Adsorption of Zn²⁺ from aqueous solutions by si‐substituted carbonated hydroxylapatite: Equilibrium, kinetics, and mechanisms

Abstract

A kind of low‐cost silicon‐substituted carbonate hydroxyapatite (Si‐CHAP) powder was successfully fabricated by using eggshell powder, H3PO4, Ca(OH)2, Na2SiO3, and Na2CO3 under sonochemistry coprecipitation condition. Si‐CHAP could serve as an ideal adsorbent to remove zinc ion (Zn2+) from aqueous solution. Under the optimized conditions, the removal efficiency of Zn2+ in solution by Si‐CHAP could reach to 96.2%. The adsorption mechanism was investigated by X‐ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Notably, the adsorption process followed the Langmuir isotherm and pseudo‐second‐order model, and the saturation adsorption capacities were calculated to be 102.0, 103.1, and 105.3 mg g−1 at 293, 303, and 313 K, respectively. Thermodynamic studies indicated that the adsorption of Zn2+ by Si‐CHAP is endothermic. Mechanism studies revealed that the dominate mechanism was chemical adsorption. These results showed that Si‐CHAP is an effective adsorbent for the removal of Zn2+ from aqueous solution, and thus providing a good method to treat Zn2+ in the waste water. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018

Preparation and Characterization of a Novel Amidoxime-Modified Polyacrylonitrile/Fly Ash Composite Adsorbent and Its Application to Metal Wastewater Treatment

“…At present, there are many industrial methods available for treating Zn 2+ in heavy metal wastewater such as chemical precipitation [ 11 ], chemical redox [ 12 ], filtration [ 13 ], ion-exchange [ 14 , 15 , 16 ], electrolysis [ 17 ], evaporation recovery [ 18 ], and adsorption [ 19 , 20 , 21 , 22 , 23 ]. Among them, the adsorption method has the advantages of simple operation, high selectivity, and high purification.…”