Physicochemical characterization of sodium bentonite clay and its significance as a catalyst in plastic wastes valorization

Abstract

This study reveals the physicochemical characterization and catalytic behavior of locally available sodium bentonite clay. The clay was treated with hydrochloric acid to identify the characteristics. This paper explains XRF, FT-IR, XRD, SEM, and TGA characterization of commercially available sodium bentonite clay, a potential catalyst for thermo-catalytic pyrolysis in waste plastic valorization. Phase identification, structural properties, and chemical compositions were investigated. Less value of a loss on ignition (LOI) was found as 9.8% by weight which shows better acceptance performance for thermo-catalytic process of plastic wastes recycling. SiO2 (52.55%), Al2O3 (15.34%), and Fe2O3 (11.92%) three major compounds were identified by XRF and satisfy the XRD pattern. Spectra show that at 1009.25 cm−1, 1032.05 cm−1 and 1112.90 cm−1 band positions are strong bands of Si-O stretching of monosubstituted and tetrahedral compounds. Alcohols and phenols group of compounds have sharp band positions of H- O-H stretching at 3620.59 cm−1 and 3695.17 cm−1. The maximum average crystallite size was found 26.55 nm for 25.09° (2Θ) absorption. The morphology indicates that the presences of large particles are in the form of agglomerates. The high weight percentage of SiO2 and CaCO3 were spotted respectively 45.40% and 42.18% by weight for raw clay in the scanning electron micrograph. After acid treatment, it was found that the % weight of CaCO3 was decreased as 20.99% and % weight of SiO2 was increased as 48.88%. Thermo gravimetric graph shows that the reliable temperature range is 450°C to 500°C, which satisfies the pyrolysis process temperature range. The objective of this paper is to explore the similar utilization of the montmorillonite group of clay as a catalyst and useful engineering aspects for recycling plastic wastes.