Abstract
Municipal waste is an essential issue worldwide. The achievements in this field needs to be maximized to meet the increase in municipal waste generated every year. The challenge is to correlate municipal waste management systems to the high valued applications. The present work fills this gap by tracing the elemental analysis of municipal waste slag (MWS) over 10 months for the use of MWS as a visible light photocatalyst for the degradation of methylene blue (MB) and the recovery of valuable metals. The compositions of 10 samples collected at different times have been evaluated using X-ray fluorescence spectroscopy for the major composition and photon activation analysis for the minor composition analysis. The degradation efficiency is controlled by the iron oxidation state and sample's basicity. For as collected slag the degradation is attributed to both Fenton and photo-Fenton reaction while for the melted samples, the prominent reaction is photo-Fenton. The best performing sample, 4-M, shows a pseudo-first-order rate constant k of 1.5 x 10(-1) min(-1) for MB degradation after 20 minutes under a pH of 11 and 0.35 M of H2O2. This sample shows good stability after seven successive cycles.