Abstract
Six composite materials have been successfully developed: CAL5, CAL10, CAL15, CAL20,
CAL30 and pure TiO2 by the Sol-Gel method. The characterizations (chemical, textural and
morphological) of the elaborate composites were used to observe the evolution of their
properties. The characterization of the catalysts developed has shown that the raw material CAL
is mainly composed of carbonate in the form of calcite and some aluminosilicate in the form of
palygorskite. The introduction of TiO2 at different concentrations improved their chemical,
thermal and textural properties. To test their catalytic performance, we applied these catalysts
in the elimination of two pollutants widely found in aquaculture releases. Tetracycline which is
an antibiotic, an organic molecule, and ammonium NH4
+ an inorganic molecule, excreted by
fish. The photodegradation tests of tetracycline proved a good photocatalytic activity for all the
catalysts elaborated but with a preference for CAL30 which degraded 97% of the TC at an
initial concentration of 50 mg. L
-1 and in a neutral medium (pH =7). The CAL20 composite has
the optimal photocatalytic performance for the oxidation of ammonium ions in aqueous medium
with majority production of NO3
- nitrates.
The toxicity tests were carried out on larvaes of Artemia salina carried out with populations of
nauplii of first instar larvae. This test reveals the existence of kinetics of mortality for the
samples treated by UV lamp, as well as by samples treated by solar irradiations. The elaborate
CAL30 and CAL20 could be applied as promising catalysts in the treatment of waste fish
farming loaded with refractory organic molecules such as tetracycline and ammonium ions.
Keywords
Aquaculture, waste fish farming, tetracycline, ammonia, photocatalysis, ecotoxicity.
Six composite materials have been successfully developed: CAL5, CAL10, CAL15, CAL20,
CAL30 and pure TiO2 by the Sol-Gel method. The characterizations (chemical, textural and
morphological) of the elaborate composites were used to observe the evolution of their
properties. The characterization of the catalysts developed has shown that the raw material CAL
is mainly composed of carbonate in the form of calcite and some aluminosilicate in the form of
palygorskite. The introduction of TiO2 at different concentrations improved their chemical,
thermal and textural properties. To test their catalytic performance, we applied these catalysts
in the elimination of two pollutants widely found in aquaculture releases. Tetracycline which is
an antibiotic, an organic molecule, and ammonium NH4
+ an inorganic molecule, excreted by
fish. The photodegradation tests of tetracycline proved a good photocatalytic activity for all the
catalysts elaborated but with a preference for CAL30 which degraded 97% of the TC at an
initial concentration of 50 mg. L
-1 and in a neutral medium (pH =7). The CAL20 composite has
the optimal photocatalytic performance for the oxidation of ammonium ions in aqueous medium
with majority production of NO3
- nitrates.
The toxicity tests were carried out on larvaes of Artemia salina carried out with populations of
nauplii of first instar larvae. This test reveals the existence of kinetics of mortality for the
samples treated by UV lamp, as well as by samples treated by solar irradiations. The elaborate
CAL30 and CAL20 could be applied as promising catalysts in the treatment of waste fish
farming loaded with refractory organic molecules such as tetracycline and ammonium ions.
Keywords
Aquaculture, waste fish farming, tetracycline, ammonia, photocatalysis, ecotoxicity.