正渗透膜对印染废水中铬的处理特性

Treatment characteristics of chromium in dyeing wastewater by forward osmosis membrane

利用水通道蛋白正渗透(FO)膜对含铬模拟废水和印染废水进行处理,分别研究了汲取液浓度和原料液pH对FO膜的水通量、盐返混通量及重金属铬截留效果的影响.结果表明,汲取液浓度对通量影响显著,处理模拟废水时,当氯化钠浓度从0.5 mol/L增加到2.0 mol/L时,膜的水通量从9.7 L/(m^2·h)增加到16.9 L/(m^2·h),盐返混通量从4.35 g/(m^2·h)增加到7.65 g/(m^2·h).而在处理印染实际废水的时候,膜的水通量从6.5 L/(m^2·h)增加到13.3 L/(m^2·h),截留率随汲取液浓度的增加而减小;另外随原料液pH的不断提高,对重金属铬的截留率也不断提高,在模拟废水的pH从3.0增加到11.0的过程中,对铬的截留率从98.8%增加到了99.7%,而对印染实际废水的处理中铬的截留率均高于99.5%,此外随着氯化钠浓度的提高,铬的截留率有所下降.这些数据可为FO应用于印染废水和重金属处理提供一定的参考.

The simulated waste water of chromium and dyeing wastewater were treated by aquaporin forward osmosis membrane.The effects of the concentration of the draw solution and the pH of the feed solution on the water flux,the salt flux and the rejection of chromium of the forward osmosis(FO)membrane were studied.The results show that the concentration of the draw solution has a significant effect on the flux.When the simulated wastewater was treated,the water flux of the membrane increased from 9.7 L/(m^2·h)to 16.9 L/(m^2·h)and the salt flux increased from 4.35 g/(m^2·h)to 7.65 g/(m^2·h)with the concentration of NaCl increased from 0.5 mol/L to 2.0 mol/L.When the actual dyeing wastewater was treated,the water flux increased from 6.5 L/(m^2·h)to 13.3 L/(m^2·h),and the rejection decreased with the increasing concentration of the draw solution.With the pH of feed solution increased,the rejection of chromium was continuously improving.During the pH of simulated wastewater increased from 3.0 to 11.0,the rejection rate of chromium increased from 98.8%to 99.7%,while the rejection of chromium in the actual wastewater was higher than 99.5%.And the retention rate of chromium decreased with the increasing of the NaCl concentration.These data can provide a reference for the application of FO in the treatment of dyeing wastewater and heavy metals.