Fuglein, Alexander

Gerressen, Marcus

Ghassemi, Alireza

Holzle, Frank

Modabber, Ali

Noroozi, Nelson

Riediger, Dieter

Stiller, Maria Barbara

Piven, А. О.

Noskova, А. А.

Electronic archive of Tomsk Polytechnic University

Том 2 XXII Международная конференция «Химия и химическая технология в XXI веке»224which filled with 1 mol L–1 KCl. 2 M NaOH solu-tion was chosen as the background electrolyte and solvent for the substance [2].Cyclic voltammograms were recorded in the potential range of 0–1 V for searching of electro-chemical signal from pharmaceutical substance (Fig. 1). According to the results, IMN is oxidized only in the anode region.Figure 2 shows the anodic voltammograms of IMN electrooxidation, where intensity of the peak current increases with an increase of the concentra-tion of the substance.The dependence of the anodic peak current on the concentration is linear in the range of 0–0.4 mM (Fig. 3).The proposed method for determining IMN will be used to develop a method for the quantitative de-termination of a substance in pharmaceuticals.«The reported study was funded by RFBR and Czech Science Foundation according to the research project № 20-54-26001»References1.  Kormosh Z., Antal I. // Chemical sciences, 2013. – №24. – P. 93–128.2.  Arvand M., Gholizadeh T. // Sensors and Actua-tors B: Chemical, 2013. – №186. – P. 622–632.THE THERMAL DECOMPOSITION OF POLYLACTIDE WASTEА.О. Piven, А.А. NoskovaResearch advisor – PhD, associate professor Т.N. VolginaNational Research Tomsk Polytechnic University 634050, Russia, Tomsk, 30 Lenin Avenue, anastasiaapiven@gmail.comOver the last years, polymers have been used in almost all areas of modern life. However, one of the most important problems here is that most polymers do not decompose in nature, which leads to sustainable environmental pollution. The devel-opment and appliance of polymers able decompose to under specified conditions is a solution to this problem. Biodegradable polymers are materials that break down into innocuous to the environment compounds during certain natural microbiological and biochemical processes. The products of com-plete ones decomposition are mainly carbon diox-Fig. 1.  Cyclic voltammograms of oxidation – reduction of IMN on GCE in 2 mol L–1 NaOH, W = 100 mV/sFig. 2.  Anodic voltammograms of INM in 2 mol L–1 NaOH, W = 100 mV/sFig. 3.  Dependence of the IMN electrooxidation current on its concentration in 2 mol L–1 NaOH, W = 100 mV/s Секция 7.  Химия и химическая технология на иностранном языке (английский)225ide, water and humus. Such polymers easy can be recycled which allows to conserve resources and reduce environmental pollutions.Polylactide, produced from a lactic acid dimer, is one of the most widespread biopolymers. Due to its biocompatibility and sustainability, lactide-based polymers are used in various areas of life, from the production of short-life servicing goods such as disposable tableware, plastic wrap to medical prod-ucts, such as surgical sutures and pins. Synthesis of lactide is an integral part of the polylactide produc-tion. Conditions of this process, such as pressure, temperature and catalytic system, heavily affect the quality and properties of the derivable monomer.The purpose of this work is to synthesize lac-tide by thermal decomposition of polylactide waste and to study structure, composition and purity of the monomer obtained. Depolymerisation of the polylactide was per-formed on a vacuum distillation unit under pressure of 10 mbar and at a temperature of 180 200 °C in the presence of a ZnO catalyst in an amount of 1 % by weight. The experiment was carried out in parallel with two samples of polymer. The first sample was 3D printing filament (PA-1), and the second was products made from it, obtained by printing with a 3D pen (PA-2). The purification of raw lactide was performed by recrystallization from ethyl acetate. The content of lactic acid in the samples was determined by titrimetric method. The lactide struc-ture was analyzed by Infrared (IR) spectroscopy. Lactide is a substance existing in the form of two optical isomers: L-lactide and D-lactide. Howev-er, the forms of meso-lactide and racemic mixture of L, D-lactides are also known. Depending on its configuration, the substance has a different melting point (Tmelt). The Tmelt for L- and D-isomers is 96 °C, for racemic mixture is 125 °C and for meso-form is 54 °C. The sample obtained by depolymerization of the 3D printing filament (PA 1) has the melting point closest to the reference one after recrystallization. Studies showed that the obtained monomer with a melting point within 72–96 °C (PA-1) is a mixture of monomers, such as individual L-, D-forms and a racemic mixture. A wide temperature range of melt-ing point indicates the presence of impurities in the analyzed substance. These can be residues of lactic acid, meso-lactide, other optical isomers, oligomer, and water. The yield of pure lactide in terms of used poly-lactide under experimental conditions was 34.03 % (wt.) and 44.53 % (wt.) for new polylactide (PA-1) and polylactide waste (PA-2), respectively. The analysis of IR spectrums of the lactide showed next results.The absorption band in the area of 3,000–2,900 cm–1 indicates the presence of C–H bonds in the sample, the intensive absorption band in the area of 1,700 cm–1 indicates the presence of a C=O bond and bands in the area of 1,450–600 cm–1 belong the C–O– bond. The absorption bands in the region of 3,100–3,000 cm–1 of the sample PA-1 are more expressed than the bands in the same region of the sample PA-2, which indicates the presence of more impurities in the sample PA-2 containing a hydroxyl groups.In conclusion, the studies have demonstrated that the 3D printing filament and products from its are a valuable raw material for producing a mono-Fig. 1.  