MICROPARTICLES SYNTHESIZED BY HIGH PRESSURE SPRAYING ... · A 10-a editie a Seminarului National de nanostiinta si nanotehnologie 18 mai 2011, Biblioteca Academiei Romane •To study

A 10-a editie a Seminarului National de nanostiinta si nanotehnologie 18 mai 2011, Biblioteca Academiei Romane

MICROPARTICLES SYNTHESIZED BY HIGH PRESSURE SPRAYING METHOD

AND THEIR ADSORPTION PROPERTIES FOR PHENOL DERIVATIVES

Sandu Peretz1, Dan F. Anghel1, Manuela Florea-Spiroiu2, Daniela Bala2, Cristina Stoian3 and Gheorghe Zgherea3

1 Institute of Physical Chemistry “I. Murgulescu”, Department of Colloids, 202 Spl. Independentei, 060021, Bucharest, Romania, e-mail: [email protected]

2 University of Bucharest, Department of Physical Chemistry, 4-12 Regina Elisabeta Blvd., 030018, Bucharest, Romania

3 University “Dunărea de Jos” of Galaţi, Department of Chemistry, 111 Domnească Street, 800201, Galaţi, Romania


• To study the interaction between cationic chitosan and an anionic surfactant sodium bis-(2-ethyl hexyl) sulfosuccinate (AOT).

• To synthesize chitosan based microparticles at atmospheric pressure and by high pressure method.

• To prove the chitosan/AOT complex formation by Fourier Transform Infrared (FTIR) Spectroscopy, and to characterize the size and shape of micropaticles by optical and SEM microscopy.

• To investigate the behaviour of lyophilized microparticles in contact with phenol derivatives.

• To study the influence of medium pH and the amount of microparticleson the phenol adsorption efficiency.

• To monitor the time evolution of phenol derivatives sorption by microparticles.

OBJECTIVES


EXPERIMENTAL

Methods

• Fourier Transform Infrared (FTIR) Spectroscopy - Nicolet iN10 FT–IR Microscope –Thermo Scientific

• UV-Vis spectroscopy Cary 100 Bio - VARIAN• Optical Microscopy - Magnum T Microscope• Scanning Electron Microscopy (SEM) using a Zeiss EVO LS10 Apparatus • Freeze drying - ALPHA 1-2 LD

Materials

• Chitosan - medium molecular weight (Mw = 120±70 kDa) - Aldrich • Sodium bis (2-ethyl hexyl) sulfosuccinate (AOT) 98% - Sigma• Carbon dioxide with 99.9% - Linde Gas Romania


Syring pump

Chitosan solution

AOT solutionFormed microparticles

MICROPARTICLES PREPARARED AT ATMOSFERIC PRESSURE


Domains of phase diagram

1) HOMGENEOUS SOLUTIONS, monophasic and transparent within domain C;

2) PRECIPITATES, preceded by the apparence of an advanced turbidity within domain PP;

3) GEL-TYPE MEMBRANES:- domain MEC (microcapsule that expels its content - Fig. 2b); - domain MP (microparticles - Fig.2a); - domain DM (shrinked microcapsule - Fig.2c).

MICROPARTICLES PREPARARED AT ATMOSFERICPRESSURE


Domains of solubility for Chitosan-AOT complex-gel

MICROPARTICLES PREPARARED AT ATMOSFERIC PRESSURE

1E-3 0.01 0.1

0.01

0.1

DM

MPMEC

PP

CCon

c. C

hito

san

(bas

e-m

ole/

L)

Conc. AOT (mole/L)

1E-3 0.01 0.1

0.01

0.1

DM

MPMEC

PP

C

Con

c. C

hito

san

(bas

e-m

ole/

L)

Conc. AOT (mole/L)

Protonated with 1% wt acetic acid Protonated with 2.5% wt acetic acid


GEL-TYPE MEMBRANESMicrocapsule

Microcapsule that expels its content

Shrinked microcapsule

Bar = 1000 μm


MICROPARTICLES PREPARED BY HIGH PRESSURE SPRAYING METHODExperimental apparatus

Input pressure CO2

High pressure cell

Low pressure cell


Optical microscopy

POLYMER-SURFACTANT COMPLEX PREPARED AT HIGH PRESSURE

Microparticles Wiresbar = 500 μm


CHITOSAN-AOT WET MICROSPHERES

SEM micrographs

Microparticle Surface of microparticle


SEM micrographs

Microparticle Surface of microparticle


INTERACTION BETWEEN CHITOSAN-AOT

4500 4000 3500 3000 2500 2000 1500 1000 5000.4

0.5

0.6

0.7

0.8

0.9

1.0

Chi/AOT particles AOT Chitosan

T (%

)

