Photolyse (CR /Aqueous solution) Adsorption (CR/ZnO) Photocatalytic degradation (CR/ZnO/UV-A) Initial pH t=0 min t=30 min t=20 min t=40 min t=60 min PDE (%) A Species λ (nm) A Species λ (nm) AE (%) A Species λ (nm) ABS Species λ (nm) A Species λ (nm) (CR-)2 (CR-) (CR-) (CR-) (CR-) (CR-) 2 0.359 595.5 - - - - - - - - - - - 4 0.986 537.5 - - - - - - - - - - - 6 0.83 - 497 0.679 497 18.19 0.605 497 0.415 497 0.202 492 70.25 8 0.628 - 497 0.562 498 10.51 0.357 496 0.116 492 0.028 D 95.02 10 0.83 - 497 0.706 499 14.94 0.222 481 0.146 481 0.075 D 89.38 12 0.83 - 498 0.732 497 11.81 0.281 488 0.184 488 0.1 D 86.34

Table1: The position of the absorption bands of CR in aqueous solution and during the ZnO-mediated photocatalytic degradation of dye as a function of pH ([ZnO] =0.5g/L, [CR]=20mg/l, T=298K, λmax=365 nm, I=90 J /cm2 and irradiation time =60min)