Synthesis of an efficient hydroxyapatite-chitosan-montmorillonite thin film for the adsorption of anionic and cationic dyes: adsorption isotherm, kinetic and thermodynamic study

摘要

Adsorption of indigo carmine (IC), methyl orange (MO) and methylene blue (MB) onto hydroxyapatite-chitosan-montmorillonite (HAP-CTS-Mt) film was studied. The influence of contact time, solution pH, initial dyes concentration, amount of HAP-CTS-Mt film and solution temperature were scrutinized. Characteristic bands and structure of HAP-CTS-Mt film were determined using Fourier infrared spectroscopy and X-ray diffraction. The optimal concentrations of IC, MO, and MB were 20 mg/L, 50 mg/L, and 20 mg/L, respectively. Optimal dose of HAP-CTS-Mt was 0.2 g/L for IC and MB and 0.5 g/L for MO. The adsorption process of IC, MO, and MB using HAP-CTS-Mt film was verified by Langmuir isotherm model with maximum adsorption capacities of 243.18 mg/g, 137.5 mg/g and 168.52 mg/g for IC, MO, and MB, respectively. The adsorption kinetics of IC, MO, and MB onto HAP-CTS-Mt film were well fitted by the pseudo-second-order model. The HAP-CTS-Mt thin film can be employed as an efficient adsorbent for removal of IC, MO, and MB dyes from aqueous solutions.