钙离子对正渗透中海藻酸钠溶液污染特性的影响

Effect of Calcium Ions on Fouling Properties of Alginate Solution in Forward Osmosis Process

研究钙离子对海藻酸钠溶液在正渗透过程中过滤行为的影响及其潜在机理。结果发现,过滤含有低浓度Ca^(2+)(1 mmol/L)的海藻酸钠溶液导致最大的水通量下降。增大Ca^(2+)浓度(5、10、15 mmol/L)使得水通量下降减小。Ca^(2+)浓度对海藻酸钠污染层的官能团组成没有显著影响,但污染层的微观结构受到Ca^(2+)浓度的显著影响,低浓度Ca^(2+)(1 mmol/L)下形成的污染层没有明显的多孔结构,增大Ca^(2+)浓度(5、10、15 mmol/L)形成具有大尺寸孔的污染层。化学势可以用来解释正渗透过程中不同浓度Ca^(2+)下形成的污染层所导致的过滤行为差异。

The effect of calcium ions on the filtration behavior of sodium alginate solution and its potential mechanism during forward osmosis process were investigated.The results showed that,filtering sodium alginate solution containing low Ca^(2+)concentration(1 mmol/L)resulted in the highest flux decline.Increase in Ca^(2+)concentration(5,10,15 mmol/L)reduced the flux decline.Ca^(2+)concentration exerted no apparent effect on the composition of functional groups of foulants layer.However,the microstructures of the foulants layers were significantly affected by Ca^(2+)concentration.Foulants layer formed with low Ca^(2+)concentration(1 mmol/L)had no obvious porous structure,and large size pores and structure defects occurred with increased Ca^(2+)concentration(5,10,15 mmol/L).The chemical potential can be used to explain the difference in filtration behavior caused by foulants layers formed with different Ca^(2+)concentrations in FO process.