Gabriela Geanina Vasile, Cristina Dinu, Lidia Kim, Anda Tenea, Marius Simion, Corina Ene, Claudiu Spinu, Eleonora-Mihaela Ungureanu, Daniel Manolache - Platinum Group Elements in Road Dust and Vegetation from Some European and National Roads with Intensive Car Traffic in Romania

The extraction efficiency together with the active transport assisted by the pH gradient through liquid membrane of some aromatic native and derivative amino acids by using heptakis (2,3,6-tri-O-acetyl)-β-cyclodextrin as extractant agent or carrier has been studied. The modified cyclodextrin extracted aromatic amino acids, native (l-tryptophane, l-phenylalanine, and l-tyrosine) and their methylester derivatives from aqueous phase into the organic phase. Moreover, the modified cyclodextrin exhibits the carrier abilities for amino acid methylesters through liquid membrane. In the case of transport processes involving liquid membranes, the physicochemical properties of the solvents play an important role in membrane stability. The results demonstrated that the inclusion properties of the investigated host are correlated with the structural properties of amino acids, and they also suggest further possibilities for optimal separation of amino acids derivatives. Extraction and active transport through liquid membrane of some aromatic amino acids by using modified cyclodextrin.

The purpose of this study was to produce additional data for the valorization process of vegetable waste originating from dietary supplement technology. Two types of vegetable waste originating from different technological processes of sea buckthorn oil were used: vegetable waste from organic solvent extraction (P1) and vegetable waste from cold extraction (P2). Batch experiments evaluated the influence of pH, initial metal concentration, contact time, and Langmuir and Freundlich adsorption isotherms. The following pollutants—Cu, Cr, Co, Ni, Pb and Zn—from the wastewater were studied. The removal efficiency of metals from wastewater was evaluated at pH 3, 5 and 7. The highest metals removal efficiency was obtained at pH 5. It was observed that the Langmuir isotherm fits the adsorption process very well. Based on the results obtained, it can be concluded that vegetable waste resulting from the sea buckthorn oil industry could have potential applications for removing toxic metals from wastewater due to its high removal efficiency (>80%).

The leather industry is one of the most polluting industries in the world due to the large amounts of waste following raw hide processing but also due to the high content of chemical substances present in leather waste. The main problem with chromium-tanned leather solid waste is related to the storage, due to the ability of chromium to leach into soil or water, and also owing to the high ability of trivalent chromium to oxidize to its toxic form, hexavalent chromium. The purpose of this article is to present the most current methods of chromium extraction from solid tanned leather waste in order to obtain non-polluting leather, which can constitute secondary raw material in new industrial processes. The extraction methods identified in the present study are based on acid/basic/enzymatic hydrolysis and substitution with the help of organic chelators (organic acids and organic acid salts). In addition, this study includes a comparative analysis of the advantages and disadvantages of each identified extraction method. At the same time, this study also presents alternative chromium extraction methods based on the combination of conventional extraction methods and ultrasound-assisted extraction.