Papers by Keyword: Purification

Abstract: A novel technique that makes use of electrophoretic deposition (EPD) in upgrading the quality of Philippine clay, specifically for smectite recovery, was explored in this study. Focus was given on understanding the electrophoretic behavior of smectite and kaolinite to effectively control colloidal stability during EPD. Zeta potential measurements showed that pH has negligible effect on the electrophoretic mobility of smectite, but has an appreciable effect on the mobility of kaolinite with the isoelectric point (IEP) of kaolinite recorded around pH 5. Knowing this behavior, EPD of a 3.5wt% smectite-kaolinite slurry was carried out at pH 5 and pH 10. Separation of clay minerals was expected only at pH 5 where kaolinite is almost immobile. However, analysis of deposits using XRD showed some degree of separation (~60% smectite recovery) for both pH values when EPD was performed using stainless steel electrodes at a specific applied voltage and electrode gap, for twenty minutes, without stirring. Further investigation of EPD design is needed to improve smectite recovery.

Abstract: Functionalized of Multi Wall Carbon Nanotubes (MWCNTs) were demonstrated using the nitric acid (HNO₃) oxidation technique in order to get opened caps, removing carbonaceous and metal particles impurities for carboxylic groups (-COOH). The surface morphology and the existence of the carboxyl-group on the MWCNTs were examined using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM), respectively. The carboxylic groups were observed at the peak of 1640.40cm^-1 via FTIR and indicate the absorbance intensity of the functionalized MWCNTs is 2.22 A which is higher than raw material. Furthermore, SEM image shows the bundle of structure on the raw MWCNTs signified the Van der Waals interaction between MWCNTs while after functionalized a groovy CNTs wall were observed due to presence of carboxyl group at the defect sites.

Abstract: Purification of metallurgical-grade silicon (MG–Si) by a combination of Al-Si solidification refining and electromagnetic oscillating separation and acid leaching collection has been studied. The primary Si crystals and Al-Si alloy in hypereutectic Al-30%Si melt were separated during solidification under the pulse electromagnetic field (PEF). The results show that the Si content in Si-rich layer increases with increasing discharging frequency. The typical metallic impurities (Fe, Ti, and Ca) have removal fraction higher than 99.5%. The removal fractions of the impurities B and P which are more difficult to remove are over 90% and 85%, respectively.

Abstract: High purity spherical silica powder was obtained using silica fume as the raw material in this study. The mixture acids of HF and HCl were used in the purification process to remove the impurities contained in the silica fume. The phase of the product was characterized by X-ray diffraction, indicating that the spherical silica powder was amorphous. The chemical composition of the product was investigated by X-ray fluorescence, showing the SiO₂ content was 99.9096 wt%. It had been proved that the purification process could improve the dispersion of the product powder via the morphology comparison and the laser particle analyses. The experimental results showed that the parameters of the product spherical silica powder met all the standards of the electronic-grade packaging materials.

Abstract: The thermal stability of molten salts, operating temperature range and latent heat of melting for the molten salts at high temperature have been studied in the present investigation. The multi-component molten salts composed of purified potassium nitrate, purified sodium nitrate were prepared by statical mixing method [1]. The stability experiments were carried out at 500 to 600°C, and the experimental result showed that the purified nitrate molten salts performed better high-temperature thermal stability and its optimum operating temperature was increased from 500°C to 550°C. DSC analysis indicated that the purified nitrate molten had a lower melting point and a higher phase change latent heat. The melting point of purified binary nitrate molten salts was sharp decreased to 225.2°C and latent heat of melting for molten salts was also reduced from 78.41J/g to 81.15J/g compared with unpurified nitrate salts. Besides, the change in the concentration of impurities by analyzing in the binary molten salts, and combination of XRD test results can be found that the degree of degradation reduce and improve the thermal efficiency of the storage of binary molten salts by purified sodium nitrate and potassium nitrate.

Abstract: Separation and purification of hypocrellin A (HA) and hypocrellin B (HB) are conducted for extracted concentrated solution of hypocrellin through dry packing of molecularly imprinted polymers (MIPs) of hypocrellin A and B and preparative solid phase extraction column. The result shows that the optimum packing column combination for mixed adsorption is H5 (i.e. MIP of hypocrellin A and B are respectively 10.5g and 4.5g), and that the elution sequence is hypocrellin A elution first and then hypocrellin B elution next after the eluent is changed.

Abstract: D301 resin was used to separate and purify total anthraquinones in Radix et Rhizoma Rhei. It was found that the optimized dynamic adsorption conditions is pH7.0, flow velocity of 1.0 BV/h and extracting solution with concentration of 0.3g/mL and optimized dynamic elution conditions is hydrochloric acid with concentration of 0.15mol/L, 75% ethanol, and flow velocity of 1.0 BV/h. Under the above conditions,the average adsorption rate and desorption rate are respectively 89.75% and 91.15%, indicating that extraction efficiency of total anthracenone of emodin is relatively high and that the technology enjoys strong stability.

Abstract: Present study was aimed to identify and isolate the red pigment from Serratia marcesce zl3, and to investigate the factors affecting on the light stability of the purified red pigment. Silica gel and Sephadex LH-20 column chromatography were used for purification, identification was done by TLC, UV, FTIR and HPLC-MS techniques. The effect of pH and light intensity on the light stability of the purified red pigment prodigiosin was analyzed by TLC, UV and HPLC. The stability of identified prodigiosin pigment at pH 1, 3, 5 was superior to that at pH 7, 10, 14 according to the determination of OD₅₃₅. Significant level of degradation of the prodigiosin was observed for 24 h, using 10 klx continuous white light. The effect of pH to the stability of prodidgiosin was partly reversible, while the degradation of prodigiosin under 4, 10, 20 klx white light was irreversible.

Abstract: In this study, the new technological parameters have been optimized for running Single factor experiment and orthogonal design test. Furthermore, the optimal extractible condition of SOD activity from Alfalfa was determined by the assay of NBT photoreduction method. The results reveal that when the ratio of liquor to material is 1 to 10; pH value of phosphate buffer solution is 7.5; ultrasonic power is 400 w, therefore, the SOD activity of Alfalfa is up to 66.54 U/mL. In addition, we characterized the activity analysis of Alfalfa proteins using heat denaturation, ammonium sulfate precipitation and ultraviolet spectroscop. The results showed that the protein removal rate is approximate 91.70 % and SOD specific activity is 6.5 times. Based on the above results, we reached a preliminary estimate that the SOD from Alfalfa is a kind of Cu/Zn-SOD.

Abstract: China is a big country of coal production, in the coal mining process, the great massive mine drainage has caused not only the waste of groundwater resource, but also environmental pollution. On the other hand, mining production and life supply water is very scarce. According to the mine water features, the majority of mine drainage water belonging to the mine water containing suspended, the mine water needs to do the necessary purification then can be used. What the purification mainly eliminates is the suspended. In this paper, the method of purification and the technological process about mine water are discussed. The main methods of handling are coagulation, sedimentation, filtration and disinfection. According to different characteristics of water quality, different ways of handling and technological processes have to be chosen. Finally, the purification and utilization of mine water are shown through practical examples, Pingdingshan Coal Group Company, Wannian Coal Mine of Fengfeng Group Limited Company and Tangshan Coal Mine of Kailuan Group Company, to have obvious social, economic and environmental benefits.