MATERIALE PLASTICE ♦53♦No.2♦2016 http://www.revmaterialeplastice.ro 308 Industrial Tanned Leather Waste Embedded in Modern Composite Materials GABRIELA EMILIA POPITA 1 , CRISTINA ROSU 1 *, DORIN MANCIULA 1 , OFELIA CORBU 2 , ANTOANELA POPOVICI 3 , OVIDIU NEMES 4 , ANDREI VICTOR SANDU 5,6 *, MARIAN PROOROCU 7 , SEBASTIAN BOGDAN DAN 1 1 Babes Bolyai University, Faculty of Environmental Science and Engineering 30 Fantanele Str., 400294, Cluj Napoca, Romania 2 Technical University of Cluj-Napoca, Central Laboratory of the Faculty of Civil Engineering, 28 Memorandumului Str., 400114, Cluj Napoca, Romania 3 National Environmental Protection Agency, 294 Splaiul Independenþei, 060031 Bucharest, Romania 4 Technical University, Cluj-Napoca, Faculty of Materials and Environmental Engineering, 28 Memorandumului Str., 400114, Cluj Napoca, Romania 5 Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, 41 D. Mangeron Blvd., 700050, Iasi, Romania 6 Centre of Excellence Geopolymer & Green Technology (CeGeoGTech), School of Material Engineering, University Malaysia Perlis (UniMAP), P. O. Box 77, d/a Pejabat Pos Besar, 01000 Kangar, Perlis Malaysia 7 University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, 3-5 Calea Manastur, 400372, Cluj Napoca, Romania The aim of this study is to demonstrate that tanned waste leather can be successfully incorporated in cement matrix and the resulted composite material can be proposed as construction material. The composite leaching tests for total chromium (maximum concentration registered = 2.76 mg/kg), which is the most used tanning agent, shown low levels in leachate lower than maximum allowed concentration MAC for non-hazardous waste (MAC = 10 mg/kg). The study proposes a new environmentally friendly recycling method for tanned leather waste. Keywords: leather, waste, recycling, composite material In the European Union the concept of sustainable development covers all the environmental fields including the appropriate waste management. The leather industry production and processing sector generates high quantities of tanned leather waste, whereby, an important amount reaches the municipal landfills. Leather industry is one of the most important industries of the European economy and in Asia is the largest amount of generated waste from leather processing [1, 2]. Romania have an important tradition in leather processing, leather products representing 41% of all industrial uses for this material. The leather industry use only 80% of the rawhide material, the processing waste representing 20%. From 1,000 kg of tanned leather is obtained 600 - 700 kg of solid waste and 40-50 m 3 of wastewater [2]. Even the leather waste is framed into the European Waste Catalogue as a non-hazardous waste, because of the high concentration of heavy metals founded in waste leather scraps, leads to a real environmental risk. Therefore, because of the chromium content, it’s important to not discard the industrial leather waste in nature or to store it in open dump landfills; it is indicated to manage it properly through recycling and recovery thereof or by storage in compliant landfills. The open dump landfills generate impact and risk to the environment and public health, due to lack of facilities and poor exploitation [3, 4]. The waste from tanneries must be handled and stored so as to avoid leakage, odor problems and air emissions [5]. In the tannery process, generally, as tanning agent are used trivalent chromium (III) compounds. The processed leather waste has a major impact on human health and environment because of the chromium content. In certain tanning processes the added chromium (III) in the leather may be transformed by oxidation in chromium (VI) [6] which is considered a prioritary/ hazardous substance [7- 9]. In the Regulation 301/2014 was considered that an unacceptable risk to human health appears in the case of chromium (VI) concentrations equal to or greater than 0.0003 % by weight in leather goods and articles containing parts of leather that comes into contact with the skin [6]. Some leather products may contain traces of hexavalent chromium (Cr VI), and it may appear as a contaminant, in the following situations: !after UV exposure (at over 80°C) the fat-liquoring acids is possibly to lead to the oxidation of Cr III; ! in the process of the storage of fat-liquored leather at 35% humidity; !in the shoe production, the use of alkaline glues may contribute to the formation of Cr VI [10]. Also, the forming of chromium VI compounds, appears in the collagen subunits crosslink tanning processes, destined to increase leather’s resistance to mechanical action and heat [6]. There are numerous studies on tanned leather waste treatment for recycling and recovery [11-16], etc.). Most of these studies are related to the extraction of chromium from waste and its reuse in the tanning process [11]. For leather processing, the reference documents for best available techniques (BAT - Best Available Techniques) are covered by the Directive 2010/75/EC [17]. In the European legislation, as well as in the Romanian one, the waste from the leather industry, fur and textiles are listed and coded under Chapter 04 Wastes from the leather, fur and textile industries [18, 19]. It must be noticed that the leather waste, containing chromium salts isn’t framed as hazardous waste ; this waste is coded at code 04 01 08: waste tanned leather (blue sheeting, shavings, cuttings and buffing dust) containing Chromium . Only the codes marked with an * email: cristina.rosu@ubbcluj.ro; sav@tuiasi.ro