Transcript Photocatalytic Degradation of Pharmaceuticals and Pesticides in

International Conference
WATER USE AND RE-USE
University of Basilicata-Potenza, Italy 17-18 June, 2015
Photocatalytic Degradation of Pharmaceuticals
and Pesticides in water over TiO2 supported on
glass tubes
Prepared by: Samer Khalaf
Supervised by:
Prof. Sabino Bufo
Introduction
Advanced oxidation processes (AOPs)
Have been proved as promising alternative rout for the
conventional water treatment methods towards removal of
recalcitrant organic compounds
Pesticides
Pharmaceuticals
Coloring
matters
Surfactants
AOPs
Is an oxidation processes based on generating highly reactive
species such as hydroxyl radicals (·OH) which are able to
oxidize and mineralize almost all kinds of organic compounds
Heterogeneous photo-catalysis
•The dispersed solid particles of semiconductor in the treated solution efficiently absorb
large fractions of the UV spectrum, under radiation the semiconductor material may be
photo-excited by photons to form electron-donor sites (reducing sites) and
electron-acceptor sites (oxidizing sites).
•Mechanisms of TiO2 photocatalysis
The Problem
The vast majority of the investigations and applications on heterogeneous
photocatalysis (TiO2) have employed the suspension form of semiconducting
particles
The need for post treatment stages to recover the catalyst
from the reaction mixture
Methodology
Fixation or immobilization of catalyst over a stationary
substrates
Objectives
Is to study the photocatalytic activity of titanium dioxide
(TiO2) semiconductor supported on a glass tubes
towards removal of a mix of persistent organic
pollutants (POPs) from water
Experimental
TiO2 supported on glass tubes substrates
Thickness of the coating film = 100 nm.
Length (L) = 14.9 cm
Thickness = 3 mm
Sol-gel coatings glass tube
sol-gel technique with dip
coating method
Plasma enhanced chemical
vapor deposition (PECVD)
process
Thickness of the coating film = 100 nm.
Length (L) = 14.9 cm
Thickness = 3 mm
Photochemical reactor
Photodegradation system
Photo-degradation experiments
1 Liter
Photocatalysis
Sol-gel glass
tube
Photocatalysis
PECVD glass
tube
Direct
Photolysis
Results and discussion
Photolysis experiment
MCPA sodium monohydrate
was decreased by about 53 %
from its initial concentration
after
3
hours,
and
approximately 96 % after 12
hours.
Ibuprofen was decreased to
about 6 % from the initial
concentration after 24 hours
since
beginning
the
experiment.
Mefenamic decreased by
about 42 % from its initial
concentration
after
24
hours
Results and discussion
Photovatalysis experiment
Sol-gel coatings glass tube
Mefenamic acid decreased
by about 54 % from its initial
concentration after 3 hours,
followed by MCPA sodium
monohydrate
which
decreased by about 49 %
during the same period and
then
ibuprofen
decreased
approximately by 34 % in the
same time also
Results and discussion
The degradation rate was
approximately slow for all
compounds,
the
order
of
degradation versus time was
as follow:
-MCPA sodium monohydrate
-Mefenamic acid
-and Ibuprofen respectively
Photovatalysis experiment
PECVD coatings glass tube
Kinetics studies
ln C(t) = ln C(0) - kt……(1)
C : is the concentration at time t
C0 : is the initial concentration
k : is the reaction rate constant
Photolysis experiment
Kinetics studies
Photovatalysis experiment
Sol-gel coatings glass tube
PECVD coatings glass tubes
Kinetic parameters for photolysis and catalytic photodegradation of
MCPA sodium, ibuprofen and mefenamic acid.
Conclusions
Direct photolysis of recalcitrant organic compounds in water is insufficient
for removal some types of these compounds and insufficient to induce a
complete mineralization for other compounds.
Titanium dioxide (TiO2) supported on glass tubes are able to act as
catalysts for the photo-degradation of organic compounds tested in these
study.
The activity of supported glass tubes depend on the technique used for
immobilization, sol-gel technique was found to be a successful method
for preparation of catalyzed glass substrate.
The overall results of this study along with photochemical reactor system
employed could be used to optimize a large scale applications since
there is no significant deactivation of the catalyst on glass tubes was
observed during experiments.
MANY THANKS FOR
YOURS ATTENTION