Electrokinetic properties of chemically modified jute fabrics

Abstract

This work aims to study the alkali and oxidatively modified jute fabrics electrokinetic properties. In contrast to control fabric, chemically modified jute fabrics have a small positive zeta potential in a basic pH range which can be attributed to the presence of sodium cations (originating from mentioned chemical modifications) on their surfaces. At lower pH values, samples modified under milder alkali and oxidative conditions have about 2.2‑3.5 times lower zeta potential since the protonation process leads to the formation of higher positive charge in the electrochemical double layer causing higher adsorption of Cl^- ions (originating from the electrolyte). On the other hand, more intensive chemical modifications increased the zeta potential at lower pH values due to the increased amount of carboxyl groups and fibers ability for water retention and hence swelling. The isoelectric point of fabrics having lower zeta potential than control fabric was shifted toward higher pH values pointing out lower contribution of fabrics surface acidic groups. In the case of extensive oxidation conditions (60 and 90 min), the isoelectric point was shifted toward lower pH values as a result of lignin removal and mentioned higher availability of newly formed carboxyl groups.