Phosphate adsorption improvement using a novel adsorbent by CaFe/LDH supported onto CO2 activated biochar

Autor: Juliano Missau, Marco Antonio S. Rodrigues, Daniel Assumpção Bertuol, Eduardo Hiromitsu Tanabe
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Water Science and Technology, Vol 86, Iss 9, Pp 2396-2414 (2022)
Druh dokumentu: article
ISSN: 0273-1223
1996-9732
DOI: 10.2166/wst.2022.332
Popis: It is imperative to remove phosphate from the aquatic system. This nutrient in excess can cause environmental problems such as eutrophication. Therefore, aiming to enhance phosphate removal, this work presents a novel adsorbent developed from the construction of Ca2+/Fe3+ layer double hydroxides (CaFe/LDH) supported onto biochar physically activated with CO2 [CaFe/biochar (CO2)]. Pristine biochar was produced from the pyrolysis of Eucalyptus saligna sawdust, activated with CO2, and then impregnated with CaFe/LDH. The CaFe/biochar (CO2) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET). The characterization confirmed a proper synthesis of the new adsorbent. Experiments were conducted in the form of batch adsorption. Results indicated that the optimum pH and adsorbent dosage were 2.15 and 0.92 g L−1, respectively. Adsorption kinetics, isotherms, and thermodynamics were also evaluated. Adsorption kinetics and isotherms were better fitted by the pseudo n order and Freundlich models, respectively. Results also indicated a better adsorption capacity (99.55 mg·g−1) at 55 °C. The thermodynamic indicators depicted that the adsorption process was favorable, spontaneous, and endothermic. Overall, CaFe/biochar (CO2) could be potentially applied for the adsorptive removal of phosphate from an aqueous solution. HIGHLIGHTS A novel adsorbent, CaFe/biochar (CO2), was satisfactory synthesized.; Adsorption capacity of 99.55 mg·g−1 was obtained for phosphate removal.; Freundlich isotherm model properly described the equilibrium curves.; Thermodynamic results reported a favorable, spontaneous, and endothermic process.; CaFe/biochar (CO2) showed potential for phosphate removal in aqueous solutions.;
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