Ultrahigh adsorption capacity of a new metal sieve-like structure nanocomposite-based chitosan-graphene oxide nanosheet coated with poly-o-toluidine for the removal of Acid Red dye from the aquatic environment

Figures & data

Scheme 1. Illustration of the fabrication route of the ternary P(OT)/GO/CS, P(OT)/GO/SE, and P(OT)/GO/ST NCs.

Figure 1. XRD patterns (A), IR spectrum (B), Raman spectrum (C) and Isotherm curve (D) of P(OT) and its NCs.

Table 1. The S_BET, total pore volumes, and average diameters of P(OT) pure, P(OT)/GO, P(OT)/GO/CS, (OT)/GO/SE, and P(OT)/GO/ST NCs.

Sample	SBET (m²/g)	Vtotal (cc/g)	Average diameter (nm)
P(OT)	53.2849	0.188997	7.7642
P(OT)/GO	49.23	0.184915	8.38327
P(OT)/GO/CS	44.2405	0.180873	8.9876
(OT)/GO/SE	41.0004	0.152185	8.11972
P(OT)/GO/ST	37.4357	0.128237	7.48426

Figure 2. SEM images of P(OT) (A), P(OT)/GO NCs (B), P(OT)/GO/CS NCs (C), P(OT)/GO/SE NCs (D) and P(OT)/GO/ST NCs (E), and TEM images of P(OT) (F), P(OT)/GO NCs (G), P(OT)/GO/CS NCs (H), P(OT)/GO/SE NCs (I), and P(OT)/GO/ST NCs (J).

Figure 3. (A) TGA curves and (B) DTG curves for pure P(OT) and its NCs.

Table 2. Thermal behaviour of P(OT), binary P(OT)/GO NCs, ternary P(OT)/GO/CS NCs, ternary P(OT)/GO/SE NCs and ternary P(OT)/GO/ST NCs.

	Temperature (°C) for various percentages of decompositions^a
Sample	T10	T25	PDTmax^b (°C)	CDTfinal^a (°C)
P(OT)	60	266	444	523
P(OT)/GO	47	502	465	528
P(OT)/GO/CS	50	478	455	511
P(OT)/GO/SE	128	316	446	510
P(OT)/GO/ST	202	356	448	510

^aThe values were determined by TGA at a heating rate of 10 °C min⁻¹.

^bDetermined from DTG curves.

Scheme 2. Illustration of the fabrication procedure of ternary P(OT)/GO/CS NCs (a) and proposed mechanism of dye removal (b).

Figure 4. (A) Comparison of the efficiency of the five samples in removing the A.R. dye from an aqueous phase. (B) The electronic spectra of 20 ppm concentration of A.R. dye in aqueous phase (a), and after shaking with 5 mg of P(OT) solid phase (b), and after shaking with 5 mg of P(OT)/GO/CS solid phase (c).

Table 3. Adsorption capacity of various adsorbents on Acid Red dye.

Dyes	Material	Shaking time	Uptake capacity	Reference
A.R.	Black tea leaves	300 min	30.3	2021 [74]
A.R.	Carboxylatedalginic acid	60 min	9.17	2020 [75]
A.R.	Ferrous sulphate flocs	60 min	6.623	2013 [76]
A.R.	Activated carbon	1440 min	18.76	2017 [77]
A.R.	Halloysite nanoclay	50 min	13.89	2022 [78]
A.R.	Sugarcane bagasse-based biocomposites	60–75	143.4–205.1	2022 [74]
A.R.	Zinc ferrite Mn0.8Zn0.2Fe2O4 magnetic	40	49.9	2022 [75]
A.R.	Titanate nanotubes/layered double hydroxides/graphene oxide	90	124	2023 [76]
A.R.	P(OT)/GO/CS NCs	75 min	169.5	This work

Figure 5. Optimization of parameters for the adsorbent solid phases of A.R. dye from the solution samples. Effect of the solution pH with contact time 120 min (a), mass of material with shaking time 90 min (B), contact time (C), temperature at 10, 20, 35, and 50 °C (D) and Influence of concentration of KNO₃ (E). (experimental conditions: A.R. dye (20 ppm), pH = 2, 20 ± 0.1 °C temperature, 5 mg of P(OT) (a) and P(OT)/GO/CS NCs (b) solid phases.

