Production of solid acid catalyst using waste cigarette filters for esterification.

Cigarette filters were utilized as carbon source for the production of solid carbon acid catalysts. In this study, the process of carbonization and simultaneous sulfonation via hydrothermal treatment was employed. The catalysts were prepared by mixing cigarette filters and sulfuric acid at temperatures of 100, 150, and 190 °C for durations ranging from 2 to 8 h.