Application of Treated Iraqi Rice Husk as Adsorbent for Phosphate Removal from Aqueous Solution

Abstract

n the present work, agricultural waste, (Iraqi rice husk A’anbartype) was developed with thermal and chemical treatments for using as an adsorbent to remove phosphate anion from aqueous solution and the thermal treatment at 500oC was the best.Batch experiments were conducted to obtain the maximum removal of phosphatevia changing the parameters oftheprocess, such as contact time, pH, adsorbent dose, initial solute concentration, and the existence of competitive anions upon the removal of phosphate and was investigated. The adsorbent characterization was performed employing Fourier transform infrared (FTIR), X-ray fluorescence (XRF), scanning electron microscope (SEM), the BET surface area and pore volume, and X-ray diffraction spectrophotometric analysis (XRD).The maximum removal of phosphate was achieved as (98.37 %), at contact time 140 min., pH 2.0, adsorbent dose 20 g/L, and initial concentration 5 mg/L at room temperature. The effects of competing ions of CO3-2, NO-3,and SO4-2anions were studied. The experimental data manifested the best fit for the Langmuir isotherm model (R2 = 0.99) and the pseudo-second-order kinetic model (R2 = 0.99). Rice husk ash was found efficient for phosphate removal from the industrial wastewater and aqueous solutions