1
Vol.:(0123456789)
Scientific Reports | (2022) 12:12972
| https://doi.org/10.1038/s41598-022-17305-w
www.nature.com/scientificreports
Reusable kaolin impregnated
aminated chitosan composite
beads for efficient removal
of Congo red dye: isotherms,
kinetics and thermodynamics
studies
Mohamed M. Abou Alsoaud
1
, Mahmoud A. Taher
1
, Abdelrahman M. Hamed
1
,
Mohamed S. Elnouby
2
& Ahmed M. Omer
3*
In this investigation, Kaolin (K) impregnated aminated chitosan (AM-CTS) composite beads
were fabricated with multi-features including low-cost, high performance, renewable and ease
of separation for adsorption of anionic Congo red (CR) dye. Characterization tools such as FTIR,
XRD, SEM, TGA, BET, XPS and Zeta potential were thoroughly employed to confirm the successful
formulation process. The results revealed that K@ AM-CTS composite beads displayed higher specific
surface area (128.52 m
2
/g), while the thermal stability was prominently improved compared to pure
AM-CTS. In addition, the adsorption equilibrium of CR dye was accomplished rapidly and closely
gotten within 45 min. The removal efficiency was significantly enriched and reached 90.7% with
increasing kaolin content up to 0.75%, compared to 20.3 and 58% for pristine kaolin and AM-CTS,
respectively. Moreover, the adsorption process obeyed the pseudo-first order kinetic model, while
data were agreed with the Freundlich isotherm model with a maximum adsorption capacity reached
104 mg/g at pH 6. Furthermore, D–R isotherm model demonstrated the physical adsorption process of
