壳聚糖改性粘土去除城市湖泊中藻类的研究

摘要

对壳聚糖改性粘土用于城市湖泊中藻类的絮凝去除进行了研究。实验表明,粘土经过壳聚糖改性后,对高藻水中藻细胞的去除效能得到很大的提高。相比单独投加壳聚糖,粘土的加入增加了絮体密实度,减少了絮体体积,并使絮体分布更均匀。在壳聚糖与粘土配比为1∶20时,叶绿素的去除率和浊度的去除率均为最佳。粘土的种类对除藻效果有一定影响,其中以高粘凹凸棒石为最佳,在最佳投加量28 mg.L-1时,对叶绿素的去除率达到96.2%;粘土的粒径对絮凝效果基本没有影响,在粒径为60μm与300μm之间改性粘土对藻细胞的凝聚效果是一致的。经壳聚糖改性的粘土在酸性条件下絮凝效果较好,当pH值大于7时,其絮凝能力迅速下降。%The flocculation and removal of algae in urban lake water by chitosan-modified clays was studied.The algal removal efficiency was greatly improved after the modification of the clays.Compare with chitosan alone,the chitosan-modified clays increased the density of flocs,reduced the flocs volume and improved the distribution of flocs.The optimized proportion between chitosan and clay was 1∶ 20,in which the best removal efficiencies of Chlorophyll-and turbidity were obtained.The different kinds of clays affected the algal removal efficiency.The algal removal capacity of high viscosity attapulgite was best.The optimum total loading was 28 mg·L-1 and the corresponding Chlorophyll-removal rate was 96.2%.The chitosan-modified clays with particle size ranging from 60μm to 300μm had almost the same algal removal efficiency,indicating that the particle size of clays did not have influence on the algal removal efficiency.The algal removal efficiency was higher in acidic conditions,and declined rapidly with the increase of pH in alkaline conditions.