摘要：

研究了聚偏氟乙烯（PVDF）膜膜蒸馏处理脱硫废水过程中污染物对膜通量的影响，并确定处理过程中不同时期造成通量变化的先驱污染物和主导污染物。流速对污染物的分布起主导作用。采用三维单相计算流体力学（CFD）方法来评估膜模块系统中的流动状态，并通过SEM、X射线能谱仪（SEM-EDS）、FTIR分析不同污染时期污染物在膜表面水平方向和垂直方向上的分布、组成和结构。研究发现，膜通量的变化主要分为2个阶段：缓慢下降阶段和快速下降阶段，两阶段截然不同的通量变化归因于主导污染物的差异。有机污染物是前期导致通量缓慢下降时的先驱性污染物，矿物结垢是后期通量急速下降的主导因素。有机污染物主要包括腐殖酸和富里酸，在膜蒸馏过程中通过与膜表面的疏水-疏水相互作用首先沉积在膜表面造成通量的缓慢下降；矿物污染物主要是硫酸钙，随着进料液的浓缩，在液体中成核结晶，在膜表面快速生长导致通量的快速降低。

关键词: 脱硫废水, 膜蒸馏, 有机污染物, 无机污染物, 膜污染

Abstract:

The effect of pollutants on flux during the treatment of desulfurization wastewater by polyvinylidene fluoride（PVDF） membranes were investingated. Then，the pioneer pollutants and dominant pollutants causing flux changes at different periods in the treatment process were determined. The flow rate playd a dominant role in the distribution of the membrane fouling layer. A three-dimensional single-phase computational fluid dynamics（CFD） method was used to evaluate the flow state in the membrane module system，while SEM，X-ray energy dispersive spectrometer（SEM-EDS），and FTIR were used to analyze the distribution，composition and structure of pollutants on the membrane surface in the horizontal and vertical directions in different fouling periods. It was found that the change in membrane flux is divided into two main phases： a slowly decreasing phase and a rapidly decreasing phase， and the distinct flux variation in the two phases were attributed to differences in the dominant pollutants. Organic pollutants were the pioneer pollutants that lead to a slow decline in flux in the early stage，and mineral scaling was the dominant factor in the rapid decline of flux in the later stage. Organic pollutants mainly included humic acid and fulvic acid， which first deposited on the membrane surface during the membrane distillation process through hydrophobic-hydrophobic interaction with the membrane surface， causing a slow decrease in flux. Mineral contaminants， mainly calcium sulfate， nucleate and crystallize in the bulk solution as the concentration process， and grew rapidly on the membrane surface resulting in a rapid decrease in flux.

Key words: desulfurization wastewater, membrane distillation, organic contaminant, inorganic contaminant, membrane fouling

中图分类号: 

• X703