A novel partitioning process for treatment of high level liquid waste using macroporous silica-based adsorbents

Adsorption Behaviors of Platinum Group Metals in Simulated High Level Liquid Waste Using Macroporous (MOTDGA-TOA)/SiO2-P Silica-based Absorbent

“…A complexing agent such as thiourea is necessary in elution. Thiourea showed ability of elution of Pd(II) adsorbed on the adsorbent in the literature (20).…”

“…For this reason, it is suggested that long contact time is needed for the dynamic adsorption of Ru(III) and Rh(III) by the (MOTDGA-TOA)=SiO 2 -P packed column. Actually, Ru(III) and Rh(III) were eluted from the adsorbent packed column as soon as simulated HLLW was fed to the column with 0.3 cm 3 =min in previous work (20). However, it could be considered that the adsorbent adsorb Ru(III) and Rh(III) from HNO 3 solution when the adsorbent have been contacting with the solution in long time.…”

“…In our previous work, we have suggested a novel partitioning process for HLLW using only macroporous silica-based adsorbents (20). The process consisted of five kinds of adsorbents, namely 1. a column packed with (Calix [4]arene-R14 þ Dodecanol)= SiO 2 -P for the removal of Cs and Rb in the first step (Calix [4]arene-R14; 1,3-[(2,4-diethylheptylethoxy)oxy]-2,4-crown-6-calix [4]arene) (21); 2. a column packed with (DtBuCH18C6 þ Dodecanol)= SiO 2 -P for the removal of Sr and Ba from raffinate of the first step in the second step (DtBuCH18C6; 4,4 0 ,(5 0 )-di-(tert-butyl-cyclohexano)-18-crown-6) (22); 3. a column packed with a novel adsorbent of (MOTDGA-TOA)=SiO 2 -P for the removal of Pd from raffinate of the second step in the third step (TOA; Tri-n-octylamine); 4. a column packed with TODGA=SiO 2 -P for the separation Ru, Rh and Mo from raffinate of the third step in the fourth step (TODGA; N,N,N 0 ,N 0 -tetraoctyl-3-oxapentane-1,5-diamide); 5. a column packed with a isobutyl-BTP=SiO 2 -P for the mutual separation of rare earth and minor actinide from eluted out solution in the fourth step (isobutyl-BTP; 2,6-di(5,6-diisobutyl-1,2,4-triazin-3-yl) pyridine).…”

Adsorption of N,N,N′,N′-Tetraoctyl Diglycolamide on Hypercrosslinked Polysterene from a Supercritical Carbon Dioxide Medium

“…Such materials can adsorb metals from acidic aqueous solutions, which allows them to be used in solid phase extraction and extraction of metals from complex mixtures. Previous research [ 1 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ] shows that it is possible to use impregnated sorbents based on TODGA and other similar ligands for chromatographic separation of mixtures containing lanthanides, actinides and other metals of valences II, III and IV. The role of carrier matrices in production of sorbents of this type can be played by materials of different kinds, such as silica gels modified by polymers [ 7 ], graphene aerogels [ 13 ], hypercrosslinked polystyrene (HCP) [ 1 , 14 ], etc.…”

“…Such carriers are commonly impregnated with TODGA solutions in volatile solvents (methanol, dichloromethane, etc.). The solvents are removed by evaporation (reaching complete deposition of the chelating agent on the carrier) [ 1 , 6 , 8 , 10 , 11 , 12 ] or the carrier with a certain amount of the adsorbed chelating agent is filtered out of the solution residue [ 7 , 13 ]. Such approaches to impregnation require volatile toxic organic solvents and, in addition, are rather labor- and time-consuming, which encourages us to use more environmentally friendly and cheaper solvents such as supercritical (SC) CO 2 .…”