Cerium tetraboride synthesized by a molten salt method and its Congo red adsorption performance

Widely used synthetic dyes are one of the main pollutants that contaminate water environments seriously. From the environmental perspective, efficient adsorption of these wastes such as Congo red (CR) is of great importance, and numbers of adsorbents including inorganic materials have been developed. Herein, a lanthanide tetraboride nanocrystal powder CeB4 with an average particle size of 50 nm synthesized for the first time via inorganic molten salt synthesis route using cerium fluoride (CeF3) and sodium borohydride (NaBH4) as the cerium and boron precursors in argon atmosphere exhibits good performance for the adsorption of CR. Essential effluence factors, such as initial pH value, contacting time, and initial concentration, were experimentally evaluated. The adsorption was pH dependent, and the kinetic data follow the pseudo-second-order kinetic model. It was also found that the equilibrium adsorption data could be represented by Langmuir and Freundlich isotherm models, with a maximum capacity of 491.8 mg/g. On the basis of the adsorption-desorption experiments, CeB4 exhibits good reusability. (C) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Automated summary

The study successfully synthesized CeB4 nanocrystal powder via an inorganic molten salt synthesis route, demonstrating excellent adsorption performance for CR and good reusability. Experimental results showed that the adsorption of CR by CeB4 was pH dependent, with kinetic data following a pseudo-second-order kinetic model, and equilibrium adsorption represented by Langmuir and Freundlich isotherm models.