Turning Pore Size of Silica-Based Nano-TiO2 for Treating Cyanide Wastewater

Cyanide wastewater is a very highly toxic substance. In this study, a kind of silicon-based nano-TiO2 material by turning pore size accurately is prepared to treat cyanide wastewater. The materials are characterized by XRD, TG analysis, N2 adsorption/desorption test, UVAS analysis and TEM. Results show that adding NaCl to the synthesis of silica supports can change the size of pores. It emerges that pore size can affect the catalytic performance of the material. Catalytic experiments confirm that cyanide has the best catalytic effect when it has a pore size of 16.47 nm. UVAS spectrum demonstrate that the cyanide has been broken down rather than adsorbed onto the material.

COMPATIBILITY STUDY BETWEEN PRAVASTATIN AND EZETIMIBE, AND PHARMACEUTICAL EXCIPIENTS USED IN FIXED-DOSE COMBINATION TABLET

Objective: The purpose of this study was to qualitatively predict drug-excipient binding interactions for stable drug formulation of a pravastatin and ezetimibe fixed-dose combination (FDC) tablet. Methods: Drug impurity-excipient interactions under accelerated conditions (40°C/75% relative humidity) for 4 weeks were confirmed by high-performance liquid chromatography, X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. Results: Pravastatin impurity was affected by four excipients under accelerated conditions for 4 weeks. Ezetimibe was affected by two excipients. Any other results were within the acceptance criteria. XRD analysis for physical stability revealed characteristic peaks of pravastatin and ezetimibe at a diffraction angle of 2θ (pravastatin: 4.1–24.4°, and ezetimibe: 13.62–29.59°) without a change in the crystalline form after 4 weeks. DSC and TG analysis showed evidence of stability in Alu-Alu foil. Conclusion: Thus, the tested excipients were confirmed to be compatible with pravastatin and ezetimibe and can be used in FDC bi-layer tablets.

Influence of organosilicon admixtures on the hydration of Portland cement

The impact of three different organosilicon compounds: poly(dimethylsiloxane) (PDMS), potassium methylsiliconate (MESI) and triethoxyoctylsilane (OTES), used as integral admixtures, on Portland cement hydration has been investigated by isothermal calorimetry and DTA-TG analysis. The silicon-based compounds are widely used as internal hydrophobic agents added into batch water; therefore, their effectiveness was investigated by means of capillary water absorption test. The isothermal calorimetry was used to measure the rate and amount of heat released during ordinary Portland cement hydration with integral organosilicon admixtures at 20 °C, 30 °C, 40 °C and 50 °C. It allowed to determine the activation energy as well. The results indicate that used admixtures (except MESI admixture) decrease in the rate and amount of heat release during cement hydration. In addition, it is noticeable that the addition of MESI admixture significantly prolongs the induction period and delays hydration. In contrast to MESI and OTES admixtures, PDMS-based admixture does not affect significant on the activation energy. DTA-TG analysis had shown differences between reference sample and samples containing organosilicon admixtures during thermal decomposition, in terms of the amount of moisture and bound water, as well as Ca(OH)2 or carbonates. The results presented in this paper enable a better understanding of the interactions between the organosilicon integral admixtures and the cement matrix. The study shows the effect of integral admixtures on cement hydration and thus the potential effect on the final properties of the cement-based material.

Thermogravimetric analysis of cancellous bone of humerus head in patients undergoing total shoulder arthroplasty

Prior to shoulder replacement, the quality of cancellous bone stock of humerus head should be evaluated. Thermogravimetric analysis (TGA) has already been utilized to assess thermal stability of cancellous bone mineral, collected from the femoral head of patients with osteoarthritis and osteoporosis. Our workgroup has recently examined the thermal parameters of rotator cuff of patients undergoing reversed shoulder replacement. We hypothesized that TGA of humerus head would indicate difference in the bone quality of orthopedic and trauma patients. We also hypothesized that the calorimetric data could correlate with the grade of degenerative changes. Cylindrical subchondral humeral head samples were collected from patients subjected to reversed shoulder replacement due to orthopedic or trauma indications. Then, calorimetric parameters were measured using DTA/TG analysis. Radiological evaluation was also performed to classify the grade of osteoarthritis. In case of orthopedic samples, the calorimetric parameters indicated a moderate to severe degree of bone damage and loss of mineralization, because of the progressed osteoarthritis. Meanwhile, the trauma samples exhibited only moderate or minimal subchondral bone degeneration. DTA curves showed different patterns and indicated shifts in transition temperatures, comparing control and pathologic samples. In addition, correlation was found between the degree of osteoarthritis and calorimetric enthalpy. DTA/TG analysis of humerus head samples indicated marked differences in bone quality of orthopedic and trauma patients. Further investigation is needed to differentiate the calorimetric parameters of different layers of subchondral bone.

