University of Tabriz Water and Soil Science 2008-5133 22 1 2012 04 20 Effect of Carbonates Removal on Zinc Sorption in the Selected Calcareous Soils of Iran Effect of Carbonates Removal on Zinc Sorption in the Selected Calcareous Soils of Iran 125 150 1112 FA A Reyhanitabar Journal Article 2014 04 16 Zinc is one of the micronutrients for plants and its deficiency is common in calcareous soils. On the other hand, many features of arid and semi-arid soils are affected by the presence of carbonates. To evaluate carbonates influence, Zn sorption was studied in 20 composite soil samples (0-30 cm) collected from the central region of Iran before and after carbonates removal. Carbonates were removed with sodium acetate buffer (pH=4.75). X- ray diffraction (XRD) analysis showed that calcite was the most commonly carbonate found in the studied soils. Original and free carbonate soils described L- curves isotherm and carbonate removal did not change the isotherm type. With increasing the applied Zn concentration, the effect of carbonate removal became more obvious. Upon carbonates removal, specific surface areas of the soils decreased and so did the amount of sorbed Zn (mg Zn/ kg soils). Sorbed Zn in per unit particles surface area (mg Zn/m² soil) however, significantly increased. Freundlich empirical model ( ) adequately described Zn sorption data in both original and carbonate free samples and the K – Freundlich variation was much higher than the n- coefficient. Single site Langmuir sorption model did not properly describe Zn sorption data, but double site Langmuir equation was well fitted to the data. The results showed that, k₁ and k₂ coefficients considerably decreased after carbonate removal.  Zinc is one of the micronutrients for plants and its deficiency is common in calcareous soils. On the other hand, many features of arid and semi-arid soils are affected by the presence of carbonates. To evaluate carbonates influence, Zn sorption was studied in 20 composite soil samples (0-30 cm) collected from the central region of Iran before and after carbonates removal. Carbonates were removed with sodium acetate buffer (pH=4.75). X- ray diffraction (XRD) analysis showed that calcite was the most commonly carbonate found in the studied soils. Original and free carbonate soils described L- curves isotherm and carbonate removal did not change the isotherm type. With increasing the applied Zn concentration, the effect of carbonate removal became more obvious. Upon carbonates removal, specific surface areas of the soils decreased and so did the amount of sorbed Zn (mg Zn/ kg soils). Sorbed Zn in per unit particles surface area (mg Zn/m² soil) however, significantly increased. Freundlich empirical model ( ) adequately described Zn sorption data in both original and carbonate free samples and the K – Freundlich variation was much higher than the n- coefficient. Single site Langmuir sorption model did not properly describe Zn sorption data, but double site Langmuir equation was well fitted to the data. The results showed that, k₁ and k₂ coefficients considerably decreased after carbonate removal.  https://water-soil.tabrizu.ac.ir/article_1112_c85287c1f65f5bbea2adb6022eac871c.pdf