Photochemical decomposition of Brij-35 and hexachlorobenzene by UV/hydrogen peroxide and photo-Fenton oxidation

Author

Mack Bradley Sparks

Date of Award

8-1998

Degree Type

Thesis

Degree Name

Master of Science

Major

Environmental Engineering

Major Professor

Mriganka M. Ghosh

Committee Members

Kevin G. Robinson, Michael E. Sigman

Abstract

The performance of UV/H2O2 and UV/H2O2'Fe(II) (photo-Fenton) technologies was evaluated for treatment of Brij-35 surfactant and HCB + Brij-35. To evaluate photolysis of organic contaminants in Brij-35 surfactant solutions, the equilibrium partitioning of contaminants into the surfactant was determined. Analysis of the molar solubility ratio (MSR) demonstrated that 0.0611 mol of HCB could be solubilized by each mole of Brij-35 added to solution, and the micelle-water partitioning coefficient was determined to be 4.21x10⁴ (log K_m= 4.63). The photochemical treatment of Brij-35 solutions (5.05x10^-3 M) showed that photo-Fenton oxidation (UV+ 3% H₂O₂ + 2.Sx10^-4 M Fe(II)) doubled the rate of TOC degradation (initial TOC between 2700-3000 mg/L) over UV + 3% H₂O₂ oxidation, and that increasing the Fe(II) concentration to 1.0x10·3 M improved the TOC degradation rate by an additional 22.6%. The photo-Fenton treatment of Brij-35 + HCB (1.71x10^-4 M) increased the rate of TOC degradation by 52% over the UV + 3% H₂O₂ method. The consumption of H₂O₂ was zero-order during UV/H2O2 and photo-Fenton oxidation, and the TOC degradation was zero-order until the depletion of H₂O₂ by photolysis. The pH profile during both UV/H₂O₂ and photo-Fenton oxidation showed an initial drop in pH which reflected the formation of organic acids from the degradation of Brij-35. A subsequent rise in pH during each experiment showed destruction of the organic acids by further photolysis. The rate of chloride removal was increased 129% by the photo-Fenton reaction over UV/H₂O₂ oxidation; and, 83.1 % of the chloride from solubilized HCB was removed by the photo-Fenton reaction. An evaluation of the electrical energy per unit mass (EE/M) for each treatment showed that the photo-Fenton technology reduced the cost of remediation per gallon by as much as 62.5%.

Recommended Citation

Sparks, Mack Bradley, "Photochemical decomposition of Brij-35 and hexachlorobenzene by UV/hydrogen peroxide and photo-Fenton oxidation. " Master's Thesis, University of Tennessee, 1998.
https://trace.tennessee.edu/utk_gradthes/10370