scholarly journals Low-temperature conversion of Fe-rich sludge to KFeS2 whisker: a new flocculant synthesis from laboratory scale to pilot scale

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Dongxu Liang ◽  
Yu Chen ◽  
Suiyi Zhu ◽  
Yidi Gao ◽  
Tong Sun ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cold Rolling ◽  
Mass Production ◽  
Freeze Drying ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Vacuum Drying ◽  
Air Drying ◽  
Electroplating Effluent ◽  
And Storage

AbstractHerein, a KFeS2 whisker was formed in mass production at a low temperature, with waste cold-rolling sludge as Fe source, which exhibited good performance in the removal of Zn/Ni from real electroplating effluent. At laboratory scale, KFeS2 was generated at 80 °C by the hydrothermal method, and KFeS2 whisker grew radially with the extension of the reaction time. This method was applied at pilot scale, where a similar KFeS2 whisker was also produced with waste cold-rolling sludge as Fe source, and a residual brownish supernatant was observed after the reaction and then completely recycled in the next round for KFeS2 synthesis. After recycling five times, the produced KFeS2 whisker did not change. The drying and storage of KFeS2 have also been verified. Freeze drying and vacuum drying were applicable, whereas air drying was not profitable. Moreover, the efficiency of Zn/Ni removal using undried KFeS2 was similar to that of dried KFeS2. The efficiencies of Zn/Ni removal using KFeS2 were apparently higher those of common reagents for wastewater treatment.

Low-temperature Conversion of Fe-rich Sludge to KFeS2 Whisker: a New Flocculant Synthesis From Laboratory Scale to Pilot Scale

2021 ◽  
Author(s):  
Dongxu Liang ◽  
Yu Chen ◽  
Suiyi Zhu ◽  
Yidi Gao ◽  
Tong Sun ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cold Rolling ◽  
Freeze Drying ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Raw Material ◽  
Electroplating Wastewater ◽  
One Dimensional ◽  
Electroplating Effluent ◽  
Pure Grade

Abstract KFeS2 is a one-dimensional material and commonly used raw material for synthesising AgFeS2 and CuFeS2. With the solvothermal method, KFeS2 cluster could be synthesised at 190 °C with chemically pure grade Fe salt as Fe source. Herein, a KFeS2 whisker was formed in mass production at a low temperature, with waste cold-rolling sludge as Fe source, and exhibited good performance in the removal of Zn/Ni from real electroplating effluent. At laboratory scale, results showed that KFeS2 was not generated after heating at 50 °C for 24 h; however, after heating at 80 °C for 10 h, KFeS2 whisker (diameter and length of 0.2 and 0.5–1 mm, respectively) was produced, which grew radially to 1–4 mm after 24 h. This method was applied at pilot scale, where a similar KFeS2 whisker was also produced with waste cold-rolling sludge as Fe source. At pilot scale, a residual brownish supernatant was observed after the reaction and then completely recycled in the next round for KFeS2 synthesis. After recycling five times, the produced KFeS2 whisker did not change. For KFeS2 drying, freeze-drying and vacuum-drying were applicable, whilst air-drying was not profitable. The prepared KFeS2 was spontaneously hydrolysed in electroplating wastewater to generate Fe/S-bearing oxyhydroxide colloid for Zn/Ni removal. By adding 1 g of KFeS2, the residual levels of Zn/Ni were 0.22 and 0.02 mg/L, met the discharge standard of electroplating wastewater. Undried KFeS2 showed similar efficiencies of Zn/Ni removal to dried KFeS2, whose efficiencies were apparently higher than those with Na2S·9H2O, polymeric ferric sulfuric, sodium diethyldithiocarbamatre and lime. With the method, KFeS2 whisker was produced at pilot scale without generating any secondary waste and exhibited good performance in the treatment of electroplating wastewater.

Simulations and Measurements of Water Vapor Flow and Ice Dynamics in a Freeze-Dryer Condenser

2011 ◽  
Author(s):  
Arnab Ganguly ◽  
Alina Alexeenko ◽  
Frank DeMarco
Keyword(s):  
Water Vapor ◽  
Low Temperature ◽  
Mass Flux ◽  
Freeze Drying ◽  
Laboratory Scale ◽  
Vapor Flow ◽  
Ice Accretion ◽  
Production Scale ◽  
Ice Dynamics ◽  
Freeze Dryer

