腐殖酸与粘土矿物混合体系对稀土镧、钕吸附特性的研究

Research on Adsorption Characteristics of Mixed System of Humic Acid and Clay Minerals to Lanthanum and Neodymium in Rare Earth

为进一步研究土壤固相之间对稀土元素的竞争吸附趋势，将腐殖酸和7种粘土矿物（高岭石、蒙脱石、伊利石、蛭石、绿泥石、凹凸棒石、膨润土）组合成一个相对独立的复合吸附体系，采用振荡平衡法，对稀土镧、钕进行吸附研究，通过ICP检测，对数据进行拟合，结果显示：Langmuir能更好地描述稀土吸附过程，而且经过验证实验得到，在La3＋体系中，腐殖酸的吸附量为粘土矿物的3倍，且2：1型粘土矿物的吸附能力是1：1型的3.68-5.44倍；在Nd3＋体系中，腐殖酸吸附量约为粘土矿物的3.5倍，且2：1型粘土矿物的吸附能力是1：1型的3.49-4.74倍；腐殖酸与粘土矿物的吸附竞争趋势为：腐殖酸﹥蒙脱石﹥膨润土﹥蛭石﹥伊利石﹥凹凸土﹥绿泥石﹥高岭石。

In order to further study the competitive adsorption trend among various soil solid phases to rare earth elements,the author combined humic acid with 7 kinds of clay minerals（ kaolinite,montmorillonite,illite,vermiculite,chlorite,attapulgite, bentonite）to form a relatively independent mixed adsorption system,and studied their adsorption characteristics to lanthanum and neodymium in rare earth through vibration equilibrium method and ICP detection. The results of data simulation showed that the process of adsorption to rare earth could be better described by Langmuir isothermal equation. The further verification experimental results indicated that：in the La3＋ system,the adsorption capacity of humic acid was 3. 0 times that of the clay mineral,and the ad-sorption capacity of 2：1-type clay mineral was 3. 68-5. 44 times that of 1：1-type clay mineral;in the Nd3＋ system,the adsorp-tion capacity of humic acid was about 3. 5 times that of the clay mineral,and the adsorption capacity of 2：1-type clay mineral was 3. 49-4. 74 times that of 1：1-type clay mineral;the competitive adsorption among humic acid and 7 kinds of clay minerals had the following trend：humic acid﹥montmorillonite﹥bentonite﹥vermiculite﹥illite﹥attapulgite﹥chlorite﹥kaolins.