It is observed that the adsorption of chromium are greater on kaolinite minerals, red soil (R) and laterite (L) colloids than that on montmorillonite, indicotic black (IB) and yellow brown (YB) soil colloids. The adso...It is observed that the adsorption of chromium are greater on kaolinite minerals, red soil (R) and laterite (L) colloids than that on montmorillonite, indicotic black (IB) and yellow brown (YB) soil colloids. The adsorption process of Cr Ⅵ on these media can be further described by Langmuir or Freundlich equation quite well. The adsorption reaction of Cr Ⅵ is fast, and the adsorption equilibrium can be reached within the first two hours in moderate temperature. The adsorption quantity of Cr Ⅵ to kaolinite mineral increased with the increasing pH in the range of 2.0 to 7.0, then decreased at higher pH. But it showed some consistence among the four soil colloids. The lower the pH, the stronger the adsorption. The possible mechanisms are further discussed here. Meanwhile the influence of temperature on Cr Ⅵ adsorption on different soil colloid and clay minerals are also investigated.展开更多
The leaching characteristics of a garden soil may be greatly affected by application of poultry and livestock manures from intensive farming. Packed soil columns of a garden soil （CK） and the soils after respectivel...The leaching characteristics of a garden soil may be greatly affected by application of poultry and livestock manures from intensive farming. Packed soil columns of a garden soil （CK） and the soils after respectively receiving 2% pig manure （PM）, chicken manure （CM）, and commercial organic manure （OM） were leached with 0.05 mol L^-1 Ca（NO3）2 and 0.01 mol L 1 EDTA solutions. The leachate EC （electric conductivity） values gradually increased at the beginning and then reached a stable value when the soil columns were leached with 0.05 mol L^-1 Ca（NO3）2 solution. The leachate EC values showed a peak-shape when leached with 0.01 mol L^-1 EDTA solution. In all the soil columns, the pH values of the leachates decreased with increase of displacement volumes when the Ca（NO3）2 solution was used. The total amounts of Cu and Zn eluted from the four soil columns were significantly correlated with the extracted soil Cu and Zn concentrations by 1.0 mol L^-1 NH4NO3, but were not correlated with the leachate dissolved organic carbon （DOC） contents. The Zn concentration in the leachate of the PM-treated soil column with 0.05 mol L^-1 Ca（NO3）2 solution was above the Quality Standard III for Ground Water of China （GB/T 14848-93, Zn 〈 1.0 mg L^-1）. When compared with 0.05 mol L^-1 Ca（NO3）2, the EDTA solution significantly accelerated Cu and Zn elutions in the manure-treated columns. This suggested that applying poultry and livestock manures from intensive farming to farmland might pose a threat to the groundwater quality.展开更多
文摘It is observed that the adsorption of chromium are greater on kaolinite minerals, red soil (R) and laterite (L) colloids than that on montmorillonite, indicotic black (IB) and yellow brown (YB) soil colloids. The adsorption process of Cr Ⅵ on these media can be further described by Langmuir or Freundlich equation quite well. The adsorption reaction of Cr Ⅵ is fast, and the adsorption equilibrium can be reached within the first two hours in moderate temperature. The adsorption quantity of Cr Ⅵ to kaolinite mineral increased with the increasing pH in the range of 2.0 to 7.0, then decreased at higher pH. But it showed some consistence among the four soil colloids. The lower the pH, the stronger the adsorption. The possible mechanisms are further discussed here. Meanwhile the influence of temperature on Cr Ⅵ adsorption on different soil colloid and clay minerals are also investigated.
基金Project supported by the Knowledge Innovative Program of Chinese Academy of Sciences (Nos.KZCX3-SW-435 and KZCX2-YW-404)the Natural Science Foundation of Jiangsu Province (No.BK2004219).
文摘The leaching characteristics of a garden soil may be greatly affected by application of poultry and livestock manures from intensive farming. Packed soil columns of a garden soil （CK） and the soils after respectively receiving 2% pig manure （PM）, chicken manure （CM）, and commercial organic manure （OM） were leached with 0.05 mol L^-1 Ca（NO3）2 and 0.01 mol L 1 EDTA solutions. The leachate EC （electric conductivity） values gradually increased at the beginning and then reached a stable value when the soil columns were leached with 0.05 mol L^-1 Ca（NO3）2 solution. The leachate EC values showed a peak-shape when leached with 0.01 mol L^-1 EDTA solution. In all the soil columns, the pH values of the leachates decreased with increase of displacement volumes when the Ca（NO3）2 solution was used. The total amounts of Cu and Zn eluted from the four soil columns were significantly correlated with the extracted soil Cu and Zn concentrations by 1.0 mol L^-1 NH4NO3, but were not correlated with the leachate dissolved organic carbon （DOC） contents. The Zn concentration in the leachate of the PM-treated soil column with 0.05 mol L^-1 Ca（NO3）2 solution was above the Quality Standard III for Ground Water of China （GB/T 14848-93, Zn 〈 1.0 mg L^-1）. When compared with 0.05 mol L^-1 Ca（NO3）2, the EDTA solution significantly accelerated Cu and Zn elutions in the manure-treated columns. This suggested that applying poultry and livestock manures from intensive farming to farmland might pose a threat to the groundwater quality.
