title: Efficiency of a zeolitized pumice waste as a low-cost heavy metals adsorbent.
abstract: The unextracted residue obtained after a countercurrent two-step extractive process of silica from pumice lapillus, at 100 degrees C and room pressure, has been found mainly crystallized to the pseudo-cubic form typical of zeolite P. This residue could be active as a low-cost agent for the removal of heavy metals from wastewater. In this paper the removal capacity of six metallic cations (i.e. Cu(2+), Ni(2+), Zn(2+), Cd(2+), Pb(2+) and Cr(3+)) was studied in a stirred batch reactor. Results obtained showed that the removal of metal ions (100-500mgg(-1)) from wastewater is achieved in a short time and the concentration lowered under the legal limits. The adsorption mechanism mainly involves an ionic exchange between sodium ions from the solid phase and heavy metals in solution. However, if wastewater was accompanied by free acidity, it first should be neutralized to pH 4-5 to prevent zeolite destruction.
authors.affiliation: Dipartimento di Chimica Industriale e Ingegneria dei Materiali, Università di Messina, via Salita Sperone 31, 98166 Messina, Italia.
authors.forename: Paola
authors.initials: P
authors.lastname: Catalfamo
authors.forename: Ileana
authors.initials: I
authors.lastname: Arrigo
authors.forename: Patrizia
authors.initials: P
authors.lastname: Primerano
authors.forename: Francesco
authors.initials: F
authors.lastname: Corigliano
mesh_terms: D000327:Adsorption; D007477:Ions / Q000737:chemistry; D019216:Metals, Heavy / Q000737:chemistry* / Q000302:isolation & purification*; D008855:Microscopy, Electron, Scanning; D017640:Silicates / Q000737:chemistry* / Q000191:economics*; D014865:Waste Disposal, Fluid / Q000191:economics* / Q000379:methods*; D014873:Water Pollutants / Q000191:economics / Q000302:isolation & purification*; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry*
chemical_list: D007477:Ions; D019216:Metals, Heavy; D017640:Silicates; D014873:Water Pollutants; D017641:Zeolites; C005144:pumice