Banca de QUALIFICAÇÃO: JÉSSYCA EMANUELLA SARAIVA PEREIRA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JÉSSYCA EMANUELLA SARAIVA PEREIRA
DATE: 26/03/2021
TIME: 07:00
LOCAL: Sala Virtual
TITLE:

Synthesis of magnetic lignin nanoparticles obtained from coconut bagasse for heavy metal removal

KEY WORDS:

Biomass; Lignin nanoparticles; Heavy metals; Adsorption.

PAGES: 54
BIG AREA: Engenharias
AREA: Engenharia Química
SUMMARY:

The exploration of viable processes for the use of lignocellulosic biomass in clean fuels and chemicals with high added value is essential for sustainable development. Large amounts of lignin are available annually as byproducts of the paper and biorefinery industries, generating many problems, especially environmental ones. Due to its structure and composition, lignin offers a pathway compatible with the concept of sustainability since it is possible to produce new chemical products with high added value. In this perspective, this work aims to synthesize magnetic nanoparticles of lignin extracted from coconut bagasse, as well as to verify its applicability as an adsorbent for the removal of heavy metals in aqueous effluents. For this purpose, the lignocellulosic biomass will be submitted to three different pretreatments: alkaline with sodium hydroxide, organosolv using glycerol and the combined use of sodium hydroxide and hydrogen peroxide. The alkaline and organosolv pretreatment was followed by an oxidation reaction with hydrogen peroxide. After the delignification process, lignin and magnetite nanocomposites will be produced using the co-precipitation method. The lignins resulting from the pretreatments will be evaluated for chemical composition, Infrared Spectrometry (FTIR), Ultraviolet Spectrometry (UV), Nuclear Magnetic Resonance (NMR), solubility in organic solvent and Thermogravimetric Analysis (TGA). The synthesized lignin/Fe3O4 nanoparticles will be evaluated by Scanning Electron Microscopy (SEM), zeta potential, hydrodynamic size and X-Ray Diffraction (XRD). The adsorption assays using the lignin/ Fe3O4 nanoparticles as adsorbents for the removal of Cu (II), Ni (II) and Cd (II) ions will be conducted in a batch system, whose effects of pH, adsorbent concentration, particle size and initial metal concentration will be investigated. The adsorption equilibrium will be described by the Langmuir and Freundlich isotherm models. In the kinetic study, the experimental data will be analyzed using the pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The adsorption studies will also include the analysis of thermodynamic parameters to evaluate the spontaneity, the degree of disorder and whether the adsorption process is exothermic or endothermic. Finally, the efficiency of the desorption cycles will be evaluated. From the results that will be obtained, it is expected that the lignin/Fe3O4 nanoparticles present appropriate characteristics for the adsorption process of metallic ions and, consequently, constitute an alternative to the classical adsorbents used for treating aqueous effluents and contribute to the valorization of lignin.

BANKING MEMBERS:
Externo à Instituição - CARLOS EDUARDO DE ARAÚJO PADILHA
Presidente - 1308273 - EDUARDO LINS DE BARROS NETO
Externo à Instituição - FRANCISCO WENDELL BEZERRA LOPES - UnP
Externo ao Programa - 1566922 - LINDEMBERG DE JESUS NOGUEIRA DUARTE
Externa ao Programa - 3151141 - PAULA FABIANE PINHEIRO DO NASCIMENTO