adina prezentare re
TRANSCRIPT
Adina Iulia TALMACIU1, Liliana LAZAR2, Irina VOLF3, Valentin I. POPA1
“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 1Department of Natural and Synthetic Polymers; 2Department of Chemical Engineering;
3Department of Environmental Engineering and Management, 73 Dimitrie Mangeron Street, Iasi 700050, Romania
Objectives
Ultrasound assisted extraction
(UAE)
Why UAE? it’s a “green’’ technique it’s rapid (10 - 60 min extraction time) consumes low amounts of solvent, biomass
and energy it’s easy to use offer high extraction yields is a low-cost technique
Biomass: Spruce bark resulted as waste from wood processing industry
Operation conditions: Extraction using 70% ethanol as solvent Solid - solvent ratio 1:10 (g biomass/ mL solvent) Temperatures: 45 0C, 50 0C and 60 0C (318, 323, 333 K) Variable extraction time: 5 to 75 min
Experimental equipment: ultrasound bath SONOREX RK 100H, 35 kHz frequency, 320 W power, automatic control of time and temperature
Materials and methods
Experimental procedure
Ultrasound bathTemperature = 45 0C, 50 0C, 60
0C Time = 5 – 75 min
Extraction vessel
5 g spruce barkEthnol 70 %
(50 mL)
Filtration4 min, 4000 rpm
Solid phase
FTIR
Spectrophotometric analysis for total
polyphenolic content determination using
Folin-Ciocalteu method
HPLC analysis for qualitative t polyphenols
identification
Liquid phase
Extract characterization
Polyphenols
Ret. timemin
AreamAU min
Amountmg/L
HeightmAU
Rel. area%
Gallic acid 2.99 0.06 5.45 0.65 5.58Catechin 9.35 2.16 112.08 5.76 3.33Vanilic acid 13.66 0.53 15.20 2.45 0.82Siringic acid 15.77 0.75 12.91 4.43 1.16p-cumaric acid 19.93 13.29 99.47 39.54 20.42Ferulic acid 23.59 0.57 9.70 3.54 0.88Sinapic acid 23.77 0.33 13.36 2.50 0.52Total 17.71 268.20 58.90 32.71
Figure 3: Chromatographic profile of spruce bark extract obtained by UAE 500C, 30 min
Table1: Polyphenolic content quantified by HPLC analysis
Experimental data - parameters study
Figure 4: Effect of time on polyphenols extraction
Figure 5: Effect of temperature on polyphenols extraction
Kinetics investigation - second-order kinetic model
T, K B = 1/Ce A = 1/h Ce =1/B,mg/g h = 1/A k = h/(Ce)2
g/mg·min R2
318 0.0268 0.1402 37.31343 7.133 0.0051 0.9867323 0.0248 0.0841 40.32258 11.891 0.0073 0.9926333 0.0232 0.0574 43.10345 17.422 0.0094 0.9972
21
t ee
t t A B tC CC k
2
1e
te
C k tC
C k t
1t
e
tCt
h C
2 eh C k
Figure 6: Mathematical checking of second-order kinetic model
Table 2: Kinetic parameters of second-order kinetic model
Goula (2013). Ultrasound-assisted extraction of pomegranate seed oil – Kinetic modeling. Journal of Food Engineering, 117, 492-498. Pan et al., (2012). Continuous and pulsed ultrasound-assisted extraction of antioxidants from pomegranate peel. Ultrasonics
Sonochemistry, 19, 365-372.
Kinetics investigation - second order kinetic model
3
2
33725.6exp8.314
33.726 ( / )
R 0.922
1.901 10
a
kT
E kJ mol
9
2
6013.421.26 exp
0 9 3
1
3
9
.
0hT
R
2
0.3706T 80.07, ( / )
R 0.9554eC mg g
Figure 7: Relationship between temperature and second-order extraction rate constant (lnk) Figure 9: Relationship between
equilibrium concentration (Ce) and temperature
Figure 8: Relationship between initial extraction rate (lnh) and
temperature
Kinetics investigation - second-order kinetic model
9 6013.42exp
0.3706 80.
/1.269
71
00
tt mg GAEC
tT T
g
1t
e
tCt
h C
9
2
6013.421.26 exp
0 9 3
1
3
9
.
0hT
R
2
0.3706T 80.07, ( / )
R 0.9554eC mg g
Validity of model prediction
2*12
21
2
1
0.9993
ni ii
nii
y yr
y y
r
Figure 10: Comparison between experimental and modeling concentrations for UAE of polyphenols from spruce bark
Influence of temperature on the extraction yields concluded that the ultrasonic assisted extraction process of polyphenols from spruce bark is endothermic and based on a second-order kinetic model [1];
The extraction mechanism proceeds in two steps: a fast dissolution at the beginning followed by a slow diffusion[1];
Using the second-order model the second-order extraction rate constant, the equilibrium concentration and the initial extraction rate can be predicted, their dependence of temperature can be used to determinate the activation energy of the extraction[1,2];
Predicted values obtained from the second-order model are in a very good accordance with experimental results.
Conclusions
[1] Rakotondramasy-Rabesiaka et al.,(2007). Solid–liquid extraction of protopine from Fumaria officinalis L.- Analysis determination, kinetic reaction and model building. Separation and Purification Technology, 54, 253-261.[2] Su, C-H., et al., (2014). Solid-liquid extraction of phycocyanin from Spirulina platensis: Kinetic modeling of influential factors. Separation and Purification Technology, 123, 64-68.
THANK YOU VERY MUCH FOR YOUR KIND ATTENTION!
PhD. eng. Adina Iulia TALMACIUE-mail: [email protected]@gmail.com