【摘要】 根据NO-3、Cl-和SO24-对可变电荷土壤和恒电荷土壤吸附Cu2+的影响的比较,探讨了阴离子对可变电荷土壤吸附Cu2+的影响机理。结果表明,当3种阴离子的浓度相同时,在SO24-体系中铁质砖红壤对Cu2+的吸附率较在NO3-和Cl-体系中大得多,而在浓度相同的3种阴离子体系中,黄棕壤对Cu2+的吸附率相差不大。在离子强度相近的NaCl体系中,砖红壤对Cu2+的吸附率相近。在3种阴离子体系中,随着pH升高,砖红壤对Cu2+的吸附率均增大;但在NO-3体系和Cl-体系中Cu2+的吸附率相近;而在SO24-体系中Cu2+的吸附率最大。随着Na2SO4浓度的增大,铁质砖红壤和砖红壤对Cu2+的吸附率减小。但在0.005 mol L-1和0.05 mol L-1Na2SO4体系中,Cu2+的吸附率大于在不含Na2SO4的体系中者。而在0.5 mol L-1Na2SO4体系中,Cu2+吸附率小于在不含Na2SO4体系中者。在3种浓度的Na2SO4体系中,黄棕壤对Cu2+的吸附率均小于在不含Na2SO4体系中者。总之,阴离子可通过离子强度、专性吸附和形成离子对影响土壤对Cu2+的吸附。在可变电荷土壤中,阴离子对Cu2+吸附的影响机理较在恒电荷土壤中复杂得多。更多还原

【Abstract】 Based on comparison between the effects of NO-3,Cl-and SO 2-4 on the adsorption of Cu2+ by variable charge and constant charge soils,the mechanism of the anion effect was studied.Results show that when the initial concentrations of NO-3,Cl-and SO 2-4 in the systems studied were identical,the adsorption percentage of Cu2+ by Hyper-Rhodic Ferralsol was larger in the SO 2-4 system than in the NO-3 and Cl-systems,while the adsorption percentage of Cu2+ by Cambisol in the three anion systems were very close to each other.The adsorption percentage of Cu2+ by Rhodic Ferralsol in the systems containing different concentrations of NaCl differed insignificantly,suggesting the effect of ionic strength on the adsorption of Cu2+ by variable charge soils was small.The adsorption percentage of Cu2+ by Hyper-Rhodic Ferralsol in the systems containing NO-3,Cl-and SO 2-4 increased with increasing pH of the media.At the same pH value,the percentage in the system containing NO-3 was close to that in the system containing Cl-,but lower than that in the system containing SO 2-4.The adsorption percentage of Cu2+ by Hyper-Rhodic Ferralsol and Rhodic Ferralsol decreased with increasing concentration of Na2SO4.However,the percentages were larger in the systems containing 0.005 mol L-1 and 0.05 mol L-1 Na2SO4,but smaller in the system containing 0.5 mol L-1 Na2SO4 than in the system without Na2SO4.On the other hand,all the adsorption percentages of Cu2+ by Cambisol were smaller in the systems containing different concentrations of Na2SO4 than in the system without Na2SO4.It is,therefore,concluded that kind of anion species can affect the adsorption of Cu2+ by soils through changing the ionic strength of the media,the degree of formation of ion-pairs and the specific adsorption of anions by soils.The mechanism of anion effect on the adsorption of Cu2+ is more complicated in variable charge soils than in constant charge soils.更多还原