Wyniki wyszukiwania - BazTech

1

Spray drying as a method of producing silk sericin powders

Genç G., Narin G., Bayraktar E.

Journal of Achievements in Materials and Manufacturing Engineering

|

2009

|

Vol. 37, nr 1

78-86

EN

Purpose: The purpose of paper is to analyse Spray drying as a method of producing silk sericin powders. Design/methodology/approach: Aqueous sericin solutions were used as raw material for the production of dry powders using a lab-scale spray dryer. A linear regression analysis of agglomeration was employed, in addition to experimental designs at two levels with three factors for the analysis of three responses: moisture content, particle type and agglomeration degree. The process factors were the drying air temperature (120şC and 160şC), the feed rate (1.25 × 10-7 and 2.5 × 10-7 mł/s), and the concentration of sericin solutions of 10% and 30% (w/w) fed to the spray dryer. Findings: The three responses were analyzed statistically to determine the effective parameters and it was concluded that moisture content depended on three factors--drying air temperature being the dominant parameter. Particle size and shape depended mainly on feed rate and agglomeration depended on the moisture content of the product. Practical implications: As a result of the growing interest in drug delivery through a pulmonary route for local and systemic effects, the crucial physical characteristics of the spray-dried sericin influencing the dispersion and deposition behaviour including particle size, morphology, moisture content and agglomeration degree were examined for formulation and spray drying variables. Originality/value: The most effective parameters on particle size and morphology were found to be the feed solution concentration and feed rate, while the temperature was an insignificant variable.

2

Spray drying as a method of producing silk sericin powders

Genc G., Narin G., Bayraktar O.

Archives of Materials Science

|

2008

|

Vol. 29, nr 1-2

16-28

EN

Aqueous sericin solutions were used as raw material for the production of dry powders using a lab-scale spray dryer. A linear regression analysis of agglomeration was employed, in addition to experimental designs at two levels with three factors for the analysis of three responses: moisture content, particle type and agglomeration degree. The process factors were the drying air temperature (120 degree C and 160 degree C), the feed rate (1.25 × 10 to -7 and 2.5 × 10 to -7 m3/s), and the concentration of sericin solutions of 10% and 30% (w/w) fed to the spray dryer. The three responses were analyzed statistically to determine the effective parameters and it was concluded that moisture content depended on three factors--drying air temperature being the dominant parameter. Particle size and shape depended mainly on feed rate and agglomeration depended on the moisture content of the product.

3

Removal of trivalent chromium from aqueous solutions by amphiphilic core-shell poly(methyl acrylate)/silk sericin nanospheres

Song Y., Jin Y., Sun J., Wei D.

Polimery

|

2007

|

T. 52, nr 11-12

880-884

EN

Well-defined, core-shell poly(methyl acrylate/silk sericin) (PMA-SS) nanospheres, ranging from 100 to 150nm in diameter, were prepared via a direct graft copolymerisation of methyl acrylate (MA) with silk sericin (SS). The polymerisation was induced by a small amount of tert-butyl hydroperoxide (TBHP) in water at temp. 353K. The PMA-SS core-shell nanospheres were used as adsorbent in a series of batch adsorption experiments for the removal of trivalent chromium from aqueous solutions. The experimental results showed that PMA-SS nanospheres were an effective adsorbent for trivalent chromium from aqueous solution, and the maximum amount of adsorption reached 4.876mg Cr3+/g of sorbent within the experimental range. With the increase in pH values of solutions, the adsorption increased obviously, while the addition of electrolyte had a little effect on the adsorption. The adsorption equilibrium was reached after about 3h. The adsorption of trivalent chromium by PMA-SS nanospheres was significantly higher than that done by SS powder under the same adsorption conditions.

PL

Metodą bezpośredniej kopolimeryzacji szczepionej akrylanu metylu (MA) na serycynie (SS) otrzymano nanosfery typu rdzeń-otoczka (PMA-SS) o średnicach zawierających się w przedziale 100-150nm (rys. 1 i 2). Kopolimeryzację prowadzono w temp. 353K w roztworze wodnym i inicjowano za pomocą wodoronadtlenku tert-butylu (TBHP). Zbadano zdolność otrzymanych nanosfer PMA-SS do adsorbowania Cr3+ z roztworów wodnych. Stwierdzono, że ilość zaadsorbowanego Cr3+ rośnie wraz ze wzrostem stężenia początkowego roztworu (Co) osiągając wartość 4,876mg Cr3+/g sorbentu w temp. 293K w przypadku roztworu o pH=6,0 i Co=3,5mg Cr3+/L (rys. 3). Zaobserwowano, że w badanym przedziale pH od 4,0 do 6,0 adsorpcja wyraźnie rośnie ze wzrostem pH (rys. 4). Badania wykazały także, że ilość zaadsorbowanego Cr3+ nieznacznie wzrasta pod wpływem dodania do roztworu niewielkiej ilości KCl jako dodatkowego elektrolitu (rys. 5). Na podstawie badań kinetyki adsorpcji określono, że równowaga jest osiągana po ok. 3 godz. Na zakończenie porównano wyniki adsorpcji Cr3+ za pomocą nanosfer PMA-SS z wynikami uzyskanymi w takich samych warunkach z zastosowaniem jako adsorbenta samego proszku SS i stwierdzono zdecydowanie większą efektywność adsorpcji w pierwszym przypadku.