Kinetics of manganese sorption by using miscible displacement technique in some calcareous soils

Abstract

Manganese (Mn) sorption plays an important role in controlling its mobility, bioavailability, and environmental behavior in calcareous soils. The current study examines the kinetics of manganese sorption in six calcareous soils sampled within the vertisols (Chromic Haploxererts) order in Duhok Governorate in Kurdistan Region, Iraq. A solution of manganese (MnSO4) 300 mg L-1 with 10 pore volumes (PV) at 298o K was added to soil. The findings indicate that the lowest Mn adsorption capacity was in the Imerik soil (1230.5) while Derabun soil having the highest value (1475.4 mg kg-1) by using miscible displacement technique. Mathematical description of Mn-adsorption according to kinetics approach gave the following best fitting: Power function, First ‎order, Zero-order, Elovich equation, Parabolic equation, Second order, respectively, based on the highest R2 value and lowest SE. Rate coefficient of Mn adsorption ranges from (0.99 to 1) and (95 to 96) x 10-4 hr-1 with an average 96 x 10-4 hr -1 according to power function and First order, respectively. The physicochemical and mineralogical characteristics are reflected in variations of Mn adsorption in the investigated soils.