Degradation of dimethyl phthalate using persulfate activated by UV and ferrous ions: optimizing operational parameters mechanism and pathway

Mojtaba Yegane Badi; Ali Esrafili; Hasan Pasalari; Roshanak Rezaei Kalantary; Ehsan Ahmadi; Mitra Gholami; Ali Azari

doi:10.1007/s40201-019-00384-9

Degradation of dimethyl phthalate using persulfate activated by UV and ferrous ions: optimizing operational parameters mechanism and pathway

J Environ Health Sci Eng. 2019 Jul 12;17(2):685-700. doi: 10.1007/s40201-019-00384-9. eCollection 2019 Dec.

Authors

Mojtaba Yegane Badi^{1

2}, Ali Esrafili^{1

2}, Hasan Pasalari^{1

2}, Roshanak Rezaei Kalantary^{1

2}, Ehsan Ahmadi^{3

4}, Mitra Gholami^{1

2}, Ali Azari^{5

3

4}

Affiliations

¹ 1Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran.
² 2Department of Environmental Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
³ 3Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
⁴ 5Students' Scientific Research Center (SSRC), Tehran University of Medical Sciences, Tehran, Iran.
⁵ 4Department of Environmental Health Engineering, School of Public Health, Kashan University of Medical Sciences, Kashan, Iran.

Abstract

The present study aimed to model and optimize the dimethyl phthalate (DMP) degradation from aqueous solution using UV_C/ Na₂S₂O₈/Fe²⁺ system based on the response surface methodology (RSM). A high removal efficiency (97%) and TOC reduction (64.2%) were obtained under optimum conditions i.e. contact time = 90 min, SPS concentration = 0.601 mM/L, Fe²⁺ = 0.075 mM/L, pH = 11 and DMP concentration = 5 mg/L. Quenching experiments confirmed that sulfate radicals were predominant radical species for DMP degradation. The effect of CO₃ ^- on DMP degradation was more complicated than other aquatic background anions. The possible pathway for DMP decomposition was proposed according to HPLC and GC-MS analysis. The average oxidation state (AOS) and carbon oxidation state (COS) values as biodegradability indicators demonstrated that the UV_C/SPS/Fe²⁺ system can improve the bioavailability of DMP over the time. Finally, the performance of UV_C/SPS/Fe²⁺ system for DMP treatment in different aquatic solutions: tap water, surface runoff, treated and raw wastewater were found to be 95.7, 88.5, 80.5, and 56.4%, respectively. Graphical abstract.

Keywords: BBD; DMP; Degradation pathway; Statistical analysis; Sulfate radicals.