Chicken bone ash as a cost-effective and efficient adsorbent for phenol removal from aqueous solution

Phenol is a highly toxic compound and widely produced from various industrial wastes. Removal of phenol by chicken bone ash (CBA) from an aqueous solution was studied. CBA was prepared and characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The SEM analysis shows that the CBA has a rough and large porous surface with interconnected irregular shape cavities. The XRD proved that hydroxyapatite was the main component of the ash. Batch and column adsorption procedures were performed to study the adsorption process. Adsorbent weight, solution pH, initial concentration and contact time revealed that the use of 0.8 g CBA for 180 min, 94.4% of phenol was removed at initial concentration of 250 mgphenol/L. The highest removal rate of CBA was achieved at pH value of 8.0; it reached 91.6%. Eight analytical models were investigated to study the performance of fixed-bed columns for phenol removal by the adsorption process. The best values obtained were for Log-Gompertz with R 2 = 0.8748. Langmuir isotherm constant with a coefficient of determination (R 2 ) = 0.9842 fits successfully the adsorption process. The experimental data obey the pseudo-second-order with R 2 = 0.9624 and phenol removal is attributed to chemical precipitation reaction. Cost analysis revealed that for the production of 0.1 kg of CBA about 0.77 $ is required. In conclusion, for pollutant removal, the CBA proved to be cost effective, sustainable and renewable compared with activated carbon.