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In this work, mesoporous spherical ��-AlOOH and ��-Al2O3 particles were rapidly prepared by spray pyrolysis (SP) at different temperatures (400��C���700��C) without the use of template materials. A sol-gel-derived colloidal solution of boehmite was ultrasonicated to generate fine droplets, which were continuously and rapidly transferred into a quartz reactor heated at a specific temperature by a constant flow of N2 gas. Under ultrasonication-assisted spray conditions, a phase change from boehmite to ��-alumina occurred at a temperature of 500��C, leading to a decrease in the surface area and surface hydroxyl group density of the products. At 400��C, the produced ��-AlOOH microspheres exhibited the highest surface area values of ca. ~ 510 m2/g and a surface hydroxyl group density of ca. ~ 2.92 mmol/g, surpassing those of commercial boehmite. The Cr (VI) removal experiments revealed that ��-AlOOH and ��-Al2O3 microspheres have good adsorption performance towards Cr6+. The optimal ��-AlOOH spheres exhibited the highest Cr(VI) adsorption capacity of ca.~ 44.5 mg/g (~74%) at 27 ��C and pH = 5.5. After five adsorption-desorption cycles, the synthesised boehmite powder remained a Cr6+ adsorbing capacity of ~ 78%. Notably, the fabricated SP-��-AlOOH was capable of simultaneously removing Cr6+ and textile dye from the solution. This study provides a facile, rapid, and scalable approach for producing boehmite powder with improved properties for Cr (VI) adsorption.

The problem of employment is always a crucial problem and is the concern of most parents and school students. The survey on the perception of 40 students about vocational guidance was carried out in Nguyen Viet Dung High School in Can Tho City, Vietnam. Results show that students are very concerned about their future career; students have a proper perception of vocational guidance and recognize well factors which affect their career choice.

In this study, hybrid poplars were genetically engineered to increase their biomass volume and change their biochemical composition to improve the pyrolytic production of bio-oil. Wild-type hybrid poplars (WT) and genetically engineered hybrid poplars (TP) were comparatively investigated with regard to their pyrolysis characteristics and kinetics via thermogravimetric analysis (TGA) and isothermal pyrolysis within a micro-tubing reactor. Model-free methods were used to determine the activation energy for the thermal decomposition of the WT and TP samples. The results showed that the activation energy of the WT sample was always greater than that of the TP sample at the same level of conversion. Isothermal pyrolysis experiments of the two biomass samples were performed at various temperatures (360–400°C) and durations (1–5 min) using a micro–tubing reactor. A reaction network and quantitative kinetic model were proposed for pyrolysis of the WT and TP samples. Kinetic parameters were obtained through an optimization function and used to explore the parameter space in order to predict product yields as a function of reaction time and temperature for both WT and TP feedstocks.