Robert Kurdi

University of Pannonia, Veszprém · Institute of Environmental Engineering

In recent years, the circular economy has become an important element of sustainable development. Products become waste at the end of their life cycles. This problem is accompanied by a parallel decline in the availability of certain critical raw materials. It is obvious that the materials that become waste should be recycled and their components r...

The increasing environmental consideration and the growth of instability of the energy market call for methods that can process the organic fraction of municipal solid waste (OFMSW) into fuel instead of disposal. Due to the pyrolysis and gasification that are efficient procedures to achieve valuable products, gasification of OFMSW with different pa...

Under the era of circular economy, the deposit-refund system (DRS) for e.g. polyethylene terephthalate (PET) is thought to be a good choice to achieve a more structured plastic recycling. The present research has the aim to make a comprehensive description and a practical guideline in order to evaluate how collection and separation system influence...

Municipal solid waste management is crucial in terms of the environment, sustainability and the circular economy. The directly landfilled organic fraction of municipal solid waste (OFMSW) offers a lot of potential with regard to energy recovery or as a soil substrate. In this study, the regional differences in Hungary according to various living st...

Magyarország hulladékgazdálkodása 2023-tól több jelentős változáson megy át. A tanulmány hazánk és a vármegyeszékhelyek települési hulladékának mennyiségét vizsgálja, ezen belül kiemelten kezelve a szelektív hulladékot. A kutatás a Központi Statisztikai Hivatal 2017–2021 időszakra vonatkozó adatait elemzi. E szekunder statisztikák alapján megállapí...

One of the significant problems in our society is the handling and processing of the vast amount of waste produced by households and industrial processes. Nowadays, packaging material regulations are constantly changing, which can significantly impact the quality of municipal waste, requiring the continuous development and redesign of waste process...

Phosphorous (P) is an essential nutrient with finite and non-renewable resources; however, it can cause eutrophication in freshwater. The use or storage of red mud (RM), a by-product of alumina production with high iron and aluminium content, poses another environmental issue. Objective: This paper examines the possibility of P recovery from variou...

Transforming economies towards the increased circular use of raw materials and keeping resource consumption within planetary boundaries is a major challenge. In our previous research, we utilized sewage sludge to produce artificial soil mixtures well-suited to the biological recultivation of degraded areas. The present study investigated how we can...

Anaerobic bioprocesses, such as anaerobic digestion and dark fermentation, provide energy carriers in the form of methane and hydrogen gases, respectively. However, their wastewater-type residues, that is, the fermentation effluents, must be treated carefully due to the incomplete and non-selective conversion of organic matter fed to the actual sys...

The research subject is the deposit-refund system of beverage packaging (PET, glass and aluminium) in Hungary, which is under development. For the success of the planned system, it is important to consider the population’s opinion. Therefore, data from a primary questionnaire survey were used for the analyses. This questionnaire was conducted in 20...

Despite efforts to utilise bauxite residue, the amount of red mud stored in reservoirs is increasing. This paper aims to evaluate the potential of red mud and other sludge waste types as a soil substitute by monitoring plant development. Pot experiments were carried out testing two types of mixtures: dredging sludge from Lake Balaton mixed with gar...

In this work, two polymeric membrane separators (a proton exchange membrane (PEM), Nafion, and an anion-exchange membrane (AEM), 1,4-diazabicyclo[2.2.2]octane (DABCO)-functionalized PSEBS) deployed in microbial fuel cells (MFCs) are comparatively assessed. The performances of MFCs according to membrane type were evaluated by biological and electroc...

Napjainkban számos olyan környezetvédelmi problémával küzdünk, amelyek megoldásához naprakész ismeretekkel rendelkező környezetvédelmi szakemberekre van szükség. A környezetvédelmi problémák okozói között meghatározóak a már hosszú ideje működő iparvállalatok, melyek esetében egyrészt a meglevő környezeti károk felmérése és felszámolása, másrészt a...

Long‐armed multifunctional organosilicon molecules display self‐replicating and self‐perfecting behavior in asymmetric autocatalysis (Soai reaction). Two representatives of this class were studied by statistical methods aiming at determination of probabilities of natural abundance chiral isotopomers. The results, reported here, show an astonishing...

