Simultaneous removal of diclofenac sodium, cadmium and bacterial inactivation from aqueous solutions by activated MgO nanoparticles

Figures & data

Figure 1. Diclofenac sodium chemical structure.

Figure 2. (a) and (b) are SEM images and (c) and (d) are TEM images of MgO.

Figure 3. The X-ray diffraction (XRD) patterns of the MgO products synthesized using citric acid as a fuel and subjected to calcination at 800 °C.

Figure 4. The FT-IR spectra of the MgO nanostructures that were produced and subsequently calcined at 800 °C, using citric acid (a) diclofenac sodium (b) MgO and (c) MgO and diclofenac sodium.

Figure 5. DCF and Cd²⁺ removal efficiency from aqueous solution using B-nZVI composite (●), activated charcoal (▲), MgO (■) versus time, adsorbent dose 0.1 g, C₀100 mg L⁻¹, pH 7, and T = 25 °C.

Figure 6. The effect of pH on the removal of DCF and Cd²⁺ by MgO nanoparticles.

Figure 7. Variables influencing the adsorption efficiency of DCF at a concentration of 100 mg L⁻¹ and Cd²⁺: MgO nanoparticles dosage at 25 °C and pH 7.

Figure 8. The effect of DCF and Cd²⁺ initial concentration on the removal efficiency using MgO nanoparticles.

Figure 9. Plotting the pseudo-second-order kinetic parameters for the removal of DCF and Cd²⁺ by MgO. (●) DCF and Cd²⁺ (■).

Table 1. The Langmuir isotherm model was utilized to obtain values of K, q_max, and the coefficient of determination (R²) for the removal of both DCF and Cd²⁺ using the B-nZVI composite at 25 °C.

DCF				Cd^2+
	R^2	Qm	KL	R^2	Qm	KL
B-nZVI	0.9916	46.5	0.021	0.9978	43.3	0.023
MgO	0.997	66.2	0.015	0.9996	50.8	0.020

Figure 10. Linear graphs representing the Langmuir isotherm model for the adsorption of DCF and Cd²⁺ using MgO nanoparticles and the B-nZVI composite at of 298 K, respectively.

Figure 11. Influence of temperature on the percentage removal of diclofenac sodium and Cd²⁺ at pH = 7, C₀=25mg L⁻¹, adsorbent dose = 0.1 g and time = 3h.

Table 2. The thermodynamic parameters determined at various concentrations.

Parameter pollutant		ΔG° (kJ mol^−1)		ΔS° (kJ (mol^−1 K^−1))
	ΔH◦ (kJ.mol^−1)	298K	318K	298K	318K
DCF	−14.77	−18.11	−17.00	−14.71	−14.72
Cd^2+	−9.56	−16.39	−16.01	−9.50	−9.51

Table 3. The filtration procedure involved the passage of 1 liter of pure water solutions containing DCF and Cd²⁺ at concentrations of 100, 10, 1.0 and 0.01 mg.L⁻¹ through laboratory filters.

Initial concentration (mg.L^−1)	Column type^a	Average eluted DCF concentration (mg.L^−1)	±SD	Average eluted Cd^2+ concentration (mg.L^−1)	± SD
100	MgO	b.l.d.	–	b.l.d.	–
100	B-nZVI	14	1.8	18.4	2.3
10	MgO	b.l.d.	–	b.l.d.	–
10	B-nZVI	4.1	0.6	5.2	0.8
1.0	MgO	b.l.d.	–	b.l.d.	–
1.0	B-nZVI	0.22	0.1	0.28	0.1
0.01	MgO	b.l.d.	–	b.l.d.	–
0.01	B-nZVI	b.l.d.	–	b.l.d.	–

These filters consisted of either MgO or B-nZVI mixed with an excess of sand at the ratio of 1:49 (w/w). To ensure the reliability and accuracy of the results, the experiments were carried out in triplicate.

^aFlow rate, 2 mL min⁻¹; temperature, 25 °C; b.l.d., below the detection limit of the analytical method used

Table 4. Antibacterial activity of Cd²⁺, DCF, MgO, MgO + DCF, MgO + Cd²⁺, MgO + Cd²⁺ + DCF, levo the positive control to gram-positive bacteria and the negative control (water) in relation to the inhibition zone using the agar well diffusion method.

Gram positive bacteria
No.	Compounds	S. aureus	M. luteus	B. subtilis	E. faecalis	S. epidermidis
1	Cd^2+	23.8	35	24.3	31.3	36.8
2	DCF	20.7	–	16.7	–	25.8
3	MgO	6.0	6.0	6.0	6.0	6.0
4	MgO + DCF	–	–	18.3	–	13
5	MgO + Cd^2+	19.2	–	16.2	23.7	24.5
6	MgO + Cd^2++DCF	–	26	20	21.7	29.3
7	H2O	–	–	–	–	–
8	Levo	45	43	40.7	40.3	45.3