Effects of Disodium Hydrogen Phosphate Addition and Heat Treatment on the Formation of Magnesium Silicate Hydrate Gel

The formation of magnesium silicate hydrate gel is crucial in preventing magnesia aggregates from over hydrated during the construction of refractory castables since the presence of magnesium hydroxide diminish the mechanical properties of the material. This work aimed to investigate the accelerating effects of sodium hydrogen phosphate and heat treatment on the formation of magnesium silicate hydrate gel. Time-dependent pH of magnesia - silica fume slurries with and without sodium hydrogen phosphate addition and heat treatment was measured to verify the dissolution of MgO and magnesium silicate hydrate formation. The effects of sodium hydrogen phosphate were differentiable only at small added amounts, whereas heat treatment at 50 degrees Celsius performed noticeable acceleration. This observation could be applicable in molding to maintain the stability of basic refractory castables.

DIELECTRIC MEASUREMENTS ON PURE AND KDP ADDED DISODIUM HYDROGEN PHOSPHATE (DSHP) SINGLE CRYSTALS

Electrical conductivity is an elegant experimental tool to probe the structural defects and internal purity of crystalline solids. In the present study we have grown pure and KDP added DSHP single crystals by the slow evaporation method from aqueous solutions at room temperature. Good quality transparent crystals have been obtained. Melting point and density measurements were done. Electrical conductivity measurements were carried out with two frequencies, 100 Hz and 1 kHz at various temperatures ranging from 2 to 30oC by using the parallel plate capacitor method. The present study indicate that the dielectric constant and AC and DC conductivities increase with increase of temperature.

Laccase production by Pycnoporus sp. W-9 using rose dregs and its application for phenol degradation

Rose dregs were used for laccase production by the strain Pycnoporus sp. W-9 under liquid fermentation, and the obtained laccase was used for phenol degradation. The conditions for laccase production were optimized by Box-Behnken design, and the phenol degradation conditions using the crude laccase were optimized by central composite design. The optimal conditions for laccase production by the strain W-9 were as follows: rose dregs (40 g/L), KCl (0.144 g/L), KH2PO4 (1 g/L), K2HPO4 (0.699 g/L), NaCl (0.2 g/L), MgSO4·7H2O (0.3 g/L), CuSO4·5H2O (0.306 g/L), Tween 80 (0.2 g/L), and CaCO3 (1 g/L), at a pH of 6.0, incubated at 30 °C and 200 rpm for 7 d. The corresponding laccase yield reached 17.4 U/mL, which was approximately 1.8 times the original production. The optimal conditions for phenol removal by the crude laccase were as follows: laccase (12.2 U/mL), 0.1 mol/L citric acid-disodium hydrogen phosphate buffer (pH 3.5), phenol (100 μg/mL), and Triton X-100 (284 μg/mL), incubated at 45 °C for 2 h. The corresponding phenol degradation rate reached 86.6%. These results should be useful for utilization of rose dregs and bioremediation of soil and wastewater.

Ultrasound assisted synthesis and pharmacological evaluation of some (E)-1,2,3-triphenylprop-2-en-1-ones

More than 85% yield of (E)-1,2,3-triphenylprop-2-en-1-ones were synthesized using disodium hydrogen phosphate (Na2HPO4) catalyzed ultrasound assisted aldol condensation of 1,2-diphenylethanone and various substituted benzaldehydes. Synthesized (E)-1,2,3-triphenylprop-2-en-1-ones were examined by their spectroscopic data, yield, micro analysis and physical constants. The effect of solvent on the yield was investigated. The pharmacological effects such as antibacterial and antifungal activities of synthesized enones were evaluated with Bauer-Kirby disc diffusion method.