石墨烯掺杂分子筛负载氧化铁芬顿催化降解苯酚影响因素的研究

The influence factors on the fenton catalytic degradation of phenol using ironloaded graphene modified molecular sieve catalyst

通过水热晶化法制备了石墨烯掺杂介孔分子筛MCM-41复合载体,利用该载体浸渍负载氧化铁制备了非均相芬顿催化剂gh-MCM-41-Fe.以苯酚为模拟有机废水,考察了催化剂和H2O2投加量、水质因素(苯酚初始浓度、反应温度和水中腐殖酸和草酸)等对gh-MCM-41-Fe芬顿催化降解苯酚效能的影响.结果表明,当苯酚初始浓度为100 mg·L-1,催化剂在60 min催化降解苯酚去除率高达97.6%,COD去除率为65.9%,反应符合准一级反应动力学模型;苯酚降解速率随着催化剂和H2O2投加量的增加而增加,但投加过多会消耗·OH自由基从而不利苯酚降解过程;苯酚初始浓度从10 mg·L-1增至100 mg·L-1,苯酚降解速率相应降低,但体系中H2O2及·OH自由基的有效利用率反而增加;反应温度对于苯酚废水降解率和COD去除率影响不大,反应表观频率因子为105.68 min-1,表观活化能为18.43 k J·mol-1;腐殖酸和草酸对苯酚废水降解和COD去除均有抑制作用.

The graphene modified molecular sieve MCM-41-supported iron oxide（ gh-MCM-41-Fe） was synthesized by hydrothermal crystallization and impregnation method. The effects of catalyst dosage and H2O2 amount,water-quality conditions（ initial concentration of phenol,reaction temperature,humic acid and oxalate） on the phenol degradation using gh-MCM-41-Fe as catalyst in the heterogeneous Fenton reaction were investigated systematically.The experimental results suggested that phenol degradation efficiency and COD removal could reach 97.6% and 65.9%,respectively,after 60 min reaction when the initial concentration of phenol was 100 mg·L-1. The kinetics of phenol degradation in the system of heterogeneous Fenton reaction was well-fitted with a pseudo first-order model. A positive relationship was observed between phenol degradation rates and the dosage of catalyst and H2O2. However,excessive dosages would quench ·OH free radical,which inhibited the degradation of phenol. With the increase of phenol initial concentration（ from 10 to100 mg·L-1）,the removal efficiency of phenol decreased,while the effective utilization of H2O2 and ·OH free radical in the system were inversely strengthened. The reaction temperature showed little influence on the phenol and COD removal. The apparent frequency factor was 105.68 min-1and the apparent activation energy was 18.43 k J·mol-1. Humic acid and oxalate in water both inhibited phenol degradation and COD removal.