摘要
利用葡萄籽提取液合成纳米零价铁(GS-nZVI),作为类芬顿反应体系的催化剂,用于降解水中甲基橙(MO)。考察溶液pH值(3~11)、反应温度(25~40℃)、MO初始浓度(50~200 mg/L)以及H2O2加入量(浓度为5%~30%)对其降解效果的影响。结果显示:随pH的降低、温度的升高、初始浓度的减小,MO的降解率增大;研究范围内,H2O2浓度为10%时,MO的降解效果最佳。在不调节pH(pH=6.8),其他条件相同时,GS-nZVI/H2O2类芬顿体系对MO的降解效果明显优于传统芬顿法。采用拟一级和伪二阶动力学模型,研究了类芬顿体系对MO的降解过程。拟一阶模型(r^2=0.907 9~0.969 0)和伪二阶模型(r^2=0.938 7~0.961 0)均能很好地描述GS-nZVI为催化剂的类芬顿法降解MO的行为,说明降解是氧化还原与吸附共存的过程,表观活化能(Ea=45.65 kJ/mol),表明降解是受表面控制;其中吸附过程与伪二级吸附模型关联性更高,表明吸附以化学吸附为主。热力学分析结果表明,降解为自发的吸热过程。降解过程中紫外-可见吸收光谱的变化,显示GS-nZVI/H2O2类芬顿法能够有效降解MO。
The green synthesized nano-zero-valent iron(GS-nZVI),prepared by grape seed extract,was used as the catalyst of Fenton-like system to degrade methyl orange(MO) in water.The effects of pH(3~11),reaction temperature(25~40 ℃),initial concentration of MO(50~200 mg/L)and the concentration of H2O2(5%~30%) on the degradation of MO were investigated respectively.The results shows that the efficiency of degradation improved with the lower pH of solution,the higher temperature and the lower initial MO concentration.In range of the experiment,the degradation efficiency of MO was the best when the concentration of H2O2 was 10%.At unadjusted value of pH(pH=6.8),the degradation efficiency of MO by the Fenton-like method was obviously superior to the traditional Fenton method at the same conditions.The results of kinetic analysis show that degradation behavior of MO by the Fenton-like method can be well described by both of the pseudo-first-order model(r^2=0.907 9~0.969 0) and the pseudo-second-order model(r^2=0.938 7~0.961 0).It indicates that the degradation is the coexistence of redox reaction and adsorption.The apparent activation energy(Ea=45.65 kJ/mol) indicates that the degradation is a surface-controlled reaction;The adsorption process is more related to the pseudo-second-order adsorption model,which indicates that chemical adsorption is dominant.The results of thermodynamic analysis indicate that the degradation of MO is a spontaneous and endothermic process.The change of UV-Vis absorption spectrum shows that the degradation of MO is very effective by the Fenton-like method.
作者
李赛
田瑜
徐婷婷
郭波
LI Sai;TIAN Yu;XU Ting-ting;GUO Bo(College of Environmental Science and Engineering,Taiyuan University of Technology,Jinzhong 030600,China)
出处
《应用化工》
CAS
CSCD
北大核心
2020年第2期302-307,共6页
Applied Chemical Industry
基金
国家自然科学基金项目(U1610105)
山西省重点研发计划项目(201803D31040)。
关键词
绿色合成
纳米零价铁
类芬顿反应
甲基橙
green synthesis
nano-zero-valent iron
Fenton-like system
methyl orange
