采用酸浸-水热-煅烧法从腐泥土型红土镍矿中制备磁性多金属共掺杂型MgFe2O4异相类芬顿(Fenton)催化剂.利用X射线衍射(XRD)、傅立叶红外光谱(FTIR)、扫描电子显微镜(SEM)和比表面积及孔径分布测定(BET-BJH)等手段,考察了煅烧温度对所制备产物结构、形貌和比表面积及孔径分布的影响,并研究了所制备产物作为异相Fenton催化剂降解罗丹明B(Rh B)溶液的催化活性.结果表明,水热合成产物为层状双(多)金属氢氧化物和尖晶石型MgFe2O4复合物.通过300℃的煅烧,层状双(多)金属氢氧化物就能分解并生成MgFe2O4;随着煅烧温度的提高,产物结晶度增加、粒径尺寸变大,形貌逐渐生长为近球型颗粒且分散度渐渐提高,同时介孔数量减少、比表面积减小.经过500℃煅烧的试样H-C500显示出优异的催化降解活性.在体系反应温度为45℃、pH值为6. 44、催化剂用量为0. 625 g·L-1且H2O2体积分数为1. 0%的条件下,经过300 min,10 mg·L-1的罗丹明B溶液降解率可达到97. 8%,同时总有机碳(TOC)去除率达到77. 8%.重复使用3次后,催化剂仍能保持较高活性,降解率和TOC去除率减少量分别少于3. 0%和5. 0%.
Heterogeneous Fenton-like method has attracted considerable attention because of its potential effectiveness in mineralization of organic contaminants in a wide range of reaction medium pH.Spinel ferrites MFe2 O4(M=Fe,Zn,Cu,Ni,Mn,Co)as heterogeneous Fenton-like catalysts have been studied extensively due to their good catalytic activity,prominent physical and chemical stability,and excellent magnetic properties,which allow their easy separation from the reaction medium by magnetic field for further circular utilization.Considering the group of ferrites,limited research focused on the utilization of MgFe2 O4 as heterogeneous Fenton catalytic agent,whereas most of the catalysts are synthesized by pure chemical reagents.In this study,magnetic multi-metal co-doped MgFe2 O4 heterogeneous Fenton-like catalyst was synthesized from saprolite laterite by acid leaching-hydrothermal calcination method.The effect of calcination temperature on the phase,morphology,specific surface area,and pore size distribution of samples were characterized by X-ray diffraction,scanning electron microscopy,Fourier-transform infrared,Brunauer-Emmett-Teller/Barrett-JoynerHalenda analysis.The catalytic activity of the as-prepared products as heterogeneous Fenton catalysts for the degradation of Rhodamine B(Rh B)solution was also investigated.The results show that the layered double(multi)hydroxides coupled with a portion of magnesium ferrite are synthesized by hydrothermal method,and the cubic crystal MgFe2 O4 is obtained by decomposition of the layered double(multi)hydroxides after calcination above 300℃.With the increase in calcining temperature,the crystallinity of the products increases,and the particle size becomes larger.The morphology gradually grows to near spheroidal particles,and the dispersion degree gradually increases.Meanwhile,the pore size becomes larger,and the specific surface area is reduced.Calcination of sample H-C500 exhibits the best catalytic activity for the degradation of Rh B after 500℃,achieving 97.8%degradation e
Journal of University of Science and Technology Beijing