具有静态混合单元的气泡分步结晶过程研究

在气泡分步结晶工艺基础上 ,开发了静态混合气泡结晶技术来提纯均四甲苯。实验表明 ,将静态混合单元引入传统气泡结晶器后 ,拓宽了有效鼓泡气速范围 ,明显改善了结晶过程气体均布及压强均布等状况 ,强化了传热、传质过程 。

Ultrasonic-assisted condensation of chitosan with salicylaldehyde

In order to synthesize an improved adsorbent for heavy metal ions,we studied the condensation reaction of chitosan with salicylaldehyde in ethanol to form a Schiff base.The effect irradiating the reaction using an ultrasonic liquid processor was contrasted with conventional methods.The IR spectra of condensed chitosan prepared by the two methods showed that their molecular structures were identical.The reaction conditions,including solvents,ultrasonic power density and irradiation time,pH,and reactant ratio,were optimized by orthogonal design.A shorter reaction time and a higher product yield were obtained using ultrasonic-assisted synthesis compared with the traditional method.A condensation degree of 89.63% was achieved using the optimized conditions:i.e.ultrasonic irradiation at 180 W for 60 min;95% ethanol as the solvent,pH 4.0,and salicylaldehyde:chitosan ratio of 6:1.

A novel respirometer for biological toxicity tests

A respirometer has been developed for microbial toxicity tests. The respirometer is based on luminescence quenching by molecular oxygen. The oxygen sensing film consists of luminescent ruthenium complex adsorbed on amorphous fumed silica and immobilized inside silicone rubber. The luminescence intensity depends on the oxygen concentration of sample in contact with sensing film. The inhibition effect of heavy metals on the respiration rate of microorganisms can be evaluated by monitoring the luminescence intensity of the sensing film. The toxicity of Cu 2+ , Zn 2+ , Ni 2+ , Cr 3+ , Pb 2+ and Hg 2+ on activated sludge was tested using the respirometer. The results indicated that the proposed method was sensitive to the heavy metals tested in this experiment. It was feasible to use the respirometer for microbial toxicity tests.

STUDIES OF THE EVAPORATION AND SCALING MITIGATION IN A RECIRCULATING THREE-PHASE FLUIDIZED BED

Heat transfer of liquid evaporation was studied in a recirculating three-phase fluidized bedin which an inert gas serving as'carrying gas'was introduced.The gas velocities,particle sizes,par-ticle densities and particle concentrations in the liquid were examined.Heat fluxes were measured aswell.Significant enhancement in heat transfer was resulted when an inert gas and solid particles wereintroduced into the flow boiling liquid.Scaling mitigation was to be expected in the process.

STUDY ON STYRENE-BUTADIENE BLOCK COPOLYMER FOR THE MODIFICATI0N OF TIRE TREAD

This paper mainly deals with the design and synthesis of a novel styrene-butadieneblock copolymer. When this copolymer is used in the tread portion of tyres, it can improvewet skid resistance and reduce rolling resistance without sacrificing its general physical-mechanical properties. The visco-elastic curve of tire tread using the novel copolymer asits rubber portion was showed. Reactivity ratios for two monomers in the polymerizingsystem were calculated. The diagrams of differelitial, integral and finite difference calculithroughout the whole molecular chain were presented. The influence of the micro- andmacro-structure of the copolymer chain on wet skid resistance and rolling resistance wasdiscussed

Response Surface Methodology as an Approach for Optimization of the Synthesis of 1-(2-Aminoethyl)-2-imidazolidone

Ruthenium loaded on activated carbon pre-treated by HNO3 was used to catalyze the reaction of 1-(2-Aminoethyl)-2-imidazolidone (AEI) synthesized from ethylenediamine, ethanolamine and CO2. Response surface methodology (RSM) based on Box-Behnken design (BBD) was employed to optimize the synthesis of AEI. The statistical analysis results showed that the yield of AEI was significantly affected by the CO2 pressure, reaction temperature and reaction time. According to the results of variance analysis, the value of the determination coefficient of 0.9854 was in reasonable agreement with the “Adj R-Squared” of 0.9666, which means this model can predict the yield of AEI well and can be used to optimize reaction conditions for higher AEI yield. The optimal values of AEI yield predicted by RSM was 84.9% under temperature 206.51?C, CO2 pressure 9.35 Mpa, reaction time 10.11 h, and the verification experiment yield of AEI was 83.1%.

