REVALORIZATION OF FOOD INDUSTRY WASTE 3rd Metallurgical & Materials Engineering Congress of South-East Europe 2017 REVALORIZATION OF FOOD INDUSTRY WASTE Zorica Lopičić1, Tatjana Šoštarić1, Jelena Milojković1, Jelena Petrović1, Marija Mihajlović1, Marija Petrović1, Mirjana Stojanović1 1Institute for Technology of Nuclear and Other Mineral Raw Materials z.lopicic@itnms.ac.rs Abstract Various industries produce and discharge waste containing different heavy metals into the environment, which presents serious threat both to environment and human health. Most commonly used techniques for removing heavy metals from wastewater have certain limitations which have induced necessity for developing low-cost processes. Application of cheap and abundant low-cost polymers in sorption process represents one of the promising techniques for heavy metal removal, especially at its low concentrations. On the other hand, worldwide depleting of non-renewable energy sources are causing a serious economic and environmental threats, leading to intensive research and investments in renewable resources. The most important source of renewable energy in Serbia represents biomass, where almost half of this energy potential is agricultural and industrial waste. Unfortunatelly, most of these wastes are disposed at open landfills with negligible revalorization. The eleectricity production in the Republic of Serbia is still based on the combustion of low – rank domestic coals in thermal power plants and utilization of available hydro potential. For all the reasons previously described, the authors have investigated the possibility of application of this cheap, wasted material from food industry in sustainable manner-first as heavy metal sorbent and later as fuel based on energy renewable source. For this purpose, sorption experiments with different heavy metals (Cu, Pb, Zn, Cd) were conducted, and after desorption process, the exhausted sorbent was thermally degraded. Sorption and energetic characteristic were investigated using FTIR, SEM and TG techniques. Obtained equilibrium results confirmed possible application of this waste material as a heavy metal sorbent, while the kinetic parameters calculated from thermal degradation results, confirmed its possible application as a fuel. Keywords: heavy metals pollution, sorption, desorption, thermal degradation, fuel Peach (Prunus persica L.) has an important role in Serbia’s fruit production with average annual production in 2016 of 96502 t that generates more than 18000 t peach stone (PS) waste. This kind of lignocellulosic waste has been proven as renewable source of many chemicals, components and biofuels. Methods In order to characterize PS, following analysis were performed: Structural, ultimate and proximate analysis of PS biomass FT-IR, XRD, SEM and TG. Sorption experiments, including optimization of operational parameters, were conducted in batch mode, including Cu(II) as a sorbent. Analysis of thermal degradation kinetics was performed in air atmosphere, at instrument „NETZSCH 409 EP“ under non-isothermal conditions, at different heat rates: 5, 10, 15 i 20 oC/min. Fig 1. FTIR analysis of PS Fig 2. SEM image of PS sample Results Results presented in Table 1. indicate composition that satisfy requirements for effiecient burning. Dominante presence of the functional groups: carbonyl, carboxyl and hydroxyl that acted as the binding sites for Cu sorption (Fig. 1) Temperature has promoting effect on Cu(II) sorption, increasing capacity from 22,78 mg/g (20 oC) to 29,99 mg/g na 50 oC.  TABLE 1. Parametar KB Ultimate analysis, % C 47,42 H 6,06 N 0,27 S 0,21 O 45,58 Proximate analysis Water, % 6,07 Volatiles, % 76,62 Fixed carbon, % 16,33 Ash, % 0,98 Structural components Crude celulose 58,05 Lignin 16,54 Average HHV (MJ/kg) (Sheng and Azevedo, 2005) 18,99 Fig 3. (a) isoconverional FWO model (b) Variation of activation energy with conversion Multilayer porous structure with average pore diameter of 22.2 nm, favorable for ions diffusion (Fig. 2) Thermal decomposition data confirmed the lignocellulosic composition of PS and its thermal stablity Thermal kinetics modelled by FWO model (Fig 3.(a)) showed that the reaction parameters vary significantly with conversion (Fig 3.(b) Dependance α - Eα) indicating multistage kinetics. Key objectives of this paper were to investigate the possible application of bio based waste material, PS, as a heavy metal sorbent and later as a fuel. Obtained results confirmed good sorption and energetic characteristic and indicated that mecjhanically treated PS can be efficiently applied in both cases. This would improve environment quality by avoiding waste landfilling, reducing GHG emissions and increase the application of renewable energy sources Acknowledgements: These results are part of the project supported by the Ministry of Education and Science of the Republic of Serbia, TR 31003.