Table 1.

Pseudo Zero-Order Rate Constant (k) and Correlation Coefficient (R²) for Photocatalytic Reduction of 100 μM Cr(VI) by Tartaric Acid in the Presence of Cu(II) at pH 4 and 25°C

Conditions	k(μM/min)	R2
1 mM tartaric acid−0 μM Cu(II)	0.11	0.9694
1 mM tartaric acid−100 μM Cu(II)	0.61	0.9913
1 mM tartaric acid−200 μM Cu(II)	0.94	0.9969
1 mM tartaric acid−400 μM Cu(II)	1.29	0.9948
1 mM tartaric acid−800 μM Cu(II)	1.70	0.9950
1 mM tartaric acid−1,200 μM Cu(II)	2.06	0.9922
0.5 mM tartaric acid−400 μM Cu(II)	1.01	0.9957
2 mM tartaric acid−400 μM Cu(II)	1.39	0.9940
4 mM tartaric acid−400 μM Cu(II)	1.56	0.9972