Chicken feet yellow membrane waste as new bio-adsorbent for cationic methylene blue dye removal: adsorption, equilibrium, kinetic and thermodynamic studies

Abstract

<strong>Background and objective: </strong>Dye molecules as an important type of organic pollutants are potentially toxic and have carcinogenic and mutagenic impact on living systems. Today, uncontrolled discharge of organic pollutants is environmental problem. Dissolution of synthetic dyes in aqueous media causes decreased light penetration into water and interferes photosynthesis reactions. This research introduces a new and eco-friendly adsorbent based on chicken feet yellow membrane(CFYM) for removal of cationic dye.<br /> <strong>Materials and methods: </strong>Untreated CFYM was collected from slaughterhouse and prepared for analysis after washing by deionized water, drying at 90°C for 12-24 h and grinding to fine powders. The adsorbent was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy and Emmett and Teller techniques. Functional groups of C=O, O–H, N–H, C–N, C–C and H–C–H could confirm that the pre-treated CFYM has mainly organic nature. Removal applicability and efficiency of bio-adsorbent were studied using cationic methylene blue (MB) as s model. To reach the best results, main parameters including pH, adsorbent mass, contact time and temperature were optimized by one-factor-at-a-time method through adsorption experiments in a batch system. The equilibrium adsorption experiments were evaluated by Langmuir, Freundlich, Tempkin and Dubinin-Raduskovich isotherm models. The adsorption kinetic models of pseudo-first order, second first order, Elovich and intra-particle diffusion were also studied.<br /> <strong>Results and conclusion: </strong>Results were in accordance to Langmuir isotherm model. Obtained kinetic and thermodynamic parameters confirmed that pseudo-first order model was the best kinetic model and adsorption process of MB on CFYM was exothermic and spontaneous. Based on the results, CFYM, as a novel natural adsorbent, was efficient for removal of cationic organic pollutant from aqueous solutions.