Characterization of the Physical, Chemical, and Adsorption Properties of Coal-Fly-Ash–Hydroxyapatite Composites

(1) Hydroxyapatite (HAp), which can be obtained by several methods, is known to a good adsorbent. Coal fly ash (CFA) commonly reused byproduct also used in environmental applications as an We sought answer the following question: Can CFA included method of HAp wet synthesis produce composite capable adsorbing both heavy metals and dyes? (2) High calcium lignite from thermal power plant Bełchatów (Poland) was base prepare CFA–HAp composites. Four types designated CFA–HAp1–4 were synthesized via situ precipitation. The conditions differed terms reactants used, pH, temperature. investigated equilibrium adsorption Cu(II) rhodamine B (RB) on CFA–HAp1–4. data fitted using Langmuir, Freundlich, Redlich–Peterson models validated R2 χ2/DoF. Surface changes CFA–HAp2 RB assessed SEM, SE, FT-IR analysis. (3) composites contained hydroxyapatite (Ca/P 1.67) aluminosilicates. mode could explained model. CFA, Ca(NO3)2, (NH4)2HPO4 at RT pH 11 exhibited highest maximal capacity: 73.6 mg Cu/g 87.0 RB/g. (4) clear advantage chemisorption over physisorption indicated Cu(II)–CFA–HAp system. molecules present form uncharged lactone favorably adsorbed even strongly deprotonated surfaces.