Removal of methylene blue from aqueous solution by natural phosphate

This study investigated the potential use of natural phosphate (Djebel Onk - Tebessa-Algeria) as alternative adsorbents for removal of methylene blue from wastewater. The adsorbent was characterized by powder X-ray diffraction, FT-IR spectroscopy, BET surface area and scanning electron microscopy (SEM). The effects of initial dye concentration, contact time, adsorbent dose, stirring speed, pH, salt concentration and temperature were studied in batch mode. The experimental isotherms were analyzed using Langmuir and Freundlich isotherm equations. Thermodynamic parameters such as, Delta G, Delta H, Delta S and the activation energy were calculated. The kinetic studies indicated that the adsorption process followed the pseudo second-order mode, suggesting that the adsorption might be a chemisorption process. The present study implied that natural phosphate was a promising candidate for the removal of dye molecules from aqueous solution.