http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Mesoporous silica synthesis in sub- and supercritcal carbon dioxide
Phillip Pendleton,전병수,Alexander Badalyan,Sun-Young Park 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.3
Mesoporous silicas were synthesized from sodium silicate (Na2Si3O7) and tetraethylorthosilicate (TEOS)with Pluronic F127 (polyethylene oxide-polypropylene oxide-polyethylene oxide, EO106PO70EO106) triblock copolymer using sub- and supercritical carbon dioxide (SubCO2 and SCO2) respectively, as solvents. Templates were removed using liquid carbon dioxide (LCO2) and SCO2. The most efficient template removal was achieved by LCO2 - 92.7%(w/w), followed by LCO2 with ethanol entrainer - 85.6% (w/w), and by methanol - 78.8% (w/w). The best efficiency of template removal by SCO2 was 50.7%. Values of specific surface areas, ABET, were increased by 10% with the increase of an ageing time from 6 to 24 hours for Na2Si3O7-based silicas at aqueous synthesis conditions, whereas the use of SCO2 reduced this value by 19.4%. For TEOS-based silicas synthesized using SCO2, ABET values increased by 3.8 times. Application of SCO2 for synthesis of TEOS-based silicas resulted in higher mesopore volumes of 0.719 and 1.241 mL/g with an average mesopore width varying from 3.4 to 3.9 nm. Although Na2Si3O7-based silicas have almost similar mesopore width range, their mesopore volumes were 7 times less than those for TEOS-based silicas. Formation of mesopores in Na2Si3O7- and TEOS-based silicas was at the expense of micropores when synthesized in SCO2.
David Nkurunziza,Phillip Pendleton,Saravana Periaswamy Sivagnanam,박진석,전병수 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-
This study aimed to enhance the hydrolytic conversions of conjugated isoflavones to non-conjugatedaglycones from soybean byproducts (okara) using subcritical water hydrolysis. Processing parameters fortemperature, pressure and solid liquid mixing ratio were set as constant variables following theexperimental design performed in our previous study for the optimization of isoflavones extraction andkinetics modeling using subcritical water and response surface methododology. Fixed operatingconditions were temperature (T: 150 C), pressure (P: 4 MPa) and solid liquid ratio (s/l: 20 mg/mL), andthe reaction time was the sole control variable. The results revealed that prolonging the reaction timeincreased the concentrations of genistein and daidzein by 6.5 and 9 fold, respectively. Total phenoliccontents increased up to 55%, and the antioxidant activities exhibited a strong correlation with isoflavoneaglycones and phenolic contents.
Adsorption Kinetics of Anionic Surfactants onto Activated Carbon in Fixed-bed
Kim, Jung-Hee,Jeong, Yong-Ok,Pendleton, Phillip 한국공업화학회 2004 Journal of Industrial and Engineering Chemistry Vol.10 No.6
A fixed-bed adsorption column was modeled mathematically using a plug-flow heterogeneous surface diffusion model (PFHSDM) representing the axial dispersed plug-flow, external mass transfer, adsorption equilibrium on the fluid-particle interface, and intraparticle diffusion. The equations were solved simultaneously using the Newton-Raphson method and the finite element method. The external mass transfer coefficients and the surface diffusion coefficients of octanoic acid and dodecanoic acid onto activated carbon were determined respectively from the PFHSDM on a single-component adsorption. The longer molecular dimension of the anionic surfactant led to a faster external mass transfer rate onto the activated carbon, but a slower surface diffusion rate inside its narrow pores. Using the extended Langmuir isotherm for binary component adsorption, the estimated kinetic coefficients of the two anionic surfactants agreed remarkably well with those of the single-component adsorption. Also they were applied to a differential column batch reactor system to predict the concentration level required for the optimal design and operation of the system.