title: Nanoalginate based biosorbent for the removal of lead ions from aqueous solutions: Equilibrium and kinetic studies.
abstract: Population explosion, depletion of water resources and prolonged droughts and floods due to climatic change lead to scarcity of pure and hygienic drinking water in most of the developing countries. Recently nanomaterials attained considerable attention as biosorbent for water purification purpose. However difficulties in removing polymeric surfactants and organic solvents used for nanoproduction and instability of the generated nanoparticles limit the scope of this approach in water cleanup. Here, we describe a novel green method for synthesizing polysaccharide nanoparticles in aqueous medium using honey as the capping agent. The highly stable alginate nanoparticles, characterized by various microscopic and spectroscopic techniques, exhibited a maximum uptake capacity of 333 mg g (-1)of Pb(II) ions from aqueous solution. The effect of various parameters such as initial metal concentration, pH, contact time, temperature and adsorbent dose on sorption process was investigated in batch mode technique. The maximum removal percentage was 94.81 at 45 °C and at pH 4.5 in 60 min contact time. The biosorption followed Freundlich model indicating multilayer adsorption and pseudo second order kinetics. The mechanism involves both surface adsorption and pore diffusion. The positive values of ΔH°, ∆S° and the negative value of ΔG°, confirmed the endothermic nature, randomness and spontaneity of biosorption process.
authors.affiliation: Department of Chemistry, D.B Pampa College, Parumala, Mannar, Kerala, India; Department of Chemistry, Bishop Moore College, Mavelikara, Kerala, India.
authors.forename: P
authors.initials: P
authors.lastname: Geetha
authors.affiliation: Department of Chemistry, S.N. College, Chengannur, Kerala, India. Electronic address: lathams2014@gmail.com.
authors.forename: M S
authors.initials: MS
authors.lastname: Latha
authors.affiliation: Department of Chemistry, N. S. S. Hindu College, Changanacherry, Kerala, India; Department of Chemistry, Bishop Moore College, Mavelikara, Kerala, India.
authors.forename: Saumya S
authors.initials: SS
authors.lastname: Pillai
authors.affiliation: Department of Chemistry, Bishop Moore College, Mavelikara, Kerala, India.
authors.forename: Mathew
authors.initials: M
authors.lastname: Koshy
mesh_terms: D000327:Adsorption; D000464:Alginates / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D007854:Lead / Q000737:chemistry / Q000302:isolation & purification*; D053758:Nanoparticles / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D007477:Ions; D012996:Solutions; D014874:Water Pollutants, Chemical; D007854:Lead; D020723:Glucuronic Acid
keywords: Calcium alginate nanoparticles; Cross-linking agent; Honey; Lead removal; Polysaccharide; Water purification