冻融作用对土壤镉吸附特征的影响

选择东北地区棕壤为供试土壤,采用人工控温方法进行冻融处理（冻-融时间为12h-12h,冻-融温度为-30℃-30℃）,进行不同含水量和冻融频次处理下土壤镉的静态等温吸附试验和动力学等温吸附试验,并选择不同模型对吸附曲线进行拟合,研究冻融作用与土壤镉吸附特征之间的关系。结果表明：未冻融和冻融处理土壤对镉的吸附量均随着含水量的增加先增加后减少;冻融作用会增加土壤镉的吸附量,加快土壤镉的吸附速率;Henry模型和Temkin方程可以较好拟合土壤镉静态等温吸附曲线,双常数方程、Elovich方程和型曲线方程则可以很好拟合土壤镉动力学等温吸附曲线。

Effect of the Freezing/Thawing on the Soil Cadmium Adsorption Characteristic

Cadmium adsorption isotherms and kinetics adsorption isotherms of freezing/thawing soil under different treatments were carried out using brown earth. The condition of the freezing/thawing cycles was adopted as the temperature of freezing and thawing being -30 ℃ and 30 ℃, respectively; Both freezing and thawing were lasted for 12 h. The results indicated that the soil cadmium adsorption initially increased and then decreased with the soil water content increasing; Both the cadmium adsorption amount and the adsorption rate increased with freezing/thawing treatment; The cadmium adsorption isotherms for the experimented soil was preferably stimulated by Henry modal（Y=a＋klg C）and Temkin equation（lg Y=lg k＋1/alg C）, and the cadmium kinetics adsorption isotherm for the soil was preferably stimulated by the equation of ln S=A＋Bln t, S=A＋Bln t and S=1/A＋Bexp（-t）].