Experimental Study and evaluation of kinetic models of cadmium desorption from bed sediment load in a circular Flume

Articles in Press

Document Type : Research Paper

Authors

1 Department of Water Science and Engineering, Faculty of Agriculture and Environment,, Arak University, Arak, Iran.

2 Department of Irrigation and Reclamation Engineering,, Faculties of Agricultural and Natural Resources, University of Tehran, Karaj, Iran.

Abstract

Most surface water sources and rivers are exposed to various pollutants in all around the world. One of the industrial pollutants is the entry of heavy metals into rivers and their absorption by sediments. In this study, to investigate the cadmium desorption from sediments, the sediments with an average diameter of 0.54 mm were first artificially contaminated with cadmium at different concentrations. Then, the effect of cadmium concentration and flow velocity on the desorption rate from contaminated sediments was investigated experimentally in a circular flume with a diameter of 1.6 m and a width of 0.2 m at velocities of 0.18 and 0.35 m/s. The results of the desorption experiments showed that most of the desorbable cadmium was removed from the sediments in about 0.5 h. With increasing cadmium concentration, the desorption rate also increased, so that with increasing concentration from 7 mg/kg to 49.5 mg/kg, the desorption rate increased from 10.7 to 30%. Also, increasing the flow rate had a negligible effect on the desorption rate; so that at the maximum concentration, the desorption rate was observed to be 25 and 30% for velocities of 0.18 and 0.35 m/s, respectively. After examining the desorption kinetic models, it was found that the double parabolic diffusion equations with R2 = 0.99, SSE = 5.77, and mean relative error of 7.02% are more accurate than the other equations.

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Iranian Journal of Soil and Water Research

Articles in Press, Accepted Manuscript
Available Online from 27 August 2025

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