Oxalated blast-furnace slag for the removal of Cobalt(II) ions from aqueous solutions

This study showcases an original blast-furnace slag, an industrial waste material, successfully and readily converted into Slag-Oxalate (Slag-Ox) to capture Co2+. The obtained material exhibited a fast adsorption rate and a maximum adsorption capacity of 576 mg/g, which is the highest Co2+ adsorption capacity achieved to date. The adsorption kinetics and isotherms of Slag-Ox for Co2+ were well-fitted by the pseudo-second order and Sips models, respectively. Ion exchange between Ca2+ and Co2+ was the main adsorption mechanism. Slag-Ox exhibited stable adsorption performance at pH 5-9 and was chemically stable at wider pH ranges. As the temperature increased, the adsorption capacity also increased. Furthermore, Slag-Ox removed Cs+ and Sr2+ ions from multi-metal aqueous solutions, revealing its potential for the remediation of radiocesiumand radiostrontium-contaminated waters. Overall results demonstrated that Slag-Ox is an effective and low-cost cobalt adsorbent and highlighted that waste material recycling will contribute to the betterment of industrial waste management. (c) 2020 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

This study converted an original blast-furnace slag, an industrial waste material, into Slag-Oxalate to capture Co2+. The obtained material showed a high adsorption capacity and fast adsorption rate, with ion exchange being the main mechanism. Additionally, Slag-Ox was able to remove Cs+ and Sr2+ ions from multi-metal aqueous solutions, indicating its potential for remediating contaminated waters.