Black wattle tannin‐immobilized mesostructured collagen as a promising adsorbent for cationic organic dyes (methylene blue) removal in batch and continuous fixed‐bed systems

Abstract

AbstractBlack wattle tannin‐immobilized mesostructured collagen (TC) was synthesized by using exfoliated mesostructured collagen as carriers. The structure of TC was characterized by scanning electron microscope, Fourier transform infrared spectroscopy and zeta potential test. Methylene blue (MB) as a cationic dye model was applied to evaluate the adsorption ability of TC through batch and continuous fixed‐bed system experiments. Results of batch adsorption experiment indicated that the adsorption behaviors of TC conformed to the Freundlich isotherm model and the pseudo‐second‐order kinetic model as well as the intraparticle diffusion model. The maximum adsorption amount (Qmax) of TC was 46.5 mg/g at 303 K. Fixed‐bed adsorption experiments revealed that the initial concentration, flow rate, and column height significantly influenced the removal of MB, and all breakthrough curves were well fitted by Thomas and Yoon‐Nelson models. Adsorption–desorption experiments demonstrated that TC possessed excellent stability and reusable ability. The removal efficiency of MB was still above 80% after five adsorption–desorption cycles. The excellent adsorption capacity of TC owed to the immobilized tannins as binding sites to MB and support of mesostructured collagen with hierarchical structure. This work developed a novel collagen‐based adsorption material for efficient removal of cationic dye.