Electrochemical degradation of a methyl paraben and propylene glycol mixture: Interference effect of competitive oxidation and pH stability

Author(s)

Dionisio, Dawany ^{[1, 2]} ; Rodrigo, Manuel A. ^[2] ; Motheo, Artur J. ^[1]

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Inst Chem, POB 780, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Castilla La Mancha, Fac Chem Sci & Technol, Dept Chem Engn, Campus Univ S-N, Ciudad Real 13071 - Spain

• Document type: Journal article
• Source: Chemosphere; v. 287, n. 3 JAN 2022.
• Web of Science Citations: 1

Abstract

Endocrine disrupting compounds (EDCs) are one of the many classes of harmful pollutants frequently found in water resources. Even at low concentrations, EDCs might accumulate in the organisms and interfere on numerous processes controlled by hormones. Parabens, for example, are preservatives widely used in pharmaceutical and cosmetic industries, but several studies related them to human breast cancer. It is well-known that electrochemical technologies are an efficient alternative for wastewater treatment, promoting the appropriate destruction of EDCs. However, most studies are applied to single target contaminant solutions, which may neglect the impact from co-exited inorganic/organic pollutants. Based on that, this study aimed to elucidate the interfering effects of two target organic contaminants of very different nature during electrochemical mediated process. For that, methyl paraben (MeP) and propylene glycol (PG) were selected as models of aromatic/phenolic and carboxylate compounds versus low-molecular aliphatic alcohols. These two compounds are often together used in preservative blends and cosmetic/pharmaceutical formulations. PG is not a harmful chemical, but it is present in several types of effluents in relatively high concentrations. Thus, it may interfere on the degradation of numerous pollutants of low concentrations. The electrochemical treatment of a mixture containing 100 mg L-1 MeP +1000 mg L-1 PG showed that both contaminants suffered interfering effects. The presence of MeP negatively interfered on PG degradation; the carboxylate compound is more easily oxidized even at lower molecular concentration. On the other hand, the presence of PG showed an unexpected positive effect on MeP degradation, that was not reflected on its mineralization. The results indicate that in addition to the expected effect of anodic competition, polymerization and copolymerization reactions may also occur in the studied system. The use of an acidic buffer medium increased the removal of both contaminants and favored the oxidation pathway over the polymerization. In this case, the increase in the removal was reflected in the mineralization process, which increased up to 6 times when the mixture was treated in the buffered medium. (AU)

• FAPESP's process: 17/10118-0 - Study and application of electrochemical technology for the analysis and degradation of endocrine interferents: materials, sensors, processes and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/19662-1 - Preservatives degradation: coupling processes, organic interfering effect and scale-up
• Grantee: Dawany Dionisio
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• FAPESP's process: 16/04825-2 - Effect of interferents and operational features on the degradation of endocrine disruptors
• Grantee: Dawany Dionisio
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 17/20444-1 - Electrochemical processes applied to the remediation of simulated and real complex aqueous systems
• Grantee: Artur de Jesus Motheo
• Support Opportunities: Regular Research Grants