Efficient removal of direct yellow dye using chitosan crosslinked isovanillin derivative biopolymer utilizing triboelectric energy produced from homogeneous catalysis

Abstract

A tailored chitosan crosslinked isovanillin (CCIV) polymeric adsorbent generated using homogeneous catalysis was applied for the extraction and removal of direct yellow dye 50 (DY 50), through rapid adsorption due to an electrostatic attraction between the dye molecules and CCIV frameworks. The removal efficiency of DY 50 was systematically investigated to determine the effect of contact time, incubation temperature, pH of the solution, initial dye concentration, and adsorbent mass. The adsorbent also appeared to exert a novel tribocatalytic energy effect for dye decompositions, which is confirmed through comparison of removal from agitation (friction) which is thought to promote the generation of reactive oxygen species. The DY 50 adsorption was almost instantaneous, where up to 83.3% of the initial DY 50 load was removed within and up to 10 min, and then to 90–97.9% by physicochemical adsorption after 45–180 min using 0.05 g of CCIV bio sorbents under ambient temperature. The variations of DY 50 initial concentrations, contact time, and temperatures allowed us to implement three isotherm models, kinetics, and thermal dynamic studies. The comparison of adsorption equilibrium data of DY 50 on the CCIV surfaces was obtained from Langmuir, Freundlich, and Temkin isotherms models, indicating the “monomer to bilayer” is favorable through van der Waals interaction. Validation of the kinetic models was obtained through the ratio of 95% and 5% extraction time (t95/t5=19.42) and residual sum of squares (RSS<0.01). These statistical tolerance analyses confirmed the kinetics was consistent with a pseudo-second-order adsorption kinetic profile. The thermodynamic state functions and operational parameters (ΔH, ΔS, and ΔG) were calculated, suggesting DY 50 adsorption underwent a spontaneous and exothermic process.