Banca de DEFESA: YAGO NECO TEIXEIRA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : YAGO NECO TEIXEIRA
DATE: 12/04/2022
TIME: 14:00
LOCAL: BLOCO M , SALA 408, PRODER/CCAB/UFCA , CAMPUS CRATO
TITLE:

REMOVAL OF PHOSPHORUS FROM EFFLUENTS USING BIOADSORBENT MATERIAL ORIGINATED FROM ASH FROM PEQUI BARK AND ITS USE AS A SOURCE OF NUTRIENT FOR SOILS.

KEY WORDS:

Phosphor; adsorption; Bioadsorbents; Eutrophication; ashes.

PAGES: 81
BIG AREA: Outra
AREA: Ciências Ambientais
SUMMARY:

The entry of pollutants into aquatic systems causes the degradation of rivers, lakes and coastal areas, reducing the availability of good quality water and increasing costs for later use. High concentrations of phosphorus in water are capable of upsetting the ecological balance, deteriorating water quality and raising issues from eutrophication to the intelligent and sustainable use of this resource in human activities. Therefore, the objective of this work was to study the adsorptive capacity of pequi peel ash and its efficiency in the removal of phosphorus from aqueous solutions, determine the ideal conditions for such a process, stipulate the parameters of kinetics, equilibrium and thermodynamics of the process. The pequi of the species Caryocar coriaceum WITTM is a fruit widely found in the region of Cariri, Ceará, Brazil. The pequi extractivism generates a large amount of waste, especially the fruit peels that do not have a specific destination. Therefore, these peels were used as raw material for the production of the bioadsorbent used in this study. The pequi bark ash was produced at 500°C in an oxidative atmosphere. Analysis by energy dispersive spectroscopy confirmed the adsorption of phosphorus by the ash, with an increase of phosphorus in the ash composition from 1.5% to 3.7% after the adsorption process. In addition, it was also possible to confirm that the pequi peel in natura is not able to adsorb phosphorus from aqueous solutions. The x-ray fluorescence analysis, in addition to confirming the adsorption of phosphorus in the same proportions of energy dispersive spectroscopy, showed the composition of the oxides present in the pequi peel ash, the main oxides being: SiO2 (17.59%), CaO (13.41%), K2O (4.79%), MgO (2.94%), P2O5 (1.98%), SO3 (1.16%), Fe2O3 (0.82%), Al2O3 ( 0.73%) and MnO (0.20%). The analysis of the ash after the adsorption process by Fourier transform infrared spectroscopy showed the formation of new bonds and an increase in the intensity of existing bonds even before the adsorption process, indicating chemical adsorption (chemisorption). The thermogravimetric analysis indicated that there are four mass loss events in the production of ash, with the highest mass loss (41.44%) in the last event at temperatures above 400 °C. The first mass loss has an endothermic character, while the following three have an exothermic character (related to the oxidation of the material). The residual mass after thermogravimetric analysis was 8.8%. The study of the zero load point (pHPCZ) showed that the pequi peel ash has a pHPCZ = 9.8. For the study of adsorption kinetics, the pseudo-second order model was the best suited to the process at a concentration of 100 mg L-1 of phosphorus, presenting an adsorption capacity at equilibrium of approximately 19.80 mg g-1 . The Elovich kinetic model was the one that best fitted the process at concentrations of 150-200 mg L-1 of phosphorus, presenting very low desorption constants for both concentrations (< 1 mg g-1), evidencing chemisorption. For the equilibrium study, the monolayer Jovanovic isotherm model was the best suited to temperatures of 10-20°C, with maximum adsorption capacities of 67.99-55.21 mg g-1, respectively. The Langmuir isotherm model was the one that best fitted the process at a temperature of 30 °C, with a maximum adsorption capacity of 48.64 mg g-1. The highest removal efficiency was 98.88% at 30 °C for a phosphorus concentration of 100 mg L-1, the maximum experimental phosphorus adsorption capacity was approximately 71.08 mg g-1. Thermodynamic studies indicate that the process of phosphorus adsorption by pequi peel ash is a spontaneous and favorable process, exothermic and with structural changes. Therefore, pequi bark ash has the potential to be used as an excellent bioadsorbent for phosphorus removal from aqueous solutions.

BANKING MEMBERS:
Presidente - 1513585 - FRANCISCO JOSE DE PAULA FILHO
Externo ao Programa - 1305746 - THIAGO MIELLE BRITO FERREIRA OLIVEIRA
Externo à Instituição - RAIMUNDO NONATO PEREIRA TEIXEIRA - URCA