RESUMEN
Zirconium is commonly used as a cladding material for nuclear reactors. The purity of the zirconium material seeks to control reactor efficiency. A novel composite of reduced graphene oxide-grafted polyacrylic acid, malic acid, and trioctylamine (rGO-g-PAA-MA/TOA) was prepared using in situ radical polymerization with gamma radiation at a dose of 25 KGy from a 60Co cell to preconcentrate zirconium Zr(IV) from zircon raffinate. Five distinct rGO-g-PAA-MA/TOA composite compositions were created and evaluated. The best composite composition was 62.95% acrylic acid, 15.8% malic acid, and 15.8% trioctylamine. After 60 min, the sorption reaction reached equilibrium at pH 0.35 and 20 °C. The pseudo nth order indicated that the order of the sorption reaction was 1.8476. The Elovich model and Dubinin-Radushkevich model controlled the kinetic mechanism and adsorption isotherm of the sorption reaction, respectively; based on estimated regression plots and quantitatively with three different error functions: coefficient of determination (R2), chi-square statistic (χ2), and corrected Akaike information (AICc). The adsorption capacity of rGO-g-PAA-MA/TOA was 75.06 mg g-1. Exothermic reaction and spontaneous sorption took place. Using 2 M H2SO4, 98% of the zirconium was efficiently desorbed. The separation of contaminated Ti(IV) from desorbed Zr(IV) by raising pH to 2.5 through hydrolysis and ZrO2 formation.
Asunto(s)
Circonio , Circonio/química , Rayos gamma , Polimerizacion , Adsorción , Concentración de Iones de Hidrógeno , CinéticaRESUMEN
BACKGROUND AND STUDY AIM: Elevated levels of alpha-fetoprotein (AFP) can be seen in patients with chronic hepatitis C (CHC) and liver cirrhosis without hepatocellular carcinoma and were negatively associated with treatment response. However, factors associated with its changes are not identified. We aimed in this study to verify a cut-off value for AFP as a predictor of response to standard of care (SOC) antiviral therapy in Egyptian chronic hepatitis C virus (HCV)-infected patients and identify factors associated with its changes post treatment. PATIENTS AND METHODS: A total of 175 chronic non-cirrhotic HCV-infected patients were evaluated for baseline serum AFP and liver biopsy were classified according to Ishak scoring system of hepatic fibrosis. All patients were scheduled to receive SOC antiviral therapy for 48weeks and had been followed up to week 72. Reassessment of AFP and repeated liver biopsy at week 72 were feasible only in 79 patients. RESULTS: High baseline AFP levels were observed in non-respondents (non-sustained virological respondents (non-SVRs)) (P<0.01); the AFP level decreased in all patients post treatment (P=0.01), especially in the SVRs (P<0.01). In multivariate analysis, hepatic fibrosis was a predictor of response to treatment (P=0.02), while body mass index (BMI) (25-30kgm(-2)), hepatic activity (A2), hepatic fibrosis stage (F2-F4) and fibrosis improvement were predictors of AFP difference (P=0.007, 0.01, 0.012, <0.001, 0.030, and 0.018), respectively. The diagnostic performance to predict the HCV treatment response was best by adding both AFP and hepatic fibrosis stage factors; the best cut-off value for AFP was 3.57ngdl(-1) with 50% sensitivity and 68% specificity with area under the curve (AUC) of 0.55 and for hepatic fibrosis stage was 3, with a sensitivity of 88%, a specificity of 30% with an AUC of 0.58. CONCLUSION: In chronic HCV-infected patients, serum AFP below 3.57ngdl(-1) and hepatic fibrosis ⩽stage 3 are expected to have good response to treatment; BMI (25-30kgm(-1)), A2, fibrosis >2 and fibrosis improvement predict AFP change post treatment.