Infrared study of N-H...π hydrogen bonding. N-methylbenzamide - Aromatic donor systems

The present paper reports the results of an infrared study in the region of the fundamental NH stratching vibration for six N-methylbenzamide - aromatic donor systems. The thermodynamic properties for 1:1 NMBA - aromatic donor complexes are given. The contribution of the charge transfer mechanism to the hydrogen bonding in the studied systems is considered

Biodegradation of a mixture of benzophenone, benzophenone-3, caffeine and carbamazepine in a laboratory test filter

The biodegradation of a mixture of four pharmaceutical and personal care products (PPCPs) (benzophenone (BP), benzophenone-3 (BP-3), caffeine (CF) and carbamazepine (CBZ)) was studied in a laboratory test filter. The column was filled with inert material to exclude the adsorption processes and to enable the development of the biofilm, while river water was recirculated. High removal for BP, BP-3 and CF was observed from the beginning of the experiment at the initial concentration of 20 μg L-1 (90–99 %). In the case of CBZ analytical difficulties were experienced. The efficacy of biodegradation reflected as a change of the overall toxicity of initial mixture of selected PPCPs vs. toxicity of samples which were undergone different biodegradation phases was assessed with two standard laboratory tests with apical endpoint – acute toxicity test with Daphnia magna (immobilisation) and bioluminescence inhibition with Vibrio fisheri. Toxicity tests showed the substantial reduction of the overall mixture toxicity in a laboratory test filter. The residual toxicity to D. magna might be attributed to undetected transformation products. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. OI172028

Influence of Carbon Agglomerate Formation on Micropollutants Removal in Combined PAC-Membrane Filtration Processes for Advanced Wastewater Treatment

Micropollutants (MPs) are ubiquitous in wastewater and are not effectively removed by the existing conventional treatment processes, resulting in increased environmental pollution. Nowadays, dosing of powdered activated carbon (PAC) prior to membrane filtration has emerged as an advanced wastewater treatment method for MPs removal. This study investigated the carbon agglomerate formation in the PAC stock suspension and its influence on MPs removal in PAC-capillary membrane filtration processes at both lab- and pilot-scale levels. Both lab- and pilot-scale membrane filtration results revealed that MPs removal efficiency is affected with the increase of PAC concentration in the stock suspension. For example, one of the investigated pilot tests showed a significantly reduced removal of good adsorbable MPs (from 57 to 17%) when stock suspension concentration was increased from 0.2 to 20 g/L. It is assumed that PAC agglomerates led to a slower adsorption kinetic and an inhomogeneous distribution of PAC in the membrane system. Maintaining PAC concentration in the stock suspension as low as possible (below 0.2 g/L for investigated PAC) certainly would help to avoid agglomeration problems and enhance the overall performance of the processes

Assessment of the retardation of selected herbicides onto Danube sediment based on small column tests

Purpose: This study utilizes column tests to investigate the retardation of certain herbicides with different hydrophobicities (atrazine, alachlor and trifluralin) during transport through surface Danube sediment. The influence of water matrix on the retardation factor Rd and Freundlich constant Kf is investigated. The results are compared with batch tests to establish whether different methodologies result in similar or different conclusions. Materials and methods: A stainless steel column was filled with natural Danube sediment. Three water matrices were investigated: synthetic, Danube surface, and deep groundwater rich in natural organic matter (NOM). The goal was to examine whether different water matrices would result in changes in the Rd and corresponding Kf values. After a tracer experiment, single herbicide solutions were tested in the three water matrices. Herbicides were analyzed by gas chromatography coupled with electron capture detector (GC/ECD). Retardation factors obtained in the column experiments were calculated using Transmod software (version 2.2). The Kf values calculated were compared with the values obtained in previous batch experiments. Results and discussion: A breakthrough curve (BTC) for trifluralin could not be obtained during the experiment. Atrazine Rd values were almost the same in the natural matrices (54 and 55 for the ground and surface waters, respectively), and lower in the synthetic water (40). Alachlor Rd values in the three water matrices were very similar (30–35). The corresponding Kf values for alachlor (8.47–17.4) were lower than those of atrazine (13.5–27.9). These results differ from those obtained by earlier batch tests, which showed similar Kf values for both atrazine (4.4–9.2) and alachlor (4.43–10.35) in all three matrices. In contrast to the results observed during the batch tests, the column tests exhibited higher Kf values in the natural water matrices than the synthetic water, possibly due to the influence of dissolved organic carbon on herbicide sorption. Conclusions: Of the three herbicides investigated, the smallest retardation was observed for alachlor. This was unexpected given the relative hydrophobicities of alachlor and atrazine. The potential risk of transport through the sediment may therefore be greater for alachlor than the other two herbicides. This was indicated neither by the batch tests nor from the Koc–Kow estimations. Both herbicides exhibited similar Kd and Kf values in the batch tests, and lower values in the natural water matrices. In comparison, the column tests showed higher Kf values, with higher values in the natural matrices than in the synthetic water matrix

