Biosorption of anionic and cationic dyes via raw and chitosan oligosaccharide-modified Huai Flos Chrysanthemum at different temperatures

RSC Adv. 2019 Apr 10;9(20):11202-11211. doi: 10.1039/c9ra00378a. eCollection 2019 Apr 9.

Abstract

Raw Huai Flos Chrysanthemum (HFC) and modified HFC (HFC@CO) were used for the first time as a biosorbent material to remove cationic dyes Malachite green (MG) and Crystal violet (CV), and anionic dyes Sunset yellow (SY), Lemon yellow (LY), and Carmine (CM), at different temperatures (5-50 °C). The highest removal rates (R) for dye adsorption were observed at low temperature (5 °C) and room temperature (20 °C). At high (500 mg L-1) dye concentration, adsorption was completed within one minute, but the time required to reach adsorption equilibrium was longer than at the low (20 mg L-1) concentration. The experimental data fitted very well to the Langmuir model and the values of the maximum adsorption capacity for SY, LY, CM, CV, and MG, were 481.41, 507.23, 141.78 mg g-1, 526.32, and 769.23 mg L-1, respectively. The adsorption data fit well to a pseudo-second-order kinetic model.