Biodegradable cellulose nanocrystals hydrogels for removal of acid red 8 dye from aqueous solutions

Abstract

Biodegradable cellulose nanocrystals hydrogels (CNCsH) were synthesized from cellulose nanocrystals (CNCs) which were prepared from office wastepaper (OWP) by a chemical crosslinking method using epicholorohydrin (ECH) as a cross-linker. CNCsH were tested for their swelling behavior and biodegradability and the point of zero charge had been determined. The ability of CNCsH for removing the Acid Red 8 (AR8) anionic dye from its aqueous solution was evaluated. The different parameters affecting removal of the dye, such as pH, initial concentration of dye, content of CNCs, temperature and adsorbent dosage were investigated. The optimum conditions for 68% removal efficiency were pH = 1, initial concentration of dye = 10 ppm, contact time = 105 min, CNCs content = 5% and CNCsH dosage = 0.5 g at 30 °C. The adsorption isotherms, kinetics, and thermodynamic parameters have been studied. The results showed an appropriate fit for Langmuir adsorption isotherm and pseudo-second order kinetics model with an adsorption capacity of 17.12 mg/g. According to the obtained values of thermodynamic parameters, the removal of Acid red 8 by CNCs hydrogels was exothermic spontaneous process.

Cellulose-based hydrogel for adsorptive removal of cationic dyes from aqueous solution: isotherms and kinetics

“…This in turn implied that a dye molecule monolayer may form at the hydrogel–dye interface. 29 From Fig. 7a, it was noted that the removal percentage decreased from 85 to 78% with increasing dye concentration at 0.1 g NCC–CH.…”

“…The crystallinity degree of the samples was determined using an X-ray diffractometer (XPERT-PRO D8 Bruker) at 30 mA current and 40 kV voltage. 29 The Cu K radiation ranged from 5° to 400°. Amorphous subtraction method was used to calculate the crystallinity index ( X c ) by eqn (2) where, I c and I am are the peak intensities of crystalline and amorphous materials, respectively.…”

“…At rst, a huge amount of water enters the hydrogel structure and formed hydrogen bonds; later, as more water slowly diffused into the hydrogel network, the osmotic pressure between the water surrounding the hydrogel network decreased, lowering the force opposing elastic contraction. 29 The surface charge of the adsorbent material in an aqueous solution is characterized by the point of zero charge. The pH zpc of the cellulose-chitosan hydrogel beads was found to be 4.4 (Fig.…”

An Interpenetrating Polymer Network Hydrogel Based on Cellulose, Applied to Remove Colorant Traces from the Water Medium: Electrostatic Interactions Analysis

“…The oxygen of the eosin Y dye molecule was strongly attracted to the hydrogen atoms in group -OH of the cellulose hydrogel in the IPN network, and the Br of eosin Y was weakly attracted to H of the group -OH from the PHEMA hydrogel [ 57 ].…”

Nanocellulose: A Fundamental Material for Science and Technology Applications

“…Recently researchers have been working on replacing toxic dyes using biomaterials such as cellulose or modified forms of cellulose [128][129][130]. Abdelaziz et al [131] isolated nanocrystals from wastepaper (using acid hydrolysis) and used the nanocrystals for the preparation of hydrogels using epichlorohydrin as a crosslinker. The nanocrystal hydrogels are positively charged at lower pH and are negatively charged at higher pH.…”