大孔树脂吸附去除水中的2,4,6-三硝基甲苯

研究了2种大孔树脂XAD-4和NDA-804对水中的TNT的吸附行为。2种树脂对TNT的吸附等温线表明,温度的升高有利于吸附,在35℃条件下XAD-4树脂与NDA-804树脂对TNT的最高平衡吸附量分别达82.86 mg/g和94.26mg/g。采用Langmuir方程和Freundlich方程用于吸附等温线的解释,结果表明,吸附等温线更加符合Langmuir模型,相关系数均大于0.99。TNT在2种树脂上的吸附符合准二级动力学方程,TNT初始浓度越低,达到吸附平衡所需时间越短,在1 h内可达到吸附平衡。采用NDA-804处理对TNT废水,废水中TNT浓度由103.58 mg/L降至0.4 mg/L,去除率达99.6%,吸附后的树脂采用pH=2的乙醇和盐酸的混合液脱附可再生,高浓度再生溶液经蒸馏可回收TNT,实现了废水治理与资源化。

Removing 2,4,6-trinitrotoluene from water by macroporous resins

Adsorption of 2,4,6-trinitrotoluene onto two kinds of macroporous resin including XAD-4 and NDA-804 was studied. The adsorption isotherms of TNT onto resins were measured. Raising the temperature was advantageous to adsorption. The maximum equilibrium adsorption capacities of XAD-4 and of NDA-804 at 35 degrees were 82.86 mg/g and 94.26 mg/g, respectively. The TNT adsorption behaviors could be better described using the Langmuir adsorption model than the Freundlich adsorption model, and the correlation coefficient was greater than 0.99. The kinetics of TNT adsorption onto resins obeyed pseudo-second order kinetic model. The lower the initial TNT solution concentration, the shorter time of the adsorption equilibrium was. The time until equilibrium was 1 hour. The NDA-804 was applied to treat TNT manufacturing wastewater. The TNT concentration in the wastewater decreased from 103.58 mg/L to 0.4 mg/L after adsorption by NDA-804, indicating a high removal efficiency of 99.6%. The NDA-804 could be regenerated by a mixed solution of HCl and methanol with pH of 2. The TNT would be subsequently recovered from the high concentrated regenerant solution by distillation.