离交法提取柠檬酸所用离交柱结构改进及操作参数的优化

通过对单室和双室离交柱吸附柠檬酸运行效果的对比,确定采用双室固定床离交柱,并对其结构进行了改进,同时优化了树脂填装高度和流体流速等。通过测量单室不同高度时树脂膨胀所引起的阻力,得出最佳高径比为2∶1。对比相同树脂高度时的双室和单室树脂膨胀所引起的阻力,说明采用双室可以明显减小树脂膨胀所引起的阻力,下室最佳高径比为2∶1,上室为1.2∶1,最佳流体流速为4倍树脂体积/h,树脂的膨胀率约为10%。

碳柱酸、碱水综合利用探讨

离交柱再生的碱、酸水,进行再次利用,可降低盐酸、烧碱用量和蒸汽消耗,减少废水排放。同时不会影响味精液的质量,达到一举多得的目的。

Biocontrol Efficiency of Bacillus subtilis SL-13 and Characterization of an Antifungal Chitinase

The seed germination and tomato seedling tests showed that Bacillus subtilis SL-13 could promote the sprouting and seedling growth of tomato.The fresh and dry weight of tomato seedlings increased 42.86%and 18.75%,respectively.The control efficacies of the SL-13 to tomato Rhizoctonia rot were 20.65%and 35.23%in the greenhouse and field,respectively.The growth of the plant-pathogenic fungus Rhizoctonia solani was considerably inhibited in the presence of the strain SL-13 culture supernatant.The main antifungal protein was detected to be chitinase through vitro assay.The chitinase was purified with DEAE-Sepharose fast flow ion exchange column chromatography and Sephadex G-75 gel filtration for further characterization.The optimal pH and temperature for the chitinase activity were 7.0 and 50°C,respectively.It was demonstrated that the enzyme was stable at pH 5-9 and 40-60°C.70%of the enzyme activity was retained when incubated at 121°C and 0.11 MPa for 20 min,and the enzyme was not sensitive to protease K and ultraviolet radiation.Thus it is suitable for effective biological control in relatively unstable environment.

Removal of Uranium（Ⅵ） by Fixed Bed Ion-exchange Column Using Natural Zeolite Coated with Manganese Oxide

The adsorption of uranium(Ⅵ)on the manganese oxide coated zeolite(MOCZ)from aqueous solution was investigated in a fixed-bed column.The experiments were conducted to investigate the effects of bed height,flow rate,particle size,initial concentration of uranium(Ⅵ),initial pH,presence of salt and competitive ions.The U-uptake by MOCZ increased with initial uranium(Ⅵ)concentration and bed height,but decreased as the flow rate and particle size increased.In the presence of salt and competitive ions,the breakthrough time was shorter.The adsorption capacity reached a maximum at pH of 6.3.The Thomas model was applied to the experimental data to determine the characteristic parameters of the column for process design using linear regression.The breakthrough curves calculated from the model were in good agreement with the experimental data.The BDST model was used to study the influence of bed height on the adsorption of uranium(Ⅵ).Desorption of uranium(Ⅵ)in the MOCZ column was investigated.The column could be used for at least four adsorption-desorption cycles using 0.1mol.L-1 NaHCO3 solution as the elution.After desorption and regeneration with deionized water,MOCZ could be reused to adsorb uranium(Ⅵ)at a comparable capacity.Compared to raw zeolite,MOCZ showed better capacity for uranium(Ⅵ)removal.

Simulation of one-dimensional column leaching of weathered crust elution-deposited rare earth ore

The ion exchange model of the leaching process was determined via batch leaching experiments using the Kerr model, with the selectivity coefficient experimentally determined to be 12.59×10^-10 L^2/g^2. Solute transport laws of ammonium ions (NH4 +) and rare earth ions (RE^3+) in column leaching were described by the convection-dispersion equation (CDE). The source and sink in the CDE were determined by the Kerr model. The CDE with strong nonlinearity was solved using the sequential non-iterative method. Compared with the breakthrough curve of RE^3+, the correlation coefficient between the simulated and experimental curves reached 0.8724. Therefore, this method can simulate the one-dimensional column leaching of weathered crust elution-deposited rare earth ore. Moreover, the effects of different concentrations of ammonium sulfate ((NH4)2SO4) solution on the leaching rate of rare earth were analyzed. The optimal concentration of the (NH4)2SO4 solution had a linear relationship with the rare earth grade.

