Catalytic degradation of real-textile azo-dyes in aqueous solutions by using Cu–Co/halloysite

• Published in: Bulletin of materials science 2019-08, Vol.42 (4), p.137, Article 137
• Main Authors: Torres-Luna, Juan A, Giraldo-Gómez, Gloria I, Sanabria-González, Nancy R, Carriazo, José G
• Format: Article
• Language: English
• Subjects: Adsorption; Aqueous solutions; Catalysts; Chemical analysis; Chemical oxygen demand; Chemical synthesis; Chemistry and Materials Science; Clay; Cobalt; Copper; Degradation; Dilution; Dyes; Electron microscopy; Energy consumption; Engineering; Environmental impact; Environmental protection; Hydrogen peroxide; Materials Science; Nitrates; Organic carbon; Oxidation; Pollutants; Raman spectroscopy; Toxicity; Wastewater treatment
• ISSN: 0250-4707; 0973-7669
• DOI: 10.1007/s12034-019-1817-1

Catalytic degradation of textile dyes in diluted aqueous solutions with minimal consumption of energy is a great challenge for wastewater treatment and environmental protection. Efficient heterogeneous catalysts are needed to completely oxidize azo-dyes under soft conditions. In this work, catalysts of Cu–Co oxide (1:2 molar ratio) supported on halloysite (Ha) nanotubes (CuCo(5%)/Ha and CuCo(10%)/Ha) were synthesized and used in the catalytic wet peroxide oxidation of reactive yellow 145 (RY-145) and basic red 46 (BR-46). The catalysts were characterized by chemical analysis, X-ray diffraction, Raman spectroscopy, N 2 adsorption isotherms, scanning electron microscopy and transmission electron microscopy. The results showed that the synthesized catalysts possess nanotubular structure with good mesoporosity, and the spinel structure CuCo 2 O 4 was identified as the active phase deposited on Ha. The catalysts degraded these azo-dyes in diluted solutions ( 22 mg l - 1 of RY-145 and 35 mg l - 1 of BR-46) under mild reaction conditions ( 25 ∘ C , atmospheric pressure, pH 4 and minimum amounts of both catalyst and H 2 O 2 ) . Significant levels of dye conversion ( 93.1 ± 2.2 % for RY-145 and 54.4 ± 2.0 % for BR-46) were achieved in a relatively short time. In addition, significant values of total organic carbon removal ( 59.5 ± 1.8 % for RY-145 and 33.9 ± 1.4 % for BR-46) were obtained, indicating the total oxidation of a significant fraction of these dyes to CO 2 and H 2 O .