Preparation Of Hydroxyapatite Biobased Microcomposite Film For Selective Removal Of Toxic Dyes From Wastewater

The present work focused on designing and preparing a nature-based composite in film form to be used as an adsorbent for toxic dyes from wastewater. The composite film was prepared by a double decomposition and coprecipitation methods using hydroxyapatite (HAp), hydroxyethyl cellulose (HEC), and polyethylene glycol (PEG)-1000. Several films with various proportions were prepared. HEC used in this study was prepared from cellulose extracted from the natural plant Sparta "Stipa tenacissima" that is grown in the eastern region of Morocco. Prepared composite films were water insoluble, smooth, and flexible. The films were characterized by attenuated total reflectance infrared spectroscopy, thermal gravimetric analysis (differential thermal analysis), field emission scanning electron microscopy, and X-ray diffraction. The tendencies of the films for adsorbing methyl orange (MO) from water were evaluated. The film adsorption efficiencies were monitored by ultraviolet spectroscopy. Experimental data were described by Langmuir and Freundlich isotherm models. Results showed that the equilibrium data of MO adsorption were best represented by Freundlich isotherm model. The kinetic data of MO fitted well with the pseudo-second-order kinetic model. The results demonstrated that HAp/HEC/PEG composite achieved favorable removal of the toxic dye MO from water. The high efficiency of the composite toward MO could be related to the multi-coordination sites available on the film surface, the H-bonding sites, and the availability of macro tunnels in the composite structure. The antibacterial activities of several films were evaluated against gram-positive and gram-negative bacteria; all tested samples showed moderate to good activities. The results suggest that the composite of this study could be used as a potential low-cost alternative for removal of toxic dyes and bacteria from industrial wastewater.