爬山虎茎粉对水体中氨氮的吸附特性

Adsorption of ammonia nitrogen from aqueous solution by Boston ivy stem powder

为从植物材料中筛选适宜的氨氮吸附材料,通过批实验研究了爬山虎茎在不同初始pH值、振荡时间、初始浓度和温度下对水溶液中氨氮的吸附情况,进而分析了吸附等温线、动力学和热力学特性.结果表明,爬山虎茎已经达到或超过矿物吸附氨氮的水平.氨氮吸附最适pH值为5～9.吸附过程基本在第18h达到平衡,控速步骤主要是膜扩散和粒内扩散.等温吸附符合Langmuir模型,最大吸附量在15,25,35°C下分别为3.18,4.69,5.19mg/g.热力学参数△G°、△H°和△S°表明,爬山虎茎对氨氮的吸附属于自发的吸热反应,且属于物理吸附.因此,爬山虎茎可以作为开发氨氮吸附剂的原材料.

Batch experiments were carried out to study adsorption characteristics of ammonia from aqueous solution onto Boston ivy （Parthenocissus tricuspidata Planch） stem powder.Effect of pH,initial ammonia concentration,contact time and temperature on adsorption of ammonium were investigated as well.The results showed that the ammonia adsorption capacity of Boston ivy stem powder could be comparable to those of minerals.The optimum pH range for ammonia adsorption was 5～9.The adsorption reached equilibrium at about 18 h,and the rate-controlling steps were film diffusion and intraparticle diffusion.The equilibrium data fitted well with the Langmuir model and the maximum adsorption capacities was 3.18,4.69 and 5.19 mg/g at 15,25 and 35°C respectively.Thermodynamic study proved that the adsorption process was a spontaneously endothermic process,and implied that ammonia adsorption by Boston ivy stem powder might be physisorption.Therefore,the Boston ivy stem could be a considerable raw material to develop the ammonia adsorbent.