摘要
采用直接接触式膜蒸馏处理焦化废水,通过监测出水电导率、 DOC、色度、 UV254并利用三维荧光光谱对出水水质进行分析,探究了焦化废水的进水温度对膜蒸馏处理效果的影响。结果表明,随着温度升高膜通量明显升高,当进水温度为40、 50和60℃时,初始膜通量分别为8.7、 14.6和21.7 kg/(m2·h)。随着温度的升高,焦化废水中污染物的扩散程度也随之加剧, 60℃时出水中有机物浓度比40、 50℃提高了约40%。膜蒸馏能有效截留焦化废水中的类腐殖酸和类富里酸等大分子污染物,而芳香烃及杂环类有机物是影响膜蒸馏产水水质的主要因素,随着温度升高,苯酚等易挥发的小分子有机物扩散也明显加快。此外,不同进水温度下膜污染形成的规律不同, 40℃时以无机污染为主, 50℃时以有机污染为主, 60℃时以有机和无机复合污染为主,这可能与温度升高后有机物扩散速率加快有关。综合比较,采用膜蒸馏处理焦化废水时进水温度拟选择50℃为宜。
Using direct contact distillation to treat coking wastewater, the conductivity, DOC, chroma and UV254 of the effluent water were monitored, the effluent water quality was analyzed by three-dimensional fluorescence spectrum, and then, the influence of feedwater temperature on coking wastewater treatment by membrane distillation was investigated. The results showed that, with the increasing feedwater temperature, the membrane flux increased obviously, when the feedwater temperature were 40, 50 and 60 ℃ respectively, the initial membrane flux were 8.7, 14.6, 21.7 kg/(m2·h) respectively. The pollutants diffusion was aggravated with the increase of the feedwater temperature, compared to the feedwater at 40 and 50 ℃, the organic matters concentration in the effluent water at 60 ℃ was increased by about 40%. Membrane distillation could effectively intercept macromolecular pollutants such as humic acid-like organics and fulvic acid-like organics in coking wastewater. Aromatic hydrocarbons and heterocyclic organics were the main components affecting produced water quality, and the diffusion speed of phenol and some other volatile low molecular weight organic matters were obviously accelerated with the increasing temperature. In addition, there was different membrane fouling propensity under different feedwater temperatures, inorganic pollutants were predominant at 40 ℃, organic pollutants were dominant at 50 ℃, while the major pollutants over 60 ℃ were organic/inorganic composite. The above phenomenon might be related to the accelerated diffusion of organic matters under high temperature. Therefore, through a comprehensive comparison, 50℃ should be a proper feedwater temperature for membrane distillation treating coking wastewater.
引文
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