一种新型复合纳滤膜对污水的深度处理研究

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COD_Cr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COD_Cr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NO ^3-或NO ^2- ；该纳滤膜适于油田采出污水处理、污水（中水）脱磷、氮和COD_Cr的深度处理及含磷废水的脱磷处理。

Advanced Treatment of Produced Water with a Novel Composite Nanofil Tration Membrane

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 NO ^3- and NO ^2- and COD_Cr are above 70%,83% and 94% respectively,and the chroma is almost entirely disappeared.The concentration of CODCr,total nitrogen in NO ^_3- and NO _^2- 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 PO₄ ^3- is prone to be associative or complexing ions with H ⁺ ,Ca ²⁺ ,Mg ²⁺ which weaken coulomb repulsion strength between the negative charged nanofiltration membrane and the ions,so the removal rate of PO₄ ^3- is less than NO ^3- or NO ^2-.Negative membrane is effective to remove phosphorus,nitrogen and COD_Cr in produced water (the reclaimed water) and remove phosphorus from the phosphorous wastewater and produced water.