Ozone Kinetic Studies Assessment for the PPCPs Abatement: Mixtures Relevance
Round 1
Reviewer 1 Report
The manuscript has been improved by the authors. All the peer-review comments were addressed. I recommend that the paper could be accepted in present form by Editor to get published.
Best Regards
Author Response
We acknowledge the reviewer acceptance of the manuscript.
Reviewer 2 Report
The paper addresses the abatement of different contaminants alone or in a mixture using ozone as the oxidant species.
The paper is interesting, is well written as is clear enough. However, there are some comments for the authors to improve the quality of it work.
1) There is not data available about the concentration of ozone measured in the different experimental runs and the time evolution of ozone concentrations.
2) The authors should be explaining the methods used to calculate estimate the values of the integral of equation 1 for the different runs.
3) It is possible to complete the data with Total Organic Carbon analysis?
4) The authors should analyse the difference between low reaction rate and low selectivity.
Author Response
The paper addresses the abatement of different contaminants alone or in a mixture using ozone as the oxidant species.
The paper is interesting, is well written as is clear enough. However, there are some comments for the authors to improve the quality of it work.
We acknowledge the comments will improve the overall quality of our work.
1) There is not data available about the concentration of ozone measured in the different experimental runs and the time evolution of ozone concentrations.
Regarding the concentrations of ozone, we measure the gas phase concentration considering the Henry law’s it is possible to determine the liquid ozone concentration since the pressure and temperature in the system are kept constant. However, during these experiments we followed the transferred ozone dose (TOD). In fact, although the dissolved ozone is an important parameter to the reaction performance, it is not easy to determine when complex solutions are used. Moreover, for real scale applications and bearing in mind the economic feasibility of the process, TOD will be more relevant since it considers the ozone dose (mgO3/L) that is consumed during the process. In fact, ozone production is the main operating cost of this technology and must be taken into account while optimizing the process. For example, in Figure 2 we have the data regarding to the contaminant’s abatement in function of transferred ozone dose (TOD).
We introduced a sentence in accordance to this in the revised version of manuscript. (P.12, L. 406-409).
“In fact, for real scale applications and bearing in mind the economic feasibility of the process, TOD will be more relevant since it considers the ozone dose (mgO3 L-1) that is consumed during the process. In fact, ozone production is the main operating cost of this technology and must be consider while optimizing the process.”
2) The authors should be explaining the methods used to calculate estimate the values of the integral of equation 1 for the different runs.
The TOD values calculated from equation 1 were obtained by numerical integration using the trapezoidal rule. We measure the inlet and outlet gas concentration for different periods of time with the same gas flow, and by the numerical integration it is possible to obtain the TOD values during the reactions.
We introduced a sentence in the revised manuscript. (P.4, L.151-154)
“The numerical integration through trapezoidal rule was made for Equation 1 to obtain the TOD values during the reactions due to the values of inlet and outlet gas concentration for different periods of time with the same gas flow.”
3) It is possible to complete the data with Total Organic Carbon analysis?
According to our theorical TOC calculation for these initial concentrations of pollutants the value is about 3 mg of C per liter, and with this concentration for our apparatus is difficult to follow the organic carbon concentrations lower than this value. In future work we are thinking to perform experiments with the secondary municipal wastewater matrix and then will be possible to follow the TOC and the chemical oxygen demand.
4) The authors should analyse the difference between low reaction rate and low selectivity.
The selectivity is defined as the ratio between the rate of the desired reaction and the parasite reactions rate. When we refer that molecular ozone is selective we meant to highlight that molecular ozone reaction rate towards the organic compounds degradation (desired reaction) is low when compared, for example, to the hydroxyl radicals.
