HETEROGENEOUS SODİUM DECATUNGSTATE CATALYSTS FORCONTAMİNANTS DEGRADATİON İN AQUEOUS MATRİX

Luisa Pasti, Claudia Stevanin, Tatiana Chenet, Alessandra Molinari Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Italyluisa.pasti@unife.it

Sources of organic contaminants in surface waters

Human: incomplete removal in wastewater treatment, production plant, waste disposal

Veterinary: via manure dispersion and animal excretion onto soils

Increase of antibiotics resistance

Pharmaceuticals

Remediation technologies:

Advanced Oxidation

Nanofiltration

Adsorption

Advanced Oxidation

Ozone

Hydrogen peroxide

photocatalysys

Levofloxacin(antibiotic)

Sulfamethoxazole(sulfa drug)

Trimethoprim(antibiotic)

Carbamazepin(antiepilectic)

Atenolol/Propranololb- BLOCKER

361.4

253.3

290.3

363.3

266.3

1.44 mg/mL

0.459 mg/mL

0.615 mg/mL

0.152 mg/mL

0.0794 mg/mL

5.4

5.6

7.1

13.9

9.6

pKaSwMW

LEVO

SMX

TMP

CBZ

ATN/PRP

………….and study how to remove them by an ADVANCED OXIDATION METHODbased on the use of Na4W10O32

323 nmSpectralpropertiessimilar to those of TiO2

General mechanism in water:

Drugmolecule

RHOH

Formation of OH• has been definitely demonstrated by:

350 400 450 500 550 600

Em

issio

n i

nte

nsit

y [

a.u

.]

Wavelength (nm)

(a)

(b)

(c)

O O O OHO

+ OH. (4)

3425 3450 3475 3500

inte

nsi

ty (

a.

u.)

magnetic field (gauss)

DMPO DMPO-OH.

ESR spin trapping technique Luminescence

(lecc= 322 nm, lanal=455 nm)

cumarin 7-hydroxycoumarin

5,5-dimethyl-1-pyrroline-N-oxide

ATN

LEVO

TMP

Removal of atenolol, levofloxacin, trimethoprim, propranolol, sulfamethoxazole and carbamazepine from water occurs by irradiation of Na4W10O32

• mediation by OH• radicals• hydroxylated derivative compounds

(HPLC-MS)

Drug t1/2

(min)

k (min-1) R2

ATN 7.5 0.0924 0.9915

LEVO 38.5 0.0180 0.9866

TMP 53.3 0.0128 0.9882

Molinari A., Sarti E., Marchetti N., Pasti L., Applied Catalysis B: Environmental 203 (2017) 9-17

Heterogenization of decatungstate anion

Drug t1/2 (min) k (min-1) R2

ATN 102 0.0068 0.9822

LEVO 94 0.0074 0.9861

TMP 124 0.0056 0.9811

PRP 119,5 0.0058 0.9867

SMX 1980,4 0.00035 0.9881

CBZ 1732,0 0.00040 0.9837

Silica-NH3+-- - -Na3W10O32

-

amino-functionalized silica particles

RHOH

DMPO

Why CBZ and SMX are not degraded?Does it depend on the photocatalyst?

Dissolved Na4W10O32 Silica-NH3+-- - -Na3W10O32

-

Without CBZ

With CBZ (10 ppm)

Conclusion: it does notdepend on W10O32

4-

DMPO[DMPO-OH] ·

RH

%

pH

%

pH

ATN

CBZ

SMX

At the operative pH of 6:• ATN is positive• CBZ is neutral• SMX is neutral and negative

Silica-NH3+-- - -Na3W10O32

-

Why CBZ and SMX are not degraded?Does it depend on the nature of support?

%

pH

Heterogenization of decatungstate anion

Na4W10O32/SiO2/BTESE

Simultaneous hydrolysis of tetraethylorthosilane (TEOS) and of 1,2 bis(triethoxysilyl)ethane (BTESE).

SSA 725 m2g-1.

Micro and important fraction of mesopores with

a pore width between 13 and 28 ˚A.

This material concentrates toluene from water

0

2

4

0 0,1 0,2n

ads

(mm

ol/

m2)

p/po

BTESE

Microgravimetric adsorption isotherms of toluene vapour

The photocatalytic systemdegrades propranolol(PRP) as well.

We understand that the charged form of the drugis not the only factor, but

HYDROPHOBICITYof the support is alsoimportant0 10 20 30 40 50 60

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

time (min)

C/C

0

CBZ L

CBZ D

SMX L

SMX D

PRP L

PRP D

Irradiation of Na4W10O32/SiO2/BTESE system degrades CBZ and SMX and…also PRP

Pasti L., Sarti E., Martucci A., Stevanin C., Marchetti N., Molinari A., Applied Catalysis B: Environmental (2018) https://doi.org/10.1016/j.apcatb.2018.08.015

HPLC-MS of oxidation intermediates of SMX.

Degradation of SMX passes throughhydroxylated

products

Precursor Ion

(m/z)

tr

(min)

MS2

(m/z)

Structure

301 9.18 177

133

283 9.18 239

177

133

270 10.25 206

228

174 10.20 156

190 3.76 158

216 13.54 198

288 14.46 270

228 14.70

HPLC-MS of oxidation intermediates of CBZ

Degradation of CBZpasses throughhydroxylated

products

Precursor Ion

(m/z)

tr

(min)

MS2

(m/z) Structure

237.1 14.35 194.01

220.06

251.1

253.1

12.3 208.0

210.0

236.0

267.1 16.2 168

196.1

211.1

271.1 9.6 210

253

RHOHRH

drugdegradation

CONCLUSIONS

Photoexcited W10O324- is able to oxidize water producing OH• radicals

OH• radicals attacks drug molecule and produce mono or dihydroxylated intermediates

Then, these intermediates degrade to lighter molecules

Silica-NH3+-- - -Na3W10O32

- and Na4W10O32/SiO2/BTESE are recyclable material.

Na4W10O32/SiO2/BTESE is active in the degradation of every kind of the explored drugs

independently from their charge

Hydrophobicity is an important parameter of the support to be considered

Na4W10O32/SiO2/BTESE IS THE FIRST EXAMPLE IN PHOTOCATALYTIC DEGRADATION OF

DRUGS THAT COMBINES ADSORPTION CAPABILITY OF THE SUPPORT WITH PHOTO

ACTIVITY OF THE CATALYSTS

Dott.ssa TognoloChiaraDott. Colla Davide

Dr. Sarti ElenaDr. Marchetti Nicola

Prof. Alessandra Molinari

…..and all of you for your very kindattention!

PRP

ATN

Distribution diagram of propranolol: