Effect of CaO/SiO2 compositions on the structure formation of mesoporous calcium silicate (CaSiO3) composite particles as adsorbent for organic dye removal

Abstract

The primary objective of this paper was to synthesize a calcium silicate (CaSiO3) and investigate the effect of CaO/SiO2 compositions on the structure formation of synthetic material. CaSiO3 was prepared through the solid-state method using CaO from chicken eggshells and commercial SiO2 powder as starting material. To investigate the effect of CaO/SiO2 on the structure of CaSiO3, the different molar ratios of CaO/SiO2 (i.e., 1:1, 1:7, 2:7, and 3:7) were used. BET results show the resulting product has a high specific surface area of 13,18 ±30.53 m2g-1 and a pore size of 15,16 ±18.4 nm obtained as mesoporous material. The obtained CaSiO3 particles, then to be applied for the degradation of dye pollutants in water. The adsorption capacity was evaluated by methylene blue (MB) and brilliant green (BG) degradation. The parameters of CaO/SiO2 mass ratio and contact time on the degradation efficiency of BG and MB were investigated, respectively. The results showed that the best model for BG adsorption onto CaSiO3 was a pseudo-first-order model, whereas the best model for MB adsorption was a pseudo-second-order model.