This study aims to develop technical knowledge about cashew nut shell, presenting
and characterizing the biochar from this biomass, generated through the pyrolysis process. So
that it can be verified the potential of using activated carbon in the adsorption of pollutants
present in gray water. Through immediate and elemental analysis, the characterization of this
biomass and activated carbon obtained through the pyrolysis of cashew nut shell in a fixed bed
reactor at temperatures ranging from 400ºC to 600ºC and heating rate of 15ºC was carried out
/min at 25°C/min. The fixed bed reactor is made of stainless steel material, which is 100 cm
long and has an external diameter of 10 cm, is heated by a bipartite reclining oven and operates
in a batch regime. The study of coal was complemented with thermogravimetric analysis
(TGA) and Fourier transform infrared spectroscopy (FTIR) analysis. The mass yield of coal
ranged from 33.10% to 36.10% when subjected to a temperature of 500°C and heating rate at
20°C/min, which indicates a favorable yield to the values defined for these central point
variables in the experimental planning . Regarding the behavior of activated charcoal from
cashew nut shells in the adsorption process of contaminants from gray water through the
methylene blue index adsorption test, the experiment showed that, with low mass and high
concentration dye, its adsorption capacity becomes more efficient. In addition, the treatment
of gray water with the use of biochar, was developed first with the step of decantation,
sedimentation and flocculation and later with the step of filtering this effluent using activated
carbon and sand. The treatment of greywater in these steps was shown to be appropriate, as it
removes COD, volatile solids, soluble orthophosphate, residual chlorine and ammonia in
percentages above 80% and high removal of the turbidity parameter (above 90%).
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