水溶液中苯甲酸钠的辐照降解效果及辐解机理

Irradiation Degradation Effect and Radiolysis Mechanism of Sodium Benzoate in Aqueous Solution

摘要:

为了探究水溶液中苯甲酸钠的辐照降解效果及辐解机理，该实验对不同浓度苯甲酸钠水溶液（0.5、1、3、5、7 mmoL·L-1）在不同辐照剂量（1、3、5、7、9 kGy）下的降解规律进行了研究，通过GC、降解动力学等方法对苯甲酸钠的辐照降解规律进行分析，利用量子化学计算手段阐明其辐照降解机理，最后通过菌实验考察辐照处理对苯甲酸钠抑菌能力的影响。结果表明，实验浓度下的苯甲酸钠随着辐照剂量的增加降解率逐渐增加，低浓度下的降解率几乎达到100%，苯甲酸钠的辐照降解遵循一级动力学降解规律。高浓度的苯甲酸钠水溶液经过辐照之后会产生微量的苯酚。在辐照处理下苯甲酸钠与羟基自由基发生反应从而形成降解，其反应过程中的自由能活化能为11.3 kcal·mol-1，放热17.2 kcal·mol-1。苯甲酸钠的抑菌能力随辐照剂量的增加而呈逐渐降低的趋势。综上所述，辐照剂量和样品的初始浓度对苯甲酸钠的降解率、降解后苯酚含量及抑菌能力均会产生一定的影响，苯甲酸钠在使用过程中在限量范围内（6.94 mmol·L-1）不影响使用效果的情况下可选择合适的浓度，并根据使用浓度选择合适的辐照剂量进行辐照。该研究为苯甲酸钠的辐照降解规律及机理提供了一定的理论基础。

Abstract:

To investigate the irradiation degradation effect and mechanism of sodium benzoate in aqueous solution, this experiment studied the degradation patterns of sodium benzoate solutions at different concentrations (0.5, 1, 3, 5, 7 mmoL·L-1) under varying irradiation doses (1, 3, 5, 7, 9 kGy). The degradation behavior of sodium benzoate was analyzed using GC and degradation kinetics, while quantum chemical calculations were employed to elucidate its irradiation degradation mechanism. Finally, bacterial experiments were conducted to examine the impact of irradiation treatment on the antibacterial capacity of sodium benzoate. The results showed that the degradation rate of sodium benzoate at experimental concentrations gradually increased with higher irradiation doses, reaching nearly 100% at lower concentrations. The irradiation degradation of sodium benzoate followed first-order kinetics. Trace amounts of phenol were generated after irradiation of high-concentration sodium benzoate solutions. Under irradiation, sodium benzoate reacts with hydroxyl radicals to form degradation products, with a free energy activation barrier of 11.3 kcal·mol-1 and an exothermic release of 17.2 kcal·mol-1 during the reaction process. The antibacterial capacity of sodium benzoate exhibited a gradual decline with increasing irradiation doses. In conclusion, both the irradiation dose and the initial concentration of the sample have a certain impact on the degradation rate of sodium benzoate, the post-degradation phenol content, and the antimicrobial activity. When using sodium benzoate, an appropriate concentration can be selected within the permissible limit (6.94 mmol·L-1) without compromising its effectiveness, and a suitable irradiation dose can be chosen based on the applied concentration. This study provides a theoretical foundation for understanding the patterns and mechanisms of sodium benzoate degradation under irradiation.