Online recovery of radiocesium from soil, cellulose and plant samples by supercritical fluid extraction employing crown ethers and calix-crown derivatives as extractants

摘要

Two crown ethers (CEs) viz. dibenzo18crown6, and dibenzo12crown7 and three calix-crown derivatives viz. (octyloxy)calix[4]arene-mono-crown-6 (CMC), calix[4]arene-bis(o-benzocrown-6) (CBC), and calix[4]arene- bis(naphthocrown-6) (CNC) were evaluated for the recovery of ~(137)Cs from synthetic soil, cellulose (tissue paper), and plant samples by supercritical fluid extraction (SFE) route. CEs showed poor extraction of ~(137)Cs from soil matrix. SFE experiments using 1 9 10~(-3) M solutions of CMC, CBC and CNC in acetonitrile at 3 M HNO3 as modifiers displayed better extraction of ~(137)Cs, viz. 21(±2) % (CMC), 16.5(±3) % (CBC), and 4(±1) % (CNC). It was not possible to recover ~(137)Cs quantitatively from soil matrix. The inefficient extraction of ~(137)Cs from soil matrix was attributed to its incorporation into the interstitial sites. Experiments on tissue papers using CMC showed near quantitative ~(137)Cs recovery. On the other hand, recovery from plant samples varied between 50(±5) % (for stems) and 75(±5) % (for leaves).