Adsorption of Cationic Dyes on a Cellulose-Based Multicarboxyl Adsorbent

Abstract

A novel adsorbent based on cellulose (CGD) was prepared via modifying with glycidyl methacrylate (GMA) and diethylenetriamine pentaacetic acid (DTPA), characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential thermogravimetry (DTA/TGA). Malachite green (MG) and basic fuchsine (BF) were used to resemble cationic dyes in wastewaters. The influences of several parameters (contact time, pH, temperature, initial concentration) were evaluated to determine the best adsorption conditions. Langmuir adsorption isotherm items explained MG adsorption well, while BF was fitted well with the Freundlich model. The maximum adsorption capacities were greater than some other reports, 1155.76 mg·g–1 for a BF internal concentration of 2000 mg·L–1 and 458.72 mg·g–1 for MG in theory. Kinetics and thermodynamics were adopted to explain in-depth information associated with the adsorption process. The adsorption processes of dyes were both feasible spontaneous and well-described by the pseudosecond-order model. The dynamic adsorption/desorption experiments, with saturated sodium bicarbonate solution as the eluent, show that the adsorbent could be reused for five cycles or four cycles, keeping the adsorption rate above 85 % and 90 % for BF and MG, respectively.