糖类对正渗透膜的膜污染研究

Research on fouling propensity of carbohydrate for forward osmosis

正渗透膜(FO)是一种低能耗的膜处理工艺,而膜生物反应器(MBR)是一种高效的污水处理工艺,其最大的瓶颈就是严重的膜污染问题,将FO应用到MBR中,即正渗透膜生物反应器。根据传统膜生物反应器的膜污染特点,研究SMP和EPS的主要组成成分中的糖类物质对膜的污染情况,利用海藻酸钠模拟糖类物质,并根据生活污水的特点,在海藻酸钠中加入钙、镁离子,研究其在含有不同金属离子时膜不同放置方式时的膜污染情况,将运行后的污染膜片剪下做SEM、AFM、FTIR-ATR分析。研究表明,海藻酸钠加不同金属离子的膜污染情况不一致,其膜污染大小顺序为藻酸钠+钙>藻酸钠+钙+镁>藻酸钠+镁,且不同膜放置方式的膜污染不同,活性层面向驱动液的通量较大。

Forward osmosis （FO） is a kind of low energy consumption technology, and membrane bioreac- tor （MBR） is an effective process for wastewater treatment. However, the membrane fouling is a major obstacle to the wide application of MBRs. The FO combined with MBR in a system,a new technology appeared --osmosis membrane bioreactor （OMBR）. Based on the characteristics of conventional MBR and OMBR membrane foul- ing, we analyzed the fouling property of carbohydrate, which is the major composition of soluble microbial products （SMP） and extracellular polymeric substances （EPS）. Alginate was used to simulate carbohydrate, and based on the composition of wastewater, calcium and magnesium ions were added in the alginate solution, at the same time, as the membrane was asymmetrical, we analyzed the fouling attendance of different membrane orientation. After the experiment, SEM, AFM, FTIR-ATR were carried out to analyze the different fouling membrane. The result indicated that the membrane fouling propensity was alginate ＋ Ca2 ＋〉 alginate ＋ Mg2＋ ＋ Ca2 ＋ 〉 alginate ＋ Mg2 ＋ and different membrane orientation showed different fouling properties, the active layer faced the feed tank pres- ented a more serious membrane fouling.