Solid-liquid-solid extraction of heavy metals (Cr, Cu, Cd, Ni and Pb) in aqueous systems of zeolite-sewage sludge.
This paper presents results of kinetic and equilibrium studies of the removal of heavy metals (Cr, Cu, Cd, Ni and Pb) from the sewage sludge using a new technique of solid-liquid-solid extraction with the adsorption-diffusion column filled by the zeolite. The metal extraction onto the zeolite from aqueous solution of the clinoptilolite and the sludge composition is characterized by three stages: intensive extraction, inversion and stabilization with the moderate extraction increase. Addition of 25% of the zeolite provides extraction efficiency of cadmium and lead of about 84%, chromium, copper and nickel of 66%, 61% and 50%, respectively. The estimated values of Gibbs free energy change DeltaG show that the metals extraction by the clinoptilolite may be considered as a physical adsorption. The negative values of DeltaG testify to an exothermic nature of the process. The difference between energetic potentials of the components is a driving force of the metal redistribution in the system "clinoptilolite-water-sludge".
Sprynskyy
Myroslav
M
Chair of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolas Copernicus University, 7 Gagarina Street, 87-100 Toruń, Poland. sprynsky@yahoo.com
D002104:Cadmium / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical / Q000379:methods; D002857:Chromium / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D007700:Kinetics; D007854:Lead / Q000737:chemistry*; D019216:Metals, Heavy; D009532:Nickel / Q000737:chemistry*; D016062:Porosity; D012722:Sewage; D013816:Thermodynamics; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*; D017641:Zeolites / Q000737:chemistry*
D019216:Metals, Heavy; D012722:Sewage; D014874:Water Pollutants, Chemical; D002104:Cadmium; D014867:Water; D002857:Chromium; D017641:Zeolites; D007854:Lead; D003300:Copper; D009532:Nickel