FLOW CHARACTERISTICS IN ENERGY DISSIPATION UNITS OF LABYRINTH PATH IN THE DRIP IRRIGATION EMITTERS WITH DPIV TECHNOLOGY

The energy dissipation mechanism and anti-clogging properties of drip irrigation emitters are closely related to flow characteristics of the fluid in its flow paths, and flow field tests using modem flow visual technologies were carried out by a large number of designers. The Digital Particle ImageVelocimetry （DPIV） system was built for un-disturbed flow tests in the labyrinth path. In this article, the flow field was measured in the flow path section, the structural unit and the local region near sawtooth. Under the pressure level of 10 Kpa, 50 Kpa, 100 Kpa and 150 Kpa, the flows in the two labyrinth paths were in the turbulence state, with flow stagnation regions and whirlpool regions in the structure of the labyrinth path sections. The flow stagnation regions should be eliminated as much as possible. But the vortex should be fully developed, which could increase the self-cleaning capacity and the anti-clogging capacity of the emitter. With respect to the anti-clogging performance and the energy loss efficiency of the emitter, the M-type flow path is better than the K-type flow path.

Recoverable Mn~Ⅲ (salen) supported on diamine modified zirconium poly(styrene-isopropenyl phosphonate)-phosphate as an efficient catalyst for epoxidation of unfunctionalized olefins

Chiral Mn Ⅲ (salen) (Jacobsen's catalyst) was axially immobilized onto a new type of organic polymer-inorganic hybrid materialzirconium poly(styrene-isopropenyl phosphonate)-phosphate(ZPS-IPPA) with different linkage lengths and evaluated as catalysts for the epoxidation of unfunctionalized olefins. The results demonstrated that the prepared catalysts exhibited moderate to good activity and enantioselectivity in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the immobilized catalysts were relatively stable and could be conveniently separated from the reaction system by simple precipitation in hexane. Moreover, higher enantioselectivity was obtained with catalyst 2c than that of homogeneous counterpart catalyzed even after eight times. The excellent recycling of the catalyst was attributed to its structure feature of ZPS-IPPA which is different from either pure polystyrene or pure zirconium phosphates.

Mechanism investigation and catalyst screening of high-temperature reverse water gas shift reaction

Reverse water gas shift(RWGS)catalysis,a prominent technology for converting CO2 to CO,is emerging to meet the growing demand of global environment.However,the fundamental understanding of the reaction mechanism is hindered by the complex nature of the reaction.Herein,microkinetic modeling of RWGS on different metals(i.e.,Co,Ru,Fe,Ni,Cu,Rh,Pd,and Pt)was performed based on the DFT results to provide the mechanistic insights and achieve the catalyst screening.Adsorption energies of the carbon-based species and the oxygen-based species can be correlated to the adsorption energy of carbon and oxygen,respectively.Moreover,oxygen adsorption energy is an excellent descriptor for the barrier of CO2 and CO direct dissociation and the difference in reaction barrier between CO2(or CO)dissociation and hydrogenation.The reaction mechanism varies on various metals.Direct CO2 dissociation is the dominating route on Co,Fe,Ru,Rh,Cu,and Ni,while it competes with the COOH-mediated path on Pt and Pd surface.The eights metals can be divided into two groups based on the degree of rate control analysis for CO production,where CO–O bond cleavage is rate relevant on Pt,Pd,and Cu,and OH–H binding is rate-controlling on Co,Fe,Ru,Ni,and Rh.Both CO-direct dissociation and hydrogen-assisted route to CH4 contribute to the methane formation on Co,Fe,Pt,Pd,Ru,and Rh,despite the significant barrier difference between the two routes.Besides,the specific rate-relevant transition states and intermediates are suggested for methane formation,and thus,the selectivity can be tuned by adjusting the energy.The descriptor(C-and O-formation energy)based microkinetic modeling proposed that the activity trend is Rh~Ni>Pt~Pd>Cu>Co>Ru>Fe,where Fe,Co,Ru,and Ni tends to be oxidized.The predicted activity trend is well consistent with those obtained experimentally.The interpolation concept of adsorption energy was used to identify bimetallic materials for highly active catalysts for RWGS.

Enantioselective epoxidation of nonfunctionalized alkenes catalyzed by recyclable new homochiral bis-diamine-bridged bi-Mn(salen) complexes

Three new homochiral bis-diamine-bridged bi-Mn（salen） complexes were synthesized. Their catalysis on asymmetric epoxidation of a-methylstyrene, styrene and indene was studied with NaC10 and m-CPBA as oxidants respectively. This homogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to the Jacobsen＇s catalyst in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the catalyst could be conveniently recovered and reused at least five times without significant losses of both activity and enantioselectivity. Specially, it also could be efficiently used in large-scale reactions with superior catalytic disposition being maintained at the same level, which provided the potential for the applications in industry. The effect of axial bases, temperature and solvent on activity and enantioselectivity of the catalytic system were also studied.

通过二级污水的深度处理进行废水再生

本研究的目的是探讨二级市政污水再生深度处理系统的性能和污水处理后环境质量的问题。经过活性污泥处理的二级污水被输送到深度废水处理系统，包括移动床沙滤器、粒状活性炭吸附床和臭氧消毒。通过测量再生水的物理化学、微生物和生态毒物学特征评估该设备的性能。沙滤使约45％的浊度被去除，而碳吸附主要提高了有机物去除率，如总有机碳的去除率超过80％。