Adsorption and Photodegradation of Organic Compounds in Wastewater by Hierarchical Organic Molecular Sieves

Abstract

Dyes with aromatic structures are known for their persistence and high toxicity. Once these dyes enter aquatic environments, they pose significant threats to both the ecosystem and human health. In this study, N,N-dimethylethylenediamine(DMEN) was used as a template to synthesize the ZIF-8 material, characterized by a high specific surface area and high mesoporosity. The hierarchical ZIF-8 material is utilized to remove dyes from simulated wastewater. It can adsorb organic dye molecules and harmful metal ions from dye-laden wastewater. And the two processes do not exhibit significant interference with each other. The results indicate that the hierarchical ZIF-8 exhibits excellent adaptability to wastewater environments with high salinity and extreme pH levels. The equilibrium adsorption capacity of hierarchical ZIF-8 for methylene blue is twice that of microporous ZIF-8, and its photocatalytic efficiency is enhanced by 30% compared to microporous ZIF-8. Moreover, the photocatalytic performance significantly improves under alkaline conditions: at a pH of 12, the degradation rate of methylene blue reaches 96.9%. The study found that hierarchical ZIF-8 primarily follows the photocatalytic reaction mechanism during the catalytic degradation of methylene blue. Hierarchical ZIF-8 demonstrates significant potential for application in textile wastewater treatment.