Recyclable Xanthan/TiO₂ Composite Cryogels towards the Photodegradation of Cr(VI) Ions and Methylene Blue Dye

Table 3

Fitting parameters to first-order and second-order kinetic models corresponding to the reduction of Cr(VI) to Cr(III) at pH 1.0 and pH 2.0 and to the photodegradation of MB at pH 7.0 (Tris-HCl buffer) in the presence of XG or XG/TiO₂ 10% cryogels. The control experiment was done in the absence of cryogels.

Medium pH	Cryogel	1st order		2nd order
		(min^-1)		(L mol^-1 min^-1)
Cr(VI) reduction
1.0	XG	0.015	0.9780	72	0.8766
	XG/TiO2 10%	0.019	0.9867	125	0.8615
2.0	XG	0.012	0.9229	54	0.8267
	XG/TiO2 10%	0.012	0.9898	50	0.9318
MB photodegradation
7.0	XG	0.0046	0.9552	704	0.8924
	XG/TiO2 10%	0.0096	0.9971	2304	0.9752
	Control	0.0009	0.8651	93	0.8828