Photodegradation using TiO2-activated borosilicate tubes
Date
2018-08-16
Authors
Khalaf, Samer
Shoqeir, Jawad H.
Scrano, Laura
Karaman, Rafik
Bufo, Sabino A.
Journal Title
Journal ISSN
Volume Title
Publisher
Springer
Abstract
This study examines the photocatalytic activity of titanium dioxide (TiO2) semiconductor supported on borosilicate tubes (cut-off
290 nm) towards removal of a mix of persistent organic pollutants (POPs) from water. For this purpose, two widely used
analgesic and anti-inflammatory drugs (NSAIDs), ibuprofen (IBU) and mefenamic acid, along with MCPA sodium
monohydrate, which is a common herbicide frequently used in the agricultural activities, were selected as a case study.
Borosilicate tubes were coated with titanium oxide through two different approaches: sol-gel dip-coating and a hybrid nanoparticle
dip-coating and plasma-enhanced chemical vapour deposition (PECVD) process. The photochemical reactor that hosts the
titania-coated tubes was designed to permit continuous throughput of liquid feed stream. The photodegradation experiments were
performed in laboratory conditions under artificial irradiation simulating solar light. The efficiency of direct photolysis and
heterogeneous photocatalysis (TiO2) was investigated, and the performance of each coating method was evaluated. Kinetic
studies for each experiment were accomplished, the overall results showed poor efficiency and insufficient removal for
NSAIDs through direct photolysis, whereas applying heterogeneous photacatalysis with TiO2 coated on borosilicate tubes was
found to accelerate their degradation rate with complete decomposition. Concomitantly, kinetic experimental results showed a
critical difference of performance for the two coating methods used; in particular, the degradation rates of pollutants by the solgel-
coated tubes were much faster than the degradation by the nanoparticle/PECVD-coated tubes. Using TiO2 supported on
borosilicate tubes appears to be a promising alternative to conventional TiO2 suspension and avoid post-separation stages. The
results achieved in this study can be used to optimise large-scale applications, and expanding the study to cover a wide range of
pollutants will lead to achieve more representative results.
Description
Keywords
Ibuprofen , Mefenamic acid , MCPA , AOPs , Wastewater , Photocatalysis , Sol-gel coating , PECVD , Borosilicate tubes , TiO2 , Photo-degradation , Emerging contaminants