The effect of cationic surfactants on improving natural clinoptilolite for the flotation of cesium

• Published in: Journal of hazardous materials Vol. 402; p. 123567
• Main Authors: Prajitno, Muhammad Yusuf, Tangparitkul, Suparit, Zhang, Huagui, Harbottle, David, Hunter, Timothy N.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.01.2021
• Subjects: Cationic surfactants; Cesium; Clinoptilolite; Flotation; Ion exchange; Clinoptilolite; Cesium; Flotation; Ion exchange; Cationic surfactants
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2020.123567

[Display omitted] •Rapid dewatering of cesium contaminated clinoptilolite was studied using flotation.•Adsorption of EHDa-Br and CPC surfactant collectors were analysed.•<8% of contaminated cesium was removed with surfactant co-adsorption.•Optimum conditions were found with 0.5 mM CPC and 30 μL of MIBC frother.•Flotation achieved ∼90% clinoptilolite recovery and > 4 water reduction ratio. Flotation using cationic surfactants has been investigated as a rapid separation technique to dewater clinoptilolite ion exchange resins, for the decontamination of radioactive cesium ions (Cs+) from nuclear waste effluent. Initial kinetic and equilibrium adsorption studies of cesium, suggested the large surface area to volume ratio of the fine zeolite contributed to fast adsorption kinetics and high capacities (qc = 158.3 mg/g). Adsorption of ethylhexadecyldimethylammonium bromide (EHDa-Br) and cetylpyridinium chloride (CPC) surfactant collectors onto both clean and 5 ppm Cs+ contaminated clinoptilolite was then measured, where distribution coefficients (Kd) as high as 10,000 mL/g were evident with moderate concentrations CPC. Measurements of particle sizes confirmed that adsorption of surfactant monolayers did not lead to significant aggregation of the clinoptilolite, while < 8% of the 5 ppm contaminated cesium was remobilised. Importantly for flotation, both the recovery efficiency and dewatering ratios were measured across various surfactant concentrations. Optimum conditions were found with 0.5 mM of CPC and addition of 30 μL of MIBC frother, giving a recovery of ∼90% and a water reduction ratio > 4, highlighting the great viability of flotation to separate and concentrate the contaminated powder in the froth phase.