Ag掺杂MnFe_(2)O_(4)/UV活化过硫酸盐降解废水中对硝基苯酚

Ag-doped MnFe_(2)O_(4)/UV-activated persulfate degradation of p-Nitrophenol in

以水热法合成MnFe_(2)O_(4),将Ag粒子按照2%、4%、6%、8%的负载比掺杂其中合成Ag-MnFe_(2)O_(4),并以X射线衍射(XRD)、扫描电镜(SEM)、X射线光谱(EDS)、紫外漫反射光谱(UV-Vis DRS)、比表面积分析(BET)等对其结构进行表征分析.结果表明,复合材料具有优异的催化性能,取10组制药厂废水水样,当PNP浓度为(152±56)mg·L^(-1),添加(2.0±0.5)g·L^(-1)6%Ag-MnFe_(2)O_(4),PDS浓度为(20±5)mmol·L^(-1),调节pH值>7,在UV强度54 W、温度25℃的环境中,1 h内降解率达到99.8%±0.2%.复合材料抗干扰能力强,在降解PNP的过程中受水体中高浓度共存无机阴离子(SO^(2-)_(4)、CO^(2-)_(3)、HCO^(-)_(3)、Cl^(-)、NO^(-)_(3))的影响小.通过自由基淬灭和顺磁共振(EPR)分析确定了6%Ag-MnFe_(2)O_(4)/PDS/UV体系中的主要活性物质为SO^(-)_(4)∙、h^(+)、OH∙及O^(-)_(2)∙,并提出了可能的降解途径及中间产物.复合材料具有较好的稳定性,循环使用10次后,仍可达到96.4%±0.2%的降解率,Ag^(+)、Mn^(2+)、Fe^(3+)的最大溶出浓度分别为0.01、0.12、0.24 mg·L^(-1).

MnFe_(2)O_(4)was synthesized by the hydrothermal method,and Ag particles were doped into it according to loading ratios of 2%,4%,6%,and 8%to synthesize Ag-MnFe_(2)O_(4).The structure of the material was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS),UV-visible diffuse reflectance spectroscopy(UV-Vis DRS),and Brunauer-Emmett-Teller(BET)surface area analysis.The results show that the composite material has excellent catalytic performance.Ten sets of wastewater samples were taken from pharmaceutical factories with a p-nitrophenol(PNP)concentration of(152±56)mg·L^(-1).Under conditions of(2.0±0.5)g·L^(-1)6%Ag-MnFe_(2)O_(4),persulfate(PDS)concentration of(20±5)mmol·L^(-1),pH>7,UV intensity of 54 W,and temperature of 25℃,the degradation rate reached 99.8%±0.2%within 1 hour.The composite material has a strong anti-interference ability and is minimally affected by high concentrations of coexisting inorganic anions(SO^(2-)_(4)、CO^(2-)_(3)、HCO^(-)_(3)、Cl^(-)、NO^(-)_(3))in the water during the PNP degradation process.Through free radical quenching and electron paramagnetic resonance(EPR)analysis,the main active substances in the 6%Ag-MnFe_(2)O_(4)/PDS/UV system were determined to beSO^(-)_(4)∙、h^(+)、OH∙andO^(-)_(2).Possible degradation pathways and intermediate products were proposed.The composite material has good stability,and after 10 cycles of use,it can still achieve a degradation rate of 96.4%±0.2%.The maximum leaching concentrations of Ag+,Mn2+and Fe3+were 0.01,0.12,and 0.24 mg·L^(-1),respectively.