Thermogravimetric devolatisation behavior of agricultural residue for generation of syngas

The thermal degradation characteristics of eucalyptus, pearl millet cob, and corncob were investigated using non-isothermal thermogravimetric method. This investigation was performed with the objective of carrying out thermochemical conversion for obtaining syngas. TG and DTG analysis were carried out to understand thermal devolatisation behavior and estimation of various thermophysical properties of the biomasses. The degradation behavior was analysed in the light of lignocellulosic composition that was found to have definitive influence on degradation outcomes. TG analysis has been utilized to obtain proximate analysis of biomass. Activation energy using Flynn-Wall-Ozawa method have been estimated and found to be 201, 150 and 68 kJ mol−1 for eucalyptus, pearl millet cob, and corncob respectively. The TG analysis and activation energy together indicated that corncob is easiest for thermochemical conversion amongst the three biomasses. The TG curve also confirms the same.

Effect of CaO on catalytic combustion of semi-coke

Generally, adding a certain amount of an additive to pulverized coal can promote its combustion performance. In this paper, the effect of CaO on the combustion characteristics and kinetic behavior of semi-coke was studied by thermogravimetric (TG) analysis. The results show that adding proper amount of CaO can reduce the ignition temperature of semi-coke and increase the combustion rate of semi-coke; with the increase in CaO content, the combustion rate of semi-coke increases first and then decreases, and the results of TG analysis showed that optimal addition amount of CaO is 2 wt%. The apparent activation energy of CaO with different addition amounts of CaO was calculated by Coats–Redfern integration method. The apparent activation energy of semi-coke in the combustion reaction increases first and then decreases with the increase in CaO addition. The apparent activation energies of different samples at different conversion rates were calculated by Flynn–Wall–Ozawa integral method. It was found that the apparent activation energies of semi-coke during combustion reaction decreased with the increase in conversion.

DTA/TG analysis of mechanochemicaly activated sodium carbonate

Sodium carbonate is a material that is very good sorbent of carbon dioxide from the atmosphere, and it is a reason of it is increasing importance in environmental protection. In order to improve it is sorption characteristics, activation of Na2CO3 was performed by mechanochemical procedure and monitoring of changes during the relaxation time. This research is based on differential thermal analysis with thermogravimetry, in order to determine the changes that occurred on the activated samples during the relaxation period under controlled conditions. Sodium carbonate was activated for 2 and 7 minutes in a vibro mill, and then the activated samples were deposited in at room temperature and atmosphere of carbon dioxide at a humidity of 95% for 96h.

Multi-method (XRF, FTIR, TGA) analysis of ancient bricks from Karabalgasun : A preliminary study

Ancient ceramic artefacts attracted the attention of scientists as being a chronological indicator within the archaeological context; however, they can also provide information about the tech-nology and provenance. A series of brick samples from an ancient nomadic town at Karabal-gasun (Mongolia) have been analyzed using X-ray fluorescence (XRF) spectroscopy, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis in order to obtain information on the performance of the kilns used and on the technological skills of ancient pot-ters.

2,4,6-Tris(4-Iodophenyl)-1,3,5-trimethylbenzene

2,4,6-Tris(4-iodophenyl)-1,3,5-trimethylbenzene was synthesized from 2,4,6-triphenyl-1,3,5-trimethylbenzene, using [bis(trifluoroacetoxy)iodo]benzene as the iodinating agent. The title compound was characterized by means of NMR, IR, and mass spectrometry, as well as TG analysis.