Reaction kinetics of waste sulfuric acid using H₂O₂ catalytic oxidation

Figures & data

Table 1. Characteristics and components of waste sulfuric acid.

Item	Parameter
Appearance	Thick black liquid with fine particles
Smell	Intense smell
Density	1.644 g/cm^3
Viscosity (20°C)	28.47 mPa-s
Chrominance	80,000×
COD (mg/L)	1.7–2.5 × 10^5
TOC (mg/L)	6.4–9.3 × 10^4
Mass fraction of H2SO4 (wt)	89–93%
Anions like F^−, Cl^−, PO4^3-	None
Cations like Na^+, Ca^2+, and Fe^3+	<1 mg/L

Table 2. Physical and chemical characteristics of activated carbon.

Strength(%)	BET surfacearea (m^2/g)	Apparentdensity(kg/m^3)	Totalpore volume(cm^3/g)	Iodineadsorptionvalue (mg/g)	Porosity(%)
90	1100	500	0.9	1000	55.56

Figure 1. Device for waste sulfuric acid oxidation.

Figure 2. Catalyst dosage and degradation of impurities.

Table 3. K values at different dosage of catalyst.

Catalyst dosage	0	1:900	1:700	1:500	1:300	1:100
K (hr^−1)	0.1084	0.1613	0.1711	0.1856	0.1885	0.1916

Figure 3. Relationship between catalyst dosage and K.

Figure 4. Effect of feed rate of H₂O₂ on degradation of impurities.

Table 4. K values at different rates of addition of H₂O₂.

H2O2 adding rate (g/(kg waste acid-hr))	20	30	40	50	60
Initial H2O2 concentration (mg/L)	1120	1443	1676	1775	2086
K (hr^−1)	0.1200	0.1389	0.1585	0.1856	0.1893
R^2	0.9988	0.9987	0.9987	0.9998	0.9997

Figure 5. Relationship between K and dosage of H₂O₂.

Table 5. Ln k values at different reaction temperatures.

Reaction temperature (K)	303	323	343	363
ln k	–17.67	–17.17	–16.63	–16.33

Figure 6. Change in k values at different temperatures.

Figure 7. Relationships with time for COD and chrominance of reaction solution.