Calcium ferrites for phosphate adsorption and recovery from wastewater

Matheus Henrique Pimentel Araújo; José Domingos Ardisson; Alisson Carlos Krohling; Rochel Montero Lago; Walber Guimarães Júnior; Juliana Cristina Tristão

doi:10.1039/d3ra05871a

Calcium ferrites for phosphate adsorption and recovery from wastewater

RSC Adv. 2024 Jan 4;14(3):1612-1624. doi: 10.1039/d3ra05871a. eCollection 2024 Jan 3.

Authors

Matheus Henrique Pimentel Araújo¹, José Domingos Ardisson², Alisson Carlos Krohling², Rochel Montero Lago³, Walber Guimarães Júnior⁴, Juliana Cristina Tristão¹

Affiliations

¹ Universidade Federal de Viçosa - Campus Florestal - UFV Rodovia LMG 818, km 06, s/n, Campus Universitário Florestal MG 35690-000 Brazil matheus.pimentel@ufv.br.
² Centro de Desenvolvimento da Tecnologia Nuclear - CDTN/CNEN, campus da Universidade Federal de Minas Gerais Avenida Presidente Antônio Carlos, No 6627, Rua Mário Werneck, S/N - Pampulha Belo Horizonte MG Brazil.
³ Universidade Federal de Minas Gerais - UFMG Avenida Presidente Antônio Carlos, No 6627, Rua Mário Werneck, 2 - Pampulha Belo Horizonte MG 31270-901 Brazil.
⁴ Universidade Federal de São Carlos - UFSCar Rodovia Washington Luís, s/n - Monjolinho São Carlos - SP 13565-905 Brazil.

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., CaFe₂O₄ and Ca₂Fe₂O₅ 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^-1 for CaFe1:2-700 and 28-43 mg g^-1 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%.