Li Jin, Song Xuanyu, Pan Jinfen, Zhong Lian, Jiao Shufang, Ma Qimin
Key Laboratory of Marine Environment & Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
Int J Biol Macromol. 2013 Nov;62:4-12. doi: 10.1016/j.ijbiomac.2013.08.009. Epub 2013 Aug 21.
Chitosans with different degrees of deacetylation (DD) and molecular weights (Mw) were tested for the flocculation of bentonite suspensions prepared with demineralized water (DW) and tap water (TW), respectively. Flocculation kinetics model of particles collisions combining zeta potential and turbidity measurements was employed to investigate the effects of the DD and Mw of the chitosans on the flocculation properties. The results indicated that the chitosan (Mw 232 kDa) dosages required for maximum flocculation are 20 mg/L in DW and 5 mg/L in TW, respectively, regardless of DD from 54.6% to 95.2% and pH of bentonite suspension. Chitooligomers (Mw 1.5 kDa, DD 95.2%) failed to reach the required residual turbidity (i.e., 10 NTU) in DW under all investigated conditions, whereas good results were obtained using 5-20 mg/L in TW. The polymer-induced flocculation processed obeyed Von Smoluchowski's bimolecular rate equation. The flocculation performance in TW was very different from that in DW due to the presence of salts in TW. The results were consistent with the destabilization of bentonite by the combined mechanisms of charge neutralization and bridging.
分别用去离子水（DW）和自来水（TW）制备膨润土悬浮液，测试了不同脱乙酰度（DD）和分子量（Mw）的壳聚糖对其絮凝效果。采用结合zeta电位和浊度测量的颗粒碰撞絮凝动力学模型，研究壳聚糖的DD和Mw对絮凝性能的影响。结果表明，无论膨润土悬浮液的DD为54.6%至95.2%以及pH值如何，达到最大絮凝所需的壳聚糖（Mw 232 kDa）剂量在DW中为20 mg/L，在TW中为5 mg/L。在所有研究条件下，低聚壳聚糖（Mw 1.5 kDa，DD 95.2%）在DW中未能达到所需的残余浊度（即10 NTU），而在TW中使用5 - 20 mg/L可获得良好结果。聚合物诱导的絮凝过程符合冯·斯莫卢霍夫斯基双分子速率方程。由于TW中存在盐分，其絮凝性能与DW中的非常不同。结果与电荷中和和架桥联合机制使膨润土失稳一致。
