Speaker
Description
Cellulose-based chemicals attract significant attention from researchers not only in fundamental research but also as potential replacements for petroleum-based chemicals in industrial applications. The primary challenge to scaling up the use of functionalized cellulose nanomaterials lies in developing economically viable fabrication methods.
In the two-step reaction that produces amine-functionalized cellulose, with an intermediate step to obtain 2,3-dialdehyde cellulose, critical parameters include the quantities of oxidizing and reducing agents. By optimizing these synthesis parameters, it is possible to reduce the demand for media and chemicals, particularly oxidation reagents (sodium periodate) and the reducing agent (2-picoline-borane). Additional variables include residence time in the reactor and the temperature. Naturally, the correlation of all these parameters directly impacts the efficiency of the process.
In our study, we modelled these correlations using statistical experimental design (DOE) and radial basis neural network (RBNN) techniques. The resulting models facilitated the production of cellulose structures with varying degrees of substitution by amine functional groups (n-alkylamines, C2-C8), aiming to maximize reaction yield while minimizing the consumption of oxidation and reduction agents. The functionalized fibres were subsequently homogenized to nanometric size using high-pressure homogenization.
Finally, the stability of suspensions of fine mineral particles (galena, pyrite, chalcocite, and quartz) in the presence of these nanostructures was assessed using the multiple light scattering (MLS) technique. The morphology of the resulting aggregates was analysed using optical microscopy with numerical image analysis.
Our results demonstrate basic characteristics of the flocculation process, laying the groundwork for further research aimed at optimizing and controlling the selectivity of the process in polymineral suspensions.
