Degradation of fuchsine acid using the HP2W15Mo3Co2.5O62, 20H2O/H2O2 system: effect of organic and inorganic additives

This study aimed to evaluate the influence of mineral and organic additives on the catalytic oxidation of the dye fuchsine acid by the HP2W15Mo3Co2.5O62, 20H(2)O/H2O2 system. Initially, the effects of various organic additives, namely alcohols (methanol and 2-propanol), antioxidants (benzoic acid and ascorbic acid), and carboxylic acids (acetic acid, formic acid, and oxalic acid), on dye degradation were investigated. These organic additives were found to significantly inhibit dye degradation, except for ascorbic acid, which acted as a (OH)-O-center dot scavenger and pro-oxidant, depending on its concentration. Subsequently, the effects of mineral ions on dye degradation at natural and acidic pH were examined. At natural pH, Cl-, NO3-, and SO4- weakly inhibited the degradation of the dye, but did not limit it, whereas H3PO4-, H2PO4-, Cl-, NO3-, and SO4- seriously affected the degradation reaction at acidic pH. Thus, it is imperative to control the pH of a textile industry effluent before applying the studied system to it. Lastly, a comparison of the inorganic anions showed that they could be ranked in ascending order of impact on the dye degradation reaction in an acidic medium as follows: NO3- similar to SO4- < Cl- < H3PO4- = H2PO4-.