Calcium ferrites for phosphate adsorption and recovery from wastewater.

Authors :: Araújo MHP
Ardisson JD
Krohling AC
Lago RM
Guimarães Júnior W
Tristão JC
Source :: RSC advances [RSC Adv] 2024 Jan 04; Vol. 14 (3), pp. 1612-1624. Date of Electronic Publication: 2024 Jan 04 (Print Publication: 2024).
Publication Year :: 2024
Abstract: In this study, calcium ferrites with different Ca : Fe atomic ratios (1 : 1, 1 : 2, 1 : 3 and 2 : 1) were prepared from Ca and Fe nitrates treated at 300, 700 and 900 °C and evaluated for phosphate adsorption and recovery from wastewater. TG, XRD, Mössbauer spectroscopy, SEM, VSM magnetic measurements, and BET analyses showed the formation of two different calcium ferrite phases, i.e. , CaFe <subscript>2</subscript> O <subscript>4</subscript> and Ca <subscript>2</subscript> Fe <subscript>2</subscript> O <subscript>5</subscript> at 700 and 900 °C. The adsorption results indicated that the formation of calcium ferrite structure is critical for phosphate adsorption/recovery. Evaluation of the pH, initial phosphate concentration, contact time, coexisting ions and desorption conditions showed remarkable adsorption capacities of 62-75 mg g <superscript>-1</superscript> for CaFe1:2-700 and 28-43 mg g <superscript>-1</superscript> for CaFe1:2-900. The phosphate adsorption on the Ca ferrite surfaces is so strong that the recovery/desorption showed limited efficiencies, e.g. , 15-39%.<br />Competing Interests: There are no conflicts to declare.<br /> (This journal is © The Royal Society of Chemistry.)