论文部分内容阅读
紫外光(UV)照射下,利用Fe(Ⅲ)-富马酸盐体系对黄连素(berberine)的降解反应进行研究。探讨Fe(Ⅲ)、富马酸盐(fumarate)和黄连素的初始浓度及溶液pH值对黄连素降解率的影响,并对黄连素的降解过程进行了动力学分析和机理分析。结果表明,在紫外光照射下,Fe(Ⅲ)-富马酸盐体系对黄连素有较好的降解效果。当Fe(Ⅲ)和富马酸钠初始浓度分别为25μmol/L和250μmol/L,溶液pH值为3.0时,紫外光照75 min后黄连素降解率接近91%。在pH 2.0~6.0范围内,pH值越大黄连素的降解率越低;Fe(Ⅲ)和富马酸盐初始浓度的增大能促进黄连素的降解;而随着黄连素初始浓度的增大,其降解率逐渐降低。动力学分析表明,黄连素光降解过程符合一级动力学。利用异丙醇和硫脲猝灭法证明Fe(Ⅲ)-富马酸盐体系在光反应过程中产生了羟基自由基和超氧负离子自由基。通过紫外光谱、红外光谱、TOC检测和GC-MS分析表明,在紫外光照射下黄连素在Fe(Ⅲ)-富马酸盐体系中结构被破坏,降解为小分子物质。
The degradation of berberine by Fe (Ⅲ) - fumarate system was studied under ultraviolet (UV) irradiation. The effects of Fe (Ⅲ), fumarate and berberine on the degradation of berberine were studied. The kinetic and mechanism of the degradation of berberine were also investigated. The results showed that Fe (Ⅲ) - fumarate system had a good degradation effect on berberine under UV irradiation. When the initial concentrations of Fe (Ⅲ) and sodium fumarate were 25μmol / L and 250μmol / L, respectively, the degradation rate of berberine was 91% after 75 min UV irradiation. In the range of pH 2.0-6.0, the lower the degradation rate of berberine was, the higher the initial concentration of Fe (Ⅲ) and fumarate could promote the degradation of berberine. With the increase of the initial concentration of berberine Large, its degradation rate is gradually reduced. Kinetic analysis shows that the photodegradation of berberine conforms to the first order kinetics. The quenching of isopropanol and thiourea showed that the Fe (Ⅲ) - fumarate system produced hydroxyl radicals and superoxide anion radicals in the photochemical reaction. The results of UV-Vis, FT-IR, TOC and GC-MS showed that berberine was destroyed in the Fe (Ⅲ) -fumarate system and degraded into small molecules under UV irradiation.