Roberto Terzano 1 Caterina D’Alessandro 1 Matteo Spagnuolo 1 Marcello Romagnoli 2 Luca Medici 3 1 Department of Soil, Plant and Food Sciences, University of Bari “Aldo Moro”, Bari, Italy 2 Department of Engineery “Enzo Ferrari”, University of Modena and Reggio Emilia, Modena, Italy 3 Institute of Methodologies for Environmental Analysis, I.M.A.A. – C.N.R., Tito Scalo (PZ), Italy Research Article Facile Zeolite Synthesis from Municipal Glass and Aluminum Solid Wastes A clean and cheap procedure for the synthesis of zeolites is presented, using glass and aluminum wastes as starting materials. The products are aluminosilicate materials with a high cation exchange capacity (CEC: 259–389.5 meq/100 g) containing 25–30% of crystalline zeolites. Since the synthesized materials are free of potentially toxic elements, they could be safely used for environmental and agricultural applications. Morespecifically,amaterialcontaining30%ofzeoliteAhasbeensynthesizedat60°Cin one week, using NaOH as mineralizing agent. About 15% of zeolite A has been obtained at room temperature in six months. When KOH was employed, 25% of edingtonite has been produced in the final material after one week at 90°C. All the materials have been characterized for crystallinity, crystal morphology, particle size, pore size, surface area, and CEC. The whole process has been designed with the aim to recycle useful waste materials and reduce at minimum energy consumption and the production of harmful greenhouse gases. Keywords: Aluminosilicate; Edingtonite; Green technology; Recycling; Simple and cheap synthetic process Received: January 31, 2014; revised: May 12, 2014; accepted: May 24, 2014 DOI: 10.1002/clen.201400091 1 Introduction Zeolites are crystalline tectosilicate minerals possessing very small regular internal cavities (<2 nm) and very high cation exchange capacities(CEC);thusarelargelyemployedinanumberofindustrial applications such as water depuration, detergents preparation, water and gas sorbents, catalysts in petrochemical syntheses, soil remediation, soil fertilizers, deodorants, growth media, dietary supplements in animal nutrition, fungicide, and pesticide carriers [1]. Beside traditional methods of zeolite synthesis employing pure chemicals, in the last 30 years a large number of alternative materials have been proposed as starting reagents for the synthesis of zeolites under alkaline hydrothermal conditions. Among these, we can cite aluminosilicate minerals such as kaolinite [2], montmorillonite [3], bentonite [4], interstratified illite–smectite [5],naturalglasses[6],orwastematerialssuchaspapersludgeash[7], rice husk [8, 9], municipal solid waste incineration ash [10], steel slag [11], and especially coal fly ash [12–14]. The risk of using waste materials as starting reagents for zeolite synthesis, in particular when incineration residuals like fly ash are employed, is usually connected to the contamination from potential toxic elements such as Pb, Cd, Cr(VI), Hg, and As [15]. Such a contamination may reduce the range of possible applications of the synthesized zeolitic materials. On the other hand, using pure chemicals could make the zeolitic product very expensive thus not economically convenient for environmental and agricultural applications. New cheap processes for the synthesis of clean zeolites are therefore desirable to meet the large demand of zeolitic materials for this type of applications. Glass and aluminum commercially used to preserve food and beverages are necessarily free of potentially harmful substances and are widely and easily available from the separate collection of municipal solid wastes (MSW). Nowadays, almost the totality of collected glass and aluminum is recycled through processes which are extremely advantageous from an environmental and economic point of view, but require very high temperatures: 1500°C for glass and >660°C (melting point of Al) for aluminum, with a subsequent high energy demand and production of greenhouse gases. In this paper, we propose an alternative, very simple, and cheap procedure for the reuse of glass and aluminum separated from common MSW to produce zeolites as materials with a high added value.Forthefirsttime,zeolitesaresynthesizedfromMSWglassand aluminum by a method which aims at i) reducing to the minimum the treatment of starting materials and the need of expensive and energy consuming equipments; ii) employing cheap chemical reagents; and iii) adopting low reaction temperatures, possibly Correspondence: Dr. R. Terzano, Department of Soil, Plant and Food Sciences, University of Bari ‘Aldo Moro’, via Amendola 165/A, 70126 Bari, Italy E-mail: roberto.terzano@uniba.it Abbreviations:BET, Brunauer, Emmet and Teller; CEC, cation exchange capacity; EDS, energy dispersive spectroscopy; EXPGUI, experiment file graphical user interface; FAU, faujasite; FESEM, field emission scanning electron microscopy; GIS, gismondine; GSAS, general structure analysis system; HDPE, high-density polyethylene; ICP-OES, inductively coupled plasma atomic emission spectroscopy; LTA, Linde type A; MSW, municipal solid waste; NIST, National Institute of Standards and Technology; SEM, scanning electron microscopy; SOD, sodalite 1 © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.clean-journal.com Clean – Soil, Air, Water 2014, 42 (9999), 1–8