sg ratio of 2 cm³ g^?1, and the broth was purified with a mixture of ethyl acetate and ethanol, concentrated 6.5‐fold, and supplemented with commercial xylitol to force the precipitation. Copyright © 2006 Society of Chemical Industry     

Synthesis of aminated glycidyl methacrylate grafted rice husk and investigation of its anion‐adsorption properties

In this study, we focused on the synthesis, characterization, and adsorption capacity testing of aminated glycidyl methacrylate grafted rice husk (RH‐g‐GMA–Am). Our goal was to obtain a high‐performance surface for the adsorption of various anions. Glycidyl methacrylate grafted rice husk (RH‐g‐GMA) was prepared by the graft copolymerization of glycidyl methacrylate with rice husk; the product was further subjected to an amination reaction. The surface properties, sorption characteristic functional groups, isotherm and kinetic studies, pore diffusion models, and effects of the temperature and pH on the material properties were studied under batch conditions. The IR spectroscopy results show additional surface functional groups for RH‐g‐GMA–Am. The adsorptions of and on RH‐g‐GMA–Am were found to follow pseudo‐second‐order kinetics; this indicated a possible dominant role played by chemisorption. The rate‐limiting step for mass transfer was found to be boundary layer diffusion. Furthermore, the sorption isotherms for and fit the Langmuir model. The amination of RH‐g‐GMA drastically increased the removal efficiency from 3 to 82% and from 6 to 93% for and , respectively. Moreover, RH‐g‐GMA–Am exhibited a better removal efficiency in the pH range of 4–6.5. Regeneration studies revealed that the surface of RH‐g‐GMA–Am could be regenerated repetitively by simple acid washing with an insignificant decrease in the active surface for consecutive adsorptions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43002.     

蔗渣酶法水解过程的酶吸附和活性

以纸浆甘蔗渣纤维素为底物,使用纤维素酶为催化剂,在50℃,pH为4.8的条件下研究了釜式及固定床反应流程,考察酶的吸附及活性.结果表明,固定床反应器的酶吸附比釜式多,而酶的活性变化在两种型式反应器中比较接近.     

Preparation of grafted polytetrafluoroethylene fibers and adsorption of bilirubin

BACKGROUND: A successful hemoperfusion technique requires that the adsorbent for bilirubin should have a high specificity, adsorption capacity and adsorption rate, blood compatibility and no toxicity. Compared with polymer microbeads, polytetrafluoroethylene (PTFE) fibers have many advantages. The aim of the work reported here was to prepare a new polytetrafluoroethylene‐graft‐poly(glycidyl methacrylate)‐block‐polyethyleneimine (PTFE‐g‐PGMA‐b‐PEI) adsorbent for bilirubin based on PTFE fibers by the ⁶⁰Co radiation‐induced graft polymerization of GMA followed by the chemical modification of the epoxy groups on the PTFE‐g‐PGMA fibers with PEI. In addition, the adsorption properties of this novel adsorbent for bilirubin were examined. RESULTS: The highest content of amino groups obtained on the PTFE‐g‐PGMA‐b‐PEI fibers was 1.87 mmol g^?1. The maximum adsorption capacity of the grafted fibers was 9.6 mg g^?1 at pH = 6.5. Bilirubin adsorption on these fibers obeyed the Langmuir model. Also, these fibers possessed the ability to selectively adsorb bilirubin in the presence of bovine serum albumin. CONCLUSION: The PTFE‐g‐PGMA‐b‐PEI fibers have a high adsorption capacity for bilirubin and excellent adsorption properties. In addition, this new adsorbent is inexpensive, easy to prepare and has no toxicity. So the PTFE‐g‐PGMA‐b‐PEI fibers as a biomedical adsorbent are promising for the removal of bilirubin through the hemoperfusion technique. Copyright © 2009 Society of Chemical Industry     

凹凸棒土的改性及其对己烷异构体的吸附性能

采用十六烷基三甲基溴化铵和β-环糊精对凹凸棒土进行改性,利用红外光谱和比表面积对改性的凹土进行表征,并通过静态和动态吸附实验,研究了凹土对己烷异构体的吸附行为,考察了吸附时间、吸附温度、流速等对吸附性能的影响。实验结果表明,凹土对己烷异构体的吸附量随吸附时间的延长和吸附温度的下降而增大,相同条件下正己烷在凹土上的吸附量大于异己烷;经过有机物改性后的凹土对己烷异构体的吸附性能优于原土,十六烷基三甲基溴化铵改性后的凹凸棒土对正己烷的吸附量可达到224 mg/g。己烷异构体在凹凸棒土上的吸附等温线符合二级动力学方程模型。     

