Reusable electrospun carbon nanofiber composite for selective removal of inorganic arsenic species in water

Figures & data

Figure 1. Typical SEM images of Ce-CNM at (a) low and (b) high amplification; (c) SEM image is PAN nanofiber; (d) EDS analysis image of the Ce-CNM

Figure 2. XRD patterns of Ce-CNM

Figure 3. FTIR of (a) Ce-CNM, (b) Ce-CNM after adsorption of As^III and (c) Ce-CNM after adsorption of As^V

Figure 4. The pH dependent adsorption of arsenic by Ce-CNM

Figure 5. The adsorption efficiencies of arsenic at various temperatures

Figure 6. (a) The adsorption efficiencies of arsenic at various initial concentrations. (b) Selective kinetic adsorption of As^III at different initial concentrations by Ce-CNM (pH = 12)

Figure 7. The influence of solution volume on adsorption efficiency

Figure 8. The influence of co-existing ion on the adsorption efficiency

Figure 9. (a) Adsorption kinetics of different arsenic species; (b) Pseudo second order dynamical linear fit of As^III and As^V

Table 1. Correlation kinetic fitting parameters of arsenic by Ce-CNM

Arsenic species	First-order kinetics			Second-order kinetics
	qe(mg g^−1)	K1(min^−1)	R^2	qe(mg g^−1)	K2(g mg^−1 min^−1)	R^2
As^III	0.3892	7.500 × 10^−3	0.8217	0.9072	0.0561	0.9989
As^Ⅴ	0.3304	8.060 × 10^−3	0.8534	0.8319	0.0693	0.9991

Table 2. Adsorption isotherms fitting parameters of arsenic on Ce-CNM

Arsenic species	Langmuir isotherm			Freundlich isotherm
	qmax (mg g^−1)	kL(mg^−1)	R^2	n	kF (mg g^−1)	R^2
As^III	1.716	7.928	0.9969	3.939	1.140	0.6127
As^V	2.619	2.299	0.9135	3.284	1.406	0.7571

Figure 10. Langmuir adsorption isotherms of Ce-CNM for (a) As^III and (b) As^V

Figure 11. (a) The influence of NaOH concentrations on desorption efficiency of As; (b) Adsorption efficiency of Ce-CNM in five regeneration cycles