摘要
Oxygen radicals (ROS) generated by transition metals catalysed activation of persulfate (PS) can be applied to degrade various organic pollutants. In order to avoid related second pollution of heavy metal under homogeneous catalytic system, a stable and effective catalyst (CS-CoPcS) was developed for PS activation by immobilizing cobalt tetrasulfophthalocyanine (CoPcS) onto chitosan (CS) microspheres covalently for the heterogeneous catalytic degradation of azo dye methyl orange (MO). The effects of different reaction conditions were studied. Furthermore, the stability of CS-CoPcS and possible mechanism were analyzed. The results showed that the MO removal efficiency could up to 87.21% at 25oC under the conditions of initial MO concentration of 152.75mmol/L, pH0 value of 5.5, PS concentration of 10mmol/L and CS-CoPcS dosage of 1.25g/L. The kinetics data were fitted very well by pseudo-first-order model in 180min, and the removal rate was 1.24×10-2min-1. The comparison of the electron paramagnetic resonance (EPR) and different radical scavengers effect showed that sulfate radical was the dominant active species in the catalytic process. The results of recycling experiments after four runs indicated that the CS-CoPcS was recyclable for consecutive catalytic degradation of MO, and no detectable amount of cobalt ion in the aqueous solution after any runs reaction, which show high catalytic activity and structural stability of CS-CoPcS.
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