随着工业生产的快速发展,工业废水的排放量迅猛增加,其中大部分工业废水中都含有硫酸盐,硫酸盐的过量排放会对环境水体造成严重的污染与破坏。本研究以硫酸钠废液为原料,采用双极膜电渗析(BMED)新型工艺,实现含硫酸盐废水的回收再利用,高效、清洁地制取酸、碱。实验主要考查了电流密度、原料液浓度及初始酸碱浓度对膜堆性能的影响,并对两种离子交换膜的性能进行对比。结果表明,实验范围内,氢氧化钠的收率高达84.08%,平均电流效率为54%,能耗为5.29 kW·h/kg;氢氧化钠收率和过程能耗均随电流密度的增大而增加;电流密度恒定时,较高的原料液浓度可使膜堆电阻维持在较低的水平,进而降低能耗;适量加入初始酸碱能够降低能耗,但也会降低电流效率。
With the rapid development of massive industrial productions, the emission amount of the industrial wastewater is increasing sharply, most of which contains sulfate. The excessive emission of sulfate will cause serious pollution and damage to the environment water body. To solve this problem, in this paper, the sodium sulfate waste is used as the raw material, a new technology of the bipolar membrane electrodialysis is adopted, thus, the wastewater containing sulfate is reasonably reutilized and converted efficiently into the corresponding acid and alkaline. In the experiment, the effects of the current density, the feed concentration and the initial pH concentration on the membrane reactor are investigated, and the performances of the two ion-exchange membranes are compared. It is shown that in the experimental range the yield of the sodium hydroxide reaches 84.08%, the average current efficiency of the process reaches 54%, the energy consumption reaches 5.29 kW·h/kg, and the sodium hydroxide yield and the process energy consumption rise with the increase of the current density. When the current density is constant, a higher raw material concentration can make the membrane reactor stay at a relatively lower level during the experiment, which reduces the energy consumption. The right amount of the initial acid and alkali can reduce the energy consumption, but the current efficiency will decrease.
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