A novel adsorbent, NC-PEG, obtained by modification of nanocellulose (NC) with PEG-6-arm amino polyethylene glycol (PEG-NH 2) via maleic anhydride (MA) linker, was used for removal of Cd 2+ and Ni 2+ from water. A subsequent precipitation of iron oxide (FO) from goethite on NC-PEG was employed to produce NC-PEG/FO adsorbent which was used for As(V) and As(III) removal. In a batch test, the influence of pH, contact time, initial ion concentration and temperature on the adsorption efficiency were studied. The maximum adsorption capacities found for Cd 2+ and Ni 2+ , obtained by the use of Langmuir model, were 37.9 and 32.4 mg g-1 at 25 °C, respectively. Also, high As(V) and As(III) removal capacities of 26.0 and 23.6 mg g-1 were obtained. The thermodynamic parameters indicated endothermic, feasible and spontaneous nature of the adsorption process. The kinetic study, i.e., fitting by Weber-Morris model predicted that intra-particle diffusion was the ratecontrolling step. The ability for multi-cycle reusability of both NC-PEG and NC-PEG/FO, represents a positive indicator when considering their possible applications.

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Unsaturated polyester resins (UPe) were synthesized from maleic anhydride and products of glycolysis, obtained by polyethylene terephthalate (PET) depolymerization with dipropylene glycol (DPG) in the presence of tetrabutyl titanate catalyst. Waste PET glycolyzed product and UPes were characterized by FTIR and NMR spectroscopy, elemental analysis, acid value (AV), hydroxyl value (HV) and iodine value. Nanocomposites, based on unsaturated polyester resins and hexamethyldisilazane modified silica nanoparticles, were prepared with intention to show one of valuable applicative commercialization of UPe resin. In order to determine potential of the possible implementation of developed new technology for UPe production some aspect of technoeconomic analysis was analyzed. Economic potential/benefit and process profitability of the presented technology was based on the use of recycled raw input materials, i.e. waste PET, which is one of the most effective ways to save natural resources, protect the environment, and save money. Principles of green economy was incorporated in the results of developed UPe production technology which is related to both environmental protection and profitability achievement with no additional negative impact to environment, i.e. pollution decrease without negative effect of implemented technology.

The study of the synthesis of anticorrosive inhibitors, based on chemically modified tannins, and their use in alkyd based coatings to improve anticorrosive properties is presented in this work. Two methods of tannin modification were applied: direct method using ammonium hydroxide, ammonium hydroxide/ammonium chloride buffer or diethylenetriamine (DETA); and a two-step method including tannin modification with epichlorohydrin (ECH) in first step to produce epoxy modified tannin, ET, and further modification with heteroaromatic amines or linseed oil fatty acids (LFA) in second step. The obtained anticorrosive additives were characterized using ATR-FTIR, 1 H and 13 C NMR spectroscopies and elemental analysis. Epoxy, amino, hydroxyl, acid and iodine values of the synthesized inhibitors were determined according to standard methods. The prepared alkyd coating with tannin inhibitors was tested according to standard SRPS EN ISO 4628 method. Anticorrosive coating containing modified tannin based additive showed increased anticorrosive properties, good adhesion and coverage comparing to the coating with zinc phosphate additive. The alkyd coating films based on ET-LFA and ET modified with 2-amino-5mercapto-1,3,4-thiadiazole showed best anticorrosive results.