Zwitterionic Cellulose Nanofibrils with High Salt Sensitivity and Tolerance

Abstract

To improve the salt tolerance/sensitivity of cellulose nanofibrils (CNFs), zwitterionic cellulose nanofibrils (ZCNFs) were prepared from softwood bleached kraft pulp fibers via a sequential process of anionic modification with 2,2,6,6-tetramethylepiperidin-1-oxyl (TEMPO)-mediated oxidation, cationic modification with (2,3-epoxypropyl) trimethylammonium chloride (EPTMAC), and high-pressure homogenization. To produce ZCNFs with different contents of cation group, EPTMAC loadings of 0.15 to 1.15 g/g fiber were explored during cationization. The obtained ZCNFs were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectra (XPS), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and rheological measurements. The salt tolerance of the ZCNFs was investigated by adding mixed salts into the ZCNF dispersions. The results demonstrated that the ZCNFs with both anionic and cationic charges were produced. Compared with the TEMPO-mediated oxidized cellulose nanofibrils (TOCNFs), the ZCNFs exhibited an excellent “salt-thickening” behavior under the studied salt concentrations (2–24% w/w). Moreover, increasing the content of the cation group increased the salt tolerance/sensitivity of ZCNFs. This work demonstrated that introducing cationic charges to the anionic charged TOCNFs imparts the produced ZCNFs with excellent salt sensitivity and tolerance, which could expand the application of nanocellulose in oil recovery or wastewater treatment.

Application of Nanocellulose in Oilfield Chemistry

“…At a concentration of 2 wt %, the viscosity of the nanofluid was higher and the interfacial tension of oil−water was lower, causing the oil to drain out of the pores like a piston. As shown in Figure 7, the micron-sized nanofluid could penetrate the oil phase and form micro- To improve the salt tolerance/sensitivity of CNF, Wang et al 80 introduced cationic charges into the anionic charged TEMPO-mediated oxidized cellulose nanofibrils (TOCNFs) to prepare zwitterionic cellulose nanofibrils (ZCNFs). This product has excellent salt sensitivity and tolerance, which could expand the application of nanocellulose in oil recovery or wastewater treatment.…”

“…To improve the salt tolerance/sensitivity of CNF, Wang et al introduced cationic charges into the anionic charged TEMPO-mediated oxidized cellulose nanofibrils (TOCNFs) to prepare zwitterionic cellulose nanofibrils (ZCNFs). This product has excellent salt sensitivity and tolerance, which could expand the application of nanocellulose in oil recovery or wastewater treatment.…”

Zwitterionic Cellulose‐Based Polymer Electrolyte Enabled by Aqueous Solution Casting for High‐Performance Solid‐State Batteries

“…Preparation and characterization of ZCNF are illustrated in Figure S1. Specifically, the cellulose underwent fiber oxidation, cationic modification, and high‐pressure homogenization processes to introduce the cationic quaternary ammonium [−(CH 3 ) 3 N + ] groups and anionic carboxyl (−COO − ) groups into its backbone, as previously reported (Experimental Section in the Supporting Information for the details) [21] . Fourier transform infrared spectroscopy (FTIR) analysis revealed the absorption bands of cellulose, such as the −OH stretching (3420 cm −1 ) and −C−O stretching (1056 and 1112 cm −1 ) vibrations in the glucose ring (Figure S2).…”

“…Chemie Forschungsartikel tion processes to introduce the cationic quaternary ammonium [À (CH 3 ) 3 N + ] groups and anionic carboxyl (À COO À ) groups into its backbone, as previously reported (Experimental Section in the Supporting Information for the details). [21] Fourier transform infrared spectroscopy (FTIR) analysis revealed the absorption bands of cellulose, such as the À OH stretching (3420 cm À 1 ) and À CÀ O stretching (1056 and 1112 cm À 1 ) vibrations in the glucose ring (Figure S2). This indicates that ZCNF preserved the fundamental structure of cellulose.…”

Recent Progress in Metal‐Organic Frameworks@Cellulose Hybrids and Their Applications

“…Its applications cover papermaking, drug delivery, dietary fibers, oil recovery due to its fascinating physicochemical properties. [ 87‐94 ] Cellulose can be easily separated from plants such as cotton, bast plants, woods, bamboo, etc . Furthermore, cellulose nanofibrils (CNFs), and cellulose nanocrystals (CNCs) can also be obtained by chemical or physical treatment of cellulose.…”