Leaching of organic matter from cigarette butt filters as a potential disinfection by-products precursor

The study aimed to evaluate cigarette butt filters (CBFs) as a potential source of dissolved organic carbon (DOC) in water leading to the formation of disinfection by-products. Two different forms of CBFs - intact (I) and disintegrated (D), as they occur in the environment, were selected for leaching in chlorinated (CI, CD), nonchlorinated (NI, ND), and highly chlorinated (HCD) water samples. The UV absorbance profiles of the leachate samples showed that intact CBFs exhibited higher DOC leaching compared to the disintegrated ones, which was further accentuated in chlorinated samples (CI > CD > NI > ND). The Fourier Transform Infrared spectra of the leachates revealed the presence of characteristic functional groups of cellulose acetate and its chlorinated derivatives, indicating the potential degradation of the polymer. Moreover, trihalomethane (THM) formation in chlorinated samples was relatively higher in CI samples (2 - 11.5 times) compared to CD, consistent with the DOC leaching trends. Further, the speciation characteristics of different THMs in both CI and CD samples were similar. Although spectral and morphological analyzes of CI and CD samples revealed negligible variation, HCD samples depicted significant surface roughness characterized by the formation of pits and holes, along with the evolution of crystallinity. This suggested accelerated degradation of CBFs and disruption of acetyl groups as a factor of elevated chlorine concentrations.