溴改性金属有机骨架的合成及其对单质汞吸附

采用溶剂热法制备了溴改性的金属有机骨架(metal organic framework,MOF),通过模拟烟气动态吸附方法对材料单质汞(Hg⁰)吸附性能进行研究。利用X射线衍射(XRD)、X射线光电子能谱(XPS)、综合吸附仪对晶体结构、形貌和组分进行表征。结果表明改性后晶体结构不变,比表面积、孔容下降,溴以共价键固定在材料中。改性前和改性后材料对Hg⁰的吸附效率都有随温度升高而增加趋势。模拟烟气反应床吸附实验证明240℃条件下,溴改性MOF10h内吸附效率高于95%,同等实验条件下,非改性MOF以及传统活性炭吸附剂吸附汞5h后效率低于75%。     

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.     

胺化羧甲基改性磁性壳聚糖的制备及吸附性能研究

采用交联法制备了磁性壳聚糖,并在此基础上使用柠檬酸及二乙烯三胺对其进行化学改性,得到了磁性能良好、颗粒分布均匀、平均孔径为4.37 nm的胺化羧甲基改性磁性壳聚糖。将其用于模拟废水中进行静态吸附实验。结果表明,改性后的磁性壳聚糖在保证机械强度与回收率的基础上,提高了磁性壳聚糖的吸附性能,在最适pH=6的条件下,对Cu~(2+)、Cd~(2+)、Ni~(2+)的吸附容量分别达到76.82、54.15、62.64 mg/g。     

Microwave preparation and adsorption properties of EDTA‐modified cross‐linked chitosan

A novel chitosan‐based adsorbent (CCTE) was synthesized by the reaction between epichlorohydrin O‐cross‐linked chitosan and EDTA dianhydride under microwave irradiation (MW). The chemical structure of this new polymer was characterized by infrared spectra analysis, thermogravimetric analysis, and X‐ray diffraction analysis. The results were in agreement with the expectations. The static adsorption properties of the polymer for Pb²⁺, Cu²⁺, Cd²⁺, Ni²⁺, and Co²⁺ were investigated. Experimental results demonstrated that the CCTE had higher adsorption capacity for the same metal ion than the parent chitosan and cross‐linked chitosan. In particular, the adsorption capacities for Pb²⁺ and Cd²⁺ were 1.28 mmol/g and 1.29 mmol/g, respectively, in contrast to only 0.372 mmol/g for Pb²⁺ and 0.503 mmol/g for Cd²⁺ on chitosan. Kinetic experiments indicated that the adsorption of CCTE for the above metal ions achieved the equilibrium within 4 h. The desorption efficiencies of the metal ions on CCTE were over 93%. Therefore, CCTE is an effective adsorbent for the removal and recovery of heavy metal ions from industrial waste solutions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

甘蔗渣的酸催化常压甘油有机溶剂预处理及其酶解

预处理可以打破木质纤维素原料纤维素、半纤维素和木质素三大组分间的顽抗结构,从而提升纤维素基质可酶解性。本文针对目前常压甘油有机溶剂预处理花费时间过长的问题,尝试开展酸催化的常压甘油有机溶剂预处理研究以缩短预处理时间。实验通过单因素选择和响应面Box-Behnken设计优化,获得酸催化常压甘油有机溶剂预处理的最佳条件为：预处理温度245℃,预处理时间38min,硫酸添加质量0.1%。在此条件下获得基质48h酶解率的响应面预测值为94.0%,实际值为91.4%。结果表明响应面优化方案和回归模型适用于本实验,预处理显著提高了基质可酶解性。高浓度基质（15%～20%）酶解进一步证明了预处理后基质具有突出的可酶解性,20%浓度基质在酶载量5FPU/g干基质条件下批次酶解72h,酶解率达60%,葡萄糖浓度达83.4g/L。酸催化常压甘油有机溶剂酸预处理在明显缩短预处理时间的同时,能显著提高木质纤维素基质可酶解性,使后续工业化意义的浓醪酶解糖化成为可能。     

