Banca de QUALIFICAÇÃO: PAULA FABIANE PINHEIRO DO NASCIMENTO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : PAULA FABIANE PINHEIRO DO NASCIMENTO
DATE: 17/02/2020
TIME: 14:30
LOCAL: Auditório do PPGEQ
TITLE:

Utilization of solid waste from the processing of green coconut shell (Cocos Nucifera L.) to remove metals

KEY WORDS:

Adsorption, metal ions, monoethanolamine, sodium octanoate, steam explosion, sustainable adsorbent.

PAGES: 10
BIG AREA: Engenharias
AREA: Engenharia Química
SUMMARY:

In view of the environmental problem of the pollution of water bodies by heavy metals, caused by human activities in general, and the inadequate destination of certain solid agro-industrial residues, there is a great need to develop research that improves the technique of removing these inorganic pollutants from aqueous solutions. One way would be to take advantage of agro-industrial waste as agents that remove these pollutants. As the coconut shell powder (CP) is a residue generated from its processing, the present work aims to provide studies related to three treatment methodologies so that the CP adsorption capacity be empowered and then be reused to remove two toxic metals widely found in wastewater, Cu^{+ 2} and Cd⁺². The applied methodologies included the physical and chemical treatment of the PC surface, developed separately, according to the sequence: chemical treatment through the impregnation of Monoethanolamine in the proportion 1:1, using ethanol as solvent; chemical treatment through the impregnation of the sodium octanoate surfactant by microemulsion; and physical modification using the steam explosion technique (T = 210 °C and P = 20 atm). For all of them, CP characterization analyzes were performed before and after treatments (BET, DRX, FRX, TG, zeta potential and analysis of the composition of hydrolysables). The evaluation of the CP adsorptive capacity, against the single component adsorption of Cu⁺² and Cd⁺² ions, was performed through the static process, using CuSO₄.5H₂O and CdSO₄.8/3H₂O solution, in the concentration range of 10 - 300 mg / L. The experiments were conducted with 0.2 g of CP in contact with 50 mL of the referred solutions, at pH 5.0, submitted to mechanical agitation, at 150 rpm, for 3 h, at different temperatures (25, 40 and 50 °C ). From the experimental data obtained were investigated, the adsorption kinetics, the equilibrium isotherms, the thermodynamic parameters and the adsorption mechanism for each proposed methodology. The results of the characterization analyzes showed that the treatments carried out affected the surface of the PC, through the insertion of functional groups that interact more easily with the metal ions of interest (Cu⁺² and Cd⁺²), positively influencing the adsorptive capacity of the residue. The adsorption process on the CP after the treatments proved to be of a chemical nature (for those treated with Monoethanolamine (CPA) and with a surfactant (CPµE)) and physical (for those treated with a steam explosion (PCD), represented satisfactorily by the pseudo kinetic model second order and by the Langmuir model, presenting the following maximum adsorption capacities: 15.94 mg of Cu^{+ 2} /g of CPA and 14.02 mg of Cd⁺² / g of CPA, 26.32 mg of Cu⁺² / g of CPµE (there was no interaction between the surfactant and Cd⁺² ions), 18.86 mg Cu⁺² /g CPD and 17.90 mg Cd⁺² / g CPD. The treatments studied here were not addressed in previous work, therefore providing the scientific community others viable options for the CP to be used as a sustainable adsorbent.

BANKING MEMBERS:
Externo à Instituição - ALFREDO JOSÉ FERREIRA DA SILVA
Externo à Instituição - FRANCISCO WENDELL BEZERRA LOPES - UnP
Presidente - 350247 - JOAO FERNANDES DE SOUSA
Externo ao Programa - 1566922 - LINDEMBERG DE JESUS NOGUEIRA DUARTE