Synthesis and characterization of new Schiff base/Amine-functionalized polysiloxane: An efficient sorbent for the removal of Cr(VI)

Abstract

Traditional Schiff base reactions are used in many domains, such as adsorbent synthesis, metal chelation, liquid crystals, dyes, and catalysis. Given its numerous potential uses, we prepared a Schiff base combining amino antipyrine and vanillin and discussed its crystal structure. Then, using an economical one-pot sol-gel approach, the created Schiff base co-operated into a polysiloxane framework. The constituent AAV-Sc-m underwent extensive scrutiny, adopting all required characterization techniques and revealed the 98.9% Cr(VI) removal from the water-based media. Optimization of the initial ppm of the Cr(VI) solution, the amount of AAV-Sc-m, pH, and reaction time permitted the well-establishment of the Cr(VI) removal using AAV-Sc-m. To gain insight into the steps in the mechanism, experimental data from studies with varying initial Cr(VI) concentrations are used to fit the Langmuir, Freundlich, and Temkin models. The Langmuir model best suits the experimental results, with an R² of 0.99, revealing the single-layer chemisorption operation. The time study data was also fitted to the PFO, intra-particle diffusion and PSO models; the PSO model emerged as the finest fit. A thermal assessment indicates that the Cr(VI) elimination process is endothermic and spontaneous. Regarding the industrial approach, AAV-Sc-m is reasonable and suitable for continuous adsorption-desorption cycles based on the recycling study.