The Use of Copper Terephthalate for the Determination and Separation of Organic Dyes via Solid-Phase Extraction with Spectrophotometric Detection

Round 1

Reviewer 1 Report

This is a detailed study on dye molecule adsorption by using Cu-MOF. The results are somewhat interesting and the paper can be considered for publication after revisions.

1. The Cu-BDC is a well-known MOF, thus it should be clearly stated that the obtained MOF is the same with the reported one and give the formula of the Cu-MOF rather than simply Cu(BDC).

2. The used dye molecules are all containing -SO3Na, how about the dye molecules of other types. Closely related studies such as Micropor. Mesopor. Mater. 2019, 273, 60 and 2017, 241, 192; Dalton Trans. 2017, 46, 9022; Inorg. Chem. 2016, 55, 11821 should be mentioned, comparison and discussion should be provided. 

3. The names of the used dye molecules should be given in the abstract. 

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript by Uflyand and co-workers entitled as “The Use of Copper Terephthalate for the Determination and Separation of Organic Dyes by Solid-Phase Extraction with Spectrophotometric Detection” reports about the use of Cu-based metal-organic framework (MOF), copper benzene dicarboxylate (Cu(BDC) for the adsorptive recovery of organic dyes from aqueous solutions. The authors claimed that the adsorption capacity of Cu(BDC) was much higher than that of activated carbon. The kinetic and thermodynamic studies have also been performed for the dye adsorption. Although the manuscript is demonstrated with a lot of experimental data, but some modifications are still required before its publication. The manuscript can be accepted after the following points are addressed properly.

1. It is really difficult to understand Figure 3 which showed the comparison of simulated and experimental XRD patterns the Cu(BDC). Both the XRD pattern should be presented in same format (e.g. origin) in order to compare the peak to peak matching.
2. The Cu(BDC) framework is neutral in nature. What kind of interaction is responsible for this dye adsorption process by Cu(BDC)?
3. Is the dye adsorption selective in nature? If you mix two organic dyes together (e.g. methyl orange and orange II), will it go for a selective adsorption?
4. Is there any specific reason for selecting these particular dye molecules for the adsorption study? What will happen if you use a cationic dye (e.g. methylene blue)?
5. The authors claim about reusability of the adsorbent for the extraction of dyes from aqueous solutions. It is suggested to include the PXRD pattern of Cu(BDC) after dye adsorption and desorption process at least for 3 cycles.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors have revised the manuscript by including of all the mentioned points.