Protein drugs have attracted extensive attention from the academic community. However, crystallization of proteins is difficult and the yield of current main technologies is too low, which limits their large-scale industrial production. In this work, enhancement of continuous crystallization of lysozyme under an ultrasonic field was explored. A plug-flow tubular crystallizer, which was separated into a nucleation zone and a growth zone, was applied. The effect of ultrasound on steady-state time, crystal habit, particle size, particle size distribution, and the process yield was evaluated based on univariate analysis experiments. It was found that ultrasound can shorten the time for continuous crystallization to reach a steady state, reduce the degree of aggregation, and promote nucleation. Furthermore, the separation of the growth zone from the nucleation zone in the ultrasonic-assisted continuous crystallization can further increase the size of the lysozyme crystals, which would help in increasing the yield.
Methanol vapor as a contaminant presented
in industrial streams
leads to catalysts deactivation. Therefore, it needs deep removal
with adsorption technique. The isotherms and effective diffusion coefficients
of methanol vapor are essential to design the purification process.
The equilibrium sorption of methanol steam on commercial zeolites
NaX, KA, and CaA and activated alumina were tested using an intelligent
gravimetric analyzer, respectively. The equilibrium experiments were
carried out at 303.2 K and pressures of up to 19.6 kPa, and the results
obtained were fitted with the Dubinin–Astakhov (D-A) model.
Moreover, the diffusion of methanol vapor in the adsorbents was investigated,
and the effective diffusion coefficients were obtained with fitting
the Fick diffusion model. The adsorbents are compared on the basis
of adsorption capacities for methanol steam, and the descending order
of zeolites is NaX > CaA > KA > Al2O3. The sorption
equilibrium experimental results of methanol steam on NaX, KA, and
CaA agree well with D-A isotherm model, while it is not very well
consistent on Al2O3. The equilibrium adsorption
capacities of methanol vapor are consistent with the effective diffusion
coefficients on the adsorbents.
Ibuprofen fine crystals prepared by commonly used methods have some problems such as low‐crystallinity product and uneven distributed particle size. An ultrasonic‐assisted tubular crystallization system was developed. The effects of tubular crystallization temperature, supersaturation, residence time, surfactant, and flow pattern on the crystal size distribution and average particle size were studied. It was found that ultrasound promotes nucleation and reduces crystal aggregation. Ibuprofen crystals with an average particle size of 6.23 μm were formed owing to the high degree of continuous supersaturation and promoted micromixing. Finally, a possible mechanism of enhancement of micromixing under ultrasonic and slug flow on tubular crystallization was proposed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.