Role of functional groups in the production of self-assembled microfibrillated cellulose hybrid frameworks and influence on separation mechanisms of dye from aqueous medium

Abstract

In this article, the role of surface ζ-potential, surface charge density of functional groups and available surface functional groups (-OH and –COO−) of microfibrillated cellulose (MFC) was explored in the production of self-assembled dimensional frameworks. Furthermore, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) oxidation of MFC and in situ TEMPO functionalization of produced frameworks were performed. The effect of increased charge density of carboxylic groups (-COO−) and decrease in surface ζ-potential on binding of titanium dioxide (TiO2) and horseradish peroxidase (HRP) was investigated further. High binding of TiO2 and HRP was reported due to high density of carboxylic group (-COO-) on produced functional frameworks. Thereafter, a model water of Irgalite Violet NZ dye was targeted to understand the behavior of available functional groups and introduced surface ζ-potential of frameworks towards adsorption of dye. Possible size-exclusion of dye aggregates was also explored using neat-MFC frameworks. Photo-oxidation (TiO2) and enzymatic catalysis (HRP) were studied further and highly effective system towards dye degradation was reported. Lastly, this study has shown a well deliberated quantitative understanding of functional groups/their density responsible for the production of frameworks and separation of dye.