Table 2 Copper removal efficiency at varied contact time

0

0.00 ± 0.00^f

5

17.50 ± 0.21^e

15

43.04 ± 0.32^d

30

48.99 ± 0.23^c

60

55.03 ± 0.07^b

120

62.31 ± 0.18^a

180

62.62 ± 0.01^a

240

62.45 ± 0.08^a

p value

 < .0001