Some fragments of the reagents and of the (hypothetic) intermediates of the asymmetric autocatalysis (Soai reaction) are prochiral in the sense of isotopic substitution. The structures as well as the probability of formation of such enantioisotopomeric molecules/groups were identified and calculated by combinatorial and stochastic methods, based on...

In this paper, the anaerobic treatment of a high organic-strength wastewater-type feedstoc®k, referred as the liquid fraction of pressed municipal solid waste (LPW) was studied for energy recovery and organic matter removal. The processes investigated were (i) dark fermentation to produce biohydrogen, (ii) anaerobic digestion for biogas formation a...

Solutions of very low concentrations can not be treated by the usual concept of concentration. Stochastic calculations are performed for the analysis of such solutions, containing one or a few molecule(s). It is concluded, that these systems escape the usual concentration parameters. Two "case histories" are also shown for demonstration of practica...

Isotopic chirality influences sensitively the enantiomeric outcome of the Soai asymmetric autocatalysis. Therefore magnitude and eventual effects of isotopic chirality caused by natural abundance isotopic substitution (H, C, O, Zn) in the reagents of the Soai reaction were analyzed by combinatorics and probability calculations. Expectable enantiome...

Clay-based nanostructures were prepared from kaolinites of varying structural order by two different methods. In the first method the kaolinite-urea precursor, obtained by dry grinding, was intercalated further with triethanolamine and the tetraalkylammonium salt was synthesized in the interlamellar space. Exfoliation was achieved by the use of sod...

A novel substrate (obtained from biofraction of municipal solid waste by pressing and called LPW) rich in organic substances was used in three anaerobic degradation processes (biogas, biohydrogen fermentation and microbial fuel cells) to comparatively assess their feasibility for energy recovery. It has turned out that all the processes have succes...

Minimizing the landfill load has become a must for Europe Union (EU) member states. The mechanical and biological treatment of household wastes is one of the key methods for reaching this goal. The object of mechanical handling is to separate the recyclable fraction and transform the non-recyclable part into Refuse Derived Fuel (RDF) for energetic...

Facing the new challenge in Hungary to meet the European Union (EU) legislation diverting waste stream from the landfill is inevitable. Low-waste design products and reuse are preferred, although recycling and recovery are also necessary to reach the ambitious goal of waste management. Besides finding new methods for recycling materials from Mixed...

Geothermal heat pump systems are considered to be environmentally-friendly solutions for residential use. The popularity of these systems is expected to rise but the information on their hydrodynamic and thermal impact is scarce. This paper focuses on how the hydraulic conductivity influences the impact on the reservoir caused by a single well-doub...

Kaolinite as a remarkable industrial raw material has notable structural features despite its simple chemical composition (Al2O3⋅2SiO2⋅2H2O). We report here a systematic development of a coordination chemical model for the [6Al-6(OH)] honeycomb-like unit of the kaolinite’s octahedral sheet, which was proposed to be the adsorption site for small mol...

Autosolvation is an important factor in stabilizing the architecture of medium complicated molecules. It is a kind of “supramolecular force” acting in intramolecular manner, consisting of orbital-orbital interactions between polar groups, separated by more than one covalent bonds within the same molecule. This effect facilitates also the developmen...

Diverting household waste from landfill had become a must for EU member states. The mechanical and biological treatment of household wastes is one of the key method to reach this goal. The object of the mechanical handling is to separate the recyclable fraction and transform the non-recyclable part into Refuse Derived Fuel (RDF) for energetic use a...

Consumption and related waste production is an integral part of our daily lives. The waste generation worldwide depends on the economic strength of the given region/country, and it increases from year to year. More and more attention is drawn to the re-use, recycling, reutilization of the waste which are driven mainly by environmental concerns and...

The waste management is increasingly important from the point of view of our future and to keep our environment safe for the future generations to come. The European Union sets up strategic objectives and goals on priorities and actions in the field of waste management. The Waste Framework Directive 2008/98/EC stipulates and sets forth the goals an...

Montmorillonite (MMT) was converted to organoclays by intercalation of cationic surfactants into its interlayer space. Two types of organoclays were prepared from different surfactants (DDTMA and DDDMA) at different surfactant loadings, and the structural changes in the clays investigated using various techniques. The arrangements of surfactant mol...

