Abstract:

Based on the membrane separation technology, biopolymeric ferric sulfate (BPFS) was prepared with the optimized sequential batch processThe effect on separation of microorganisms, biocatalytical oxidation rate of Fe²⁺, preparation periods and membrane pollution were investigated by using polyvinylidene fluoride hollow fiber membrane (PVDF) to separate microorganismsThe results showed that the biomass in BPFS obviously increased through the membrane separation processBy using the optimized process, the BPFS with total iron contents of 60kg·m^-3, 80kg·m^-3, 100kg·m^-3 were preparedThe biocatalytical oxidation rate of Fe²⁺ reached 1.75 g·L^-1·h^-1, 1.85 g·L^-1·h^-1, 1.43 g·L^-1·h^-1 , preparation periods were 155h, 21h, 40h, a decrease by 38%, 42%, 18% respectively as against the process before optimizationThe biomass in BPFS reached the order of magnitude of 108 num·ml^-1With the increase of separation time and the content of total iron of BPFS,membrane pollution was intensified seriously, and membrane flux decreased obviouslyPVDF was cleaned by a mixture of 0.2 mol·L^-1sodium oxalate and 0.2 mol·L^-1sulfuric acid, and the scavenger can clean out the fouls from the membrane surface and satisfy the separation requirement.

Key words:

微生物, 生物聚合铁, 制备周期, 膜通量

摘要：

开展基于膜分离技术优化反复序批式工艺制备生物聚合铁（BPFS）的技术研究。考察了应用聚偏氟乙烯中空纤维微滤膜（PVDF）对微生物的分离效果，Fe^2+的生物催化氧化速率，制备周期及膜的污染与处理的情况。研究表明，PVDF膜可有效分离微生物，显著提高原液中的生物量。在优化工艺的基础上，制备了全铁含量分别为60、80、100 kg·m^-3 BPFS，Fe^2+的生物催化氧化速率分别达到1.75、1.85、1.43 g·L^-1·h^-1，制备周期分别为15.5、21、40 h，比工艺优化前分别缩短了38%、42%、18%，反应液中的生物量达到10⁸ 个·ml^-1数量级。实验中发现，随着分离次数和全铁含量的增加，膜污染加剧，膜通量下降;采用0.2 mol·L^-1的草酸钠和0.2 mol·L^-1硫酸的混合溶液对PVDF膜进行清洗，可基本清除膜表面的污染物，满足分离要求。

关键词:

微生物, 生物聚合铁, 制备周期, 膜通量