The Fundamental Investiation On The Sysnthesis And Characterization Of Calix[4]BisCrowns And Their Polymer-based Supramolecular Recognition Materials

Cs(I) is one of the so-called heat emitting nuclides. The isotopes of Cs(I), Cs-137 with a half-life of 30 yr contained in highly active liquid waste (HLW), is harmful to the vitrified HLW in final geological disposal. To significantly decrease the adverse impact, the separation of Cs(I) from HLW to a great extend is valuable. However, its effective partitioning and recovery has always been one of the most challenging works for decades. On the other hand, HLW is a kind of the comlicated solution with a lot of radionuclides, high HNO3 concentration, and strong radioactivity. One of the important factors making the separation difficult is the absence of the effective functional material which is suitable for HLW. Calix[4]BisCrowns is the derivatives of the third generation supramolecular recognition agents, containing calix[4]arene host unit and crown which has similar size to Cs(I). Considering the low content of cesium in HLW, it is valuable for the chromatographic separation of Cs(I) by the Calix[4]BisCrowns containing materials. For this purpose, some derivatives of Calix[4]BisCrowns and their new polymer-based supramolecular recognition materials, Calix[4]BisCrowns/XAD-7, were synthesized and characterized. Their adsorption behavior for some typical metals in the HNO3 concentration range of 0.4 M to 6.0 M was investigated. The following results were obtained.(1) Six kinds of symmetrical, and three kinds of unsymmetrical calix[4]biscrowns, such as calix[4]-bis[(4-methyl-1,2-phenelyene)-crown-6] (CalixBisMeC6), tert-butyl-calix[4]-bis[(4-methyl-1,2-phenelyene)-crown-6] (TBuCalix-BisMeC6), calix[4]-bis[(4-tert-butyl-1,2-phenely-ene)-crown-6] (CalixBisTBuC6), tet-butyl-calix[4]-bis[(4-tert-butyl-1,2-phenelyene)-crown-6] (TBuCalixBisTBuC6), tert-butyl-calix[4]-bis-crown-5 (TBuCalixBisC5), tert-butyl-calix[4]-bis-crown-6 (TBuCalixBisC6), ter5-butyl-calix[4]-crown-5-crown-6 (TBuCalixC5C6), tert-butyl-calix[4]-crown-6-crown-7 (TBuCalixC6C7) and tert-butyl-calix[4]-crown-6-naphtho-crown-6 (TBuCalixC6NC6), were synthesized. While, TBuCalixBisMeC6, CalixBisTBuC6, TBuCalixBisTBuC6, TBuCalixC5C6, TBuCalixC6C7 and TBuCalixC6NC6 have not been reported yet. The structure and composition of the Calix[4]BisCrowns were characterized by elemental analysis, FT-IR, TG-DSC, ESI-MS and [H NMR, respectively. The synthesis routes for symmetrical and unsymmetrical Calix[4]BisCrowns were proposed, respectively.(2) The extraction properties and mechanism of some typical metal ions, Na(Ⅰ), K(Ⅰ), Rb(Ⅰ), Cs(Ⅰ), Sr(Ⅱ), Ba(Ⅱ), Ru(Ⅲ) and Fe(Ⅲ), with Calix[4]BisCrown/chloroform and Calix[4]BisCrown/o-nitroanisole respectively were investigated. The results showed that in HNO3 solution, Cs(Ⅰ) was effectively extracted with TBuCalixBisMeC6 and formed to the stable complex. The composition of the extracted species of TBuCalixBisMeC6 and Cs(Ⅰ) was determined to be 1:1 type. It was comformed by the analysis of ESI-MS and FT-IR in organic phase. The extraction mechanism of the extraction system Cs(Ⅰ)/HNO3/CalixBisMeC6 could be expressed as the following. Cs(a)++NO3(a)-CalixBisMeC6(o)(?)CsNO3·CalixBisMeC6(o)(3) Nine of the new polymer-based Calix[4]BisCrown supramolecular recognition materials, CalixBisMeC6/XAD-7, TBuCalixBisMeC6/XAD-7, CalixBisTBuC6/XAD-7, TBuCalixBisTBuC6/XAD-7, TBuCalixBisC5/XAD-7, TBuCalixBisC6/XAD-7, TBuCalixC5C6/XAD-7, TBuCalixC6C7/XAD-7 and TBuCalixC6NC6/XAD-7, were prepared by impregnation and immobilization. The composition and structure of the new polymer-based supramolecular recognition materials were characterized by SEM, FT-IR, TG-DSC and BET, respectively. The composite mechanism between Calix[4]BisCrowns and XAD-7 through intermolecular interaction was discussed.(4) The adsorption of Cs(Ⅰ) and some typical co-existent metals such as Na(Ⅰ), K(Ⅰ), Rb(Ⅰ), Cs(Ⅰ), Sr(Ⅱ), Ba(Ⅱ), Ru(Ⅲ) and Fe(Ⅲ) onto the nine new polymer-based supramolecular recognition materials were investigated. The impact of contact time, the HNO3 concentration in the range of 0.4 M to 6.0 M and temperature on the adsorption of Cs(I) and others onto Calix[4]BisCrowns/XAD-7 was examined. It was showed that in 2.0 M to 3.0 M HNO3 soluion, CalixBisMeC6/XAD-7 and CalixBisTBuC6/XAD-7 had excellent adsorption ability for Cs(I), while as tert-butyl group was introduced into the calixarene units, the optimum acidity for the Cs(I) adsorption onto other materials was 4.0 M HNO3 or 5.0 M HNO3. As a result, CalixBisMeC6/XAD-7 and CalixBisTBuC6/XAD-7 showed excellent adsorption ability and high selectivity for Cs(I) over all of the tested metals. It was hopeful to separate Cs(I) from the geniune HLW in 3.0 M HNO. It might be promising to application in the separation of Cs(I) from HLW of high HNO3 concentration by CalixBisTBuC6/XAD-7. In addition, the structure of the Calix[4]BisCrowns materials were characterized by FT-IR and SEM before and after the adsorption of Cs(I). The complexation of Calix[4]BisCrowns with Cs(I) was confirmed.