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

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 influence factors on the fenton catalytic degradation of phenol using iron-loaded graphene modified molecular sieve catalyst

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 to 100 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^-1 and the apparent activation energy was 18.43 kJ·mol^-1. Humic acid and oxalate in water both inhibited phenol degradation and COD removal.