知识与财富的链接
采用动力学方法研究了环境浓度范围内的扑热息痛在含碳酸盐溶液中的光解,比较了碳酸盐自由基和羟基自由基对扑热息痛的光解效果,探讨了pH值、硝酸根离子、腐殖质、氯化钠、钙镁离子等因素对扑热息痛光解的影响.利用GC/MS技术鉴定了扑热息痛的光解产物,并探讨了扑热息痛在碳酸根体系中可能的光解途径.结果表明,扑热息痛与碳酸盐自由基反应的二级反应速率常数为 k.=5.0×107L·(mol·s)-1,低于与羟基自由基反应的二级反应速率常数kb=8.1×109L·(tool·s)-1,但是由于天然水体中碳酸盐自由基的稳态浓度较高,所以碳酸盐自由基对扑热息痛光解的影响和羟基自由基大致相当.提高体系pH值,加入硝酸根离子、氯化钠或者钙镁离子都会加快扑热息痛的光解速率;而加入Suwannee河富里酸则会降低光解速率.
The photodegradation of paracetamol in the solution of carbonate with comparably environmental concentration was studied through kinetics method. Experiments were carried out to compare the different photodegradation effects of paracetamol in the solution of carbonate radical and hydroxyl radical. The effects of such factors, pH, nitrate, humic matters, chloride sodium, calcium and magnesium were also analyzed. The products of the photodegradation were identified with GC/MS, and the degradation mechanism of paracetamol was discussed. The results indicate that, the scondary reaction rate constant (k(a)) between paracetamol and carbonate radical is 5.0 x 10(7) L (mol s)(-1), which is lower than that with hydroxyl radical [k(b) = 8.1 x 10(9) L (mol s)(-1)]. But in natural aqueous system, the stable concentration of carbonate radical is much higher than that of hydroxyl. Therefore, the effect of carbonate radical on paracetamol approximately equals to that of hydroxyl radical. The degradation rate of paracetamol increases when the system was changed with higher pH, adding of nitrate, chloride sodium, calcium and magnesium which increase the rigidity of the water, while decreases when the SRFA is present.
