Ce3+与Cu2+协同强化芬顿体系氧化苯酚的效能与机制研究

研究了Ce~(3+)与Cu~(2+)协同强化芬顿体系在不同初始条件下对水中苯酚的氧化效能与机制.结果表明,在p H适用范围的宽度和H_2O_2浓度变化方面,Ce~(3+)/Cu~(2+)/Fe~(2+)/H_2O_2体系比传统的芬顿体系更具有优势,该体系在p H=5.0、H_2O_2浓度为2.0mmol·L-1的条件下,仍可以对苯酚保持相对较高的氧化效能;Cu~(2+)可能会借助反应过程中的中间产物(醌类物质)生成Cu+,Cu+催化H_2O_2分解生成·OH,Ce~(3+)可能促进体系内醌类物质的形成,加快Fe~(3+)与Fe~(2+)的循环效能,在一定程度上提高了芬顿体系中H_2O_2分解生成·OH的速率,说明Cu~(2+)与Ce~(3+)对芬顿体系的强化作用具有协同性;自由基终止剂依然可以抑制Ce~(3+)、Cu~(2+)强化的芬顿体系对苯酚的降解,由此说明体系中起到氧化作用的活性物种仍然是羟基自由基(·OH).

Synergistic Enhancement on Oxidation of Phenol by Fenton Processes by Adding Ce3+ and Cu2+ Ions

Synergistic effect of Ce³⁺ and Cu²⁺ on the oxidation efficiency of phenol in different initial pH and H₂O₂ concentrations by Fenton processes was studied. The experiment results illustrated that Ce³⁺/Cu²⁺/Fe²⁺/H₂O₂ system had a wider scope of application than Fenton process in the aspect of pH and H₂O₂ concentration. Phenol was still efficiently degraded by Ce³⁺/Cu²⁺/Fe²⁺/H₂O₂ at a higher pH (pH=5.0) and a higher H₂O₂ concentration (2.0 mmol·L^-1). In addition, Cu²⁺ could react with quinone-like substrates, the oxidation intermediates of phenol, to produce Cu⁺, which could catalyze the decomposition of H₂O₂ to form·OH, while Ce³⁺ could accelerate the formation of quinone-like substrates and facilitate the cycling of Fe³⁺ and Fe²⁺, to enhance the decomposition of H₂O₂ to form·OH, the mechanism analysis illuminated the synergy of Ce³⁺ and Cu²⁺. The reactive species in Ce³⁺/Cu²⁺/Fe²⁺/H₂O₂ system was still proved to be·OH, resulting from the scavenging experiments by adding different radical scavengers.