预处理对超滤膜产生不可逆吸附污染的影响

Pretreatment to influence on the critical flux for irreversibility of adsorption fouling

为测定超滤膜产生不可逆吸附污染的临界通量值,采用改进通量阶梯法和通量循环法2种方法对东营南郊自来水厂的原水、沉淀池出水、砂滤池出水进行了测定与对比,发现膜进水经预处理后可明显提高产生不可逆吸附污染的临界通量值,经预处理后的沉淀池出水和砂滤池出水作为膜进水时的不可逆吸附污染的临界通量值明显高于原水,为原水的1.7～2.0倍.从膜的不可逆吸附污染速率和污染量的形成方面考虑,改性的PVC超滤膜在高于不可逆吸附污染临界通量下运行,原水的不可逆吸附污染速率急剧增大,产生的不可逆吸附污染快速增多;而沉淀池出水和砂滤池出水的不可逆吸附污染速率和污染量的增加可维持在较低的水平.

Improved flux-step method and flux cycling method are used to measure and analyze the irreversible adsorption fouling of the raw water, water after sedimentation and water after sand filter, which is from the water supply plant of Dongying. Pretreatment can obviously improve the critical irreversible adsorption flux. The critical irreversible adsorption flux of water after sedimentation and water after sand filter is higher than that of raw water, i. e. 1.7--2.0 times. The modified PVC ultra filtration membrane runs at a higher flux than critical irreversible adsorption flux. When the UF membrane operates the raw water, the irre versible adsorption fouling rate increases rapidly and the formation of irreversible adsorption fouling increases rapidly; when UF membrane operates water after sedimentation and water after sand filter can maintain the irreversible adsorption fouling rate and the formation of irreversible adsorption fouling at a low level.