Sorption Behavior of Radionuclides on Crystalline Synthetic Tunnel Manganese Oxides

• Published in: Chemistry of materials Vol. 12; no. 12; pp. 3798 - 3804
• Main Authors: Dyer, Alan, Pillinger, Martyn, Newton, Jon, Harjula, Risto, Möller, Teresia, Amin, Suheel
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-12-2000
• Subjects: Applied sciences; Exact sciences and technology; Industrial wastewaters; Pollution; Wastewaters; Water treatment and pollution; Sorption; Nuclear industry; Industrial waste water; Manganese Oxides; Physicochemical purification; Radioisotope; Ion exchange; Waste water purification; Experimental study
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm001142v

Cryptomelane-type (potassium) and todorokite-type (magnesium and calcium) manganese oxides were prepared and studied for the removal of radionuclides from aqueous solutions containing inactive metal ions of interest in radionuclide-bearing nuclear waste effluents. Batch distribution coefficients were measured as a function of pH and sodium, potassium, magnesium, and calcium ion concentrations. Trace strontium (89Sr) and cesium (137Cs) ions were taken up by ion-exchange mechanisms. Selectivity coefficients were estimated as K Cs/K = 0.6 and K Sr/K = 1.0 for cryptomelane and K Cs/Mg = 7550, K Sr/Mg = 50, and K Sr/Ca = 10 for todorokite. The cryptomelane analogue was particularly effective for the separation of trace silver ions (110Ag) in low-pH solutions. Todorokite analogues were effective for a wider range of radionuclides, including 57Co across a wide pH range (1−10) and 137Cs in acidic solution. The affinity sequence for magnesium and calcium ion-extracted (acid-treated) todorokites in 0.1 HNO3 was 137Cs > 59Fe > 51Cr ≈ 57Co ≈ 241Am > 54Mn > 63Ni > 65Zn > 236Pu > 89Sr.