α-Fe2O3催化臭氧氧化耦合陶瓷膜处理含酚废水

α-Fe2O3 catalytic ozonation coupled with ceramic membrane for phenol wastewater treatment

  • 摘要: 催化臭氧氧化是处理含酚废水的有效手段,为研究α-Fe2O3催化氧化含酚废水的降解效能同时有效回收催化剂,采用微米级α-Fe2O3催化臭氧氧化苯酚模拟废水,并耦合陶瓷膜对分散在反应体系的催化剂进行截留、回收,实现工艺的连续运行。结果表明:在间歇运行条件下,催化氧化反应30 min时废水COD去除率达到97%以上,高COD去除率的主要原因是α-Fe2O3对臭氧具有较强的催化活性,在催化氧化过程中产生了强氧化性产物·OH;在恒压条件下,通过膜污染模型拟合和串联阻力模型进行验证,Rr占总阻力的50%以上,但当操作压力超过30 kPa,一部分可逆污染向不可逆污染逐渐转化,Rir显著增加;通过动力学拟合探究膜污染形成机制,运行过程中陶瓷膜污染模型为中间堵塞或滤饼堵塞,膜污染主要发生在膜表面,膜可以对α-Fe2O3进行有效拦截并通过反冲洗恢复通量;连续进水6个周期运行过程中,模拟废水COD去除率保持在85%以上,陶瓷膜不可逆阻力控制在总阻力的13%以下,反应体系保持了稳定运行。

     

    Abstract: Catalytic ozonation is an effective method for the treatment of phenolic wastewater. In order to study the degradation efficiency of phenolic wastewater by α-Fe2O3 catalytic oxidation and effectively recover the catalyst, micron-sized α-Fe2O3 catalytic ozonation was applied to the simulated phenol wastewater, and the catalyst dispersed in the reaction system was intercepted and recovered by the ceramic membrane to realize the continuous operation of the process. The results showed that: Under the condition of intermittent operation, COD removal rate of wastewater reached more than 97% after catalytic oxidation reaction for 30 min. The main reason for the high COD removal rate was that α-Fe2O3 had strong catalytic activity for ozone and strong oxidizing product ·OH was produced during catalytic oxidation.Under the condition of constant pressure, Rr accounted for more than 50% of the total resistance, which was verified by membrane fouling model fitting and series resistance model. However, when the operating pressure exceeded 30 kPa, some reversible fouling gradually transformed into irreversible fouling, and Rir increased significantly. The formation mechanism of membrane fouling was explored by kinetic fitting. The ceramic membrane fouling model during operation was intermediate blockage or filter cake blockage. Membrane fouling mainly occurred on the membrane surface. The membrane could effectively intercept α-Fe2O3 and recover the flux through backwashing. During the six-cycle operation of continuous influent, COD removal rate of simulated wastewater remained above 85%, the irreversible resistance of ceramic membrane was controlled below 13% of the total resistance, and the reaction system maintained stable operation.

     

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