氧化石墨相氮化碳吸附水中U(VI)的性能与机理研究

Study on the Properties and Mechanism of U(VI) Adsorption in Oxidized Graphitic Carbon Nitride

摘要:

本试验采用酸刻蚀及氧化处理制备了氧化氮化碳（OCN）纳米材料，探究了OCN对水中U(VI)的吸附-解吸性能。考察了溶液pH，温度，OCN投加量，反应时间U(VI)初始浓度等影响因素对OCN吸附U(VI)的影响，并探讨了吸附机制。试验结果表明，OCN对U(VI)有良好的吸附效果，在pH为5，30℃，U(VI)的初始浓度为10mg/L，OCN的投加量为200mg/L时，OCN对U(VI)吸附率达98.9%，比未改性的石墨相氮化碳(g-C3N4)吸附U(VI)的性能提高了约30%，吸附反应在10min即到达吸附平衡。pH是影响OCN吸附U(VI)的重要影响因素，温度等因素对U(VI)的吸附影响较小。拟二级动力学方程和Langmuir模型很好地拟合了吸附过程，OCN对U(VI)的吸附过程为自发的吸热过程。吸附解吸实验结果表明OCN具有良好的重复利用性，作为一种高性能吸附剂在含U(VI)废水处理方面拥有广阔的应用前景。

Abstract:

In this experiment, oxidation-nitriding carbon nanomaterials (OCN) were successfully synthesized by a acid etching and oxidation method,and the adsorption-desorption performance of OCN on U(VI) in water was investigated.The effects of pH,temperature,OCN dosage,initial U(VI) concentration,contacting time were investigated by static batch experiments,and the adsorption mechanism was discussed.The sorption experiments indicated that OCN exhibited superior adsorption performance to U(VI),When at pH 5, the initial concentration 10 mgU(VI) L-1 ,OCN dosage 200mg/L and 30℃ ,the adsorption efficiency of OCN to U(VI) reached 98.9%.Compared with the unmodified graphite nitride carbon (g-C3N4), the adsorption performance of U(VI) was improved by about 30%,and the adsorption reaction reached the adsorption equilibrium at 10 min.The adsorption process is greatly affected by the pH of the solution and is less affected by other factors such as temperature. The pseudo-second-order kinetic equation and Langmuir model fit the adsorption process well, and the adsorption process of OCN to U(VI) is spontaneous endothermic process. The results of adsorption desorption experiments show that OCN has good reusability and a broad application prospect in the treatment of U(VI)-containing wastewater as a high-performance adsorbent.