Photo-Fenton and Fenton Oxidation of Recalcitrant Industrial Wastewater Using Nanoscale Zero-Valent Iron

Table 4

COD and TOC reductions (%) with dark-Fenton and photo-Fenton experiments.

Coded variables				Dark-Fenton			Photo-Fenton
χ 1	χ 2	χ 3	Run	% COD reduction	% TOC reduction	Run	% COD reduction	% TOC reduction
+1	+1	−1	1.1	42.6	21.4	2.1	78.4	59.4
−1	+1	−1	1.2	34.6	17.3	2.2	70.6	50.0
0	0	0	1.3	42.0	21.4	2.3	80.5	57.8
0	0	0	1.4	39.3	19.9	2.4	78.2	56.7
−1	+1	+1	1.5	35.6	19.0	2.5	77.6	56.0
−1	−1	+1	1.6	35.1	18.9	2.6	76.1	53.9
0	0	0	1.7	38.4	24.2	2.7	61.3	61.7
+1	+1	+1	1.8	43.5	23.0	2.8	60.3	61.7
+1	−1	+1	1.9	77.5	50.3	2.9	81.6	61.6
+1	−1	−1	1.10	49.2	34.9	2.10	78.5	58.0
−1	−1	−1	1.11	38.3	24.7	2.11	70.9	53.6