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This work presents the study on solid-liquid mass transfer performance of suspension in a rotating packed bed (RPB). The calculation model of solid-liquid mass transfer coefficient (ks) is deduced on the basis of the mass conversation law. The ks in RPB is measured using the suspension of cation exchange resin particle reaction with NaOH. The effects of different operating parameters such as pre-dispersion time (t), rotating speed (N), mesh packing thickness (w), liquid volume flow rate (LT), and solid loading (e) are investigated. The results show that the ks increases with the increase of N and w, and increases first and then tends to remain constant with the increase of t and LT. However, the e has no influence on ks. The obtained ks ranges from 1.00×10-5 m/s to 2.60×10-4 m/s which is higher than that in microreactor (MR) under the similar experimental conditions.

In this paper, ZSM-5@MnOx catalyst was firstly prepared by in situ growth for the selective oxidation of benzyl alcohol to benzaldehyde. The coating effects of MnOx on ZSM-5 and OV formation mechanism at the ZSM-5-MnOx interface were investigated. Results showed that the sodium ions of ZSM-5 are found to be conducive to the better coating for MnOx. Hydrogen protons of zeolite can dehydrate with the OH groups on MnOx to generate the OVs where the oxidation of benzyl alcohol occurs. Besides, the deep dehydration at the ZSM-5-MnOx interface via increasing post-treatment temperature can further enrich the OV concentrations. The ~100% benzyl alcohol conversion and ~100% benzaldehyde selectivity over the ZSM-5@MnOx catalyst can be obtained within 3 h at 383 K. The findings of the structure-activity relationship of zeolite’s surface properties and OVs over MnOx can provide important guiding principles for the rational design of oxidation catalysts.

Hierarchical (micro/mesopore) ZSM-5 zeolites were hydrothermally synthesized with enhancing micromixing of the high viscosity reaction system in a rotating packed bed (RPB). Herein, the effects of four operating processes with different micromixing intensity on nucleation/crystal growth process as well as properties of ZSM-5 zeolites were investigated. Results indicated that enhancing micromixing by RPB in the zeolite synthesis could facilitate the formation of Al sites and shorten the nucleation and crystallization period. ZSM-5 samples prepared by the RPB premix process exhibit hierarchical structure, smaller average particle size, more uniform particle size distributions, larger specific surface areas, higher catalytic stability as well as more Bronsted and Lewis acid sites. While adopting the prepared ZSM-5 zeolites with RPB premix for catalyzing C4-olefin cracking reaction, the conversion of C4-olefin and yield of propylene were higher than that obtained by traditional stirring tank reactor premix.

In this study, PS was synthesized by gaseous SO3 sulfonation of distillate oil in a rotating packed bed. The chemical compositions of the prepared PS and its raw material (distillate oil) were obtained by the combined analysis of the double-bond equivalent and carbon number at the molecular level. In addition, the EOR performance of PS has been studied by measuring surface tension, interfacial tension (IFT), wettability alteration and core-flooding experiments. An ultra-low IFT value 1.327×10-3 mN/m between the crude oil and prepared PS solution was obtained at the critical micelle concentration (CMC) of PS solution. Core flooding experiments showed that additional oil recoveries of 28.10% and 30.77% were obtained at PS concentrations of 0.3% and 0.6% respectively after conventional water flooding, indicating the prepared PS has good performance on EOR.

In this work, we have investigated the dispersion and rheological behavior of BaTiO 3 nanoparticles aqueous suspension using ammonium polyacrylate (PAA-NH 4 ) as a dispersant agent over a wide range of solids concentration ( Φ = 0.03–0.5) and of shear rate 1–1000 s −1 . The results showed that the addition of PAA-NH 4 decreased the suspension viscosity pronouncedly. The suspensions all appeared pseudoplastic over the shear-rate range investigated, revealing that the mixtures were flocculated in structure. The relative viscosity ( η r ) of the suspension, defined as the suspension viscosity over the viscosity of the suspension medium, was found increasing substantially when Φ exceeds 0.4. A derivative of η r , i.e., 1− η r −1/2 , appeared linearly proportional to Φ , from which maximum solids fraction ( Φ m ) was determined as Φ m = 0.574 for the given suspension system. Casson model was used to fit the experimental data and a useful parameter yield stress ( τ y ) obtained. Shear rate dependence on viscosity was accurately described by the Casson equation and the yield stress of the suspensions presented a power-law dependence with the solid fraction.

The aim of this work was to prepare azithromycin (AZI) nanosuspensions to increase the solubility and dissolution rate.AZI nanosuspensions were prepared by the combination of reactive precipitation and freeze-drying in presence of biocompatible stabilizer. Formulation and process variables affecting the characteristics of nanosuspensions were optimized. Various tests were carried out to study the physicochemical characteristics of AZI nanosuspensions.The nanosuspensions were parenterally acceptable and autoclavable, because soybean lecithin was the stabilizer of choice and no organic solvents were used during the preparation. The mean particle size and zeta potential of the AZI nanosuspensions were about 200 nm (±20 nm) and -36.7 mV (±7.6 mV), respectively. Solid nanoparticles were obtained by lyophilization of the nanosuspensions and nanosuspensions rapidly reconstituted when the nanoparticles were dispersed in water. X-ray diffraction and differential scanning calorimetry analysis showed that the crystal state of nanoparticles was amorphous. Solubility and in vitro release studies indicated that the saturated solubility and dissolution rate increased obviously in comparison of raw AZI. The nanoparticles were physically stable over a period of 5 months as demonstrated by unchanged crystallinity and stable particle size when stored at room temperature and protected from humidity.The results suggested that reactive precipitation is an effective way to prepare AZI nanosuspensions with increased solubility and dissolution rate.

The colloidal stability of nanosized barium titanate (BaTiO3) aqueous suspensions with ammonium polyacrylate (PAA-NH4) at different pH values has been investigated by means of zeta potential, adsorption isotherm, sedimentation, and rheology characterization. The isoelectric point of BaTiO3 powders is at pH 2.5 and the value of zeta potential is at its maximum near pH 10. The amount of leached barium ion decreases with increasing pH, but the change decreases with increasing initial pH. Adsorption of PAA-NH4 onto the surface of BaTiO3 decreases its zeta potential. Results show that PAA-NH4 adsorption follows Langmuir monolayer adsorption isotherms and the amount of PAA-NH4 required to stabilize nanosized BaTiO3 suspensions decreases as the pH increases. The mechanism of stabilization of BaTiO3 is shown to be electrosteric under the experimental conditions. Good agreement between zeta potential, sedimentation, and rheological tests is found, which identifies an optimum pH value of about 10 and an optimum dispersant concentration of about 2.0 wt%, independent of the solids volume fraction of suspensions.