高锰酸钾预氧化对高藻水超滤过程中膜污染及锰沉积的影响

Effects of potassium permanganate pre-oxidation on membrane fouling and Mn(Ⅶ)deposition during the treatment of algae-laden water by ultrafiltration

研究了高锰酸钾(KMnO4)预氧化对高藻水超滤膜污染的影响.结果表明,KMnO4预处理后超滤对藻源有机物的去除能力(29%~41%)低于单独超滤(41%),仅对荧光组分的去除率有所提高;过量投加KMnO4会诱发胞外有机物(EOM)的释放,导致腐殖酸类物质含量增加;KMnO4预氧化对超滤膜污染仅有轻微的缓解作用,即使投加50μmol/L时,末端比通量仅由0.14提高至0.19,但会增加水力不可逆膜污染;KMnO4预氧化形成的MnO2颗粒主要沉积在滤饼层中,通过物理或化学清洗均可有效去除.

The effects of KMnO4 pretreatment on the ultrafiltration membrane pollution of the algae-laden water were studied.The results show that the removal capacity of algae-derived organics by ultrafiltration after KMnO4 pretreatment(29%~41%)is lower than that of ultrafiltration alone(41%),which only improves the removal of fluorescent components;excessive addition induced EOM release,resulting in an increase in humic-acid content;KMnO4 pre-oxidation had a slight mitigating effect on ultrafiltration membrane pollution,even when 50μmol/L was added,the terminal specific flux was only increased from 0.14 to 0.19,but it would increase the hydraulic irreversible membrane pollution during the filtration process;MnO2 particles formed by KMnO4 pre-oxidation were mainly deposited in the filter cake layer,which could be effectively removed by physical or chemical cleaning.Therefore,when using KMnO4 pre-oxidation and UF technology to treat algae-laden water,the physical strength should be properly strengthened and the cleaning frequency should be increased to suppress the growth of hydraulic irreversible membrane pollution and the deposition of MnO2 particles.