There are some points which must be edited or clarified by providing additional information or comments:
It is rather difficult to make an adequate comparison of certain properties (catalysts or sorbents) with the already available results, since the concentration of the pollutant and the mass of the loaded sorbent vary in each experiment. Therefore, the authors are recommended to add the missing information (i.e. conditions for testing sorbents of Cr(VI) ions) to Table 3.