Fenton-like degradation of dimethyl phthalate enhanced by quinone species

Fenton-like degradations of dimethyl phthalate (DMP) and phenolic compounds (phenol, catechol, resorcinol, and hydroquinone) in single and binary systems were investigated by focusing on the Fe(III)/Fe(II) redox cycle during the reaction processes. Quinone-like substances were generated and found to be responsible for the autocatalytic transformation of Fe(III) to Fe(II) in the Fenton-like process with DMP or phenolics. Moreover, phenolic compounds could accelerate the Fenton-like degradation of DMP, with an increased efficiency of H₂O₂ utilization. The effect of phenolic compounds on the degradation of DMP followed the order: catechol ≈ hydroquinone > resorcinol > phenol, which could be attributed to the interaction between quinone-like substances and iron ions. Hydroquinone-like substances accelerated the Fe(III)/(II) redox cycle. The formation of iron complexes between catechol-like substances and iron ions facilitated the release of H⁺ and regeneration of Fe(II). In addition, a plausible mechanism for enhanced Fenton-like degradation of DMP by phenolics was proposed.