Freeze-drying is a low-pressure, low-temperature condensation pumping process widely used in the manufacture of pharmaceuticals for removal of solvents by sublimation. The performance of a freeze-dryer condenser is largely dependent on the vapor and ice dynamics in the low-pressure environment. The main objective of this work is to develop a modeling and computational framework for analysis of vapor flow and ice dynamics in such freeze-dryer condensers. The direct Simulation Monte Carlo (DSMC) technique is applied to model the relevant physical processes that accompany the vapor flow in the condenser chamber. Low-temperature water vapor and nitrogen molecular model is applied in the DSMC solver SMILE to simulate the bulk vapor transport. The developing ice front on the coils of the condenser is tracked based on the steady state mass flux computed at the nodes of the DSMC surface mesh. Verification of ice accretion simulations has been done by comparison with the solution for analytical free-molecular flow over a circular cylinder. The developed model has also been validated with measurements of ice growth in a laboratory and production scale freeze-dryer using time-lapse imaging. To illustrate the application of the ice accretion algorithm in the area of bio-pharmaceutical freeze-drying, the current work discusses the effect of the condenser geometry and non-condensable gas on non-uniformity of mass flux in a laboratory scale and production scale freeze-dryer condenser. In addition, the simulations are used to predict the ice formation on the coils of the condenser. It was found that in the laboratory scale dryer, the presence of a duct connecting the product chamber and condenser increased non-uniformity by 65% at a sublimation rate of 5 g/hr. The measured ice thickness on the coils of the condenser was found to increase non-linearly. This non-linearity was captured within an accuracy of 1% compared to the measurements towards the end of a 24 hour cycle using an unsteady icing model while that using a steady model was within 14%. In the production dryer, while the steady model predicted the iced coil diameter within an accuracy of 2–5% with respect to the measurements, the unsteady model captured this within an accuracy of 1–6%. The DSMC simulations demonstrate that by augmenting its capabilities with the icing model, it is possible to predict the performance of a freeze-dryer condenser with any arbitrary design.

scholarly journals Freeze-drying techniques for preserving aphids (Homoptera, Aphidodea)

1994 ◽  
Vol 5 (2) ◽  
pp. 105-113 ◽  
Author(s):  
Anders Albrecht
Keyword(s):  
Freeze Drying ◽  
Body Shape ◽  
Vacuum Drying ◽  
Drying Methods ◽  
Drying Time ◽  
Freeze Dried ◽  
Drying Techniques ◽  
Wax Coating ◽  
And Storage

Techniques for collection, preparation and storage of freeze-dried aphid samples, including galls, are described. Freeze-drying can be done with the aid of a home freezer, a drying agent, and suitable containers alone, but drying time can be reduced considerably with cheap and simple vacuum drying equipment. Freeze-drying methods have several advantages compared with traditional mounting techniques. Body shape, colours, wax coating and microsculpture are excellently preserved. The labour required per sample, for preparation as well as for identification, is reduced to a minimum, and complete colony samples can be stored as entities. Aspects of practical handling and study of freeze-dried aphid samples are discussed.

scholarly journals Effect of vacuum-drying, hot air-drying and freeze-drying on polyphenols and antioxidant capacity of lemon (Citrus limon) pomace aqueous extracts

2017 ◽  
Vol 52 (4) ◽  
pp. 880-887 ◽  
Author(s):  
Konstantinos Papoutsis ◽  
Penta Pristijono ◽  
John B. Golding ◽  
Costas E. Stathopoulos ◽  
Michael C. Bowyer ◽  
...  
Keyword(s):  
Antioxidant Capacity ◽  
Freeze Drying ◽  
Vacuum Drying ◽  
Citrus Limon ◽  
Aqueous Extracts ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air

Effects of dilution, freezing and thawing and drying on the dispersibility of isolated fat globule membrane

1966 ◽  
Vol 33 (2) ◽  
pp. 217-222
Author(s):  
H. C. Chien ◽  
T. Richardson ◽  
C. H. Amundson
Keyword(s):  
Low Temperature ◽  
Spray Drying ◽  
Freeze Drying ◽  
Vacuum Drying ◽  
Freezing And Thawing ◽  
Lipoprotein Particles ◽  
Fat Globule

SummaryThe effects of dilution, freezing and thawing, and drying on the dispersibility of fat-globule membrane (FGM) preparations were studied. Dilution of FGM favoured aggregation of the lipoprotein particles. Freezing and thawing of FGM had a similar effect. Drying FGM by roller-drying markedly decreased its dispersibility. Drying by low-temperature vacuum-drying only slightly increased the dispersibility of FGM, while freeze-drying and spray-drying gave larger increases in the dispersibility.

Preservation of Plant Cell Surfaces For Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 472-473
Author(s):  
Linda M. Sicko ◽  
Thomas E. Jensen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Filter Paper ◽  
Freeze Drying ◽  
Cell Surfaces ◽  
Air Drying ◽  
Popular Method ◽  
Critical Point Drying ◽  
Scanning Electron

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.

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