Novel Removal of Diazinon Pesticide by Adsorption and Photocatalytic Degradation of Visible Light-Driven Fe-TiO2/Bent-Fe Photocatalyst

In the study, Fe was used as a dopant to enhance photocatalytic activity of TiO2. Then, the Fe-doped TiO2 was deposited on bentonite, which was pillared by Fe. The synthesized materials were characterized by SEM, XRD, UV-Vis, BET, and point of zero charge (pHPZC). Then, the synthesized materials were used for diazinon removal under both dark and visible light conditions to investigate adsorption and photocatalytic degradation abilities of the synthesized materials. The maximum diazinon adsorption capacity of the synthesized Fe-TiO2/Bent-Fe was 27.03 mg/g. The obtained results indicated that the Fe-TiO2/Bent-Fe exhibited high photocatalytic degradation activity for removal of diazinon even under visible light. The diazinon removal experiments were also conducted using different photocatalyst dosages, under different pH and light sources to figure the optimal conditions for removal processes. The obtained results indicated that optimal photocatalyst dosage and pH were 0.5 g/L and 4.5, respectively. Finally, the natural light generated from solar could be suitable used for diazinon removal by the synthesized Fe-TiO2/Bent-Fe

Breast cancer diagnostic efficacy in a developing South-East Asian country

Background: Breast cancer, is increasing in prevalence amongst South East (SE) Asian women, highlighting the need for high quality, early diagnoses. This study investigated radiologists’ detection efficacy in a developing (DC) and developed (DDC) SE Asian country, as compared to Australian radiologists. Methods: Using a test-set of 60 mammographic cases, 20 containing cancer, JAFROC figures of merit (FOM) and ROC area under the curves (AUC) were calculated as well as location sensitivity, sensitivity and specificity. The test set was examined by 35, 15, and 53 radiologists from DC, a DDC and Australia, respectively. Results: DC radiologists, compared to both groups of counterparts, demonstrated significantly lower JAFROC FOM, ROC AUC and specificity scores. DC radiologists had a significantly lower location sensitivity than Australian radiologists. DC radiologists also demonstrated significantly lower values for age, hours of reading per week, and years of mammography experience when compared with other radiologists. Conclusion: Significant differences in breast cancer detection parameters can be attributed to the experience of DC radiologists. The development of inexpensive, innovative, interactive training programs are discussed. This nonuniform level of breast cancer detection between countries must be addressed to achieve the World Health Organisation goal of health equity

Separation of thorium and uranium from xenotime leach solutions by solvent extraction using primary and tertiary amines

This study addressed the development of a continuous countercurrent extraction-scrubbing-stripping technique using a mixture of primary and tertiary amines as an effective extractant for both thorium (Th) and uranium (U) to simultaneously separate them from the leach solutions of xenotime concentrate from the Yen Phu mine (Vietnam). Systematic studies determined the optimum parameters of the separation, including the optimum concentrations of the mixture of the primary amine (N1923) and tertiary amine (tri-n-octyl amine), the optimum acidity (pH) of the feed liquor (Yen Phu xenotime leachate), the optimum contact time between phases for extraction, scrubbing and stripping processes, and the most suitable stripping reagent mixture. Using the optimum parameters, the optimum stage number and phase volumetric ratio for extraction, scrubbing, and stripping processes were calculated using the calculus method based on the law of matter conservation. The flow rates of both phases for extraction, scrubbing, and stripping were determined from the results of these studies and calculations. To optimize the separation of uranium and thorium from the Yen Phu xenotime leachate, countercurrent simulations of extraction, scrubbing and stripping were done in a series of mixer-settler units. The results indicated that the selective separation of Th and U with almost no loss of rare earths (REs) and a minimal contamination of iron were obtained. The continuous countercurrent extraction-scrubbing-stripping technique shows potential applications in the commercial separation of Th and U from RE leachate after tests using a sequence of mixer-settler units on a pilot scale

Optimization of sulfuric acid leaching of a Vietnamese rare earth concentrate

The modeling of Yen Phu (Vietnam) xenotime concentrate leaching by sulfuric acid was studied for the purpose of optimizing the process. The response surface methodology (RSM) based on a central composite face-centered (CCF) design was empirically used to model the interactive effect of the independent variables, namely leaching temperatures of 250–450 °C, acid/concentrate (acid/conc.) mass ratios of 0.8–1.8, and leaching times of 2–6 h, on the dependent response, namely the leaching yield. And a CCF model for the leaching of the concentrate was proposed that exhibited good consistency with the experimental data. The shrinking core models for spherical particles of constant size based on the Arrhenius equation were empirically used to study the kinetics of the leaching. The activation energies calculated from the kinetic models for the chemical reaction and diffusion rate stages have the same value of 17.3 kJ·mol−1, which fitted well to a mixed control model of the chemical reaction followed by a diffusion stage at leaching temperatures in the range of 473–593 K. The kinetic studies of the leaching indicated that the leaching percent rate (or leaching yield) is controlled by the leaching temperature. The optimization of the leaching process was estimated by analyzing the contributions of the coefficients of the CCF model to the leaching yield. The results indicated that the effect of leaching temperature on leaching yield is the strongest; it is five times higher than that of the acid/conc. Mass ratio and four times higher than that of the leaching time. The effects of acid/concentration mass ratio and leaching time on leaching yield are insignificant. In addition, the optimum data for leaching are as follows: the leaching temperature, acid/conc. Mass ratio, and leaching time are 320 °C, 1.3, and 4 h, respectively. The proposed CCF model and kinetic study suggested that the optimization of the Yen Phu xenotime concentrate leaching is controlled by the leaching temperature; and the CCF model can potentially be applied in the commercial operation of Yen Phu xenotime concentrate leaching after pilot tests on 50 kg dry concentrate per batch