光催化对多通道陶瓷膜错流超滤去除腐植酸膜污染的影响

Effects of photocatalysis on membrane fouling in cross-flow system with multichannel ceramic ultrafiltration membrane for removal of humic acid

为研究光催化作用对多通道陶瓷超滤膜去除水中腐植酸膜污染行为的影响,采用光催化陶瓷膜组合工艺,考察了不同光催化剂浓度下膜通量、污染物去除率、膜污染模式、膜污染阻力变化趋势以及在线反冲洗对膜通量变化的影响。结果表明:光催化可有效减缓陶瓷膜通量衰减程度,并提高污染物去除率;催化剂浓度为0.4g/L时膜通量衰减最小,最终相对膜通量达58.6%,催化剂浓度为0.6g/L时污染去除率最高,其中DOC为76.5%,UV254为87.3%,UV436为96.8%;光催化膜工艺在过滤初期经过短暂膜堵塞及过渡阶段后,膜污染以污染物在膜表面沉积为主;光催化可明显减低膜污染总阻力及可逆污染阻力;光催化作用下在线反冲洗对膜通量的恢复作用较小,但每次反冲前的膜通量衰减程度也小,使得在周期性在线反冲洗工艺中,光催化作用下的膜通量整体运行区间明显高于无光催化时的情况。

In order to investigate the effects of photocatalysis on membrane fouling behaviors using hybrid process of photocatalysis and multichannel ceramic ultrafiltration membrane for removal of humic acid from water,the membrane flux variations,pollutant removal rates,membrane fouling models and membrane fouling resistances under different photocatalyst concentrations were discussed.The backwash effects on membrane flux variations were also observed.The results showed that the photocatalysis could effectively improve the steady permeate fluxes and removal rates of pollutants.As the catalyst concentration was0.4g/L,the relative membrane flux reached the lowest value of58.6%.As the catalyst concentration was0.6g/L,the pollutants removal rates gained the highest level,in which the DOC,UV254and UV436reached76.5%,87.3%and96.8%,respectively.In the hybrid process of photocatalysis and ceramic membrane,the membrane fouling firstly underwent a short time of membrane pore blocking and transition stage,and then were mainly controlled by the deposition of pollutants on the membrane surface.The photocatalysis can significantly reduce the total and reversible membrane fouling resistances.Under the photocatalysis,although on-line backwashing had less effect on membrane flux recovery,its membrane fluxes also decreased limitedly prior to every backwashing.Therefore,in the periodic on-line backwashing process,the overall running range of the membrane flux under the photocatalysis was much higher than that of the situation without using photocatalysis.