Kinetic Studies of Cs⁺ and Sr²⁺ Ion Exchange Using Clinoptilolite in Static Columns and an Agitated Tubular Reactor (ATR)

Round 1

Reviewer 1 Report

The authors introduce the kinetic studies of Cs+ and Sr2+ ion exchange using clinoptilolite in static columns and an agitated tubular reactor. After carefully going through the manuscript, I found this work is interesting to some extent, and the structure of this work is well organized. The logic is quite clear, even though there are some points that need to be improved. the quality of the figures is good but can be further improved. Generally, this is a good study that may help guide the development of this research field. my comments may help the authors further improve their work:

1. The abstract part is not well organized. Please make a more concise abstract with the most significant highlights by clear logic.
2. In the introduction part, the authors should provide the fundamental background of this research work to show significance. at the same time, the progress of this research direction should be better stated.
3. The authors used both Thomas and MDR fits. What is the main difference between these two fits for the achieved results? Which one is better to describe the trends of the results? Why? At the same time, the data points need to be revised by using different colors to better identify each data.
4. how about the repeatability of the achieved results?
5. the conclusion part needs to be only one concise paragraph with clear logic.
6. there are many format issues in the reference bibliography.

Author Response

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Reviewer 2 Report

Dear authors,

thank you for the manuscript. It is well written and illustrates consistent results for further development in the field of Cs+ and Sr2+ ion exchange.

There are two minor remarks:

• Choice of setup: Would it make sense to use a pulsed column in order to have a system that improves mass transport in a column setup?
• Residence time: 15 min seems rather long in the context of industrial application.

Thanks and regards

 

Author Response

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Reviewer 3 Report

The article presents the results of Strontium and Cesium adsorption on clinoptilolite in two different types of contactors: a static column and an agitated tubular reactor. The experiments performed with solution of 200 ppm concentration have shown that clinoptilolite adsorption capacity towards Strontium is significantly lower than the clinoptilolite adsorption capacity towards Cesium. Subsequent experiments achieved with the agitated tubular reactor on the adsorption of  Strontium from a diluted solution (100 ppm Strontium)  showed that the adsorption capacity of strontium is influenced by the residence time and by the length of the reactor. The article is clearly structured and presented and together with the supplementary material offer a complete description of the work done by the authors.

I have a single observation related to the caption of the Figure 4 (row 299): I suppose that the figure 4 is displaying the static column breakthrough curve data for cesium and strontium at 100 ppm (as it is clearly described in the text below the figure in the manuscript) and not at 200 ppm as it is written in the caption.

Author Response

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