改性玉米秸秆的表征及吸附性能研究
发布时间：2018-11-02 12:08
【摘要】：生物炼制是利用农业废弃物、植物基淀粉和木质纤维素材料为原料,生产各种化学品、燃料和生物基材料的工业过程。生物炼制过程可大大提高可再生植物基原料的应用范围,为化学和能源经济方面在绿色可持续发展道路上提供有效方式。玉米秸秆为生物质原料,其玉米秸秆纤维素为多孔结构,因含有大量的羟基而具有良好的亲水特性,可发生酯化、醚化、接枝共聚等反应。通过化学改性,在其活泼羟基上引入大量的功能性基团,与废水中的金属离子发生作用,可作为重金属污染的水处理吸附剂。本论文主要研究内容包括利用廉价的玉米秸秆,对其进行化学改性,得到改性玉米秸秆吸附剂,探讨关键因素交联剂投入量、反应温度、反应时间对改性玉米秸秆在废水中Cr6+吸附效率影响。通过Box-Behnken试验设计优化改性玉米秸秆吸附剂工艺参数。在单因素实验基础上,通过中心组合实验的到吸附剂的最佳制备工艺条件为交联剂二乙烯三胺用量1.25mL、接枝反应温度101℃、接枝反应时间2.15h。通过傅里叶变换红外光谱(FT-IR)、比表面积分析(BET)和扫描电镜(SEM)表征其结构特征。改性玉米秸秆FT-IR表明,胺基(N-H)官能团的伸缩振动吸收峰强度较大,可能是由于接枝到玉米秸秆上的季胺基团引起的。BET分析表明,改性玉米秸秆的比表面积相对增加,有助于吸附能力的增大。SEM分析表明,改性玉米秸秆表面明显凹凸不平,吸附六价铬后表面呈现更多的颗粒状物质,说明改性玉米秸秆吸附作用可能主要通过接枝到表面的季胺活性基团实现。改性玉米秸秆吸附剂对六价铬进行吸附研究,探讨了关键因素交联剂投入量、反应温度、反应时间对改性玉米秸秆在废水中Cr6+吸附效率影响。在改性玉米秸秆吸附剂用量为0.6g/L、pH为2、吸附温度20℃、吸附平衡时间120min条件下,对废水中Cr6+的吸附量为176.5mg/g,去除率为99.9%。玉米在全球被广泛种植,其副产物秸秆资源丰富,经过化学改性后在纤维结构中引入特定功能基团,使得改性玉米秸秆对特定的重金属离子具有高的选择性与吸附容量,将成为生物基吸附材料的重要开发方向,为将来替代价格相对较贵的吸附材料活性炭、离子树脂等奠定基础,为秸秆的高效利用提供了重要途径。
[Abstract]:Biological refining is an industrial process that uses agricultural waste, plant-based starch and lignocellulose as raw materials to produce various chemicals, fuels and biomaterials. Biological refining process can greatly improve the application of renewable plant-based raw materials and provide an effective way for chemical and energy economy in the path of green sustainable development. Corn straw is a biomass raw material, its corn stalk cellulose is porous structure, because of a large number of hydroxyl groups have good hydrophilic properties, can take place esterification, etherification, graft copolymerization and so on. By chemical modification, a large number of functional groups were introduced into the active hydroxyl groups, which acted on metal ions in wastewater and could be used as adsorbents for heavy metal contaminated water treatment. The main contents of this paper include the chemical modification of corn straw by using cheap corn straw, the preparation of modified corn straw adsorbent, and the key factors, such as the amount of cross-linking agent, reaction temperature, etc. The effect of reaction time on the Cr6 adsorption efficiency of modified corn straw in wastewater. The process parameters of modified corn straw adsorbent were optimized by Box-Behnken test. On the basis of single factor experiment, the optimum preparation conditions of the adsorbent were as follows: dosage of crosslinking agent diethylenetriamine 1.25mL, grafting temperature 101 鈩，
本文编号：2305967
[Abstract]:Biological refining is an industrial process that uses agricultural waste, plant-based starch and lignocellulose as raw materials to produce various chemicals, fuels and biomaterials. Biological refining process can greatly improve the application of renewable plant-based raw materials and provide an effective way for chemical and energy economy in the path of green sustainable development. Corn straw is a biomass raw material, its corn stalk cellulose is porous structure, because of a large number of hydroxyl groups have good hydrophilic properties, can take place esterification, etherification, graft copolymerization and so on. By chemical modification, a large number of functional groups were introduced into the active hydroxyl groups, which acted on metal ions in wastewater and could be used as adsorbents for heavy metal contaminated water treatment. The main contents of this paper include the chemical modification of corn straw by using cheap corn straw, the preparation of modified corn straw adsorbent, and the key factors, such as the amount of cross-linking agent, reaction temperature, etc. The effect of reaction time on the Cr6 adsorption efficiency of modified corn straw in wastewater. The process parameters of modified corn straw adsorbent were optimized by Box-Behnken test. On the basis of single factor experiment, the optimum preparation conditions of the adsorbent were as follows: dosage of crosslinking agent diethylenetriamine 1.25mL, grafting temperature 101 鈩，
本文编号：2305967
本文链接：https://www.wllwen.com/kejilunwen/huaxue/2305967.html
教材专著
