Kinetics and Isotherm Studies For Adsorption Of Methyl Orange Dye From Aqueous Solutions Using Hydroxyapatite

Document Type


Publication Date

Winter 12-2022


Excessive amount of dyes in the discharged wastewater from the textile industry becomes a severe problem in water pollution due to the presence of unruly toxic organic compounds. Dyes are highly toxic and carcinogenic compounds that cause extremely harmful effects on the on the human health. The adsorption method is considered one of the best methods for dye removal from wastewater because of its availability, low cost, stability, large surface area to volume ratio and high adsorption capacity. In this article, hydroxyapatite (HAP) was used as a solid adsorbent for the removal of methyl orange (MO) dye from aqueous solutions. Fourier Transform Infrared (FTIR) surface characterization test was performed before and after the adsorption process, ensuring the adsorption of the MO dye successfully using HAP. Adsorption kinetics and isotherms were studied for this adsorption system to predict the adsorption mechanism. Additionally, the effects of changing pH of solution, initial MO dye concentration, of adsorbent dose and contact time on the adsorption process efficiency were studied. The maximum adsorption efficiency for MO dye from aqueous solutions (88.3%) was achieved at the optimum operating conditions of contact time = 90 min, pH = 4, initial dye concentration = 0.5 mg/L and adsorbent dose = 2 g/L.