Surface Modification of PVDF Membranes for Treating Produced Waters by Direct Contact Membrane Distillation
Surface Modification of PVDF Membranes for Treating Produced Waters by Direct Contact Membrane Distillation
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DOI：
10.3390/ijerph16050685
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发表时间：
2019-03-01
影响因子：
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通讯作者：
Wickramasinghe, Ranil
中科院分区：
文献类型：
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作者：
Kamaz, Mohanad;Sengupta, Arijit;Wickramasinghe, Ranil
采用聚偏二氟乙烯(PVDF)膜进行直接接触膜蒸馏(DCMD)处理水力压裂采出水。为了减少溶解有机物种和矿物盐的吸附速度，调整膜的表面性质至关重要。通过接枝两性离子和聚离子液体聚合物链对PVDF膜进行了改性。此外，还用高锰酸钾和氢氧化钠对PVDF膜进行了表面氧化。选择了表面改性条件，使接触角减小到最小。因此，膜保持疏水性，这对于抑制润湿是必不可少的。用PVDF基膜和改性膜进行了DCMD研究。此外，还利用电凝聚处理后的采出水(PW)在基膜上进行了DCMD，以去除溶解的有机物。DCMD后，对所有膜进行扫描电子显微镜成像和能量色散X-射线能谱分析。表面改性导致PW在通量急剧下降之前被膜处理的体积更大。结果表明，通过调整膜的表面性质，可以提高膜的抗污染能力，降低对膜的前处理要求。
Direct contact membrane distillation (DCMD) has been conducted to treat hydraulic fracturing-produced water using polyvinylidenedifluoride (PVDF) membranes. Tailoring the surface properties of the membrane is critical in order to reduce the rate of adsorption of dissolved organic species as well as mineral salts. The PVDF membranes have been modified by grafting zwitterion and polyionic liquid-based polymer chains. In addition, surface oxidation of the PVDF membrane has been conducted using KMnO4 and NaOH. Surface modification conditions were chosen in order to minimize the decrease in contact angle. Thus, the membranes remain hydrophobic, essential for suppression of wetting. DCMD was conducted using the base PVDF membrane as well as modified membranes. In addition, DCMD was conducted on the base membrane using produced water (PW) that was pretreated by electrocoagulation to remove dissolved organic compounds. After DCMD all membranes were analyzed by scanning electron microscopy imaging as well as Energy-Dispersive X-Ray spectroscopy. Surface modification led to a greater volume of PW being treated by the membrane prior to drastic flux decline. The results indicate that tailoring the surface properties of the membrane enhances fouling resistance and could reduce pretreatment requirements.