Tratamento de efluente contendo metomil e imidacloprido em reator hermético fotolítico solar
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Data
2019-03-06
Autores
Balsan, Lucas
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Universidade Federal de Mato Grosso
Resumo
In line with the mandatory possession of the decontamination yard for individuals and
legal entities that practice aerial spraying of pesticides, provided for in Normative Instruction
N° 02 established in Brazil by the Ministry of Agriculture, Livestock and Supply (MAPA) in
2008, this study developed and evaluated an improved hypothetical model of the yard
installation required, called the retention reservoir, solarization and evaporation of wash water
from agricultural aircraft spray tanks. The system which was characterized by a hermetically
sealed photolytic system to ensure occupational safety, with the use of solar radiation as a
renewable energy source, which aims to mitigate contamination risks and energy costs in the
treatment of effluents with pesticides. Sunlight and heat can activate and accelerate the
degradation of metomil and imidacloprid pesticides in mixed solution. The experiment
compared the reference samples in the dark at 24±1 °C (R) with treatments carried out in three
reactors, which consisted of a hermetic dark reactor (EH), with matt black dyed aluminum cap
to enhance radiation absorption. and heat generation, an airtight light reactor (CH), open for
light transmittance through a clear borosilicate glass cover, to promote the greenhouse effect
and a light open reactor (CA), exposed to the atmosphere and radiation to mimic the
constructive aspect required by the MAPA Normative Instruction, which submits the effluents
to evaporation. The contribution of radiation on the thermodynamic variation of the reactors
was evaluated according to the inherent peculiarities of their constructive aspects, using
thermocouple sensors for the effluent thermometry in static regime. The environmental
variables of temperature and relative humidity, and dewpoint temperature were measured by
means of a datalogger sensor, and the illuminance was read through a lux meter for later
conversion of lux to radiation in the power unit. in W.m-2
, for comparison with data obtained
from a weather station near the experiment. High performance diode array liquid
chromatography was used to determine the residual concentrations of pesticides obtained by
averaging triplicate samples of each pesticide in the mixed solution for 13 days of effluent
solarization. The tests showed that the EH reactor does not degrade the studied pesticides and
the AC reactor concentrates them as the effluent evaporates, forming a more toxic effluent than
the original, which generates occupational health risks and biotic environment. The CH reactor
was the only one effective in reducing concentrations, with low first and second order kinetic
constants and satisfactory determination coefficients, with half-life estimates of 68 and 17 days
for metomil and imidacloprid, respectively. The results demonstrate that direct photolysis is not
efficient in reducing the concentrations of the studied pesticides and suggest that methods based
on photothermocatalytic oxidation processes, using visible light sensitive photocatalysts and
with positive effect on thermal increment efficiency, be included in the process required by the
decontamination yard.
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BALSAN, Lucas. Tratamento de efluente contendo metomil e imidacloprido em reator hermético fotolítico solar. 2019. 93 f. Dissertação (Mestrado em Gestão e Tecnologia Ambiental) - Universidade Federal de Mato Grosso, Instituto de Ciências Agrárias e Tecnológicas, Rondonópolis, 2019.