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Effect of organic matter and calcium carbonate on behaviors of zinc adsorption-desorption on/from Ningxia farmland sierozem soils |
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Abstract The laboratory batch experiments were conducted to studied the effect of organic matter and calcium carbonate on adsorption-desorption behaviors of zinc of sierozem soils in Ningxia farmland. The results showed that the adsorption capacity increased with increasing initial zinc concentrations in the sierozem. The adsorption capacity of zinc in soils removed calcium carbonate were lower than that with calcium. Organic matter had weaker effect on adsorption behaviors of zinc in sierozem soils than calcium carbonate. The adsorption process of zinc could be well described by Freundlich equation than Langmuir equation in different organic and carbonate content sierozem soil. The adjusted coefficient of determination R2' were greater than 0.90, reached a significant level (P<0.01). The desorption rates of zinc in the sierozem soil increased after removal of organic matter and calcium carbonate, and the desorption rate of soils removed calcium carbonate was slightly higher than the soils removed of organic matter. The sorption increased with the increasing adsorbance after removal of organic matter and calcium carbonate, and the sorption of the soils removed calcium carbonate was maximum, followed by the the soils removed organic matter, and the sorption of sierozem soils was minimum. The organic matter and calcium carbonate in soils could effectively reduce the migration activity of zinc for effect of complexation adsorption, leading to promoting the adsorption and inhibiting the desorption of zinc.
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Received: 18 November 2014
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