一种新型复合纳滤膜对污水的深度处理研究

ADVANCED TREATMENT OF PRODUCED WATER WITH A NOVEL COMPOSITE NANOFIL TRATION MEMBRANE

考察了一种新型荷负电羧甲基甲壳素／聚丙烯腈复合纳滤膜对污水（中水）的处理效果。结果表明：在1．0MPa、30L／h、室温下，经纳滤膜处理后，溶解态总磷、硝态和亚硝态总氮及CODCr的平均截留率分别可达70％、83％和94％以上，而色度几乎可完全去除。纳滤膜出水CODCr为3．0～10．2mg／L，达到GB3838-2002地面水Ⅰ类水质标准；硝态和亚硝态总氮（以氮计）质量浓度为2．7～3．5mg,／L，达到GB5749—85生活饮用水标准；溶解态总磷（以磷计）质量浓度为1．0～1．7mg,／L，已接近1mg／L的污水GB8978-1996Ⅱ级排放标准。提出，由于PO4^3-与水体中H^＋、Ca^2＋、Mg^2＋等阳离子较易形成缔合离子或络合离子，减弱了与荷负电的纳滤膜的库仑排斥作用，从而使其截留率小于NO3^-或NO2^-；该纳滤膜适于油田采出污水处理、污水（中水）脱磷、氮和CODCr的深度处理及含磷废水的脱磷处理。

The negative charged Carboxymethyl chitin(CM-CH)/polyacrylonitrile(PAN)composite membrane is used to treat the produced water.The results indicates that when operating pressure is 1.0MPa,flux is 30L/h,the removal rate of total soluble phosphorus,total nitrogen in NO3-and NO2-and CODCr are above 70%,83% and 94% respectively,and the chroma is almost entirely disappeared.The concentration of CODCr,total nitrogen in NO3-and NO2-and total soluble phosphorus in the permeation feed are 3.0-10.2mg/L,2.7-3.5mg/L and 1.0-1.4mg/L respectively,which have reached or approached the GB I standard.It is put forward that PO43-is prone to be associative or complexing ions with H+,Ca2+,Mg2+ which weaken coulomb repulsion strength between the negative charged nanofiltration membrane and the ions,so the removal rate of PO43-is less than NO3-or NO2-.Negative membrane is effective to remove phosphorus,nitrogen and CODCr in produced water(the reclaimed water)and remove phosphorus from the phosphorous wastewater and produced water.