无电压作用离子交换膜分离去除水中锰离子的研究

Study of the Removal of Manganese from Water with an Ion-exchange Membrane without External Voltage Application

研究了离子交换膜在无外加电压的条件下分离去除原水中锰离子的技术,探讨了锰离子浓度、补偿离子钾离子摩尔浓度、水力搅拌速度、温度和水力停留时间(HRT)等对去除效果的影响.实验结果表明,当原水中二价锰离子初始摩尔浓度为0.072 7 mmol/L(即4 mg/L)左右时,在下述的实验条件下:水温为(25±1)℃,水力停留时间HRT为6 h,水力搅拌速度为(600±25)r/min,补偿离子钾离子的摩尔浓度是原水中锰离子摩尔浓度的20倍,锰离子去除率达到80%.此外,在实验装置不改变的条件下,进水锰离子摩尔浓度增加到0.727 mmol/L(即40 mg/L)左右时,去除率会降低到66%;补偿钾离子摩尔浓度与进水锰离子摩尔浓度的比值大于20后,再增加其比值,对去除率影响不大;降低搅拌速度到(300±25)r/min,去除率降低到51%;降低水温到(16±1)℃,去除率降低到60%;水力停留时间(HRT)大于6 h后,再增加水力停留时间到12 h,去除率无明显改变.

The removal of manganese ion from water with an ion-exchange membrane under no external voltage condition was studied, and the effects, such as manganese ion concentration, the concentration of compensation potassium ions, water stirring speed, temperature and hydraulic retention time （HRT） on the removal efficiency of manganese ions were also evaluated. The results have shown that, when the initial concentration of bivalent ion Mn2＋ is 0.0727 mmol/L （4 mg/L）, under the experimental conditions of the water temperature of 25 ~C, HRT of 6 h, hydraulic mixing speed of （600＋25） r/min, and the concen- tration of the compensation ion K＋ is 20 times that of Mn2＋ , the removal efficiency of 80 % for the manganese can be achieved. In addition, with the equipments unchanged, when the inlet concentration of manganese increases to 0. 727 mmol/L （40 mg/L）, the removal efficiency will be lowered to 66% ; while the ratio of the concentration of compensation potassium ions to that of inlet manganese is higher than 20, the removal efficiency will not change significantly, if the ratio continues to increase; by lowering the stirring speed to （300±25） r/min, the removal efficiency will be decreased to 51% by lowering the temperature to （16±1） ℃ ,the removal efficiency is 60%; when the hydraulic retention time（HRT） is more than 6 h,the removal efficiency will not undergo any significant change by increasing HRT to 12 h.