Relevance of Natural polyelectrolyte complex dosage on the mechanism of micro/nanocellulose flocculation.

BASTIDA, G.A.; GALVÁN, M. V.; DELGADO-AGUILAR, MARC; AGUADO, ROBERTO; M. A. ZANUTTINI; QUIM TARRÉS

Córdoba

Workshop; ) 3 rd International Workshop on Biorefinery of Lignocellulosic Materials; 2023

IWBLCM 2023; IDM

In many industrial sectors, solid-liquid separation is a key stage in the production process. The use of flocculating agents is one of the most used alternatives. In this work, the interactions of cellulose micro/nanofibers (CMNF) with cationic polyelectrolyte complexes (PEC) and the different flocculation mechanisms are analyzed. For this, PECs were formed by addition of a xylan (Xyl) solution on a chitosan (Ch) solution at different Xyl/Ch mass ratio: 60/40; 70/30 and 80/20. Further, two CMNFs were obtained by a mechanical pre-treatment with a PFI mill refiner followed by chemical pre-treatment with oxalic acid at 25 wt% and 50 wt%, and the mechanical fibrillation using a pressurized homogenization. The interactions and flocculation mechanisms of CMNF suspension with PECs were analyzed by measuring gel point by sedimentation, floc size, z-potential and rheology measurements. The results show a correlation between the minimum gel point and the largest floc size. Besides, we confirm that the maximum flocculation of CMNFs depend on Xyl/Ch mass ratio of PECs and this phenomenon occurs with PEC dosages lower than those necessary to neutralize the systems.