Papers by Keyword: Purification

Abstract: Flow pattern and mode have a far influence on the efficiency of biological treatment systems. In order to investigate the effects of different flow patterns on the growth of Bacillus subtilis, a self-developed fluid mixing device was designed to produce different liquid fluidization. It was found that the greater Re, the more conducive to the growth of bacteria, which evidenced by the logarithmic phase shorter and reached stationary phase bacteria concentration increased; when the Reynolds number is low, growth curve of Bacillus subtilis appeared Growth - stationary - growth and cell precipitation phenomenon, both phenomena gradually disappeared when Re increases. Besides, it can consume dissolved oxygen after inoculation with Bacillus subtilis, which keeping the dissolved oxygen in the medium at a lower level (0~1mg/L)

Abstract: Mesoporous chitosan-silica composite sorbent has been successfully synthesized by a simple and facile template-free hydrolyzing route from single cheap silica precursor of sodium silicate. The overall decolorization efficiency and capacity for sugar juice between pure chitosan and composite sorbent are very close in field pilot-scale, while much lower quantity of chitosan (only 10 wt.%) is used to build the composite sorbent. The success of increased purification performance and sorption capacity of sugar juice is ascribed to the appropriate pore structure of the composite sorbent with high surface area (395 m²/g), large pore size (7.73×10^-9 m) and high percentage of accessible free amine groups of chitosan (70 %).

Abstract: Using plants Ophiopogon japonicus, with river sand and soil matrix to construct artificial wetland system, analyzes the effect of the purification of wastewater containing lead, and to study the influences of different flow on the purification efficiency. Experimental results show that the Ophiopogon japonicus artificial wetland to lead the lead in wastewater purification effect is good, with 2 L/d of wastewater flow trendy, Ophiopogon japonicus removal rate as high as 95.8%, of artificial wetland to lead bubbled into 16 L/d for wastewater discharge, removal rate can reach 85.3%.

Abstract: An ammonia synthesis using magnetic field to replace Haber-Bosch’s ammonia production is great technological challenge in novel magnetized catalysts area. The carbon nanofiber supported iron catalyst was prepared by modifying carbon nanofiber support surface and later using urea to precipitate iron nitrate by deposition precipitation. It was found that the particle size was in a range of 5-50nm and well dispersion of iron was shown by transmission electron microscopy. This was strongly influenced by alteration of carbon nanofiber surface from hydrophobic to hydrophilic and with high adsorption sites as oxygen functional groups and defects. The lower iron loading between 5 and 40%wt, the lower iron accumulation and the narrower the particle size distribution of 10-20nm. The result suggests that the iron particles are in a good size range for iron catalyst activity for ammonia synthesis as reported by Morawski et.al and Figurski et.al authors.

Abstract: Some adsorbents were tested for indoor air purification from carbon dioxide. The obtained experimental data on the capacity of adsorbents allowed to carry out estimated calculations for definition of daily quantity of a sorbent for absorption of excess quantity of CO₂. An experimental stand for assessing sorption capacity of adsorbents for gas mixtures containing CO₂ in the air composition, biogas, etc. created, allows using model gas carry out qualitative and quantitative estimation of the compositions of input and output streams and the absorptive capacity of the tested materials.

Abstract: In order to investigate the effect of absorption and purification of indoor formaldehyde by chlorophytum comosum under normal circumstance, chlorophytum comosum is used as the test material and formaldehyde concentration of different closure time is measured by indoor formaldehyde velocimeter. Absorptive capacity of chlorophytum comosum on indoor formaldehyde is analyzed by comparing formaldehyde concentration. The results of experiment show that taking closure time of 24h as an example formaldehyde concentration changes from 0.41 mg/m3 to 0.32 mg/m3 and the removal rate is 21.95% in the room of 15 square meters ,and absorption effect of chlorophytum comosum is good for indoor formaldehyde. Combined with the actual situation chlorophytum comosum can be used in the room place and decorative materials with less formaldehyde content are chosen ,and indoor temperature and humidity remain appropriate to purify indoor formaldehyde by combining with the ventilation method.

Abstract: Extracting dihydromyricetin from Ampelopsis grossedentata by water extraction method. The orthogonal test and single factor experiment were used to optimize the best extraction condition. The ratio of liquid and material is 20:1, extraction time is 90min, extraction temperature is 90°C,holding time is 1d. The results of comparison between two purification methods show: Purify with acetone and recrystallization with water is better. The purity of dihydromyricetin is high to 98%, recovery rate was 59.2%.

Abstract: AlN single crystal can be grown by physical vapor transport (PVT) method. The purity and particle size of the source material are important factors for single crystal growth to obtain good quality of AlN single crystal. The aim of this study was purification of AlN powder and growth of its particle size through thermocyclic treatment. The initial particle size was about 1.0 μm and the purity was 98.4% containing 1.6% oxygen and metallic impurities such as Fe, Sn, Ca, Na and Mg etc. which were analyzed based on KSL1612. For purification of AlN powder, it was performed using a thermocycle process with various thermocyclic numbers. After the thermocycle treatment, it is able to obtain large particle size AlN powder as much as 30μm and purity was increased to 99.6% based on chemical analysis.

Abstract: The State of Paraíba, Brazil, retains about 88.5% of all Brazilian bentonite, and much of this production comes from deposits in the District of Boa Vista, PB. Nevertheless, the deposits are almost depleted. Recently, new deposits were found, which will increases the reserves of the State, in the regions of Cubati and Pedra Lavrada, PB. The objective of this work is to characterize and develop purified clays, through sieving and hydrocycloning techniques, from those recently discovered bentonites for several applications. The characterization of the sample was done through granulometric analysis by laser diffraction, X-ray diffraction, chemical analysis by X-ray fluorescence, and thermogravimetric and differential thermal analysis. The results show that the samples are typical of bentonite clays, and that the purification solely by hydrocyclone presents the best results.

Abstract: The adsorption and desorption properties of Astragalus Polysaccharide (APS) (70% content) on Macroporous resins including X-5, AB-8 and D101 have been compared. APS solutions of different concentrations were tested to find a suitable sample concentration on the macroporous resins. According to our test results, AB-8 performs better than other resins. The adsorption capacity and desorption rate are 41.73mg/ml and 83.74%, higher adsorption speed for APS. Column chromatograph with AB-8 resin was used for the purification test, the sample concentration of APS is 20mg/ml, the purity of APS can reach 94.68%.