Advanced Treatment of the Municipal Wastewater by Lab-Scale Hybrid Ultrafiltration

In this study, hybrid ultrafiltration which involves adsorption onto activated carbon and/or coagulation was tested for the removal of ibuprofen, caffeine and diclofenac from the municipal wastewater treatment plant effluent (c0 = 2–3 µg/L). Ultrafiltration was tested in combination with powdered activated carbon dose of 5 mg/L separately or with coagulants (FeCl3, dose 4 mg Fe (III)/L and, natural coagulant isolated from bean seeds, dose 33 µL/L). In addition to the removal of organic micropollutants, the removal of As, Cr, Cu and Zn was also tested (c0~100 µg/L). The research was conducted on a laboratory pilot plant (capacity 30 L/h, in-out dead-end filtration, flux of 80 L/m2h). The best results were obtained for caffeine when adsorption on PAC is combined with a FeCl3 (removal efficiency 42–87%). The addition of a natural coagulant did not show benefits for the removal of organic micropollutants compared to the other tested processes, but both coagulants had similar effects on the content of metals and As Hybrid membrane processes proved to be the most efficient for Zn (44–87%) and Cr (33–87%) removal. The lowest efficiency was determined for As (˂19%). Ultrafiltration with PAC and coagulants removed 5–33% of effluent organic matter, depending on the type of coagulant; 57–87% of total nitrogen and PAC/FeCl3/UF was also partially effective for removing total phosphorus (11–39%)

Referentni obrazovni standardi za hemiju i srodne discipline

One of the results of the work on the TEMPUS project 'Modernisation of Post-Graduate Studies in Chemistry and Chemistry Related Programmes - MCHEM' are benchmark standards for chemistry and chemistry related subjects. The goal of this text was to make these standards available to Serbian community. Obtained text is a result of the consensus among participants of the project coming from educational institutions that are responsible for chemistry and it is based on already existing standards in Europe created by 'The Chemistry Quality Eurolabels®' and adopted by 'European Association for Chemical and Molecular Sciences' since 2003

Modernisation of post-graduate studies in chemistry - an example of TEMPUS project activities

With the ever increasing progress and achievement in science and technology it is evident that higher education is under pressure to continue to produce new generations of highly skilled individuals who will be capable of contributing further intellectual and technical advances in the 21st century. Therefore, higher education (HE) systems around the globe are facing an enormous challenge to develop programmes that will help produce such scientific graduate leaders and the necessary new generations of scientists and technologists. To further this aim of developing modern scientists who are competitive on a world stage we have created a joint-project, funded by the European Union’s TEMPUS programme, which aims to respond to current societal needs to develop and modernise existing Chemistry programmes in Serbia with a view of making programme outcomes consistent with best practice in the rest of Europe. To achieve this aim the following objectives and work programmes have been formulated: • Revisit current benchmarking statements and align them with 21st century needs. • Modernisation of the HE quality assurance (QA) system. • Staff development – both pedagogical and scientific. • Implementation of modern technologies in teaching practice. • Aligning assessment criteria and methodology with new teaching strategies. Higher education modernisation is often driven by its desire to establish the most effective ways of delivering teaching and learning. When talking about modernisation of curricula in the 21st century we often think about the use of interactive boards, public response systems and virtual learning environments. Although, it is evident that computer aided teaching and learning processes are often dominant, implementation of new teaching strategies is often dictated by: • An effective understanding of how learners learn (teaching theories). • The desired learning outcomes (stake holders input) • Available tools (technologies). • Latest scientific discoveries (research informed teaching)