正渗透处理电镀废水膜污染研究

Membrane Scaling in Forward Osmosis for the Treatment of Electroplating Wastewater

利用聚酰胺正渗透膜(TFC膜)和筛网内嵌式三醋酸纤维素正渗透膜(CTA膜)对电镀废水进行正渗透(FO)处理。通过实时监测水通量的变化,发现两种膜在处理电镀废水中的过程中水通量下降情况有较大差异。运用场发射电镜(SEM)、原子力显微镜(AFM)表征了两种正渗透膜表面结构的差异。此外,采用能谱仪(EDS)检测了实验前后膜表面元素含量,发现实验后的膜表面新增了钙、硫元素。此外,为了鉴定沉积在膜表面的物质,对收集的白色晶体进行了x射线衍射(XRD)分析。XRD分析结果表明,其主要成分为石膏。X射线光电子能谱(XPS)结果表明,含羧基官能团的TFC膜与钙离子结合。

Electroplating wastewater was treated via forward osmosis (FO) using thin-film composite (TFC) polyamide membrane and cellulose triacetate (CTA) membrane. By in situ monitoring the change of water flux, it was found that the water flux declined patterns were quite different for TFC and CTA membranes during treating electroplating wastewater via FO process. The pristine morphologies of TFC and CTA membrane were observed using scanning electron microscopy (SEM) and atomic force microscope (AFM). Moreover, the scaled TFC and CTA membrane surfaces were examined by energy dispersive spectrometer (EDS) to test the change of elementary composition of the two membrane surfaces before and after experiments. The results of EDS showed that calcium and sulfur appeared on the scaled membrane surface compared with the virgin membrane surface. Additionally, to identify the scalants deposited on the membrane surface, the collected white scalants were analyzed by X-ray diffraction (XRD). The result of XRD showed that the scalants were mainly gypsum. The results of X-ray photoelectron spectroscopy (XPS) showed that the TFC membrane with carboxylic functional groups was combined with calcium ions.