Montmorillonitin, Radyoaktif Atıkların Depolanmasında Kullanımı

Bu çalışmada ise, fosforik asit ile aktive edilmiş (Bentonit) Montmorillonitin sezyum iyonlarını emebilme özellikleri incelenmiştir. Yapılan analizler neticesinde,

Montmorillonitli bu yapıda, kayda değer miktarda süspanse katı madde üretmediği ve Sezyum alımına karşı yüksek absorbe eğilimi gösterdiği tespit edilmiştir. Absorbe özelliğinin artması, yüzey alanının artması ve yüzey yüksel yoğunluğunun daha fazla olması olarak açıklanmıştır. Bu sonuçlar ışığında, Montmorillonitli bu yapının radyoaktif atıkların depolanmasında kullanımında faydalı olduğu belirtilmiştir.

Çalışmanın İngilizce özetine aşağıda yer verilmiştir.

Performance Of Phosphoric Acid Activated Montmorillonite As Buffer Materials For Radioactive Waste Repository.
Wang TH, Liu TY, Wu DC, Li MH, Chen JR, Teng SP.
PMID: 19747773 [PUBMED – indexed for MEDLINE] J Hazard Mater. 2010 Jan 15;173(1-3):335-42
Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan. In this study, the performance of phosphoric acid activated montmorillonite (PAmmt) was evaluated by cesium ions adsorption experiments. The PAmmt samples were obtained by activating with 1, 3 and 5 mol L(-1) of phosphoric acid, respectively under reflux for 3, 12, and 24h. Experimental results demonstrated that the treatment of raw K-10 montmorillonite with phosphoric acid increased the materials' affinity for Cs uptake and no significant amount of suspension solids were produced. A relatively insignificant variation in the CEC value was observed. Furthermore, PAmmt also showed high adsorption selectivity toward Cs ions. The improved sorptive properties were mainly related to the increased surface area and the relatively higher surface charge density. Increased specific surface area was the resulted from partial decomposition of lamellar structure of mmt; while the higher surface charge density was caused by the protonation of octahedral Al-OH sites during the acid activation. Generally speaking, stronger acid concentration and longer activation times would produce relatively more decomposed PAmmt particles. However, as the activation exceeds 3h, the precipitation of Si(4+) would passivate PAmmt against further acid attacks. Based upon our results, acid activation by phosphoric acid could produce PAmmt samples with high sorption capacity and selectivity, and good structural integrity, which are beneficial to be used at radioactive waste repository.