膜孔反洗流剪切力表征膜污染变化规律探究

Study on the variation of membrane fouling characterized by the shear force of membrane pore backwash flow

采用孔径为0.2μm的PVDF平板微滤膜对酵母悬浮液进行了错流过滤与反洗.研究了在反洗过程中污染层平均孔径(d f)、膜孔内剪切力(τ)和可逆污染阻力(R r)的变化规律,并对比了有无反洗情况下的d f变化.结果表明,d f、τ和R r均随着反洗周期的增加而减小.d f随着过滤压力(TMP)、流速、反洗时间和强度的增加而增大,随着进料液质量浓度的增加而减小.当1700<Re<4200时,增加流速能有效提升d f;当Re>4200时,增加流速d f并未明显改善.τ随着TMP、流速、反洗时间和强度的增加而增大,随着进料液质量浓度的增加而减小.R r随着TMP、浓度、反洗时间和反洗强度的增加而增大,随着流速的增加而减小.周期反洗能有效提升d f,且2~10反洗周期的d f均大于未反洗的d f.

In this study,cross-flow filtration and backwash of yeast suspension were carried out using a polyvinylidene fluoride(PVDF)plate microfiltration membrane with a pore diameter of 0.2μm.The variations of the average pore size of fouling layer(d f),the shear force in the membrane pores(τ)and the reversible fouling resistance(R r)during the backwash process were studied.And the d f changes with and without backwash were compared.The results showed that the d f,τand R r decrease with increasing period.The d f increases with TMP,flow velocity,backwash duration and backwash strength,and decreases with increasing concentration.When 1700<Re<4200,increasing the flow velocity can effectively increase the d f.When Re>4200,the d f does not significantly improve by increasing the flow rate.Theτincreases with the increase of TMP,flow velocity,backwash duration and backwash strength,and decreases with the increase of concentration.R r increases with increasing TMP,concentration,backwash duration and backwash strength,and decreases with increasing flow backwash.Periodic backwash can effectively increase d f,and d f of 2~10 cycles was larger than that of non-backwash one.