First International Conference on MOLDAVIAN RISKS – FROM ...

<strong>First</strong> <strong>International</strong> <strong>Conference</strong> on MOLDAVIAN RISKS - FROM GLOBAL TO LOCAL SCALE
16-19 May 2012, Bacau, Romania
HETEROGENEOUS WATER PHASE CATALYSIS AS AN
ENVIRONMENTAL APPLICATION
Nicoleta Platon 1 , Ileana Denisa Nistor 1 , Ilie Siminiceanu 2
1 ”Vasile Alecsandri” University of Bacau, Department of Chemical and Food Engineering
2 “Gh. Asachi” Technical University of Iaşi, Department of Chemical Engineering
Corresponding author: Ileana Denisa Nistor, dnistor@ub.ro, denisanistor@yahoo.com
Abstract: The urban distribution of qualitative water for human consumption, domestic
activities and industrial use is a fundamental objective in what concerns the sustainability
of life quality for the population. However, many industrial processes generate a series of
pollutants, which have a negative impact on ecosystems and on humans (toxic,
carcinogenic and mutagenic properties). Particularly, phenol is considered as one of the
most toxic pollutants, especially for human health but also for the aquatic fauna and flora,
causing an increase in the demand of oxygen in water sources and causing unpleasant taste
and smell in drinking water even when it is found in very small quantities. Catalytic wet
peroxide oxidation (CWPO) is part of the advanced oxidation processes (AOP) and is an
efficient process because H2O2 is a strong oxidative agent. Pillared clays are successfully
used as catalysts in these processes. Study on chemically modified clays by pillaring in
Fenton and Fenton type processes were investigated due to its low cost, to its mild
conditions (room temperature, atmospheric pressure) and to lack of toxicity for the
environment of clays, hydrogen peroxide and iron salts. In this work, catalysts based on
chemically modified clays by pillaring process with Al (III) and Fe (III) using as raws
materials: commercial bentonite, KSF montmorillonite and K10 montmorillonite from
Aldrich were synthesized. After, these catalysts were tested in wet oxidation with
peroxides using the phenol as target compound. Experimental results show that Fe
chemically modified clay from bentonite presented a higher activity than the Al-Fe one.
The raw materials and chemically modified clays were characterized by: BET (Brunauer-
Emmet-Teller) method, XRD (X-ray diffraction) analysis and EDAX-SEM (energydispersive
X-ray) spectroscopy. By testing the derived catalyst from sodium bentonite, a
100% conversation of phenol was obtained after 50 minutes; by testing the KSF catalyst, a
conversion of 98 % was obtained and by testing the catalyst obtained from K10 a 28%
conversion was realized. The catalytic activity was evaluated by rate constant, considering
a first order reaction. Verifying the hypothesis that the reaction is of order 1, we observe
that the value of the rate constant K increases with the decrease of the phenol
concentration.
Key words: pillared clay, montmorillonit, phenol, catalytic oxidation.
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