Hygienic design of a unit for supercritical fluid drying – case study

Purpose The purpose of this paper is to evaluate the hygienic design of a scalable unit for supercritical carbon dioxide drying of food. Design/methodology/approach For the purpose of this study, a checklist has been developed, covering requirements from sanitary standards and industry-tailored guidelines. Beyond hygienic design, failure mode and effects analysis of the results were performed to assess the potential food safety risks that may arise from failures to hygienic design requirements. Findings The overall score of the hygienic design was 46 percent. This kind of evaluation revealed two types of nonconformities. The first type was related to inadequate sanitary procedures. The second type was associated to design failures. Research limitations/implications The highest risk was designated to problems related to cleaning and sanitation followed by risks associated with the formation of dead zones and biofilms. Practical implications This study provides valuable insight to engineers and food technologists on hygienic design issues. Originality/value Application of a similar methodology was used for evaluating hygienic design of other non-thermal food technologies.

Drying Technologies for the Stability and Bioavailability of Biopharmaceuticals

Solid dosage forms of biopharmaceuticals such as therapeutic proteins could provide enhanced bioavailability, improved storage stability, as well as expanded alternatives to parenteral administration. Although numerous drying methods have been used for preparing dried protein powders, choosing a suitable drying technique remains a challenge. In this review, the most frequent drying methods, such as freeze drying, spray drying, spray freeze drying, and supercritical fluid drying, for improving the stability and bioavailability of therapeutic proteins, are discussed. These technologies can prepare protein formulations for different applications as they produce particles with different sizes and morphologies. Proper drying methods are chosen, and the critical process parameters are optimized based on the proposed route of drug administration and the required pharmacokinetics. In an optimized drying procedure, the screening of formulations according to their protein properties is performed to prepare a stable protein formulation for various delivery systems, including pulmonary, nasal, and sustained-release applications.

Synthesis and physicochemical properties of graphene/ZrO2 composite aerogels

Graphene/ZrO2 composite aerogels with large BET areas have been synthesized using a sol–gel method together with a supercritical fluid drying process.

The Effect of pH of the Aging Solution on Microstructure of Silica/Zirconia Aerogel

ZrO2 wet gel was prepared using zirconium n-butoxide as precursor and 1,2-propylene oxide (PO) as a gelation agent in sol-gel process. Then, tetraethoxysilane (TEOS) was used to strengthen the wet gel in aging process. Finally, the monolithic silica/zirconia aerogel was obtained by supercritical fluid drying. N2 adsorption-desorption method, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) were used to characterize microstructure of the aerogel. The influence of pH of the aging solution on microstructure of silica/zirconia aerogel was studied. The results indicate that the particle size distribution of SiO2/ZrO2 aerogel was more uniform and less aggregate when aging in acid solution. However, the average pore diameter and particle size of SiO2/ZrO2 aerogel was increased by aging in alkaline solution. Aging in alkaline condition was useful for largening the pore size of SiO2/ZrO2 aerogel, and the maximum specific surface area and pore volume were obtained at pH=9. Meanwhile, different reactions were produced between the acid/alkaline solution and the hydroxyl of SiO2/ZrO2 aerogel, and the ester group/amino group was obtained relatively which can modify the network of aerogel and decrease the shrinkage of aerogel during the supercritical fluid drying.

Preparation and Kinetic Property of Iron-Doped TiO2 Nanoparticles

nanoTiO2 photocatalyst powders were prepared through the sol-gel method and with supercritical fluid drying (SCFD). The SEMXRD and particle size distribution technique were used to characterize the hyperfine TiO2 particles.The reaction of photo-catalysis for methylene blue is in conformity with the first order kinetic law in appearance within the concentration range between 5mg/L and 15 mg/L. As the initial concentration methylene blue in water increase, the appearance rate constant of the reaction decreases while the half-life period of the reaction increases.

Synthesis of Porous NiMo Sulphide Act as HDS Catalyst by Alcohol Supercritical Drying Technique

Porous NiMo sulphide was successfully synthesized from ethanol supercritical fluid drying technique using (NH4)2MoS4and Ni(NO3)2as the precursors. It was shown that the NiMo sulphide had extremely high porosity and the specific surface area was 322 m2•g-1. The results of DBT hydrodesulfurization experimental showed that the porous NiMo sulfide prepared had high HDS activity, which was 2.78 times higher than that of a commercialized supported catalyst.

Preparation and Photocatalytic Property of Lanthanum-Doped TiO2 Nanoparticles

Nano-TiO2 photocatalyst powders were prepared through the sol-gel method and supercritical fluid drying(SCFD). The TG-DTA、XRD、particle size distribution technique、SEM were used to characterize the hyperfine TiO2 particles.The lanthanum-doped TiO2 with different mass percentage of La3+ were compared with pure TiO2 when used as photocatalyst in degradation of methyl orange. The best catalytic activity was observed with 0.02(mol)%La-TiO2. Photocatalytic efficiency of the 0.02(mol)%La- TiO2 is improved by 30.79% comparing to pure TiO2.

Sol-Gel Template Synthesis and Photocatalytic Property of Nano-TiO2 Co-Doped with La and Fe

Nano-TiO2 co-doped with lanthanum and iron photocatalyst powders were prepared with the sol-gel method and supercritical fluid drying(SCFD). The XRD、particle size distribution technique、TEM were used to characterize the hyperfine TiO2 particles.The TiO2 co-doped with different mass percentage of La3+ and Fe3+ were compared with pure TiO2 when being used as photocatalyst in degradation of methyl orange.The best catalytic activity was observed by TiO2 co-doped with 0.02%La-0.05%Fe(mol).Photocatalytic efficiency of the TiO2 co-doped with 0.02%La and 0.05%Fe is 1.625 times the pure TiO2.