A novel cellulose-manganese oxide hybrid material by in situ soft chemical synthesis and its application for the removal of Pb(II) from water

We report an in situ soft chemical synthesis of a novel hybrid material, cellulose-nanoscale-manganese oxide composite (C-NMOC), and its application for Pb(II) removal from aqueous solutions. For comparison, detailed Pb(II) adsorption studies were also performed with nanoscale-manganese oxide powder (NMO), prepared through a similar route. Various spectroscopic and microscopic techniques were used to characterize the as-synthesized materials. X-ray photoelectron spectroscopic (XPS) measurements confirmed the existence of Mn(IV) phase in NMO whereas C-NMOC showed largely the Mn(III) phase. The existence and uniform distribution of manganese oxide in cellulose fiber materials was confirmed by SEM and EDAX analyses. The adsorption studies reveal that the Pb(II) uptake onto C-NMOC is a fast process and >90% of the uptake occurred within the first 10 min contact time. The Sips isotherm predicted the equilibrium data well and the maximum Pb(II) uptake capacity of C-NMOC (4.64% Mn loading) was estimeted to be 80.1 mg g-1. The Pb(II) adsorption capacity of C-NMOC (per gram of Mn present) was several times higher than commercial manganese oxide (β-MnO2) and at least twice larger than NMO. The experimental evidence reveals that physisorption plays a dominant role in Pb(II) adsorption by both NMO and C-NMOC