| Fenton is a promising technology for the printing and dyeing wastewater treatment,while its practical application is still limited because of its poor pH range.This study introduced a Fenton-like system,Cu(Ⅱ)/H2O2/HA,which could be used under near-neutral water conditions.Herein,the degradation and decolorization kinetics of Acid orange 7(A07)and the effects of several typical influence factors on this system were researched in detail.This study further clarified the main reactive oxide species involved in the system,and analyzed the role of HA in A07 degradation,thereby proving the mechanism in Cu(Ⅱ)/H2O2/HA system.1)This study researched the AO7 degradation efficiency in Cu(Ⅱ)/H2O2,HA/H2O2 and Cu(Ⅱ)/HA systems,respectively.The results showed that the degradation efficiency of A07 in the Fenton-like system was not significant(all below 10%)at pH 6.In comparison,the A07 degradation in Cu(Ⅱ)/H2O2/HA system was very efficient(81%).The degradation kinetics of A07 in this systems obeyed the pseudo-first-order kinetics,with a rate constant of about 0.128 min-1.2)This study also researched the effect of several normal influence factors on the performance of this system.The increase in the concentration of Cu(Ⅱ),H2O2,HA could considerably increase the A07 degradation performance in Cu(Ⅱ)/H2O2/HA system.The higher pH also could significantly enhance the degradation efficiency of A07,and degradation efficiency was achieved in the neutral condition(pH 6).Furthermore,the chloridion and bicarbonate ion did not show obvious influence,while HA had an inhibitory effect on the A07 degradation in Cu(Ⅱ)/H2O2/HA system.3)Mechanism study indicates that free hydroxyl radical was the main reactive species for A07 degradation in the Cu(Ⅱ)/H2O2/HA system.The primary effect of HA was to promote the transformation of Cu(Ⅱ)to Cu(Ⅰ),which is an excellent catalyst to produce HO· with reacting with H2O2,thereby efficiently increasing the conversion efficiency of Cu(Ⅱ)/Cu(Ⅰ)cycle,and thus enhanced the oxidation degradation of A07 in the Cu(Ⅱ)/H2O2/HA system.In conclusion,Cu(Ⅱ)/H2O2/HA system showed an excellent degradation of A07.The major of the added HA could be oxidized to nitrogen,and the residual Cu(Ⅱ)could also be removed to meet the guidance of wastewater standard.Thus,the process proposed in this study may be promising in the application of wastewater treatment,due to its wider working pH range. |
