Sorption Kinetics and Diffusion Behaviour of Post-Characterized, Biomodified Waste PET (RIC-1) Bottles Composites

This study dwelt on the preparation, characterization, and application of composites made from waste (PET) polyethylene terephthalate bottles with a resin identification code of 1 (RIC-1). These composites were prepared by melt mixing PET matrix with other fillers such as crab shell, clay, and chitin, resulting in binary or ternary composites. The physicochemical properties and characterization of the composites were analyzed using techniques such as , porosity testing, pH point at zero charge, surface area and FTIR. The composites were thereafter applied for the remediation of iron (III) ions from aqueous solution in which the rate and diffusion dynamics are investigated with the pseudo-first order(PFO), pseudo-second order(PSO) and the Weber- Morris intraparticle diffusion models. The results showed that the pseudo-second order (PSO) kinetic model had a good correlation for all ternary composites, with R2 values of 0.9977 for PET/CBS/CLAY and 0.9847 for PET/CHITIN/CLAY. The pseudo- first order (PFO) model also showed good correlation, with R2 values of 0.9812 for PET/CHITIN/CLAY, 0.9276 for PET/CBS and 0.9207 for PET/CHITIN. These results suggest that PSO was more prevalent, and therefore infer that chemisorption was the dominant mechanism for adsorption in these composites.Webber-Morris intraparticle diffusion model applied to data gave a multi-linear correlation of the adsorption of Fe (III) ions on the binary and ternary composites as well as the single materials. However, R2 values of crab shell, clay, chitin, PET/CLAY, PET/CBS, PET/CHITIN, and PET/CBS/CLAY, were 0.9509, 0.9737, 0.9492, 0.9366, 0.9063, 0.9317, and 0.9169 respectively. The high R2 values of the rate models shows a positive adsorbent behaviour of the composites.