Catalytic activation of persulphate with Mn3O4nanoparticles for degradation of acid blue 113: process optimisation and degradation pathway

The performance of the persulphate/Mn(3)O(4)nanoparticles (PS/Mn3O4) oxidation process was investigated for the degradation of acid blue 113 (AB113) azo dye. XRD, N(2)adsorption-desorption analysis, FE-SEM and EDX confirmed the successful synthesis of Mn(3)O(4)nanoparticles. The effect of three independent variables including PS concentration, Mn(3)O(4)dosage and solution pH on the system response was optimised by genetic algorithm (GA) and central composite design (CCD) techniques. The results of ANOVA and fit statistics (P-value < 0.0001,= 0.9772) showed that the proposed quadratic model can predict the AB113 removal efficiency with high confidence. The optimum points for PS concentration, Mn(3)O(4)dosage and solution pH were predicted to be 61.46 mg/L, 57.69 and 3.00, respectively, by CCD method. Under these conditions, after 60 min of reaction, the maximum experimental removal efficiency of AB113 in the PS/Mn(3)O(4)oxidation system and separate application of PS and Mn(3)O(4)were obtained 96.70%, 18.0% and 7.0%, respectively. The pseudo-first-order rate constants of AB113 degradation the PS/Mn(3)O(4)oxidation system and separate application of PS and Mn(3)O(4)were 0.0597, 0.0029 and 0.0015 min(-1), respectively. In this way, the synergistic effect for degradation of AB113 in the PS/Mn(3)O(4)was determined 92.6%. Oxalic acid, naphthalen-1-ol and acetic acid were the major identified intermediates due to AB113 degradation.

Automated summary

The performance of the persulphate/Mn(3)O(4)nanoparticles oxidation process was investigated for the degradation of acid blue 113 azo dye. The optimized conditions yielded a high removal efficiency of 96.70% for AB113. The major identified intermediates were oxalic acid, naphthalen-1-ol and acetic acid.