Photo-assisted electrochemical degradation of the dimethyl phthalate ester on DSA® electrode

Abstract

Phthalic acid esters are synthetic compounds used as additives in plastic structures. As these chemicals are physically bound, they can contaminate humans affecting the endocrine system. The present study focused on the photo-assisted electrochemical (PAE) method to degrade a phthalic acid ester, such as dimethyl phthalate – DMP, using a one-compartment filter press flow cell and a commercial DSA® electrode. The variables investigated to optimize the DMP compound removal were NaCl concentration, current density, and temperature. The efficiency toward the DMP concentration abatement and total organic carbon (TOC) removal was the analytical parameters analyzed. The highest rates of DMP and TOC removals were attained at high NaCl concentrations and current densities, due to the generation of high reactive oxidants in the PAE method that seemed to suppress mass transport limitations. The temperature had no significant influence on the DMP removal. Moreover, depending on the nature of the intermediate compounds generated, the PAE method could enable a rapid treatment option before disposal of contaminated effluents containing DMP, and possibly other endocrine disruptors. Despite the high levels of current efficiency attained, more work is required to optimize the electrical energy consumption, especially with respect to the choice of the UV lamp.