Preparation of cationic modified collagen extracted from leather wastes and their application in dye flocculation

A series of novel cationic flocculants are designed and synthesized successfully by grafting two monomers onto the collagen backbone, namely acrylamide (AM) and 2‐methacryloyloxyethyltrimethyl ammonium chloride (DMC). Apparently, these effective grafting modifications are well demonstrated by adopting FTIR and H¹ NMR measurements, which could be used to estimate grafting ratios of corresponding monomers approximately. Additionally, significant improvements in positive charge densities and amorphous aggregation structures are also definitely confirmed by Zeta and XRD measurements, respectively. Moreover, thermogravimetric analysis clearly proves the formation of cationic branched chain architectures, whose maximum thermal degradation temperature would significantly decrease with the introduction of AM. In addition, much more porous and rougher surface structures could be visibly observed after successful grafting modifications. Furthermore, when the feeding weight ratio between collagen and DMC is controlled at 1:3, or the equal amounts of AM and DMC are introduced meanwhile the mass ratio between collagen and mixed monomers (DMC + AM) is fixed at 1:4, the samples acquired could both perform the best in decolorizing the model wastewater containing methyl orange (MO) dyes in their groups, and hereby, a corresponding flocculation mechanism is also proposed based on the structural analysis of the formed flocs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45363.