载银活性炭活化过硫酸钠降解酸性橙

Degradation of Acid Orange 7 with Persulfate Activated by Silver Loaded Granular Activated Carbon

采用硝酸氧化的颗粒活性炭浸渍制备Ag/GAC活化剂,利用N2吸附、SEM、FT-IR及XRD对Ag/GAC进行表征,得出Ag成功负载于颗粒活性炭上,并以Ag/GAC在常温常压下活化过硫酸钠(PS)产生硫酸根自由基(SO-4·)降解偶氮染料酸性橙7(AO7).考察了Ag负载量、PS浓度、Ag/GAC投加量、初始p H对AO7降解效果的影响.结果表明,当Ag负载量为12.7mg·g-1、n(PS)∶n(AO7)为120∶1、Ag/GAC投加量为1.0 g·L-1,降解180 min后AO7降解率达95.0%以上.初始p H对Ag/GAC活化PS降解AO7有较大影响,p H为5.0时降解效果最优.通过紫外可见光谱、气相色谱-质谱(GC/MS)对AO7降解过程进行了探讨,在降解过程中AO7的偶氮键和萘环结构均被破坏,并检测出主要降解产物有邻苯二甲酸和乙酰苯.

Granular activated carbon with silver loaded as activator( Ag / GAC) was prepared using impregnation method. N2 adsorption,scanning electron microscopy( SEM),Fourier transform infrared spectroscopy( FT-IR) and X-ray diffraction( XRD) were adopted to characterize the Ag / GAC,showing that silver was successfully loaded on granular activated carbon. The oxidation degradation of acid orange 7( AO7) by the Ag / GAC activated by persulfate( PS) was investigated at ambient temperature. The influences of factors such as Ag loading,PS or Ag / GAC dosages and initial p H on the degradation of AO7 were evaluated. The results demonstrated that the degradation rate of AO7 could reach more than 95. 0% after 180 min when the Ag loading content,PS / AO7 molar ratio,the Ag / GAC dosage were 12. 7 mg·g- 1,120∶ 1,1. 0 g·L- 1,respectively. The initial p H had significant effect on the AO7 degradation,with p H 5. 0 as the optimal p H for the degradation of AO7. The possible degradation pathway was proposed for the AO7 degradation by using UV-visible spectroscopy and gas chromatography-mass spectrometry( GC / MS). The azo bond and naphthalene ring in the AO7 were destroyed during the degradation,with phthalic acid and acetophenone as the main degradation products.