Copper, Cobalt, Zinc, Phosphorous, Arsenic, Adsorption, mangrove sediment, Sundarbans

Adsorption kinetic control of As(III & V) mobilization and sequestration by Mangrove sediment

 S. K. Mandal • N. Majumder • C. Chowdhury •

 D. Ganguly • M. Dey • T. K. Jana

Environ Earth Sci, Springer,2011

DOI 10.1007/s12665-011-1183-9

Abstract:

Elevated concentrations of arsenic in the sediment and pore water in the Sundarban wetlands pose and environmental risk. Adsorption and desorption are hypothesized to be the major processes controlling arsenic retention in surface sediment under oxic/suboxic condition. This study aims to investigate sorption kinetics of As(III&V) and its feedback to arsenic mobilization in the mangrove sediment. It ranges from sand to silty clay loam and shows theadsorption of As(III & V) following the Langmuir relation. Estimates of the maximum adsorption capacity are59.11 ± 13.26 lg g-1 for As(III) and 58.45 ± 8.75 lg g-1 at 30_C for As(V) in the pH range 4 to 8 and salinity 15–30 psu. Extent of adsorption decreases with increasing pH from 4 to 8 and desorption is the rate-limiting step in the reaction of arsenic with sediment. Arsenic in the sediment could be from a Himalayan supply and co-deposited organic matter drives its release from the sediment. Arsenic concentration in the sediment is well below its maximum absorption capacity, suggesting the release of sorbed arsenic in porewater by the microbial oxidation of organic matter in the sediment with less feedback of adsorption