The paper presents the results of research on the methylene blue (MB) degradation with sodium persulfate (PDS) activated with visible light (Vis) in the presence of glucose and sucrose. The following test were examined: absence and presence of sugars in concentrations of 50–300 mM, presence and absence of Vis radiation, pH of the model solution (6.0–12.0), identification of free radicals, kinetics of the pseudo-first-order reaction....