Removal of malachite green dye from aqueous solutions using organically modified hydroxyapatite

The removal of malachite green dye (MG) from aqueous solution was studied using organically modified hydroxyapatite. Hydroxyapatite (HAP) was organically modified with different concentrations of the organic surfactant ethylhexadecyldimethyl ammonium bromide (EHDAB). The modified apatite was characterized using FTIR, XRD and SEM. The modified apatite was studied for removal of MG from aqueous solution and the experimental parameters were studied. The effect of contact time, adsorbent dose, dye concentration and temperature was studied. The equilibrium uptake was increased with increasing the initial dye concentration in solution. The experimental isotherm data were analyzed using Langmuir adsorption isotherm model. The adsorbed amount of MG onto the modified apatite was found to increase with increasing the adsorbent concentration. The maximum monolayer adsorption capacity was found to be 188.18 mg/g at 30 °C.