Decomposition of oil cleaning agents from nuclear power plants by supercritical water oxidation

Oil cleaning agents generated from nuclear power plants(NPPs)are radioactive organic liquid wastes.To date,because there are no satisfactory industrial treatment measures,these wastes can only be stored for a long time.In this work,the optimization for the supercritical water oxidation(SCWO)of the spent organic solvent was investigated.The main process parameters of DURSET(oil cleaning agent)SCWO,such as temperature,reaction time,and excess oxygen coefficient,were optimized using response surface methodology,and a quadratic polynomial model was obtained.The determination coefficient(R^(2))of the model is 0.9812,indicating that the model is reliable.The optimized process conditions were at 515 C,66 s,and an excess oxygen coefficient of 211%.Under these conditions,the chemical oxygen demand removal of organic matter could reach 99.5%.The temperature was found to be the main factor affecting the SCWO process.Ketones and benzene-based compounds may be the main intermediates in DURSET SCWO.This work provides basic data for the industrialization of the degradation of spent organic solvents from NPP using SCWO technology.

Effects of oxidants on the degradation of tributyl phosphate under supercritical water oxidation conditions

The effects of additional oxidants,such as NaNO_(3),Na_(2)S_(2)O_(3),KClO_(4),and K_(2)Cr_(2)O_(7),on the supercritical water oxidation(SCWO)of tributyl phosphate(TBP)were studied.The coupling of an ionic oxidant with SCWO can effectively enhance the oxidative degradation ability of the system,thus increasing its organic-matter-removal efficiency at a reduced reaction temperature.Moreover,the addition of NaNO_(3),KClO_(4),or K_(2)Cr_(2)O_(7)could improve this efficiency at a reaction temperature of 500℃compared with that of the original system at 550℃.Additionally,based on the conditions adopted in this study,the addition of either of these oxidants could reduce the final total organic carbon(TOC)of the effluent from~500 to<100 ppm.Concurrently,the ionic oxidants could effectively improve the processing capacity of the SCWO system to reduce the scale of the equipment,as well as the amount of produced wastewater.Compared with KClO_(4)and Na_(2)S_(2)O_(3),the addition of 10 mmol/L NaNO_(3)and K_(2)Cr_(2)O_(7)to the organic feed could increase the processing capacity of the system from 4 to 10%while maintaining the TOC removal at>99%.The effects of the ionic oxidants on the gas products,including CO_(2),CO,H_(2),and CH_(4),as well as other organic gases,have also been studied.Among these gas products,CO_(2)accounted for the main gas product with a proportion of more than half.At<500℃,temperature significantly affected the as products(CO,H_(2),CH_(4),and other organic gases).However,the gas product was mainly CO_(2)when the temperature was increased to≥500℃.This study initially revealed the enhancement effect of ionic oxidants on SCWO,which still requires further research.

The Use of Goal Attainment Scaling in the Acupuncture of Children with Intellectual Disability

Objective: The therapeutic effect of acupuncture is often evaluated based on the experience and judgment of acupuncturists and the subjective feelings of patients. Thus, we investigated the suitability of goal attainment scaling(GAS), an objective outcome measurements, to evaluate the responsiveness of children with intellectual disability to acupuncture therapy. Methods: This is an assessor-blinded, single-group cohort study that included 17 children with intellectual disabilities. The therapeutic effect of acupuncture was assessed by the T scores of GAS at four time points during the 3-month treatment. The responsiveness of GAS to acupuncture therapy was measured using the standardized response mean(SRM). Results: Compared with control, the 4-, 8-, and 12-week scores improved significantly after treatment(P < 0.01, P≤0.001,P≤0.001), with significant differences between each month(P < 0.01, P≤0.001, P≤0.001). Furthermore, all periods assessed GAS(to measure the therapeutic effect of acupuncture) showed marked responsiveness(SRMs >0.8). Conclusion: GAS is responsive in evaluating individual changes in the acupuncture treatment of children with intellectual disabilities. It is a feasible tool to match both the needs of children with intellectual disabilities and the clinical characteristics of acupuncture.