posted on 2021-02-09, 03:30authored byJifu Du, Xin Yang, Houhua Xiong, Zhen Dong, Zhiwei Wang, Zhiyuan Chen, Long Zhao
Rhodamine B (RhB) is considered as
a potential source of water
pollution because it is harmful to the environment and humans, and
thus, it should be removed from the water system. Hydrogels derived
from polysaccharides have been received much attention for dye adsorption.
In this study, acrylic acid (AAc)-grafted xanthan gum hydrogel (XGH)
was synthesized by electron beam irradiation. The effects of AAc concentration
and the adsorbed dose on the gel fraction and swelling ratio were
studied. The XGH hydrogel structure was characterized by FTIR and
SEM analyses. As a result, the sample with 75% gel fraction was selected
to investigate the adsorption behaviors toward RhB. The adsorption
kinetic data were in good agreement with pseudo-second-order mode.
The adsorption isotherms fitted well with the Langmuir equation with
an ultrahigh maximum adsorption capacity of 2612.12 to 2777.77 mg/g
at 293 to 323 K, which is a significant breakthrough in RhB uptake.
Na2CO3 and HCl were used to regenerate the RhB-loaded
XGH. The removal efficiency was found to be nearly unchanged after
five adsorption–desorption cycles. Finally, the selectivity
of XGH toward cationic/anionic mixing dyes was investigated.