High photocatalytic activity of spent coffee grounds derived activated carbon-supported Ag/TiO2 catalyst for degradation of organic dyes and antibiotics

Abstract

Titanium dioxide (TiO2) has been considered as a promising photocatalyst for degrading organic pollutants due to its stability, low energy consumption and non-toxicity. Nevertheless, the aggregation tendency, relatively wide band gap and easy recombination of electron-hole pairs confine the photocatalytic activity and practical applications of TiO2 nanoparticles. Herein, a novel Ag/TiO2/carbon skeleton derived from spent coffee grounds (CSCG) ternary photocatalyst was developed by in-situ growth of TiO2 and Ag nanoparticles onto 3D activated CSCG via a hydrothermal process and subsequent photodeposition method. The utilization of excellent conductive CSCG as catalytic carrier can not only alleviate the aggregation of TiO2 nanoparticles, but also suppress the recombination of photogenerated electron hole pairs. Besides, the surface plasmon resonance (SPR) effect of Ag reduces the band gap of the material and widens light-responsive region, thereby endowing Ag/TiO2/CSCG photocatalyst with enhanced photocatalytic degradability for organic pollutants. The as-prepared photocatalyst exhibits high degradation effects on dyes and antibiotics, such as degradation rate of 96.2% for methylene blue (MB), methyl orange (MO: 94%), tetracycline (TC: 99%), and norfloxacin (NOF: 96%). In addition, the hybrid photocatalyst displays up to 91% degradation efficiency of MB after four cycles. This work presents an innovative perspective to construct TiO2-based hybrid photocatalyst for boosting photocatalytic performance of wastewater treatment and environmental remediation.