Accepted Manuscript Molecular mechanism of anionic dyes adsorption on cationized

ACCEPTED MANUSCRIPT
21 
Table 4 Lists of adsorption kinetics and isotherms models 
Models 
Nonlinear form 
Plot 
Langmuir 
q
e 
= q
m
K
a
C
e
/(1 + K
a
C
e
) 
R
L 
= 1/(1 + K
a
C
0
) 
C
e
vs q
e
Freundlich 
q
e 
= k
f
C
e
1/nf
C
e
vs q
e
Tempkin 
q
e 
= B ln A
T
C
e
, B = RT/b
T
 
C
e
vs q
e
Sips 
q
e
= q
m
K
s
C
e
1/n
/(1 + K
s
C
e
1/n
) 
C
e
vs q
e
The Langmuir model assumes that the adsorbent surface is uniform and a 
monolayer adsorption occurs. However, the actual adsorption conditions will be more 
complicated. Therefore, the analysis using the Langmuir model alone is incomplete. 
Compared to the former, Freundlich can make up for its deficiencies and is suitable 
for the analysis of more complex purification mechanisms. The Temkin model is 
based on a linear relationship between the heat of adsorption and the temperature, 
rather than a logarithmic relationship. It can describe the purification mechanism well. 
Sips combines the characteristics of Langmuir and Freundlich to reveal the 
heterogeneity of the adsorbent surface, which is consistent with Freundlich when the 
contaminants are at a low concentration, and Langmuir when the adsorbates are at a 
high concentration. Based on the above reasons, the experimental data and behavior 
were further analyzed in this experiment using the Langmuir, Freundlich, Temkin, 
Sips adsorption model is necessary [40]. The non-linear fitting data processing results 
of Langmuir, Freundlich, Temkin and Sips models for adsorption isotherms of 
Diamine Green B (DG-B), Acid Black 24 (AB-24) and Congo red (CR) onto CRHC 
are shown in Table 5.
The higher values of correlation R
2
reveal that the purification behavior of 
CRHC for Diamine Green B (DG-B), Acid Black 24 (AB-24) and Congo Red (CR) is 
suitable for Langmuir and Sips. However, the more closely q
e
(cal) and (q
e
(exp)) 
implies that Langmuir is more suitable for analyzing the adsorption isotherm. The 
obtained Ka value of Langmuir is less than 1, which indicates that the purification 
process is beneficial. In addition, the reversibility of the purification behavior can be 

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