Table 1.

Elemental composition of the VB before adsorption (a) and after adsorption (b) from the EDS analysis.

Element	Weight %	Atomic %
(a)
O K	48.46	63.42
Mg K	0.87	0.7
Al K	9.55	6.95
Si K	17.37	14.62
Ca K	8.8	4.31
FeK	8.83	3.93
NaK	4.87	5.27
K K	1.25	0.8
Totals	100	100
(b)
O K	46.41	54.63
Mg K	0.85	0.76
Al K	9.52	7.91
Si K	17.25	14.17
Ca K	7.9	5.08
FeK	8.64	6.83
NaK	4.46	7.5
Cr K	4.97	3.12
Totals	100	100

“K” represents the combined X-ray lines of K_α1 and K_α2 in the inner shell of an atom.