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. 2023 Apr 11;16(8):3025.
doi: 10.3390/ma16083025.

Mo-LDH-GO Hybrid Catalysts for Indigo Carmine Advanced Oxidation

Octavian Dumitru Pavel  1   2 , Alexandra-Elisabeta Stamate  1   2 , Rodica Zăvoianu  1   2 , Anca Cruceanu  1   2 , Alina Tirsoaga  2 , Ruxandra Bîrjega  3 , Ioana Andreea Brezeștean  4 , Alexandra Ciorîță  4   5 , Daniela Cristina Culiță  6 , Ana Paula Soares Dias  7
Affiliations

Mo-LDH-GO Hybrid Catalysts for Indigo Carmine Advanced Oxidation

Octavian Dumitru Pavel et al. Materials (Basel). .

Abstract

This paper is focused on the utilization of hybrid catalysts obtained from layered double hydroxides containing molybdate as the compensation anion (Mo-LDH) and graphene oxide (GO) in advanced oxidation using environmentally friendly H2O2 as the oxidation agent for the removal of indigo carmine dye (IC) from wastewaters at 25 °C using 1 wt.% catalyst in the reaction mixture. Five samples of Mo-LDH-GO composites containing 5, 10, 15, 20, and 25 wt% GO labeled as HTMo-xGO (where HT is the abbreviation used for Mg/Al in the brucite type layer of the LDH and x stands for the concentration of GO) have been synthesized by coprecipitation at pH 10 and characterized by XRD, SEM, Raman, and ATR-FTIR spectroscopy, determination of the acid and base sites, and textural analysis by nitrogen adsorption/desorption. The XRD analysis confirmed the layered structure of the HTMo-xGO composites and GO incorporation in all samples has been proved by Raman spectroscopy. The most efficient catalyst was found to be the catalyst that contained 20%wt. GO, which allowed the removal of IC to reach 96.6%. The results of the catalytic tests indicated a strong correlation between catalytic activity and textural properties as well as the basicity of the catalysts.

Keywords: Mo-modified LDH; advanced oxidation process; graphene oxide; hybrid catalysts; indigo carmine; wastewater treatment.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
The chemical structure of indigo carmine (IC).
Figure 2
Figure 2
XRD patterns of HTMo-xGO materials compared to HTMo and GO.
Figure 3
Figure 3
ATR-FTIR spectra of the hybrid catalysts, compared to neat HTMo and GO.
Figure 4
Figure 4
Raman spectra of the hybrid catalysts compared to neat HTMo and GO.
Figure 5
Figure 5
SEM analysis of the hybrid materials compared to HTMo: (a) HTMo; (b) HTMo-5GO; (c) HTMo-10GO; (d) HTMo-15GO; (e) HTMo-20GO; (f) HTMo-25GO.
Figure 6
Figure 6
Dependence of IC conversion on the physico-chemical characteristics of the investigated catalysts: (a) specific surface areas; (b) the proportion of mesopores; (c) the basicity expressed as the ratio between base and acid sites; (d) Mo concentration (wt.%); (Reaction conditions: IC0 = 30 × 10−3 M, H2O2/IC = 48 catalysts concentration 1 wt.%, 150 rpm, 2 h, 25 °C).
Figure 7
Figure 7
IC conversion on HTMo-20GO (Reaction conditions: IC0 30 × 10−3 M, H2O2/IC = 48 catalysts concentration 1 wt.%, 150 rpm, 2 h, 25 °C); (a) Temporal variation; (b) UV-Vis spectra of the initial wastewater and during the process.
Figure 8
Figure 8
IC conversion in five reaction cycles on HTMo-20GO (Reaction conditions: IC initial concentration 30 × 10−3 M, H2O2/IC = 48 catalysts concentration 1 wt.%, 150 rpm, 2 h, 25 °C).
Figure 9
Figure 9
XRD patterns of HTMo-20GO before and after five reaction cycles.
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References

    1. Joel E.F., Lujaniené G. Progress in Graphene Oxide Hybrids for Environmental Applications. Environments. 2022;9:153. doi: 10.3390/environments9120153. - DOI
    1. Cavani F., Trifiro F., Vaccari A. Hydrotalcite-type anionic clays: Preparation, properties and applications. Catal. Today. 1991;11:173–301. doi: 10.1016/0920-5861(91)80068-K. - DOI
    1. Alvarez M.G., Marcu I.-C., Tichit D. Chapter 4. Recent Innovative Developments of Layered Double Hydroxide-Based Hybrids and Nanocomposite Catalysts. In: Nocchetti M., Costantino U., editors. Series on Chemistry, Energy and the Environment: Progress in Layered Double Hydroxides from Synthesis to New Applications. Volume 8. World Scientific Publishing Co. Pte. Ltd.; Singapore: 2022. pp. 189–362. - DOI
    1. Hummers W.S., Offeman R.E. Preparation of graphitic oxide. J. Am. Chem. Soc. 1958;80:1339. doi: 10.1021/ja01539a017. - DOI
    1. Smith A.T., LaChance A.M., Zeng S., Liu B., Sun L. Synthesis, properties, and applications of graphene oxide/reduced graphene oxide and their nanocomposites. Nano Mater. Sci. 2019;1:31–47. doi: 10.1016/j.nanoms.2019.02.004. - DOI

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