From cigarette filters to photocatalysts: Self-carbon-doped ZnO for effective water remediation

Abstract

A simple strategy was presented to convert a possibly problematic and harmful solid waste into a sustainable and feasible value-added product. In this regard, novel self-carbon-doped ZnO (C-ZnO) photocatalysts containing both unground cigarette filters (CF) and ground cigarette filters (CFG) as carbon sources and templates were successfully synthesized for the first time. A series of C-ZnO photocatalysts containing three different amounts of CF and CFG were obtained by a facile one-step precipitation method. Comprehensive characterization of C-ZnO photocatalysts was realized via FTIR, Raman, XRD, SEM-EDAX, TGA, BET, and PL analysis techniques. While the grinding process did not affect the structural and crystallite properties of the templates, differences were observed in CF and CFG morphology. The crystallite sizes of C-ZnO photocatalysts differed depending on the CF and CFG amounts used as templates. The as-prepared specimens were used as promising photocatalysts for the remediation of methylene blue (MB) contaminated water. C-ZnO photocatalyst with the lowest CFG amount, denoted as 0.06-CFGZ exhibited high MB degradation (98 %) under 270 min irradiation. Amounts of CF and CFG in C-ZnO photocatalysts influenced their morphology, playing an important role in their photocatalytic activities. The design of C-ZnO using CF and CFG templates not only facilitated the valorization of environmental waste but also offered a novel strategy for the preparation of efficient carbon-doped photocatalysts.