Defence Pablo Gonzales Cortes: "Nanofibrillated cellulose composites with polymers for the removals of cations from aqueous media"
| When: | Tu 22-10-2024 09:00 - 10:00 |
| Where: | Aula Academy Building |
Promotors: 1st promotor: Prof Francesco Picchioni, 2nd promotor: Prof. J.F.C. Quero, 3rd promotor: Prof Ranjita Bose
Abstract: In this doctoral thesis work, the synthesis and characterization of chemically modified polyketones was developed, through the Paal-Knorr reaction in various degrees of conversion (20,50 and 80%) for the removal of metal ions (Ca2+ and Mg2+) from aqueous solutions and its subsequent use in conjunction with nanofibrillated cellulose (CNF), for the preparation of composite materials (membranes) using impregnation and mixing methodologies. The main objective is to obtain materials with chemical and physical properties superior to those of nanofibrillated cellulose without modification. Due to this, the objective of the present work is to analyze the impact on the use of highly reactive modified polyketones with different functional groups, the chemical, thermal, mechanical and surface properties of composite materials with CNF. Additionally, the effects of the different polyketones used in the preparation of these composite materials on the removal of ions, specifically calcium and magnesium, from aqueous solutions are analyzed.
The results indicate that the adsorption of metal ions using chemically modified polyketones depends on the functional groups present in their structure, in addition to their degree of conversion and the pH of the medium, obtaining adsorption capacities of the order of 6-37 mg/g for the magnesium and calcium ions, respectively.
On the other hand, the use of chemically modified polyketones in the production of composite materials with CNF modifies the thermal properties of these materials, which depend on the type of polyketone used in their production, as well as the method (impregnation or mixing) selected. Furthermore, the mechanical properties in tensile tests were increased in relation to CNF membranes. This was also observed in the thermomechanical properties obtained for the different composite materials.
The electrical surface charges were influenced by the type of chemical structure of the modified polyketones used in the preparation of the composite materials, in which case materials with surface electrical charges similar to or higher than those of the CNF membranes were obtained. The modification of this parameter allows an increase in the adsorption of substances (metal ions) from aqueous solutions