A two-level factorial design (2k) was thus applied, using as
independent factors hydrogen peroxide concentration, catalyst
load, and pH, which were set at two levels (-1, +1): 115 mM
(slightly higher than 105 mM, the stochiometric value for the
initial COD41) to 340 mM; 0.5-1.50 g/L; 2-4 (Table 2),
respectively