| As a heavy industrial city, Taiyuan is facing the serious harm of heavymetal ions on soil and groundwater resources, such as copper ion, which is fromelectroplating, mining, steel and other industries. In order to repair thecontaminated soil, prevent the copper ion polluting groundwater by soilinfiltration, and do harm to human health through crops enrichment by naturalcycle ultimately, research on soil in-situ adsorption and immobilization ofcopper ion pollutants becomes particularly important.Based on the absence of new pollutants to the soil with iron addition, thisresearch adopted Fe6+fixative-potassium ferrate and Fe3+fixative-ferric nitrateas adsorption and fix agent. This investigation was to: understand cushionperformance of Cu2+contaminated soil; control heavy metal pollution by usingpotassium ferrate oxidation of organic matter with its properties of coagulationof reduction products; and analyze the mechanism of iron nitrate in soil solutionsystem.Therefore, four experiments were investigated by using self-made soil withcopper pollution:(1) The relationship of soil pH value with water and soil mass ratio, Cu2+initial concentration, and determined soil buffer curve;(2) The result of original soil adsorption of Cu2+affected by dosage、pH、Cu2+initial concentration、temperature、time;(3) The result of soil (adding K2FeO4) adsorption of Cu2+affected by dosage、pH、Cu2+initial concentration、temperature、time;(4) The result of soil (adding Fe(NO3)3) adsorption of Cu2+affected bydosage、pH、Cu2+initial concentration、temperature、time.The conclusions:(1) The amount of adding water has little effect on original and coppercontaminated soil pH value, and copper contaminated soil pH value is slightlylower than original soil;(2) The order of acid buffer capacity of soil was: soil A> copper pollutedsoil A> soil B> copper polluted soil B> OM removed soil A> OM removed soilB, the order of alkali buffer capacity of soil was: soil B＞soil A＞copperpolluted soil B＞copper polluted soil A＞OM removed soil B＞OM removedsoil A;(3) The best Cu2+adsorption condition of soil A was: pH=8~10, T=35℃,t=24h, the adsorption capacity is0.36mg g-1; the best Cu2+adsorption conditionof soil B was: pH=8~10, T=35℃, t=24h, the adsorption capacity is0.41mg g-1;(4) After adding Fe6+fixative, the best Cu2+adsorption condition of soil Awas: Fe/Cu(w/w)=20:1, pH=8~10, T=35℃, t=24h, the adsorption capacity is0.41mg g-1; the best Cu2+adsorption condition of soil B was: Fe/Cu(w/w)=5:1,pH=8~10, T=15℃, t=24h, the adsorption capacity is0.46mg g-1;(5) After adding Fe3+fixative, the best Cu2+adsorption condition of soil Awas: Fe/Cu(w/w)=30:1, pH=8~10, T=35℃, t=18h, the adsorption capacity is0.38mg g-1; the best Cu2+adsorption condition of soil B was: Fe/Cu(w/w)=20:1,pH=8~10, T=25℃, t=18h, the adsorption capacity is0.42mg g-1;(6) Different generating conditions of Fe3+, caused different effect on theadsorption of Cu2+. Promoting a lot of Cu2+adsorption of soil was mainlybecause the effect of a series of intermediate products generated by Fe6+changedto Fe3+combined with Fe3+, not only the role of the Fe3+; (7) The adsorption process of Cu2+by soil A and soil B satisfied theFreundlich equation, the size order of the capacity of adsorption was: soil B(adding K2FeO4)> soil B (adding Fe(NO3)3)>soil A (adding K2FeO4)>soil A(adding Fe(NO3)3)>soil B>soil A;(8) The adsorption thermodynamics showed that the adsorption was aspontaneous and endothermic process, and adsorption kinetics could be bestdescribed by pseudo second-order kinetic model, indicated that the adsorption ofCu2+by soil A and soil B were dominated by multilayer adsorption, and thephysical and chemical adsorption process exist simultaneously. |
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