Fe^(0)/H_(2)O_(2)对正渗透处理印染废水的性能影响及机理研究

Effect of Fe^(0)/H_(2)O_(2) on the performance and mechanism of forward osmosis treatment of practical printing and dyeing wastewater

采用Fe^(0)/H_(2)O_(2)体系作为正渗透(FO)处理某印染废水的预处理技术,通过分析在不同反应时间下,Fe^(0)投加浓度、H_(2)O_(2)投加浓度及pH 3个因素对COD和UV254去除率的影响,确定了预处理的最佳实验条件,探究了预处理对FO的性能及膜污染的影响,并利用SEM、接触角、EEM、XPS等表征手段分析其影响FO性能的机理.结果表明,在最佳预处理条件下,即Fe^(0)和H_(2)O_(2)投加浓度分别为1.5g/L和10mmol/L,pH为2~3,反应为60min时,FO膜比通量的下降速率大大减缓,FO膜对污染物的截留率提升了10%以上.对反应前后Fe^(0)的XPS表征验证了Fe^(0)和H_(2)O_(2)反应过程中产生了能有效去除有机物的羟基自由基和铁(氢)氧化物,对废水处理前后的EEM光谱表征发现Fe^(0)/H_(2)O_(2)预处理对废水中蛋白质样和SMP物质有明显降解作用,膜表面SEM和接触角测定表明Fe^(0)/H_(2)O_(2)预处理可显著减轻FO膜结垢的问题.

Fe^(0)/H_(2)O_(2)system is used as the forward osmosis(FO)pretreatment technology for treating a printing and dyeing wastewater.Through analyzing the effects of Fe^(0)dosage,H_(2)O_(2)dosage and pH on the removal rate of COD and UV254under different reaction time,the optimal experimental conditions for pretreatment are determined.The effects of pretreatment on the properties of FO and membrane fouling were investigated,and the mechanism of the effects was analyzed by SEM,contact angle,EEM,XPS and other characterization methods.The results show that under the optimal pretreatment conditions,1.5g/L and 10mmol/L Fe^(0)and H_(2)O_(2)dosage,pH=2~3and reaction time of 60min,the decrease rate of specific flux of FO membrane can be greatly slowed down,and the rejection rate of FO membrane to pollutants is increased by more than 10%.The XPS characterization of Fe^(0)before and after the reaction verified that hydroxyl radicals and iron(hydrogen)oxides,which can effectively remove organic matter,were produced in the reaction process of Fe^(0)and H_(2)O_(2).The EEM before and after the wastewater treatment showed that the Fe^(0)/H_(2)O_(2)system produced significant degradation of protein samples and SMP substances in the wastewater.The SEM and contact angle measurements on the membrane surface show that Fe^(0)/H_(2)O_(2) pretreatment can significantly reduce the FO membrane fouling.