Magnetite synthesis using iron oxide waste and its application for phosphate adsorption with column and batch reactors

• Published in: Chemical engineering research & design 2019-08, Vol.148, p.169-179
• Main Authors: Shahid, Muhammad Kashif, Kim, Yunjung, Choi, Young-Gyun
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Ammonium hydroxide; Batteries; Chemical analysis; Chemical synthesis; Coprecipitation; Iron oxides; Magnetite; Phosphate; Phosphates; Regeneration; Reverse coprecipitation; Scale (corrosion); Sodium hydroxide; Stoichiometry; Surface chemistry; Wastewater treatment
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2019.06.001

[Display omitted] Magnetite particles were synthesized using iron oxide waste by reverse coprecipitation method. The specific surface area and the crystalline size for magnetite were determined as 75.77m2g−1 and 11.64nm, respectively. The maximum phosphate adsorption capacity of magnetite is determined 11.78mgg−1. The magnetite particles were synthesized by reverse coprecipitation of mill scale (iron oxide waste). The particle characterization was done and confirmed by SEM, EDS, BET, XRF, FTIR and XRD. Scherrer equation determined 11.64nm single crystalline size of the magnetite and the BET surface area was found nearly 75.77m2g−1. The expected stoichiometry (3:4) of Fe:O was confirmed by elemental analysis. The magnetite particles were proven as effective adsorbent for phosphate ions from the contaminated water. The phosphate removal efficiency was inspected with several experimental setups including column reactor fed from top to bottom, from bottom to top and sequencing batch reactor. The maximum P-adsorption capacity of magnetite was determined 11.78mgg−1. The P-carrying adsorbent is regenerated with different concentrations of NaOH and NH4OH solutions for 1, 2 and 5 days. Though both solutions were appeared effective for regeneration of used particles, NaOH was appeared more efficacious than that of NH4OH. The regeneration competence of magnetite particles is also evaluated with repetitive regeneration of used particles with 0.1N NaOH. As compared with initial value, almost 20% of the adsorption capacity was reduced after 12 successive rounds of phosphate adsorption and desorption onto the surface of magnetite. The obtained results have established fine potentiality for the magnetite particles synthesized by reverse coprecipitation to be applied as phosphate adsorbent in wastewater treatment.