季铵纤维素对苋菜红染料废水吸附特性及脱色研究

发布时间：2018-11-04 18:31

【摘要】：偶氮染料是一种重要的芳香类化合物染料,广泛应用在印染、食品、农业、医药、化妆品等行业。染料使用过程中将会产生大量的化学性质复杂、高色度的染料废水,脱色是染料废水主要处理目标之一。目前广泛使用的吸附脱色和生物脱色分别存在二次污染和脱色速率缓慢等问题,兼顾两种方法优点并克服其缺点的材料开发及应用对脱色处理具有重要意义。纤维素具备来源广、可功能改性、生物相容性良好等优势在污染控制中得到广泛的重视。。本论文以纤维素为原材料,采用NaOH/尿素/去离子水为溶剂,3-氯-2-羟丙基三甲基氯化铵(CAPTAC)为醚化剂对纤维素进行醚化接枝改性制备季铵阳离子纤维素,使用红外光谱、元素分析等对材料进行表征。系统研究了季铵阳离子纤维素对苋菜红染料废水的吸附特性及强化生物脱色效果,研究表明:(1)醚化剂3-氯-2-羟丙基三甲基氯化铵(CAPTAC)与纤维素单元(AGU)的摩尔比值显著影响季铵纤维素的取代度、阳离子度,CAPTAC:AGU为7时制备的材料QC-7吸附苋菜红染料AR性能最佳。(2)QC-7可适用于pH 3-9酸碱度范围废水,1.5 h达到吸附平衡,AR饱和吸附量约为360 mg/g。QC-7/AR投加比≤4时材料的吸附容量能充分利用,而QC-7/AR投加比4时QC-7具有高效的絮凝脱色能力。(3)QC-7吸附过程符合伪二级反应动力学模型,吸附平衡过程符合Langmuir等温吸附和Dubinin-Radushkevich理论模型,吸附过程是以化学吸附为主的单分子层吸附。(4)QC-7具有良好的化学再生循环利用性能,先用0.1 mol/L NaOH和再用0.1 mol/LHCl解吸液吸附-再生QC-7-AR,循环使用5次后再生率超过95%,8次后再生率超过90%。生物再生QC-7能力较弱且再生速度较慢,引入氧化还原介体AQS可明显提高再生速度,生物再生以染料降解为主,能显著降低其二次污染风险。(5)QC-7可强化Pseudomonas sp.厌氧生物脱色AR,其最佳强化投加量为100 mg/L。QC-7能扩大生物脱色的废水pH适用范围,提高对AR的耐受浓度至150 mg/L,能明显提高AQS介导的Pseudomonas sp.生物脱色效率。(6)得出QC-7强化Pseudomonas sp.及AQS介导的生物脱色主要机理。
[Abstract]:Azo dyes are important aromatic dyes, widely used in printing, dyeing, food, agriculture, medicine, cosmetics and other industries. A large number of dyestuff wastewater with complex chemical properties and high chromaticity will be produced during the use of dyes. Decolorization is one of the main targets of dye wastewater treatment. Adsorption decolorization and biological decolorization, which are widely used at present, have the problems of secondary pollution and slow decolorization rate, respectively. The development and application of materials which take into account the advantages of the two methods and overcome their disadvantages are of great significance to the decolorization treatment. Cellulose has a wide range of sources, functional modification, good biocompatibility and other advantages in pollution control has received extensive attention. In this paper, quaternary ammonium cationic cellulose was prepared by using cellulose as raw material, NaOH/ urea / deionized water as solvent, 3-chloro-2-hydroxypropyl trimethylammonium chloride (CAPTAC) as etherifying agent. The materials were characterized by IR and elemental analysis. The adsorption characteristics of quaternary ammonium cationic cellulose on amaranth dye wastewater and the enhanced biological decolorization effect were studied systematically. The results showed that: (1) the molar ratio of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CAPTAC) to cellulose unit (AGU) significantly affected the degree of substitution and cationic degree of quaternary ammonium cellulose. (2) QC-7 can be used in the wastewater of pH 3-9 pH range, and the adsorption equilibrium is achieved in 1.5 h. When the saturated adsorption capacity of AR is about 360 mg/g.QC-7/AR, the adsorption capacity of the material can be fully utilized when the addition ratio is less than 4. When the addition ratio of QC-7/AR is 4, QC-7 has the ability to flocculate and decolorize efficiently. (3) the adsorption process of QC-7 accords with pseudo-second-order reaction kinetics model, and the adsorption equilibrium process accords with Langmuir isothermal adsorption and Dubinin-Radushkevich theory model. The adsorption process is monolayer adsorption dominated by chemisorption. (4) QC-7 has good recycling performance of chemical regeneration, first using 0.1 mol/L NaOH and then 0.1 mol/LHCl desorption adsorption-regenerated QC-7-AR,. The regeneration rate was more than 95 after 5 cycles and more than 90 after 8 cycles. The ability of regenerating QC-7 is weak and the regeneration rate is slow. Introducing redox mediator AQS can obviously improve the regeneration rate, and the bioregeneration is mainly dyestuff degradation, which can significantly reduce the risk of secondary pollution. (5) QC-7 can strengthen Pseudomonas sp.. In anaerobic biological decolorization (AR,), the best enhanced dosage of 100 mg/L.QC-7 could enlarge the application range of pH in the wastewater of biological decolorization, and increase the tolerance to AR to 150 mg/L, can obviously increase Pseudomonas sp. mediated by AQS. Biological decolorization efficiency. (6) QC-7 enhanced Pseudomonas sp. And the main mechanism of biological decolorization mediated by AQS.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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