Methylene blue (MB) removal from aqueous solution by alum; catalytic ozonation process.

Textile wastewater is among the most polluted types of industrial waste. Wastewater treatment in the textile industry is notoriously difficult because of the use of complex chemicals and dyes in the textile production steps, and conventional methods are not enough to treat these. Textile wastewater, known for its high pollution levels, poses challenges for treatment due to complex chemicals and dyes. A comparative study was conducted on simple ozonation and catalytic ozonation (CO) using alum to degrade methylene blue (MB). The authors analyzed various factors like time, pH, catalyst loading and ozone dosages during the study. Results showed that catalytic activity in ozonation depends on pH and ozone flow. The maximum MB elimination was achieved at pH 6.6 and 200 V ozone flow. Scanning electron microscopy (SEM) was used to characterize the surface morphology of the catalyst, Fourier transform infrared spectroscopy (FTIR) was used to identify the important functional groups, and energy dispersive X-ray spectroscopy (EDS) was used to characterize the catalyst's elemental composition. Compared to simple ozonation, CO showed higher removal in the initial phase. Real textile wastewater analysis confirmed the effectiveness of alum catalysts in achieving significant removal of MB (87%) through this novel cost-efficient process. Highlights: Methylene Blue was treated with the catalytic ozonation method, with first ever use of alum as a novel ozonation catalyst. Both simple ozonation and catalytic ozonation were efficient treatment processes; however, maximum removal efficiency for Methylene Blue of 86% was achieved by alum based catalytic ozonation process. On optimizing pH to 6.6, maximum removal efficiencies for Methylene Blue improve to 85% and 99% for simple ozonation and catalytic ozonation processes, respectively. The improved results for catalytic ozonation are owed to predominant hydroxyl radical mechanism. [ABSTRACT FROM AUTHOR]