乙烯基硅橡胶膜萃取含盐水中正戊酸的研究

Perstraction of Pentanoic Acid in High Salinity Wastewater by PVMS Silicon Rubber Membranes

摘要:

摘 要：通过溶胀性能、表面性能测定对比聚二甲基硅氧烷(PDMS)膜和聚甲基乙烯基硅氧烷(PVMS)膜在萃取正戊酸前后的特性变化及其自身差异，结果发现，PVMS膜的接触角和溶胀度均高于PDMS膜。膜萃取正戊酸后，膜的化学结构发生了变化，PVMS膜更利于小分子物质通过。在此基础上，针对性能优异的PVMS膜，考察了料液浓度、料液流速、萃取液种类对渗透萃取正戊酸过程的影响，讨论了乙烯基硅橡胶膜从含盐废水中分离低分子有机酸的机理，并优化其工艺条件。结果表明：随着料液浓度的提高，正戊酸的去除率和回收率先增加后减小，当料液质量分数为7%时，去除率最大可达为94%；当料液质量分数为2%时，回收率最大达到45.8%。相比于水作萃取液，碱性萃取液将传质提高几乎1倍，且碳酸钠作萃取液具有更好的适用性。流速为1-20mL/min时，增大料液流速，正戊酸的去除率和回收率都增加，可在实际应用中适当增大流速来增强分离效果。

Abstract:

ABSTRACT: Characteristics change and differences of polydimethylsiloxane (PDMS) and polymethylvinyl- siloxane (PVMS) membrane before and after extraction were investigated by measuring swelling property and surface performance. The results showed that the swelling degree and the contact angle of PVMS were higher than that of PDMS, indicating excellent hydrophobicity. Chemical structure of membrane changed after treatment. PVMS had better ability of perstraction for organic component than PDMS. Therefore, simple device equipment with PVMS was employed to remove the pentanoic acid from an aqueous solution, and the effects of the influent concentration, influent flow rate, and extraction solvent on permeation extraction were discussed. At the same time, the possible separation mechanism of this process was analyzed. It was found that with the increase of influent concentration, the removal extent and recovery of the pentanoic acid increased but decreased later. The removal extent of PVMS membrane reached 94% at concentration of 7%, and recovery extent reached 45.8% at concentration of 2%. Removal extent with the alkali solution was higher than that with the water in receptor liquor. And receptor liquor with sodium carbonate had better applicability. The removal and recovery extent can be improved by increasing the flow rate between 1 and 20 milliliters per minute, which can enhance separation effect in the practical application.