Sorption of Mn(II) Ions From Wastewater Using Dried and Blended Water Hyacinth (Eichhornia crassipes) Roots: Adsorption-Desorption Studies and Kinetics

Abstract

This study examined the sorption of Mn(II) ions from waste using dried and blended water hyacinth root (WHR). It focused on how the major process parameters influenced the sorption process. Mathematical models were proposed to explain both the equilibrium and kinetics of biosorption. A desorption study was conducted using different HNO3 and NaOH concentrations. An application study using actual industrial effluent was evaluated to analyze the fitness of the biosorbent at optimal batch conditions. The results demonstrated that the increasing initial Mn(II) ion concentration decreased Mn(II) ion removal, while an increase in the sorbent dosage increased its removal. For the rate of biosorption, the contact time was rapid between 15 and 45 min, and the maximum Mn(II) ion was removed within the initial 60 min. Equilibrium sorption was attained at pH 7, where maximum Mn(II) ion uptake was 94 %. The results also showed that Mn(II) ion biosorption at 30 °C and pH 7 for water hyacinth roots could be modeled by Langmuir and Freundlich isotherms and the pseudo-2nd order model. Furthermore, an effective desorption of Mn(II) was obtained with solutions of both NaOH and HNO3. The results also showed that the percentage biosorption and desorption of Mn(II) from the industrial wastewater were 64.68 and 27.95 %, respectively.