Modified montmorillonite was prepared at different surfactant (HDTMA) loadings through ion exchange. The conformational arrangement of the loaded surfactants within the interlayer space of MMT was obtained by computational modelling. The conformational change of surfactant molecules enhance the visual understanding of the results obtained from char...

The wall of the red mud waste disposal facility at Ajka, Hungary ruptured on October 4, 2010. Nearly about 1 million m3 of red mud sludge got out of the disposal facility and the neighbouring environment was heavily contaminated. In the emergency situation the top priority was put on the rescue of human lives and to provide first aid to the injured...

Intercalation of a kaolinite-containing halloysite from Biela Hora (Slovakia) with urea was investigated by simultaneous TG–DTA, XRD, FTIR (DRIFT), and Raman spectroscopy. The process of intercalation and thermal deintercalation was followed for the as-prepared and the washed (with isopropanol) samples. The proposed structural model was supported b...

R1OC(O)CH2Co(CO)3PR2 3 complexes (R1 = S-EtOC(O)CH(CH3), R2 = Ph a; R1 = (1S,2R,5S)-2-isopropyl-5-methylcyclohexyl, R2 = Ph, b; R1 = (1R,2S,5R)-2- isopropyl-5-methylcyclohexyl, R2 = Ph, c; R1 = isopropyl, R2 3 = Ph2{(1S,2S,5R)-2- isopropyl-5-methylcyclohexyl}, d) were prepared and characterised by analyses including IR, 1H NMR, 13C{1H} NMR spectra,...

Crystalline phases of the flexible complexes ROC(O)CH2Co(CO)3PPh3 contain enantiomeric pairs of chiral conformers characterized by two forms of the PPh3 ligand of opposed helical chirality, each of which is accompanied by only one conformation of the ester fragment. While the interconversion amongst enantiomers is very fast its stereoselectivity is...

Here, we report a study on the complexation behavior of carotenoids with cyclodextrins (CDs) using solubility experiments and molecular-modelling methods. Carotenoids are an important group of naturally occurring dyes found in vegetables and fruits. Their antioxidant property has initiated investigations on their possible use as drugs. However, car...

R1OC(O)CH2Co(CO)3PR23 complexes (3), (R1 = S-EtOC(O)CH(CH3), R2 = Ph, a; R1 = (1S,2R,5S)-2-isopropyl-5-methylcyclohexyl, R2 = Ph, b; R1 = (1R,2S,5R)-2-isopropyl-5-methylcyclohexyl, R2 = Ph, c; R1 = isopropyl, R23 = Ph2{(1S,2S,5R)-2-isopropyl-5-methylcyclohexyl}, d) were prepared and characterized by analyses including IR, 1H-, 13C{1H}-, and 31P{1H}...

Intermediates of the cobalt carbonyl-catalysed carbonylation of ortho-substituted benzyl halides were identified by IR, 1H- and 13C-NMR spectra. The molecular structures of the acyl-type derivatives 2-MeC6H4CH2C(O)Co(CO)3PPh3 and 2-PhC6H4CH2C(O)Co(CO)3PPh3 were determined by X-ray crystallography. Structural features of these complexes are discusse...

Current climate models seem to underestimate the flux of solar energy absorbed by the global troposphere. All of these models are constrained with the assumption that cloud droplets consist of pure water. Here we demonstrate in a simple laboratory experiment that aromatic hydroxy-acids which are found in continental fine aerosol can react with hydr...

Crystalline phases and solutions of the flexible complexes ROC(O)CH2Co(CO)3PPh3 contain enantiomeric pairs of chiral conformers characterized by two forms of the PPh3 ligand of opposed helical chirality, each of which is accompanied by only one conformation of the ester fragment. The interconversion amongst enantiomers is very fast and the stereose...

The paper presents the combined application of QSAR expert systems to predict the environmental hazard of ethylene oxide and its metabolites. The metabolic tree was generated in four metabolic levels by the MetabolExpert Ver.10.0 program. The toxicity of ethylene oxide and its 24 metabolites was then subjected to toxicology prediction study using t...