Study on coupling with catalytic wet air oxidation and membrane separation in the treatment of cationic red GTL

Abstract

Coupling with the advantages of catalytic wet air oxidation (CWAO) and membrane separation under room condition, a new type of integrated fluidized-bed reactor was designed, with a PVDF hollow fiber membrane module submerged in. Its performance was investigated by the simulation of catalytic degrading cationic red GTL wastewater with initial concentration of 50 mg/L. The experimental results showed that the decolorization of cationic red GTL rose with the increase in residence time, the dosage of Mo/Zn/Al/O catalysts and aeration intensity, whereas it decreased against the increase in pH value. The optimal conditions of residence time catalyst dosage, pH value, and aeration intensity were 1.5 h, 1.5 g, 4, and 0.036 m3/h, respectively. The decolorization efficiency was above 98%, and TOC removal efficiency was more than 67%, which were apparently superior to the performance of single CWAO process in the batch test, and moreover, the interception efficiency on catalyst was approximately 100%. It can be found from the FT-IR analysis of original influent and effluent of membrane that the bonds of C=C, C–N as well as N=N were destroyed, while new bonds of C=O, –NO3, and N–H were formed. The BOD/COD ratio of the treated effluent been improved from 0.05 to 0.41.