Bui Hoang Bac

Glass–ceramic from mixtures of bottom ash and fly ash

Along with the gradually increasing yield of the residues, appropriate management and treatment of the residues have become an urgent environmental protection problem. This work investigated the preparation of a glass-ceramic from a mixture of bottom ash and fly ash by petrurgic method. The nucleation and crystallization kinetics of the new glass-ceramic can be obtained by melting the mixture of 80% bottom ash and 20% fly ash at 950 °C, which was then cooled in the furnace for 1h. Major minerals forming in the glass-ceramics mainly are gehlenite (Ca(2)Al(2)SiO(7)) & akermanite (Ca(2)MgSiO(7)) and wollastonite (CaSiO(3)). In addition, regarding chemical/mechanical properties, the chemical resistance showing durability, and the leaching concentration of heavy metals confirmed the possibility of engineering and construction applications of the most superior glass-ceramic product. Finally, petrurgic method of a mixture of bottom ash and fly ash at 950 °C represents a simple, inexpensive, and energy saving method compared with the conventional heat treatment.

Highly ordered Ge-incorporated akaganeite (β-FeOOH): a tunnel-type nanorod

A highly ordered Ge-incorporated akaganeite with the atomic ratio of Ge/Fe = 0.14 and Cl/Fe = 0.11 was firstly synthesized through hydrolysis and acidification of a mixed solution of FeCl3·6H2O and TEOGe (Ge(OC2H5)4) under the α-Fe2O3 synthesis conditions. The newly synthesized Ge-akaganeite shows a monodisperse nanorod with 15–17 nm in width and ∼200 nm in length, the distinctly enhanced structural ordering and stability, and substantial differences in crystallographic and magnetic features. Here we propose a hypothetical akaganeite model with Ge occupying the tunnel sites as Ge(OH)40 based on crystallographic and chemical analyses.

Effective utilization of incinerated municipal solid waste incineration ash: zeolitic material synthesis and silica extraction.

In this study the effective utilization of two types of municipal solid waste incinerator (MSWI) ashes, namely air-cooled ash (ACS) and water-cooled ash (WCS) samples obtained from a municipal solid waste incineration plant, was examined by applying zeolitic material synthesis and silica extraction. The influence of the experimental conditions including the ratio of sample : NaOH solution, the reaction temperature and time, and the concentration of NaOH solution were investigated. The results for the 25 experimental trials can be summarized as: (1) the formation of tobermorite and/or pectolite-1A as a major component in most conditions; (2) the synthesis of hydroxycancrinite as a major phase at 200 °C; (3) a dramatic increase in the extracted SiO2 yield at 1 : 30 value of sample : NaOH ratio and 200 °C, even at short reaction times; and (4) relatively high SiO2 yields for WCS ashes rather than ACS ashes. An increase in the reaction time improved the quantity of synthesized zeolitic materials. The reaction temperature determined the type of zeolite. An increase in the NaOH concentration can be an essential factor to improve zeolitic material synthesis, but it significantly reduced the yield of SiO2 extraction. In conclusion, suitable conditions for obtaining both SiO2 extraction and synthesized zeolites from the ashes of the incinerated solid waste materials should be: 200 °C reaction temperature; a 1 : 30 (g : mL) value for the sample : NaOH ratio; 2 mol L—1 NaOH concentration; and a reaction time of more than 24 h.In this study the effective utilization of two types of municipal solid waste incinerator (MSWI) ashes, namely air-cooled ash (ACS) and water-cooled ash (WCS) samples obtained from a municipal solid waste incineration plant, was examined by applying zeolitic material synthesis and silica extraction. The influence of the experimental conditions including the ratio of sample : NaOH solution, the reaction temperature and time, and the concentration of NaOH solution were investigated. The results for the 25 experimental trials can be summarized as: (1) the formation of tobermorite and/or pectolite-1A as a major component in most conditions; (2) the synthesis of hydroxycancrinite as a major phase at 200 degrees C; (3) a dramatic increase in the extracted SiO(2) yield at 1 : 30 value of sample : NaOH ratio and 200 degrees C, even at short reaction times; and (4) relatively high SiO(2) yields for WCS ashes rather than ACS ashes. An increase in the reaction time improved the quantity of synthesized zeolitic materials. The reaction temperature determined the type of zeolite. An increase in the NaOH concentration can be an essential factor to improve zeolitic material synthesis, but it significantly reduced the yield of SiO(2) extraction. In conclusion, suitable conditions for obtaining both SiO(2) extraction and synthesized zeolites from the ashes of the incinerated solid waste materials should be: 200 degrees C reaction temperature; a 1 : 30 (g : mL) value for the sample : NaOH ratio; 2 mol L(-1) NaOH concentration; and a reaction time of more than 24 h.

Ge-incorporation into 6-line ferrihydrite nanocrystals

A Ge-incorporated ‘6-line’ ferrihydrite with 20% of total Fe3+ sites occupied by Ge4+ was synthesized for the first time through hydrolysis and acidification of the mixed solution of Fe(NO3)3·9H2O and TEOGe (Ge(OC2H5)4). The newly synthesized Ge-ferrihydrite shows a monodisperse nanocrystalline structure with diameters of ∼10 and ∼40 nm with distinctly enhanced crystallinity and stability.

A new model for water adsorption in porous ceramics

This research proposes a new isotherm model that is derived for adsorption of clustering and condensable vapors on mesoporous ceramics. The adsorption characteristics of water vapor on both experimental data and isotherm model were investigated over the relative pressure ranging from 0 to 0.95. The applicability of the model was evaluated by significance of fitting parameters. For each adsorption isotherm there are five parameters (m, qf, Kf, qm and Km). The comparison of modeling fit with experimental data was used as the methodology for selecting the most informative and the best-fitting model. The experimental testing results showed that this model is able to describe all possible behaviors of the water adsorption isotherm displaying type IV classification. The model is based on the forming and growth of the water molecule clusters and capillary condensation mechanism in mesopore. The findings suggest a significant tool for understanding the behavior of water adsorption in humidity-control porous ceramics.

A novel method of mesostructured material architecture using DBD plasma on illite with non-expandibility

The mesostructured material architecture using hydroxyl groups derived from DBD plasma within illite structure has been successfully accomplished by hydrothermal conditions under between 353 and 373 K and pH=6 condition.