Physicochemical and Sorptive Properties of a Phosphorylated Mercerized Cotton Fabric.

A process of phosphorylation for a mercerized cotton kersey fabric was investigated. After wet oxidation, the phosphorus content in each sample was determined by spectrophotometric analysis. The range was 0.179 to 0.950 mmol g-1. A significant decrease in the tensile strength of samples resulted from an increase of phosphoric acid concentration in the phosphorylating solution. The mercerization has a positive impact on the process of phosphorylation, as the phosphorus content was found to be three times higher in the samples that underwent mercerization. The sorption properties of phosphorylated cotton fabric were studied using the Cu2+ sorption process as a reference. The value of the static exchange capacity for the phosphorylated fabric was determined to reach its maximum when the concentration of the H3PO4 in the phosphorylating solution was 1.40 M, and was found to be 1.48 ± 0.11 mmol g-1 with the phosphorus content equal to 0.898 ± 0.090 mmol g-1. The sorption of Cu2+ by a single phosphorus-containing group occurred for samples with phosphorus content not exceeding 0.80 mmol g-1. The preliminary studies of micro-quantities of 241Am, 233U, and 239Pu radionuclide sorption from aqueous solutions with phosphorylated textile demonstrated the high efficiency.

Immobilization of NPP evaporator bottom high salt-bearing liquid radioactive waste into struvite-based phosphate matrices.

The high salt-bearing liquid radioactive waste (evaporator bottoms, EB) makes up the most voluminous NPP waste and needs solidification. In the paper presented, we introduce a novel formation process study of the struvite-based phosphate matrices ((K, NH4)MgPO4·6H2O) and the developed phosphate matrix compositions for the solidification of high salt-bearing solutions. The solutions simulate the EB of nuclear power plants with pressurized water reactors (NPP PWR). The effect of the EB's composition and salt content on the matrices' mechanical strength was investigated. The cesium-selective nickel-potassium ferrocyanide sorbent or 10-20% of MgO over the reaction stoichiometry, introduced at the matrix synthesis stage, allowed the production of matrices with the average 137Сs leach rate of less than 10-3 g cm-2 day-1 and the mechanical strength over 5 MPa. The matrices obtained completely satisfied the cemented radioactive waste requirements and contained up to 17-17.5 wt% of salts, which was 1.7-2.5 times higher compared to the Portland cement-based matrices.