Sorption of three PAHs profile groups using eco-friendly and inexpensive hydroxyapatite extracted from camel bone

Abstract

Hydroxyapatite (HAp) was used in the sorption study for three different polycyclic aromatic hydrocarbons (PAHs) ring structures (Naphthalene (NAP), Anthracene (ANT), and Chrysene). HAp powders were produced from Camelus bone as an eco-friendly and inexpensive source. Three distinct surface areas (66.56, 94.88, and 94.35 m²/g) at three different temperatures (500, 650, and 900 °C), were applied to prepare the HAp500, HAp650, and HAp900 samples after passing CO₂ at 700 °C. It was obvious that the surface area of HAp was greatest at 650 °C as compared to 500 °C with a very small variation in uptake between HAP650 and HAP900. Furthermore, for ANT, HAp900 provides the best uptake. In addition, HAp650 is the best since calcining at 650 °C is less expensive than calcining at 900 °C. The effect of shaking time on the sorption of NAP, ANT, and CHR dissolved in n-hexane was carried out using HAp650. The impacts of sorbent amount, concentration, and temperature were studied. The study indicated that the uptake was 66.89, 69.49, and 19.67 mg/g after 120 min of equilibration. It was observed that the uptake of NAP, ANT, and CHR increased as the temperature increased up to 35 °C. A slight increase was obtained from 35–55 °C, indicating that the adsorption occurring on the HAp650 surface is endothermic. The positive values of $\Delta$ H demonstrated the endothermic nature of the adsorption process. Furthermore, the positive entropy of adsorption represents the adsorbent material’s affinity for NAP, ANT, and CHR. In addition, several isotherm models were used to deduce an adsorption mechanism. The adsorption system’s R² values were 0.9615 for NAP, 0.8666 for ANT, and 1.00 for CHR. These values agree well with the Langmuir isotherm.