In-situ oxidation effect on pore size distribution in investigating adsorption properties under various geochemical conditions

• Published in: Solid earth sciences 2019-09, Vol.4 (3), p.113-124
• Main Authors: Rajib, Mohammad, Oguchi, Chiaki T., Hasan, S. M. Mahmudul
• Format: Article
• Language: English
• Subjects: Distribution coefficients; Pore size distribution; Pumice tuff; Redox effect; Specific surface area
• ISSN: 2451-912X; 2451-912X
• DOI: 10.1016/j.sesci.2019.06.003

Redox affected pumice tuff was used to investigate the changes of pore properties due to oxidation and its possible consequences to adsorption of nuclides on it. Porosity and pore size distribution were analyzed by mercury injection technique and scanning electron microscopy. Batch experiment was carried out with 1 cm3 block shaped intact pumice tuff samples to determine adsorption coefficient, Kd at several pH, ionic strength and initial nuclide concentrations of stable cesium (133Cs). Pore area, surface area and specific surface area were determined from pore size distribution data before and after adsorption experiment and later compared between fresh and oxidized samples. The results showed that reduction of less than 0.33 μm size micro pores due to oxidation is mainly responsible for reducing surface areas, eventually reducing the sorption quantity. Influence of pore properties became negligible in redox affected pumice tuff indicating inverse relation of oxidation phenomena with adsorption coefficients values. [Display omitted] •Sorption coefficients were measured by static batch procedure in variable experimental condition using cesium on fresh and oxidized pumice tuff.•Pore size distribution was analyzed using mercury intrusion technique.•Micropores of less than 0.33 μm size are the main responsible factor for the changes of sorption quantity in oxidized condition.•Instead of pore connectivity, changes of specific surface area of pumice tuff have significant effect on the sorption quantity.