Wavenumber (cm-1)

The specific values for Chi/AOT complex

νSO10821093

νSO12041212

δNH215221586

νNH, δNH216341642

AssignmentMicroparticlesChi/AOTν (cm-1)

AOTν (cm-1)

Chitosanν (cm-1)

FTIR measurements


ADSORPTION OF PHENOL DERIVATIVESInteraction between lyophilized microparticles with phenol and o-cresol

4500 4000 3500 3000 2500 2000 1500 1000 5000.4

0.5

0.6

0.7

0.8

0.9

1.0

Chi/AOT_o-Cresol Chi/AOT_Phenol Chi/AOT particles

T (%

)

Wavenumber (cm-1)

δNH; CH aromatic streching.

1522.561533.481532.96

C-C aromatic streching.1634.691635.961635.96

H bond; intramolecularwith C=O; chelatic OH.

2860.652873.522873.43

Bonded OH; position and shape depend on degree of association; CH aromatic streching.

3413.923396.443395.02

Assignment MicroparticleChi/AOT ν (cm-1)

Chi/AOT-Phenolν (cm-1)

Chi/AOT-o-Cresol ν (cm-1)

Specific values for interaction phenol, o-cresol

FTIR measurements


2 3 4 5 6 7 8 9 10 11 12

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

Phenol 2.5x10-4 M

5x10-4 M

7.5x 10-4 M

1x10-3 M o-Cresol

2.5x10-4 M

5x10-4 M

7.5x10-4 M

1x10-3M

Adso

rptio

n ca

paci

ty (m

g/g)

pH

ADSORPTION OF PHENOL DERIVATIVES

Effect of pH on contaminant removal


ADSORPTION OF PHENOL DERIVATIVES

Effect of sorbent dose

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2-10

0

10

20

30

40

50

60

70

80

90

100

110

Phenol 2.5x10-4 M

10x10-4 M o-Cresol

2.5x10-4 M

10x10-4 MAds

orpt

ion

effic

ency

(%)

Sorbent dose (g/L)


ADSORPTION OF PHENOL DERIVATIVESKinetics of pollutant adsorption

0 50 100 150 200 250 300 350 400 450 500 550 600 650-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

1.5x10-4M

2x10-4M

2.5x10-4M

5x10-4M

7.5x10-4M

1x10-3M

Ads

orpt

ion

capa

city

(mg/

g)

Time (min)

Phenol

0 50 100 150 200 250 300 350 400 450 500 550 600 650-0.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

1.5x10-4M

2x10-4M

2.5x10-4M

5x10-4M

7.5x10-4M

1X10-3M

Ads

orpt

ion

capa

city

(mg/

g)

Time (min)

o-Cresol


CONCLUSIONS

● Two methods to obtain ultrafine particles by the interaction between chitosan and an anionic surfactant, sodium bis (2-ethyl hexyl) sulfosuccinate (AOT), were developed. ● Chitosan-surfactant complex synthesized at atmospheric pressure may take the form of stable microparticles at optimal concentrations of the reactants. ● An experimental apparatus equipped with a high pressure cell for spraying the polymer into the anionic surfactant solution produces either ultrafine particles or wires depending on the spraining pressure.● The interaction between chitosan and AOT is proved by FTIR, whereas SEM shows that the lyophilized chitosan/AOT microparticles present a higher roughness and porosity than the wet particles.● Lyophilised chitosan/AOT microparticles have been successfully used in advanced treatment of wastewaters for the retention of phenol and o-cresol. ● The contaminant removal for phenol and o-cresol attain a maximum in the range of pH 7-8, increases with the amount of used particles and decreases with increasing of initial pollutant concentration. ● The adsorption of phenol and o-cresol occurs rapidly in the first 60-120 minutes followed by a slow process that takes about 520-600 minutes.


ACKNOWLEDGMENTS

The authors would like to acknowledge to EU (ERDF) and Romanian Government support that allowed for acquisition of the research infrastructure under POS-CCE O 2.2.1 project INFRANANOCHEM - Nr. 19/01.03.2009.


Documents

MICROPARTICLES SYNTHESIZED BY HIGH PRESSURE SPRAYING ... · A 10-a editie a Seminarului National de nanostiinta si nanotehnologie 18 mai 2011, Biblioteca Academiei Romane •To study