Influence of earth gravity on reaction engineering of tubular reactor for high concentration tungsten ion-exchange

The influence of gravity on the reaction engineering of tubular reactor is studied by analyzing the residence time distribution curves.The results show that upflow-feeding mode is more beneficial compared with downflow-feeding mode,since the flow pattern of the fluid in the reactor is closer to plug flow.The result of dynamic experiment conducted in ion-exchange of tungsten metallurgy is as good as that in reaction engineering of ion-exchange column.Whether downflow-feeding or upflow-feeding mode is adopted,breakthrough time decreases when solution concentration increases.Upflow-feeding mode has longer breakthrough time and greater improvement in adsorption capacity especially with high WO3 concentration in ion-exchange.

Identification of Fucans from Four Species of Sea Cucumber by High Temperature ~1H NMR

Acidic polysaccharide, which has various biological activities, is one of the most important components of sea cucumber. In the present study, crude polysaccharide was extracted from four species of sea cucumber from three different geographical zones, Pearsonothuria graeffei(Pg) from Indo-Pacific, Holothuria vagabunda(Hv) from Norwegian Coast, Stichopus tremulu(St) from Western Indian Ocean, and Isostichopus badionotu(Ib) from Western Atlantic. The polysaccharide extract was separated and purified with a cellulose DEAE anion-exchange column to obtain corresponding sea cucumber fucans(SC-Fucs). The chemical property of these SC-Fucs, including molecular weight, monosaccharide composition and sulfate content, was determined. Their structure was compared simply with fourier infrared spectrum analyzer and identified with high temperature 1H nuclear magnetic resonance spectrum analyzer(NMR) and room temperature 13 C NMR. The results indicated that Fuc-Pg obtained from the torrid zone mainly contained 2,4-O-disulfated and non-sulfated fucose residue, whereas Fuc-Ib from the temperate zone contained non-, 2-O- and 2,4-O-disulfated fucose residue; Fuc-St from the frigid zone and Fuc-Hv from the torrid zone contained mainly non-sulfated fucose residue. The proton of SC-Fucs was better resolved via high temperature 1H NMR than via room temperature 1H NMR. The fingerprint of sea cucumber in different sea regions was established based on the index of anomer hydrogen signal in SC-Fucs. Further work will help to understand whether there exists a close relationship between the geographical area of sea cucumber and the sulfation pattern of SC-Fucs.

Purification of Proteins from Ginkgo Biloba Seeds and Their Antioxidant Activities

Ginkgo biloba seeds were widely used for food and traditional medicine in china. In the present study, antioxidant proteins named GP were purified from Ginkgo biloba seeds. The proteins （GP） were purified by homogenization of Ginkgo biloba seeds powder in the saline solution, precipitation with 70% ammonium sulphate, and filtration on DEAE-Cellulose 52 anion exchange column. GP showed protein content of 96%, and they showed three bands with approximate molecular weight of 15 kDa, 17 kDa, 21 kDa respectively by SDS-PAGE electrophoresis analysis. Compositions of amino acids obtained by Amino Acid Analyzer showed GP were rich in Glu, Ser ,His ,Asp, Gly, Ala, Leu and Lys compared with the other fractions. The antioxidant activities of GP were investigated using DPPH （the 1, 1-diphenyl-2-picrylhydrazyl） free radical-scavenging and ferric-reducing antioxidant power assays. The GP showed antioxidant activities higher than α-Tocopherol and BHA. Therefore, the present study demonstrates proteins from Ginkgo biloba seeds （GP） can be excellent antioxidant.

Direct extraction of Mo(VI) from acidic leach solution of molybdenite ore by ion exchange resin:Batch and column adsorption studies

The adsorption behavior of ion exchange resin D301 in the extraction of hexavalent molybdenum from high acidic leach solution was investigated. SEM, EDS and Raman spectra analyses were applied to studying the adsorption capacity, reaction kinetics and possible adsorption mechanism in detail. Results showed that the adsorption capacity of D301 resin for molybdenum from high acidic leach solution was up to 463.63 mg/g. Results of the kinetic analysis indicated that the adsorption process was controlled by the particle diffusion with the activation energy 25.47 k J/mol（0.9-1.2 mm） and 20.38 k J/mol（0.6-0.9 mm）. Furthermore, the molybdenum loaded on the resin could be eluted by using 2 mol/L ammonia hydroxide solution. Besides, dynamic continuous column experiments verified direct extraction of molybdenum from acidic leach solutions by ion exchange resin D301 and the upstream flow improved dynamic continuous absorption.