SIMI 2020

Nowadays, there is a growing need for methods that contribute to the environmental protection and help increase the human well – being and, therefore, different pollutants are studied: pharmaceuticals, hormones, polycyclic aromatic hydrocarbons and dyes. Among them, a special attention needs to be paid to dyes and especially organic dyes due to the fact that their accumulation in water bodies s responsible for reducing the reoxygenation ability killing the marine organisms by blocking the sunlight. Photocatalytic degradation using metallic nanoparticles has numerous advantages to the conventional route of quick oxidation because neither polycyclic compounds nor the oxidation of different pollutants appears. This research paper describes the use of silver nanoparticles (AgNPs) and ferrite nanoparticles (Fe3O4NPs) for the catalytic degradation of three azoic dyes: Direct Orange 26 (DO26), Direct Black 38 (DBk38) and Direct Brown 2 (DBr2). Silver nanoparticles were prepared using a “green chemistry” approach from aqueous extracts of different plants with important health benefits: Gooseberry, Acacia and Jujube. The degradation of DO26 was also investigated under direct sunlight using TiO2, ferrite nanoparticles and Fenton reagent.

In this paper, photocatalytic degradation of direct orange dye solution was achieved in the presence of CoFe2O4 : TiO2 as catalyst under solar light. The process was of pseudo-first-order kinetics. The best conditions of decolourization for this dye was the following: initial dye concentration is 50 mg/L, photocatalytic system CoFe2O4: TiO2 (50%:50%) = 0.025 g/100 mL and the initial pH of an aqueous solution of dye is 8.

In the last decades, the waste electric and electronic equipment (WEEE) has increased substantially due to an accelerated development of the economy, the life time of the electronics, or the diversified supply of these products. Proper initiatives regarding the energy consumption, the reduction of disposed solid and wastewater by e-waste recycling, etc. can reduce the environmental impact. Taking into account the aspects regarding the waste separation into individual polymers, the majority polystyrene fraction of WEEE can be recycled by melt compounding as elastomer modified compounds. The method can bring significant economic and technical advantages with obtaining performance composites. The 10% share of waste printed circuit boards (WPCB) from WEEE can be also recycled, but the high content of epoxy or phenolic thermosetting resins makes it difficult to be used in a conventional melt processing method. Presently, the profitability is due to the metals and glass fiber recovery. Hence, several proposed applications of non-metallic WPCB have been comprehensively examined. One method includes its use as filler in thermoplastic composites. The research was focused on processing by extrusion and injection molding some compositions containing WEEE. The amount of waste was selected based on the processability and mechanical properties of WEEE based compounds with different percent of the polystyrene fraction and WPCB, respectively, obtained by melt compounding. The characteristics were tested after modifying the polystyrene fraction of WEEE with styrene-butadiene block-copolymer. For waste printed circuit boards, recycled polypropylene was used as continuous phase.