Figure 6. Kinetic models for the adsorption removal of A.R. by P(OT) and P(OT)/GO/CS NCs (A) Weber–Morris plot, (B) Fractional power model, (C) Lagergren plot, (D) Pseudo-second order plot, (E) Elovich model plot and (F) The plot of ln K_c vs. 1000/T for calculating thermodynamic parameters.

Table 4. Different kinetic models parameters for the adsorption of A.R. dye on the solid phases at 293 K.

Weber-Morris kinetic model
	Rd (mg/g)		R^2
P(OT)/GO/CS	12.43		0.992
P(OT)	5.68		0.993
Fractional power function kinetic model
	a	b	ab	R^2
P(OT)/GO/CS	16.61	0.45	7.47	0.993
P(OT)	0.985	0.839	0.826	0.997
The pseudo-first-order kinetic(Lagregen) model
	qe, exp (mg/g)	qe, calc (mg/g)	k1	R^2
P(OT)/GO/CS	139.9	124.5	0.025	0.982
P(OT)	50.53	62.7	0.023	0.964
The pseudo-second-order kinetic model
	qe, exp (mg/g)	qe, calc(mg/g)	k2	R^2
P(OT)/GO/CS	139.9	169.5	1.9 × 10^−4	0.993
P(OT)	50.53	126.6	4.4 × 10^−2	0.988
Elovich kinetic model
	α (g/mg min)	β (mg/g min)	R^2
P(OT)/GO/CS	0.011	34.83	0.963
P(OT)	0.01	15.4	0.933

Table 5. Illustration thermodynamic parameters at 293 K.

Samples	H (kJ mol^−1)	S (J mol^−1 K^−1)	G (kJ mol^−1)
P(OT)	33.34 ± 0.1	114.57 ± 0.5	−0.23 ± 0.01
P(OT)/GO/CS NCs	84.1 ± 0.2	296.7 ± 0.6	−2.89 ± 0.07

Figure 7. The removal percentages of A.R. dye from different real samples by solid phases P(OT) and P(OT)/GO/CS NCs, (experimental conditions: 50 ml solution, pH = 2, shaking time = 120 min, temp. = 308 K, A.R. concentration 20 mg L⁻¹, and 15 mg of P(OT)/GO/CS NCs solid phase and 30 mg P(OT) solid phase).

Table 6. The percentages of A.R. dye removed from the real samples by P(OT) and P(OT)/GO/CS NCs solid phase.

Real samples	P(OT) (%)	P(OT)/GO/CS NCs (%)
Red sea water	93.19	95.09
Waste water	94.23	96.31
tap water	94.23	98.02

Kamran U, Bhatti HN, Noreen S, et al. Chemically modified sugarcane bagasse-based biocomposites for efficient removal of acid red 1 dye: kinetics, isotherms, thermodynamics, and desorption studies. Chemosphere. 2022;291(Pt 2):132796. doi: 10.1016/j.chemosphere.2021.132796.

 PubMedGoogle Scholar

Salam MA, Gabal M, Al Angari Y. The recycle of spent Zn–C batteries and the synthesis of magnetic nanocomposite from graphene nanosheets and ferrite and its application for environmental remediation. J Mater Res Technol. 2022;18:4267–4276. doi: 10.1016/j.jmrt.2022.04.112.

 Google Scholar

Zhang J-W, Mariska S, Van HT, et al. Synthesis of titanate nanotubes/layered double hydroxides/graphene oxide composites and applications for the removal of methylene blue, methylene green 5, and acid red 1 from aqueous solutions. Inorg Chem Commun. 2023;152:110723. doi: 10.1016/j.inoche.2023.110723.

 Web of Science ®Google Scholar

Saratale RG, Saratale GD, Chang J-S, et al. Bacterial decolorization and degradation of azo dyes: a review. J Taiwan Inst Chem Eng. 2011;42(1):138–157. doi: 10.1016/j.jtice.2010.06.006.

 Web of Science ®Google Scholar

Ko SH, Lee D, Kang HW, et al. Nanoforest of hydrothermally grown hierarchical ZnO nanowires for a high efficiency dye-sensitized solar cell. Nano Lett. 2011;11(2):666–671. doi: 10.1021/nl1037962.

 PubMed Web of Science ®Google Scholar

Data Availability

The authors confirm that the data supporting the findings of this study are available within the article.