Biosorption of Mn (II) by Spirogyra verrucosa collected from Manganese Mine Water

Abstract

Mining industries frequently generates acid mine drainage (AMD) either by its operating or abandoned mines which are often characterized by an elevated levels of certain heavy metals, sulphate, low pH and some other toxic impurities in mine water creates environmental and ecological problems. Present study planned to suggest role of alga Spirogyra verrucosa in Manganese (Mn) removal by biosorption process from the mine water of Manganese mines of Nagpur District, Vidarbha Region, Maharashtra. The biosorption of Mn(II) ions from aqueous solution by using dead green algal (S.verrucosa) biomass was investigated by studying effect of pH, temperature, quantity of biosorbent, contact time as well as initial metal ion concentration. The optimized values obtained with respect to these parameters clearly indicates that pH 5, temperature 30°C, biosorbent quantity 1.0 gm/l, contact time 120 min. and initial metal ion concentration 50mg/l were the basic requirement for the biosorption of Mn(II) ions by dead algal biomass. Also, the biosorption kinetic and isotherm modeling applied to the equilibrium data for biosorption of Mn(II) ions onto alga reveals the fitness of the pseudo-second-order rate expression (R2=0.994) as well as the suitability of Langmuir (R2=0.859) and Freundlich (R2=0.761) isotherm models with an indication of the applicability of this metal ion-dried algal system for removal of Mn(II) ions in a monolayer biosorption as well as heterogenous surface conditions. However, comparatively biosorption equilibrium was better described by Langmuir isotherm model with monolayer biosorption capacity of S.verrucosa biomass 21.80 mg/g. Also, the maximum removal 40.66 mg/g (80.20%) of Mn(II) ion by alga under optimized conditions promises the potential use in mine water treatment technology.