微波辅助膜蒸馏工艺传质强化效率研究

Study on Mass Transfer Enhancement Efficiency of Microwave Assisted Membrane Distillation Process

采用直接接触式膜蒸馏(DCMD)和微波辅助膜蒸馏(MWAMD)2种工艺,以Na Cl纯盐溶液或含一定量苯酚或者腐殖酸盐溶液为进料溶液,研究了盐含量及典型有机物对MWAMD过程传质强化效率和微波辐射对膜面晶体形貌的影响。结果表明,MWAMD工艺对膜通量具有强化效果,对模拟高含盐及含酚料液浓缩传质强化效果显著,当盐质量分数为20%时,传质强化增加率(ε)可到达15.14%,当料液含2000 mg/L苯酚时,ε为22.17%;膜蒸馏过程对盐离子和腐殖酸(HA)分子截留率接近100%,对酚离子有80%以上的截留率,而且微波辐射作用对截留率没有明显影响。微波辐射会减少晶体沉积量,而且会使晶体形貌呈不规则形状。

The effect of salt content and typical organic matter on mass transfer enhancement efficiency and the morphology of Sodium chloride deposited on membrane surfacewereinvestigated for comparing the performance of direct contact membrane distillation （DCMD） and microwave assisted membrane distillation （MWAMD） processes. Sodium choride salt solution or salt solution containing typical organic matter was used as feed solution. The results showed that the MWAMD process exhibited a significant reinforcement on membrane flux, especially for simulation highsalt concentrationor phenol solutions.When the mass fraction of NaClwas 20%, the mass transfer coefficient （ε） increased up to 15.14%, when the feed contained 2 000 mg/L phenol, 6 was 22.17%. The rejection ratio of salt ions and humic acid were close to 100% by the DCMD process and the rejection rate of phenolic ions reached above 80%. Moreover, microwave irradiation had no obvious effect on rejection.The quantity of crystal deposition on membrane surface reduced by microwave radiation,and, the morphology of crystal showed irregular feature.