The IR spectrum of the lactideТом 2 XXII Международная конференция «Химия и химическая технология в XXI веке»226mer – lactide (its maximum yield reach 44.5 %). The use of zinc oxide in an amount of 1 % by weight cat-alyst, at a temperature about 200 °C and a pressure of 10 mbar leads to the formation of D- or L-lactide, with a little content of water, lactic acid and m-lac-tide as impurities.WASTEWATER REUSE FOR IRRIGATION OF MUNICIPAL GREENSA. Puškáčová, I. Růžičková, J. WannerSupervisor – Prof. J. Wanner, professor at UCT PragueUniversity of Chemistry and Technology in Prague Faculty of Environmental Technology Department of Water Technology and Environmental Engineering 166 28, Praha 6, Technická 3, adela.puskacova@vscht.czWastewater reuse is one of the alternative solu-tions for water scarcity. However, it is also connect-ed to certain risks, e.g. spreading of micropollutants, antibiotic resistant bacteria and genes, or pathogen-ic microorganisms [1]. In our work, we focus on comparison of micropollutants content in secondary effluent from municipal wastewater treatment plant (WWTP), intended for reuse, and river water, com-monly used for irrigation of municipal greens. Newly established Regulation (EU) 2020/741 of the European Parliament and of the Council of 25 May 2020 on minimum requirements for wa-ter reuse, sets several limits for quality of treated wastewater for reuse. Besides basic physico-chem-ical parameters, these limits include also E.  coli, Legionella spp. and intestinal nematodes (helminth eggs) [2]. Czech legislation for irrigation also sets several limits for irrigation water, including basic physico-chemical parameters, microbial parame-ters, heavy metals, but also some specific pollut-ants, such as polychlorinated biphenyls or radioac-tivity [3]. While there is legislation regarding these different kinds of contaminants, current legislation which would set necessary limits for micropollut-ants (e.g. pharmaceuticals) for irrigation or different wastewater reuse is still lacking [4]. However, risks connected to their presence in water used for irriga-tion must be taken into account [5]. Thus, this work focuses on their monitoring, but also on possibilities of their removal from the wastewater. Two different kinds of water were monitored – a secondary effluent from municipal WWTP and river water, which is commonly used for irrigation here in the Czech Republic. Samples of the efflu-ent were taken as 24-hours samples, while river samples were taken as grab samples, using glass vessels. Sampling campaign was carried out from autumn 2020 to spring 2021. Micropollutants were analyzed by LC/MS/MS. In total, 31 different mi-cropollutants, mainly from the group of pharmaceu-ticals, were analyzed. Results showed that effluent from municipal WWTP has generally higher concentrations of mi-cropollutants than the river. The highest concen-tration of pharmaceuticals in effluent samples was measured in 2700 ng/l for tramadol, while in river it was 130 ng/l for gabapentin. From other micropol-lutants, the highest concentration measured was that of sucralose – 30000 ng/l in the effluent, while in the river, it was only 1000 ng/l. These results suggest that despite certain benefits of wastewater reuse, we should take into account also potential risks for hu-man health or ecosystems, including the spread of these relatively new contaminants onto plants, soil, and eventually groundwater. AcknowledgmentsThis work was supported from the funding of the project Horizon 2020: Achieving wider uptake of water-smart solutions (H2020-SC5-2019-2), ID: 869283.References 1.  Rizzo L., Gernjak W., Krzeminski P., Malato S., McArdell C.S., Perez J.A.S., Schaar H. & Fat-ta-Kassinos D.  (2020). Best available  technol-ogies  and  treatment  trains  to  address  current challenges  in urban wastewater reuse  for  irri-gation of crops in EU countries. Science of the Total Environment, 710, 136312.

The thermal decomposition of polylactide waste

RWTH Publications

Computer-assisted mandibular reconstruction with vascularized iliac crest bone graft

Publikationsserver der RWTH Aachen University

Ali Modabber

Marcus Gerressen

Maria Barbara Stiller

Nelson Noroozi

Alexander Füglein

Frank Hölzle

Dieter Riediger

Alireza Ghassemi

Crossref

Aesthetic Plastic Surgery

Computer-assisted Mandibular Reconstruction with Vascularized Iliac Crest Bone Graft

http://earchive.tpu.ru/bitstream/11683/67757/1/conference_tpu-2021-C27_V2_p224-226.pdf

The thermal decomposition of polylactide waste

Abstract

Similar works

Full text

Available Versions

Electronic archive of Tomsk Polytechnic University

RWTH Publications

Publikationsserver der RWTH Aachen University

Crossref