Abstract
Dissolved copper and iron ions are regarded as friendly and economic catalysts for perox-ymonosulfate(PMS)activation,however,neither Cu(Ⅱ)nor Fe(Ⅲ)shows efficient catalytic performance because of the slow rates of Cu(Ⅱ)/Cu(Ⅰ)and Fe(Ⅲ)/Fe(Ⅱ)cycles.Innovatively,we observed a significant enhancement on the degradation of organic contaminants when Cu(Ⅱ)and Fe(Ⅲ)were coupled to activate PMS in borate(BA)buffer.The degradation ef-ficiency of Rhodamine B(RhB,20 μmol/L)reached up to 96.3％within 10 min,which was higher than the sum of individual Cu(Ⅱ)-and Fe(Ⅲ)-activated PMS process.Sulfate radi-cal,hydroxyl radical and high-valent metal ions(i.e.,Cu(Ⅲ)and Fe(Ⅳ))were identified as the working reactive species for RhB removal in Cu(Ⅱ)/Fe(Ⅲ)/PMS/BA system,while the last played a predominated role.The presence of BA dramatically facilitated the reduction of Cu(Ⅱ)to Cu(Ⅰ)via chelating with Cu(Ⅱ)followed by Fe(Ⅲ)reduction by Cu(l),resulting in enhanced PMS activation by Cu(Ⅰ)and Fe(Ⅱ)as well as accelerated generation of reactive species.Additionally,the strong buffering capacity of BA to stabilize the solution pH was satisfying for the pollutants degradation since a slightly alkaline environment favored the PMS activation by coupling Cu(Ⅱ)and Fe(Ⅲ).In a word,this work provides a brand-new in-sight into the outstanding PMS activation by homogeneous bimetals and an expanded ap-plication of iron-based advanced oxidation processes in alkaline conditions.
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