酸热水解制备蓝藻基植物激励素条件优化及产物特征

以蓝藻作为原材料,对蓝藻进行酸热水解,分析蓝藻酸热水解最优条件,并通过内梅罗指数、地累积指数法、潜在生态指数法和人体暴露健康风险评价验证各条件制备的蓝藻基植物激励素施用于土壤的安全性.结果显示,采用2%草酸进行水解可利用草酸对重金属的络合作用以降低蓝藻基植物激励素的环境风险,同时为保证蓝藻的水解效果,耦合硫酸调节pH值至0.8,水解时间保持24h是最优酸热水解条件.各条件制备的蓝藻基植物激励素内梅罗指数、地累积指数、潜在生态指数分别处于无风险、无污染和低风险水平,对人体致癌风险和非致癌风险均低于安全阈值10^(-6)和1.利用半连续流酸热水解体系可提升蓝藻基植物激励素中有益物质的浓度,发现经过3~4个周期的水解富集,植物激励素中N、P、K等营养物质稳定在3942、290.45和421.7mg/kg.2-(5H)-呋喃酮和吡咯类物质等生物刺激素类物质在植物激励素中不断富集后达到29.5646和11.261mg/kg,均可发挥促进植物生长和抑制病菌的作用.同时,生物碱类、酚类物质等化感物质在水解过程中被破坏,有效减轻了其对植物生长的抑制作用.

利用剩余活性污泥制备氨基酸叶面肥

目的与方法:优化热酸水解法制取剩余活性污泥中蛋白质及利用蛋白质制取氨基酸的条件,并利用制得的氨基酸螯合微量金属元素合成氨基酸叶面肥。结果:利用热酸水解法制取剩余活性污泥中蛋白质的最优条件为温度120℃、反应时间5h、酸碱度为2mol/L盐酸;在酸碱度为6mol/L盐酸条件下,由蛋白制取氨基酸的最优条件为温度120℃、反应时间5h;另外,利用1.5g纯化的氨基酸与微量金属元螯合生成1.9g氨基酸叶面肥。结论:利用剩余活性污泥制备氨基酸叶面肥的得率受到诸如反应温度、时间、酸碱度等条件的影响;粗氨基酸的纯化得率对最终氨基酸叶面肥的产量具有重要影响。

Kinetics of thermal decomposition of lanthanum oxalate hydrate

Lanthanum oxalate hydrate La2（C2O4）3·10H2O,the precursor of La2O3 ultrafine powders,was prepared by impinging stream reactor method with PEG 20000 as surfactant.Thermal decomposition of La2（C2O4）3·10H2O from room temperature to 900 °C was investigated and intermediates and final solid products were characterized by FTIR and DSC-TG.Results show that the thermal decomposition process consists of five consecutive stage reactions.Flynn-Wall-Ozawa（FWO） and Kissinger-Akahira-Sunose（KAS） methods were implemented for the calculation of energy of activation（E）,and the results show that E depends on α,demonstrating that the decomposition reaction process of the lanthanum oxalate is of a complex kinetic mechanism.The most probable mechanistic function,G（α）=[1-（1＋α）1/3]2,and the kinetic parameters were obtained by multivariate non-linear regression analysis method.The average E-value that is compatible with the kinetic model is close to value which was obtained by FWO and KAS methods.The fitting curve matches the original TG curve very well.

A Novel Thermally Coupled Reactive Distillation Column for the Hydrolysis of Methyl Acetate

A different pressure thermally coupled reactive distillation column(DPT-RD) for the hydrolysis of methyl acetate(Me Ac) is developed, and its design and optimization procedures are investigated. The sensitivity analysis is carried out to minimize the energy consumption, which is associated with the total annual cost(TAC). The influence of the proposed DPTRD scheme on energy consumption and economic efficiency are evaluated in comparison with the conventional reactive distillation column(CRD). Both the DPT-RD and CRD are simulated with the Aspen Plus?, and it can be observed that for the DPT-RD the energy consumption and the TAC are reduced, and the thermodynamic efficiency is increased as compared with the CRD process.

CoFe_2O_4/CdS nanocomposite:Preparation,characterisation,and application in sonocatalytic degradation of organic dye pollutants

A magnetic CoFe2O4/Cd S nanocomposite was prepared via one-step hydrothermal decomposition of cadmium diethanoldithiocarbamate complex on the surface of CoFe2O4 nanoparticles at a low temperature of 200 ℃.The nanocomposite was characterised by X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FT-IR）,scanning electron microscopy,energy-dispersive X-ray spectroscopy（EDX）,UV-visible spectroscopy,transmission electron microscopy（TEM）,N2 gas sorption analysis,X-ray photoelectron spectroscopy（XPS）,and vibrating sample magnetometry.The FT-IR,XRD,EDX and XPS results confirmed the formation of the CoFe2O4/Cd S nanocomposite.Based on the TEM analysis,the CoFe2O4/Cd S nanocomposite constituted nearly uniform,sphere-like nanoparticles of ～20 nm in size.The optical absorption spectrum of the CoFe2O4/Cd S nanocomposite displayed a band gap of 2.21 e V,which made it a suitable candidate for application in sono/photocatalytic degradation of organic pollutants.Accordingly,the sonocatalytic activity of the CoFe2O4/Cd S nanocomposite was evaluated towards the H2O2-assisted degradation of methylene blue,rhodamine B,and methyl orange under ultrasonic irradiation.The nanocomposite displayed excellent sonocatalytic activity towards the degradation of all dyes examined—the dyes were completely decomposed within 5–9 min.Furthermore,a comparison study revealed that the CoFe2O4/Cd S nanocomposite is a more efficient sonocatalyst than pure Cd S;thus,adopting the nanocomposite approach is an excellent means to improve the sonoactivity of Cd S.Moreover,the magnetic properties displayed by the CoFe2O4/Cd S nanocomposite allow easy retrieval of the catalyst from the reaction mixture for subsequent uses.

Pyrolysis of Banana and Coffee Residues after Acid Hydrolysis

The use of the residues from renewable feedstock, besides the production of fuels, but also for the generation of other chemicals products, has become a priority. Superior plants have considerable potential as carbohydrate, aryl and fatty acids sources. However, the separation of the main constituents of the samples is necessary for several purposes in the biorefinery concept. The acid hydrolysis and pyrolysis processes are very promising technology, however, some adjustments in the conditions of pyrolysis are needed for different biomasses since carbohydrates were detected （14%-17%） in the residues after the conventional acid hydrolysis of these uncommon biomasses （coffee husk and banana stem and stalk）. On the other hand, it was showed that, by pyrolysis, it is possible to obtain from the solid residue after acid hydrolysis： pyrogenic carbon （charcoal with a yield of 48.5%-52.7%） for agriculture use （biochar） and valuable chemicals in the pyrolysis oil biooil fraction （that accounted by 26.4%-29.0%, free of water）, such as lignin monomers （32.6%-56.4% of the bio-oil） and fatty acids （30%-52.5%）.