Degradation of Reactive Black 5 in a submerged photocatalytic membrane distillation reactor with microwave electrodeless lamps as light source

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• 作者：Dan Qu ; Zhimin Qiang ; Shuhu Xiao ; Qingxiang Liu ; Yuqing Lei ; Tuantuan Zhou
• 关键词：Submerged photocatalytic membrane distillation reactor ; Microwave electrodeless lamp ; Vacuum membrane distillation ; Reactive Black 5 ; Photodegradation
• 刊名：Separation and Purification Technology
• 出版年：10 February, 2014
• 年：2014
• 卷：122
• 期：Complete
• 页码：54-59
• 全文大小：1305 K

文摘

A novel submerged photocatalytic membrane distillation reactor (SPMDR) was developed and microwave electrodeless lamps were applied as the source light. Reactive Black 5 was used as a model dye with an initial concentration of 400 mg/L. The effects of TiO₂ dose and feed temperature on the photodegradation efficiency and permeate flux were first investigated. The highest degradation rate was observed at 2.0 g/L TiO₂ and 65 掳C. The permeate flux decreased by 15.8% when the TiO₂ dose increased from 0.5 to 6.0 g/L. The permeate flux of the SPMDR in the presence of 2.0 g/L TiO₂ was higher than the pure water flux using conventional heating, which confirms the enhancement of microwave irradiation to the membrane distillation mass transfer. The SPMDR achieved a high color (100%) and TOC (80.1%) removal efficiency after 300 min reaction. The byproducts identified in the feed included aliphatic acids (formic, acetic and maleic) and inorganic ions (, and ). The SPMDR produced high quality water because dye, TiO₂ and inorganic ions were completely retained in the feed side. Formic and acetic acids were detected in the permeate side with amounts of 0.08 and 0.25 mg (i.e., 1.83 and 5.29 mg/L), respectively. Scanning electron microscope (SEM) images showed that a loose TiO₂ cake layer was formed on the membrane surface, which decreased the membrane porosity and contact angle to some extent. However, the module efficiency, porosity and contact angle could be largely recovered after 30 min of washing with distilled water.