Removal of soluble divalent manganese by superfine powdered activated carbon and free chlorine: Development and application of a simple kinetic model of mass transfer-catalytic surface oxidation.

ABSTRACT: Catalytic oxidative removal of Mn²⁺ on activated-carbon surfaces by free chlorine was recently discovered and found to be potentially practicable for water treatment when using micrometer-sized activated carbon. Herein, we newly derived a kinetic model for trace-substance removal by catalytic reaction and applied it to the Mn²⁺ removal. External-film mass transfer, adsorption, and oxidation/desorption contributed similarly to the Mn²⁺ removal rate under actual practical conditions. The low removal rate in natural water was attributed to decreases in available adsorption sites: e.g., a 50% decrease in available sites in water with 0.26 mmol-Ca²⁺/L caused a 15% reduction in removal rate. Low temperature greatly reduced the removal rate by both enhancing the decrease in available sites and hindering mass transfer through increased viscosity. While adsorption sites differed 8-fold between different carbon particles, causing a 2.2-fold difference in removal rates, carbon particle size was more influential, with a >10-fold difference between 2- and 30-μm sizes.

SUBMITTER: Saito S 

PROVIDER: S-EPMC9399258 | biostudies-literature | 2022 Aug

REPOSITORIES: biostudies-literature