ST-g-NMA-AM的制备及其吸附性能

以红薯淀粉(ST)为原料,丙烯酰胺(AM)为单体,N-羟甲基丙烯酰胺(NMA)为单体和交联剂,采用反向乳液聚合法制备了NMA-AM接枝ST(ST-g-NMA-AM)。考察了NMA用量、引发剂过硫酸铵用量及反应温度对接枝率的影响,利用傅里叶变换红外光谱对其结构进行表征。以亚甲基蓝为吸附质,考察了ST-g-NMA-AM对亚甲基蓝的吸附性能。结果表明:当NMA用量为0.75 g,引发剂用量为0.0500 g,反应温度为55℃时,单体转化率和接枝率最高,分别为90.41%,45.38%;当亚甲基蓝质量浓度为20 mg/L,吸附剂ST-g-NMA-AM质量浓度为1 g/L时,吸附量随着NMA用量的增加而先增大后减小,当引发剂用量为0.0500 g,NMA用量为0.75 g时,吸附量最大,为16.140 mg/g。     

多孔有机膨润土的制备及对水中硫化物的吸附研究

将膨润土与优质煤粉按一定的比例混合挤压成型,高温焙烧,用氯化十六烷基吡啶进行有机改性,制得了表面为阳离子的多孔有机膨润土.将改性土用于水中硫化物吸附试验,结果表明:最佳吸附条件为pH=8、温度30℃、改性土用量50 g/L、振荡4 h,吸附率达93.6%.     

巯基修饰Cu-MOFs材料的制备及其汞吸附性能

为高效对废水中的Hg²⁺进行吸附,采用电化学法合成Cu-BDC金属有机骨架材料,并进行-SH修饰,制备SH-Cu-BDC材料,用于对含Hg²⁺废水的吸附研究。通过EDS与IR红外对修饰前后样品的表征分析可知,-SH基团成功修饰到Cu-BDC材料上;N₂吸附实验表明,修饰后的SH-Cu-BDC材料出现微孔结构且比表面积增大;SEM分析表明,电化学合成Cu-BDC材料具有独特花状结构,修饰后SH-Cu-BDC材料表面均匀分布着触角状物质;10 mg SH-Cu-BDC对20 ml浓度为300 mg·L^-1的Hg²⁺溶液进行吸附,当pH=5,60 min时吸附饱和,最大吸附量为585 mg·g^-1;SH-Cu-BDC材料对Hg²⁺的吸附符合拟二级反应动力学方程和Langmuir吸附等温模型,该吸附过程是以表面吸附为主的扩散过程,且符合单分子层吸附规律;吸附再生实验表明,SH-Cu-BDC作为吸附剂可重复使用,且具有一定的稳定性。     

活性炭纤维的改性及对苯酚的吸附性能研究

用硫酸铜、高锰酸钾、硫酸亚铁、氢氧化钾、柠檬酸、硝酸铜、乙酸铅、硝酸等溶液浸渍处理活性炭纤维,考察了改性活性炭纤维对废水中苯酚的吸附性能。结果表明,用硫酸铜溶液改性的活性炭纤维对苯酚的吸附性能强于未改性的活性炭纤维,经高锰酸钾、硫酸亚铁、氢氧化钾、柠檬酸、硝酸铜、乙酸铅、硝酸等溶液改性的活性炭纤维对苯酚的吸附能力下降。浓度为0.05%~1%的硫酸铜溶液对0.2 g活性炭纤维进行改性的效果优于其它浓度的硫酸铜溶液。活性炭纤维上负载的铜离子过多会降低活性炭纤维对苯酚的吸附量。     

剩余污泥吸附废水中汞和砷的研究

对剩余污泥吸附废水中汞和砷的特性进行了研究。以模拟废水为实验对象,探讨了p H、剩余污泥投加量、吸附时间等对吸附过程的影响。结果表明,在模拟水样环境下,当p H=7,剩余污泥投加量为150 g/L,吸附时间为12 h时,可以获得最佳吸附效果;吸附过程遵循Langmuir定律。研究同时发现,溶液中汞和砷的初始浓度与吸附率成反比,与吸附容量成正比。利用此方法处理环境水样可达到很好的效果。     

Effect of chemical activation of an activated carbon using zinc chloride on elemental mercury adsorption

Hg⁰ adsorption experiments with different kinds of activated carbons (ACs) were conducted in nitrogen environment to study the effects of ACs with different surface characteristics on adsorption. Three kinds of ACs prepared by steam activation did not adsorb elemental mercury (Hg⁰) in nitrogen environment, while another kind of AC prepared by chemical activation using zinc chloride (ZnCl₂) showed significant Hg⁰ adsorption capability in the same experimental conditions because Hg⁰ was oxidized by the oxidative elements on the surface of AC. ACs without oxidative elements did not adsorb Hg⁰ through physical adsorption in nitrogen environment. It was therefore concluded that Hg⁰ adsorption by AC was a chemical adsorption process.