煤制气废水处理超滤膜污染研究

采用实验室自制超滤膜装置处理碎煤加压煤制气废水二沉池出水,通过考察膜通量Jv衰减、目标污染物去除率、Jv随时间t的模型拟合及膜表面污染物质,探究处理污染规律.结果表明：5种工况下膜通量Jv先显著下降后达到稳态,其中工况5通量下降最大达35.7％,而且进水压力PF越大越先达到稳态.对比5种工况下PS超滤膜过滤纯水和煤制气废水的Jv值可以看出,过滤煤制气废水时Jv随PF呈现非线性增长且逐步接近一个定值,推断形成了滤饼层污染.模型拟合结果显示滤饼层沉积模型可以很好描述滤饼层形成的两个阶段,即在滤饼层形成初期,污染物质在膜表面沉积,此时膜的固有阻力是膜污染的主要控制因素,而当过滤一段时间后,滤饼层生长并压实,此时,控制膜污染的因素既有滤饼层的作用也有膜的固有阻力的作用.GC-MS分析结果显示,膜丝内表面污染物质主要应为邻苯二甲酸酯类和长链烯烃类.

Study on UF membrane fouling by coal gasification waste water

Crushed coal pressurized gasification wastewater from biological treatment was treated using the self-made PS UF device.In order to study the membrane fouling,flux decline,the rejection coefficients were observed.Model fitting of the permeate flux with the time and the ingredients of pollutant were analyzed.The results indicated that,the permeate flux decreased initially and then reached the state in the five operating conditions.The maximum flux occurred in the fifth operating condition declined as much as 35.7 ％.In contrast with the change of pure water permeate flux with PF,the variation of Jv with PF was non-linear when filtered by coal gasification wastewater,this effect was possibly caused by the formation of a cake layer（one of the main causes for the fouling of membranes）on the membrane surface.After regression analysis,cake resistance madel was used to describe well the two stages of the formation of a cake layer.One corresponded to cake layer initial formation,in which pollutant was deposited on the membrane surface with the membrane resistance being important at this time.The second one corresponded to its growth,at this time,cake layer was compacted with the cake and membrane resistances being important.The pollutant was identified as phthalate esters and long-chain alkene.