. 2019 Nov 19;9(64):37562–37572. doi: 10.1039/c9ra03045j

Effect of concentration of organic and inorganic additives on de-coloration of dye with KMnO₄ (Congo red = 1 × 10⁻⁴ M, KMnO₄ = 1 × 10⁻⁴ M, H₂SO₄ = 0.02 M, TiO₂ = 0.1 g/50 mL, temperature = 298 K).

[Conc.] mol dm⁻³	k ₀ = dx/dt (10⁻³) mol dm⁻³ min⁻¹	k ₁ (10⁻³) min⁻¹	k ₂ mol⁻¹ dm³ min⁻¹	R ²	% De-coloration
Urea
0.001	4.9	56.2	1.7073	0.362	98.29
0.005	5.1	41.6	0.6075	0.417	96.26
0.01	5	38.5	0.507	0.409	95.33
0.05	5.1	40.9	0.5758	0.409	95.48
0.1	4.7	28.2	0.2492	0.386	91.12

Naphthalene
0.001	4.9	31.6	0.3146	0.403	93.15
0.005	4.9	36.6	0.444	0.407	94.24
0.01	5	36.4	0.4265	0.416	93.93
0.05	4.9	30.4	0.2781	0.427	92.99
0.1	4.7	29.8	0.2781	0.397	92.37

Potash alum
0.001	3.8	31.7	0.6474	0.217	96.73
0.005	3.5	26.4	0.4916	0.194	96.42
0.01	3.7	68.8	10.043	0.198	100
0.05	4	47.2	1.9751	0.24	99.22
0.1	3.9	42.9	1.4465	0.230	98.44

Sodium chloride
0.001	5	48.6	0.9919	0.387	97.35
0.005	5.2	86.8	3.6748	0.396	100
0.01	5.2	83.9	5.829	0.406	100
0.05	5.2	98.2	6.511	0.383	100
0.1	5.2	86.1	6.1992	0.396	100

Effect of concentration of organic and inorganic additives on de-coloration of dye with KMnO4 (Congo red = 1 × 10−4 M, KMnO4 = 1 × 10−4 M, H2SO4 = 0.02 M, TiO2 = 0.1 g/50 mL, temperature = 298 K).