Fig. 1. XRD patterns of (a) montmorillonite K-10, (b) 5%Pd-0.65%In on montmorillonite K-10, (c) aluminum pillared montmorillonite K-10, and (d) 5%Pd-0.65%In on aluminum pillared montmorillonite K-10.
Fig. 2. Nitrogen sorption or desorption and average pore diameter of MK10, MK10 Pd/In, Al-MK10, and Al-MK10 Pd/In.
Fig. 3. XPS signals of (a) Pd3d (b) In3d of MK10 Pd/In and (c) Pd3d (d) In3d of Al-MK10 Pd/In.
Fig. 4. Point of zero charge (PZC) of MK10 Pd/In and Al-MK10 Pd/In.
Fig. 5. Fourier transformation infrared spectroscopy of (a) montmorillonite K-10, (b) 5%Pd-0.65%In on montmorillonite K-10, (c) aluminum pillared montmorillonite K-10, and (d) 5%Pd-0.65%In on aluminum pillared montmorillonite K-10.
Fig. 6. Reduction rates of nitrates with (a) MK10 Pd/In in distilled deionized water (DDW), (b) MK10 Pd/In in artificial groundwater (GW), (c) Al-MK10 Pd/In in DDW, and (d) Al-MK10 Pd/In in GW with different pH conditions.
Fig. 7. Reduction rates of nitrates with (a) MK10 Pd/In and (b) Al-MK10 Pd/In in different pH conditions.
Fig. 8. Ammonium produced during reduction of nitrates with (a) MK10 Pd/In and (b) Al-MK10 Pd/In in different pH conditions.
Fig. 9. The ratios of ammonium produced to degraded nitrates with (a) MK10 Pd/In and (b) Al-MK10 Pd/In in different pH conditions.
Fig. 10. The concentration of palladium in water after nitrate reduction using distilled deionized water.
Table 1. The experimental conditions for the reduction of nitrate in aqueous solution
Table 2. BET specific surface area and average pore diameter of samples
Table 3. The relative compositions of major elements (e.g., Si, Al, Pd, In) of MK10 Pd/In and Al-MK10 Pd/In measured by EDX and XPS
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