Fe3 O4－H2 O2类Fenton体系催化降解苯酚

摘要

为提出基于新型磁纳米Fe3 O4催化剂的类Fenton体系，采用化学共沉淀法制备磁纳米Fe3 O4，用四甲基氢氧化铵（ TMAH）对所制备的磁纳米Fe3 O4进行表面改性，就Fe3 O4－H2 O2类Fenton体系对苯酚废水的处理效果进行探讨，考察催化剂投量、H2 O2浓度、pH、反应时间等因素对COD和挥发酚去除率的影响．结果表明：磁纳米颗粒平均粒径为30 nm，并在20～100 nm内呈现良好的粒度分布．不同剂量TMAH包覆的3种催化剂经超声预处理后，在室温（13℃）下对50 mg／L苯酚（相当于112 mg／L COD）的降解效果基本一致．当催化剂投量为0．8 mmol／L、H2 O2浓度为2．0 mmol／L、pH为4．5、反应时间180 min时，COD去除率最高可达72％；催化剂投量为0．4 mmol／L、H2 O2浓度为2．0 mmol／L、 pH为4．5、反应时间为90 min时，挥发酚的去除率接近100％．而在重复使用方面，3＃Fe3O4－TMAH（2 mL）催化剂的回用性最好，4次反应COD的去除率分别为73％、29％、28％、26％，挥发酚去除率分别为100％、84％、67％、54％．该类Fenton体系具有不产生多余泥量的优点，且磁纳米催化剂在外磁场作用下可实现快速分离回收．%To put forward a Fenton⁃like system based on a new type of Fe3 O4 magnetic nanoparticles catalyst, Fe3O4 magnetic nanoparticles were prepared using chemical co⁃precipitation , and their surface was modified with tetramethyl ammonium hydroxide (TMAH). The catalyzed degradation of phenol by Fe3O4-H2O2 Fenton⁃like system was investigated, including the effect of catalyst dosage, H2 O2 dosage, pH value and reaction time on the removal of COD and volatile phenol. The results showed that the mean size of the Fe3 O4 nanoparticles is 30 nm and they show a good disparity between 20 and 100 nm. Three different doses of TMAH coated catalysts after ultrasonic pretreatment, revealed almost the same treatment efficiency of 50 mg/L phenol (112 mg/L COD equivalent) under the room temperature (13 ℃). Under the condition of 0.8 mmol/L catalyst dosage, 2.0 mmol/L H2 O2 dosage, pH 4.5 and the reaction time of 180 minutes, the highest COD removal efficiency was 72%; while under the condition of 0.4 mmol/L catalyst dosage, 2.0 mmol/L H2 O2 dosage, pH 4.5 and the reaction time of 90 minutes, the removal rate of volatile phenol was close to 100%. 3# Fe3 O4-TMAH(2 mL) catalysts revealed optimal reuse efficiency, the removal rate of COD were 73%,29%,28%,26%, the removal rate of volatile phenol were 100%, 84%,67%,54%. The Fenton⁃like system has the advantage of no redundant excess sludge producing, and the magnetic catalyst can realize quick separation and recycling under the action of outside magnetic field.