Abstract:

Solid waste coal gasification slag (CGS) was used as an activator to construct coal gasification slag/persulfate (CGS/PDS) and coal gasification slag/ peroxymonosulfate (CGS/PMS) systems. The microstructure and elemental composition of CGS were characterized by means of field emission scanning electron microscopy. CGS surface functional groups were characterized using Fourier transforms infrared spectroscopy and X-ray photoelectron spectroscopy. The effects of CGS dosage, PDS concentration, PMS concentration, and initial pH on phenol degradation rate were investigated. The activation pathway was speculated, and the oxidation mechanism was explored. The results showed that the Fe element content in CGS reached 11.9% and it contained multiple functional groups. With the increase of CGS dosage, the degradation efficiency of PDS and PMS for phenol gradually increased. When the dosage of CGS was 3.0g/L, the degradation rate of phenol reached 97.82% after 60min of reaction with 1.0mmol/L PDS, and 98.88% after 60min of reaction with 0.4mmol/L PMS. The degradation rates of phenol in both systems were highest at pH=3. The coexistence of Cl^- promoted the degradation of phenol in both systems, while the coexistence of NO₃^-, SO₄^2- and HCO₃^- inhibited the degradation of phenol. The CGS/PDS system produced ·SO₄^- and ·OH during the degradation of phenol, while the CGS/PMS system produced ·SO₄^-, ·OH, and ·O₂^-. However, ·SO₄^- dominated the degradation of phenol in both systems. The research can provide guidance for the high-value application of solid waste coal gasification slag, and also provide theoretical basis for the further application of coal gasification slag in water pollution control.

Key words: coal gasification slag, peroxymonosulfate, persulfate, phenol, active substance

摘要：

以固体废弃物煤气化渣（CGS）作为活化剂，构建了煤气化渣/过二硫酸盐（CGS/PDS）和煤气化渣/过一硫酸盐（CGS/PMS）体系，通过场发射扫描电子显微镜表征CGS的微观结构和元素组成，使用傅里叶红外光谱仪和X射线光电子能谱仪表征CGS表面官能团，考察了CGS投加量、PDS浓度、PMS浓度、初始pH等因素对降解苯酚的影响，推测了活化路径，探究了氧化机理。结果表明，CGS中Fe元素含量达11.9%且含有多种官能团，随着CGS投加量的增加，PDS和PMS对苯酚的降解效率逐渐增大。当CGS投加量为3.0g/L时，1.0mmol/L PDS反应60min后对苯酚的降解率达97.82%，0.4mmol/L PMS反应60min后对苯酚的降解率达98.88%。两种体系对苯酚的降解率均在pH=3时最高。共存Cl^-对两个体系降解苯酚均表现出促进作用，而共存NO₃^-、SO₄^2-、HCO₃^-对苯酚的降解产生抑制作用。CGS/PDS体系降解苯酚过程中产生了·SO₄^-和·OH，而CGS/PMS体系产生了·SO₄^-、·OH和·O₂^-，但两个体系对苯酚的降解均以·SO₄^-占主导地位。研究结果可为固体废弃物煤气化渣高价值应用提供指导，为煤气化渣进一步应用于水污染控制提供理论依据。

关键词: 煤气化渣, 过一硫酸盐, 过二硫酸盐, 苯酚, 活性物质