Organic matter removal from mother liquor of gas field wastewater by electro-Fenton process with the addition of H2O2: effect of initial pH

The electro-Fenton (EF) process was applied to treat mother liquor of gas field wastewater (ML-GFW). The Fe-Fe electrodes were used and H2O2 was added to the EF system. Effect of initial pH on chemical oxygen demand (COD) removal efficiency, specific electrical energy consumption (SEEC), specific electrode plate consumption (SEPC) and organic matter removal mechanism was investigated. The results showed that COD removal efficiency reached the maximum (71.9%) at initial pH of 3 after reaction for 3 h. Besides, considering with the SEEC and SEPC, pH of 3 was also the best choice, at which SEEC was 4.7 kW h kgCOD−1, SEPC was 0.82 kgFe kgCOD−1. Organic matter removal was achieved by two ways: oxidation and flocculation, and oxidation played a major role. With the analysis of GC-MS, the possible degradation pathways of the representative contaminants in the ML-GFW were given.


Are the interpretations and conclusions justified by the results? Yes
Is the language acceptable? Yes

Do you have any ethical concerns with this paper? No
Have you any concerns about statistical analyses in this paper? No

Recommendation?
Accept with minor revision (please list in comments)

Comments to the Author(s)
The authors reported an electron-Fenton process for organic wastewater treatment. The idea is interesting and the performance is good. This work may provide a new efficient way to treat organic wastedwater. After Minor revision, it is suitable to be published. 1. Several typing errors shold be corrected. 2. The electrochemical process as well as the electrochemical CV curves should provide. 3. The evidence for the existance of .hydroxide radicals should be given.

23-Sep-2019
Dear Dr Li: Title: Organic matters removal from mother liquor of gas field wastewater by electro-Fenton process with the addition of H2O2: Effect of initial pH Manuscript ID: RSOS-191304 Thank you for your submission to Royal Society Open Science. The chemistry content of Royal Society Open Science is published in collaboration with the Royal Society of Chemistry.
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RSC Subject Editor:
Comments to the Author: (There are no comments.) ********************************************** Reviewers' Comments to Author: Reviewer: 1 Comments to the Author(s) The authors studied the effect of initial pH on the electro-Fenton treatment of ML-GFW. They concluded the pH of 3 was the optimum choice. In addition, the organic matter removal mechanism was proposed. However, the conclusions of this paper are not justified by the results. The differences in the EF performance between pH of 3 and pH of 4 are negligible, which are within the error ranges. The authors only showed the error bars in Fig. 2 (a) and (b) and did not plot the error bar when calculating the Kobs. Furthermore, the fitting curve in Fig. 2 (c) is apparently not correct because the red curve is above all the data points. I think this paper is not appropriate for publication in RSOS.

Reviewer: 2
Comments to the Author(s) The authors demonstrated the electro-Fenton process for treatment of mother liquor of gas field waste water (ML-GFW). Organic matter removal was achieved in two ways: oxidation and flocculation, and oxidation played a major role in this study. The manuscript is well written, and the quality of article is good in my opinion. Manuscript can be accepted after minor revision. 1) English grammar, spacing should be checked out throughout the manuscript. 2) How is the manuscript advancing the present field? What is new in the manuscript compare to previous studies? Authors can highlight these points in the introduction part of the manuscript. Title: Organic matters removal from mother liquor of gas field wastewater by electro-Fenton process with the addition of H2O2: Effect of initial pH Manuscript ID: RSOS-191304.R1 It is a pleasure to accept your manuscript in its current form for publication in Royal Society Open Science. The chemistry content of Royal Society Open Science is published in collaboration with the Royal Society of Chemistry.
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Yours sincerely, Dr Laura Smith