Persulfate Degradation of Dye Reactive Blue 19 Catalyzed by Copper-Impregnated Activated Carbon
Date Issued
2014
Date
2014
Author(s)
Cheng, Meng-Hsuan
Abstract
Sodium persulfate can be thermally or chemically activated to produce sulfate free radicals (SO4˙－) and hydroxyl free radicals (HO˙), which have very powerful oxidation ability for pollutants. It has been demonstrated that under acidic condition, SO4˙－ is the dominant oxidant radical species；under neutral condition, the SO4˙－ can proceed reaction with hydroxyl ions to generate HO˙；under alkaline condition, HO˙is the major oxidant radical species.
However, Persulfate is stable at the ambient temperature and oxidate pollutants slowly. In this study, copper-impregnated activated carbon was used as the activator of PS to accelerate the degradation of anthraquinone dye RB19 by changing the ratio of copper impregnated, dosages of persulfate and Cu/AC, initial solution pH (3,5,7,9 and 11) and temperature (25,35 and 45℃). In addition, the differences of degradation potential between PS, Cu/AC and Cu/AC+PS wereinvestigated.
In PS system, increase the dosage of PS and temperature can improve the removal efficiency of RB19. The alkaline condition is more favorable to the RB19 degradation due to the production of dominant radical species HO˙ which has higher redox potential. Physical and chemical analysis of Cu/AC showed that after calcinations, impregnated copper turned into zero valent state which can provide higher catalytic ability. Impreganating excess copper decreased the specific surface area of AC. With the decrease of adsorption and activation position, the removal ratio of RB19 would reduce. The experiments confirmed that the optimum copper impregnated ratio was 1%. The removal process of RB19 followed Bangham’s Model and Intra-particle Diffusion Model in Cu/AC system.
In Cu/AC+PS system, the removal efficiency of RB19 increased with the enhancement of PS dosage and temperature. The effect of pH on RB19 degradation rate was pH 11 > pH 3 > pH 5 > pH 9 > pH 7. The optimum amounts of impreganated copper were the same with Cu/AC system; all get the best degradation efficiency at the impregnated amounts of 1%. The removal efficiency of RB19 can reach to 96.79% under optimum operational conditions of PS/RB19=25, 1 g/L 1% Cu/AC, pH=11 and 45℃ after one hour of reaction. Under the combined system, the reaction activation energyEa= 56.14 KJmol-1.
Compare the experimental results of the single systems with those of the combined system at the ambient temperature, a significant synergistic effect can be observed. The combined system displays higher removal at a high temperature and in the alkaline environment, which is exactly in line with the characteristics of dye wastewater：the high temperature and high pH. It is thus evident that this method is suitable for the degradation of dye wastewater containing RB19.
Subjects
蒽醌染料
活性藍RB19
過硫酸鹽
活性碳
銅
催化
高級氧化
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-103-R01541133-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):4646e0e537dd448bcc3091ef7192f85c