摘要
工业生产中产生的含有NaNO3的高盐废水是一种可回收再利用的资源,通过双极膜电渗析(BMED)技术可制备出相应的酸和碱,对高盐废水的资源化利用具有重要的意义.采用三隔室双极膜电渗析膜堆,以NaNO3溶液模拟高盐废水制备HNO3和NaOH.选取能耗、电流效率、转化率作为评价指标,探究电流密度、原料液浓度、极液种类及浓度、酸碱室初始浓度对BMED制酸碱过程的影响.结果表明:随着电流密度的增大,盐转化率提高,能耗增加;随着原料液浓度的增大,电流效率增加,能耗降低,原料液浓度过高会导致电流效率明显降低;极液以3%(质量分数)的NaOH最宜;酸碱室初始浓度的增加可提高盐转化率,降低能耗.综合各因素最优参数进行实验,在电压为35 V、电流密度为700 A/m2、酸碱室初始浓度为0.05 mol/L、原料液为12%(质量分数)的硝酸钠、极液为3%(质量分数)的NaOH的条件下,制得的碱浓度为2.227 mol/L,盐转化率可达93.42%,电流效率为60.83%,能耗为3.23 kW·h/kg.研究结果可为工业生产中NaNO3高盐废水的资源化利用提供参考.
Abstract
In industrial production activities,high-salt wastewater containing NaNO3 is usually produced,which is a recy-clable resource.The corresponding acids and bases of high salt wastewater can be prepared by bipolar membrane electrodi-alysis(BMED).The technique is of great significance for the resource utilization of high-salt wastewater.In this experiment,a three-compartment bipolar membrane electrodialysis membrane stack configuration was used to simulate high-salt waste-water with NaNO3 solution to prepare HNO3 and NaOH.The experiment used energy consumption,current efficiency,and conversion rate as evaluation indexes.The effects of current density,the concentration of raw material solution,type and con-centration of polar liquid,and initial concentration of acid-base chamber solution,on the preparation of acid-base by BMED were investigated.The results showed that when the current density was increased,an increase in the salt conversion rate and energy consumption could be observed.An increase in current efficiency and a decrease in energy consumption could be found as the concentration of raw material solution was increased.However,the concentration of raw material solution was too high,which would cause the current efficiency to decrease obviously.3% NaOH was best for polar solution.When the initial concentration of the acid-base chamber was increased,an increase in the salt conversion rate and a decrease in en-ergy consumption could be observed.The parameters were optimized as follows:the operating voltage was 35 V,the operat-ing current density was 700 A/m2,the initial concentration of the acid-base chamber was 0.05 mol/L,the raw material liquid was 12% sodium nitrate,and the polar liquid was 3% NaOH.Under these conditions,the concentration of base was 2.227 mol/L,the salt conversion rate was up to 93.42%,the current efficiency was 60.83%,and energy consumption was 3.23 kW·h/kg.The research results could provide a reference for the resource utilization of NaNO3 high salt wastewater in industrial production.
基金项目
企业技术开发项目(HSJS-YF-研发-23002)
NETL
NSTL
万方数据