Interaction and stabilization of organic radioactive waste in geopolymer

今年的研究工作重点是固化地聚合物中的有机化合物。以日本索布克莱的偏高岭土(MK)、硅酸钾碱式活化液(AAS)和Eneos FBK涡轮32润滑油为原料制备了地聚合物-油复合材料(GPOIL)。AAS是由硅酸钾(最初含有29.1wt.%SiO_2、21.9wt.%K2O、49.0wt.%H2O)、氢氧化钾和纯净水混合而成的。合成地聚合物样品的碱性溶液的摩尔比为K2O：SiO_2：H_2O(摩尔比)为1：1：13。将AAS与体积分数为0-50%的油以10000转/分的速度混合5min，形成乳状液。使用十六烷基三甲基溴化铵(CTAB)阳离子表面活性剂，与AAS和油(1g表面活性剂：100mLAAS)混合。所制备的地聚合物-油复合材料在20℃和相对湿度99%的条件下固化7天和28天。这种以偏高岭土为基础的地质聚合物不能固化石油。然而，在表面活性剂的帮助下，地质聚合物可以成功地固化含油量，将油的表面从负极变为正极，使其能够与地质聚合物的相反表面相互作用。对含油量为0%~50%的GPOIL-表面活性剂进行了抗压强度试验。随着含油量的增加，复合材料的抗压强度下降，这是由于油的存在导致了孔隙率的增加。这可以归因于随着含油量和孔隙率的增加，有效粘结点的数量减少，导致强度降低。

This year research work focused on solidifying organic compounds in geopolymer. Metakaolin (MK) from Sobueclay, Japan, potassium silicate alkali activated solution (AAS), and lubricant oil from ENEOS FBK turbine 32 were used to prepare the geopolymer-oil composite (GPOIL). The AAS was prepared by mixing the potassium silicate (originally containing 29.1 wt.% SiO2, 21.9 wt.% K2O, 49.0 wt.% H2O), potassium hydroxide, and purified water. The alkaline solutions synthesising the geopolymer samples are defined as K2O: SiO2: H2O (molar ratio) 1:1:13. AAS was mixed with oil (0-50% by volume) for 5 min at 10,000 rpm to produce an emulsion. CetylTrimethylAmonium Bromide (CTAB) cationic surfactant was used, which was mixed with AAS and oil (1 g of surfactant for 100 mL of AAS). The prepared geopolymer-oil composite was cured at 20 C and RH 99% for 7 and 28 days. The metakaolin-based geopolymer could not solidify the oil. However, the geopolymer can successfully solidify oil content with the help of a surfactant that changes the surface of the oil from negative to positive, allowing it to interact with the opposing surface of the geopolymer. The compression strength test was conducted on GPOIL-surfactant with oil content from 0% to 50%. As the oil content increased, the compressive strength of the composite decreased due to increment of porosity induced by the presence of oil. This can be attributed to the fact that as the oil content and porosity increased, the number of effective bonding points decreased, resulting in a decrease in strength.