Banca de DEFESA: DANIELY CARLOS HENRIQUE

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : DANIELY CARLOS HENRIQUE
DATE: 11/03/2024
TIME: 09:30
LOCAL: Sala de aulas do PPGEQ
TITLE:

CQD/LDH-ZnAl COMPOSITES FOR DYES REMOVAL FROM AQUEOUS SOLUTION VIA ADSORPTION AND FENTON REACTION

KEY WORDS:

carbon quantum dots, dye removal, adsorption. emerging contaminants, water treatment.

PAGES: 105
BIG AREA: Engenharias
AREA: Engenharia Química
SUMMARY:

When in contact with water resources, some dyes, drugs and herbicides can cause serious damage to fauna and flora, also posing a risk to human beings. As a way to reduce the amount of these substances in the effluents, the present work aimed to synthesize and characterize the LDH/ZnAl composites with carbon quantum dots by co-precipitation and hydrothermal routes, maintaining a ratio of 2:1 ZnAL. for the removal of dyes, drugs and the herbicide 2,4 D in aqueous solution. As a means of study and comparison, four composite materials were produced with the addition of carbon quantum dots (CQD) represented by H-LDH/ZnAl-CO3-CQD (Hydrothermal with CQD) and C- LDH /ZnAl-CO3-CQD ( co-precipitation with CQD) and two LDH without the CQDs (C- LDH /ZnAl-CO3) and (H- LDH /ZnAl-CO3). Initially, affinity tests were carried out with the drugs (salicylic acid, 17 alpha methyltestosterone, caffeine, propranolol, rifampicin, diclofenac sodium, paracetamol and amoxicillin), 2.4 D herbicides and dyes (methyl orange, congo red, malachite green, fuchsin alkaline, acid fuchsin, rhodamine B, alizarin, methylene blue and safranine) using the four materials. Then, the best adsorbate and the best adsorbent material were defined and chosen, continuing the studies. The adsorbent agents were characterized via infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX) and point of zero charge (pHPCZ). In the affinity tests, the C- LDH /ZnAl-CO3-CQD, C- LDH /ZnAl-CO3 materials showed high removal efficiencies for the adsorbing Congo red and malachite green dyes (91.6% and 97.35%), ( 97.6%, and 98.68%), respectively. The materials H- LDH /ZnAl-CO3-CQD and H- LDH /ZnAl-CO3 obtained good adsorption for methyl orange, adsorbing 75.55% and 73.15%, respectively. In addition to orange, malachite green also had a good interaction with H- LDH /ZnAl-CO3, being removed 72.41%. The C- LDH /ZnAl-CO3 adsorbed 71.4% of the 2.4D herbicide, while the other materials had very little interaction. Both C- LDH /ZnAl-CO3-CQD and H- LDH /ZnAl-CO3-CQD did not have good results compared to H- LDH /ZnAl-CO3, which adsorbed 43.42% of salicylic acid, 70 .51% Rifampicin and 82.6% of sodium diclofenac and the C- LDH /ZnAl-CO3 which adsorbed 60.1% of rifampicin. In view of the results obtained with the dyes, initially, it was decided to work with C- LDH -ZnAl-CO3-CQD and methylene blue. Since C- LDH -ZnAl-CO3 did not show any interaction with blue reaching 0% removal and C- LDH -ZnAl-CO3-CQD at 32%. Then, several tests were carried out to study the influence of the main parameters that could influence the adsorptive process, such as the dosage of the adsorbent (0.05 to 0.5 g) and the pH of the solution (1 to 12.1) and concentration of the adsorbate (5 to 50 mg. L-1). The best adsorption result was obtained for 0.02 g, 25 mg concentration. L-1 and pH of the solution of 6.08.

COMMITTEE MEMBERS:
Presidente - 1797785 - LUCAS MEILI
Interno(a) - 3731108 - LIVIA MARIA DE OLIVEIRA RIBEIRO
Interno(a) - 3182573 - RODOLFO JUNQUEIRA BRANDAO
Interno(a) - 1515173 - SIMONI MARGARETI PLENTZ MENEGHETTI
Externo(a) ao Programa - 1527220 - CAMILA BRAGA DORNELAS - UFALExterno(a) ao Programa - 3064870 - DANIEL PINTO FERNANDES - UFALExterno(a) ao Programa - 2151027 - ALEXANDRE URBAN BORBELY - UFAL