扑热息痛在硝酸根溶液中的光解研究

以中压汞灯为光源模拟阳光,研究了环境浓度范围内的硝酸根溶液中扑热息痛（paracetamol）的光解;探讨了pH值、硝酸根浓度以及天然水体中广泛存在的腐殖质、碳酸盐等因素对扑热息痛间接光解的影响.结果表明,扑热息痛的光解符合一级动力学,提高硝酸根浓度,其光解速率可由0.79×10^-3 min^-1增至8.90×10^-3 min^-1.提高体系pH值,加入碳酸氢根或高浓度的Suwannee河富里酸（SRFA）会促进扑热息痛的间接光解;而加入Nordic湖腐殖酸(NOHA)或低浓度的SRFA产生抑制作用.采用分子探针方法鉴定了硝酸根在光照过程中产生的羟基自由基.利用GC/MS技术鉴定了扑热息痛的光解产物,探讨了扑热息痛在硝酸根体系中可能的光解反应历程.

Photodegradation of Paracetamol in Nitrate Solution

The photodegradation of paracetamol in nitrate solutions in the range of environmental concentration was studied using mercury lamp with middle pressure as simulated solar source. Experiments were carried out to study the influences of pH value, nitrate concentration and the substances such as humic substance, bicarbonate, which are popular in natural water, on the photodegradation of paracetamol in nitrate solutions. The results demonstrate that the photodegradation of paracetamol follows a pseudo-first-order kinetics and the photodegradation rate increases rapidly with increasing initial concentration of nitrate. The first order constant increases with the increase of pH and the concentration of bicarbonate. When SRFA concentration is more than 10 mg/L, the presence of SRFA stimulates the photodegradation of paracetamol. The addition of NOHA decreases the photodegradation rate of paracetamol. Hydroxyl radical is found in the reaction solutions using methanol and isopropanol as its molecular probes. We identified the photodegradation products of paracetamol in the presence of nitrate with GC/MS methods. The photodegradation pathways of paracetamol are also discussed.