Wang Dong, Meng Wenqiao, Lei Yunna, Li Chunxu, Cheng Jiaji, Qu Wenjuan, Wang Guohui, Zhang Meng, Li Shaoxiang
College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
Shandong Engineering Research Center for Marine Environment Corrosion and Safety Protection, Qingdao University of Science and Technology, Qingdao 266042, China.
Polymers (Basel). 2020 Feb 5;12(2):343. doi: 10.3390/polym12020343.
To improve sulfuric acid recovery from sodium sulfate wastewater, a lab-scale bipolar membrane electrodialysis (BMED) process was used for the treatment of simulated sodium sulfate wastewater. In order to increase the concentration of sulfuric acid (HSO) generated during the process, a certain concentration of ammonium sulfate solution was added into the feed compartment. To study the influencing factors of sulfuric acid yield, we prepared different concentrations of ammonium sulfate solution, different feed solution volumes, and different membrane configurations in this experiment. As it can be seen from the results, when adding 8% (NH)SO into 15% NaSO under the experimental conditions where the current density was 50 mA/cm, the concentration of HSO increased from 0.89 to 1.215 mol/L, and the current efficiency and energy consumption could be up to 60.12% and 2.59 kWh/kg, respectively. Furthermore, with the increase of the volume of the feed compartment, the concentration of HSO also increased. At the same time, the configuration also affects the final concentration of the sulfuric acid; in the BP-A-C-BP ("BP" means bipolar membrane, "A" means anion exchange membrane, and "C" means cation exchange membrane; "BP-A-C-BP" means that two bipolar membranes, an anion exchange membrane, and a cation exchange membrane are alternately arranged to form a repeating unit of the membrane stack) configuration, a higher HSO concentration was generated and less energy was consumed. The results show that the addition of the double conjugate salt is an effective method to increase the concentration of acid produced in the BMED process.
为提高从硫酸钠废水中回收硫酸的效率，采用实验室规模的双极膜电渗析（BMED）工艺处理模拟硫酸钠废水。为提高该过程中产生的硫酸（HSO）浓度，向进料室中加入一定浓度的硫酸铵溶液。为研究硫酸产率的影响因素，本实验制备了不同浓度的硫酸铵溶液、不同体积的进料溶液以及不同的膜配置。从结果可以看出，在电流密度为50 mA/cm²的实验条件下，向15%的Na₂SO₄中加入8%的(NH₄)₂SO₄时，HSO的浓度从0.89 mol/L增加到1.215 mol/L，电流效率和能耗分别可达最高60.12%和2.59 kWh/kg。此外，随着进料室体积的增加，HSO的浓度也增加。同时，配置也会影响硫酸的最终浓度；在BP-A-C-BP（“BP”表示双极膜，“A”表示阴离子交换膜，“C”表示阳离子交换膜；“BP-A-C-BP”表示两个双极膜、一个阴离子交换膜和一个阳离子交换膜交替排列形成膜堆的重复单元）配置中，产生的HSO浓度更高且能耗更低。结果表明，添加双共轭盐是提高BMED过程中酸浓度的有效方法。
