淀粉微球的制备及其对污水中Pb2+的去除研究

Preparation of Starch Microspheres and Study on the Removal of Pb2+ in Wastewater

采用反相乳液交联聚合法制备淀粉基微球,以改性红薯淀粉为原料,N,N-亚甲基双丙烯酰铵(MBAA)为交联剂、Span 60与Tween 60为乳化剂,硝酸铈铵为引发剂得到比较粗糙、近圆球状、比表面积较大的淀粉微球,且在油水相混合前加入。采用红外光谱仪(FT-IR)对其官能团测试、外形图片以及比表面积及孔径分析(BET)等表征方法分析,确立制备条件:改性红薯淀粉2%,引发剂0.109g,转速为180r·min-1。得到的淀粉微球应用于模拟重金属Pb2+溶液中进行吸附初探,改变温度、淀粉微球投入量、pH值探究对吸附的影响,确定最佳吸附条件,应用于西安汉城湖实际水样中进行吸附测试。研究发现,当淀粉微球投入浓度为4.0g·L-1、吸附时间为50min时,pH值为8时吸附效果最佳,Pb2+去除率达到35.4%。

The starch microspheres are prepared with modified sweet potato starch as the raw material,N,N-methylene bisacrylamide(MBAA)as the cross-linking agent,Span 60 and Tween 60 as the emulsifiers and ammonium ceric nitrate as the initiator(adding before mixing water and oil phase)by the inverse emulsion cross-linking polymerization.And the starch microspheres are obtained whose body is relatively coarse,nearly spheri-cal,and has a larger specific surface area.The Infrared spectroscopy is used to test its functional groups,the specific surface area and pore size are analyzed by BET,and its appearance is observed.Finally the preparation conditions are confirmed as follows:the content of modified sweet potato starch is 2%(water as reference value),the dosage of initiator is 0.109 g and the rotate speed is 180 r·min-1.The obtained starch microspheres are used to simulate the adsorption of Pb2+solution,and the effects of the temperature,starch microspheres amount and pH value on the adsorption are discussed.And the optimal adsorption conditions are found and applied in the practical water sample of Xi’an Hancheng Lake.It is found that when the concentration of starch microspheres is 4.0 g·L-1,the adsorption time is 50 min,the pH value of solution is 8,the removal rate of Pb2+reaches35.4%which is the best.