亚氧化钛膜电极电化学特性及其处理印染工业废水的效能研究

Electrochemical properties of titanium sub⁃oxide membrane electrode and application for electro⁃oxidation treatment of dyeing wastewater

电化学氧化法具有稳定高效、操作灵活、集成度高等特点,在处理难降解有机废水领域具有独特优势.电化学废水处理过程通常受限于传质速率,而膜电极有望解决这一瓶颈问题.亚氧化钛膜电极(TiSO⁃ME)的化学结构与电化学性质结果显示,经过高温还原法制备的TiSO⁃ME电极主要由Ti4O7和少量Ti5O9组成,大孔体积占总孔体积的92.7%,平均孔径为0.508μm.电化学测试结果表明,TiSO⁃ME具有良好的导电性、高析氧电位和电化学稳定性.过滤试验结果表明,在0.82×10^-3~3.14×10^-3 mL·cm^-2·s^-1范围内膜通量与传质系数成正比.在电流密度为8 mA·cm^-2,膜通量为2.31×10^-3 mL·cm^-2·s^-1的条件下,电解1.5 h即可有效处理实际印染工业废水,sCOD去除率高达96.07%,电流效率可达24.22%,电能消耗较不存在膜通量时降低了32.99%.TiSO⁃ME能够实现废水在膜孔结构内部的穿流式操作,有效克服旁流式操作传质受限的问题,在小规模分散式工业废水处理中有着重要的研究价值和发展潜力.

Electrochemical oxidation(EO)process offers several unique advantages in refractory organic wastewater treatment by virtue of high efficiency,easy⁃to⁃handle operation and high integration.EO wastewater treatment is generally limited by the mass transfer rate,which can be alleviated by membrane electrode.The titanium suboxide membrane electrode(TiSO⁃ME)prepared by the high⁃temperature reduction method was mainly composed of Ti4O7 and a small amount of Ti5O9,whose macro⁃porous volume accounted for 92.7% of total volume with mean pore size of 0.508μm.The electrochemical tests indicated that the TiSO⁃ME had good electrical conductivity,high oxygen evolution potential and electrochemical stability.The flow⁃through filtration test results showed that the mass transfer coefficient was positively proportional to the membrane flux over the range of 0.82×10^-3~3.14×10^-3 mL·cm^-2·s^-1.The effective EO treatment of industrial dyeing wastewater could be achieved under current density of 8 mA·cm^-2,permeation flux of 2.31×10^-3 mL·cm^-2 ·s^-1,and electrolysis time of 1.5 h.The soluble chemical oxygen demand(sCOD)could be removed by 96.07%,accounting for current density of 24.22%.The energy consumption was decreased by 32.97%in comparison with that without membrane filtration operation.The flow⁃through filtration operation allows TiSO⁃ME to achieve a significantly enhanced mass transfer during EO process,making small⁃scale decentralized wastewater treatment more efficient and more economical.