疏水性PTFE微孔膜处理含Cr(III)稀溶液的实验研究

REMOVAL OF TRIVALENT CHROMIUM FROM ITS DILUTE SOLUTION WITH HYDROPHOBIC MICROPOROUS PTFE MEMBRANE

废水中的三价铬在自然环境中容易转化为毒性更强的六价铬。控制并回收废水中的三价铬可达到节约资源和降低污染的目的。采用减压膜蒸馏(VMD)分离装置,实验探讨了不同平均孔径大小的聚四氟乙烯(PTFE)微孔膜对处理含铬(III)溶液的膜通量、截留率等影响,研究了进料浓度、进料温度对分离性能的影响。实验结果表明,对于膜孔径较小的膜,膜内的传质阻力成为主要因素,膜内的传质是VMD过程的控制步骤。

Trivalent chromium in the wastewater could be easily converted to more toxic hexavalent chromium in environment. By vacuum membrane distillation (VMD) apparatus, a series of PTFE membrane with various mean pore sizes were used. Removal performance for VMD process was characterized with membrane flux and ion rejection rate. Factors including concentration and temperature of the feed were studied, too. The results indicated that for the small pore size membrane, mass transfer resistance in the pores played critical role in mass transport in VMD process. Mass transfer in membrane is the controlling step.