Pillared clay-based catalysts for treatment of 4-nitrophenol solutions by catalytic wet peroxide oxidation

The constant development of technological processes aggravates the problem of pollution, due to a significant change in the composition of effluents, which makes necessary new (and/or improved) treatment methods and catalytic materials. In this sense, the use of natural clays in the synthesis of low cost pillared clays for application as catalysts in oxidation technologies for the treatment of wastewaters are relevant from an environmental and sustainable point of view. In this work, inexpensive natural clays from different regions of Kazakhstan (Akzhar, Karatau and Kokshetau) were used in the preparation of pillared clays for the catalytic oxidation of organic pollutants with H2O2. Since nitrophenols are commonly found in many types of industrial wastewaters (e.g. plastic, pharmaceutical, paper or pesticides industries), 4-nitrophenol (4-NP) was used as representative model compound in the catalyst screening studies. The pillaring process of the targeted natural clays involved the incorporation of active metals such as Zr,Fe and Cu, which were responsible by increasing the catalytic activity of the materials relatively to the natural clays. High conversions of TOC (85%) and of 4-NP (100%) were obtained with the Zr-pillared clay from the Akzhar region.

Automated summary

The constant development of technological processes aggravates pollution problem and requires new (and/or improved) treatment methods and catalytic materials. The use of natural clays in the synthesis of low cost pillared clays for oxidation technologies in wastewater treatment is relevant from an environmental and sustainable perspective. This study used inexpensive natural clays from different regions of Kazakhstan to prepare pillared clays for the catalytic oxidation of organic pollutants. Zr-pillared clay from the Akzhar region achieved high conversions of TOC (85%) and 4-NP (100%).