Indoor biowaste treatment using small-scale composters has proven effective for processing organic waste and recovering valuable resources. This study evaluated the performance of the handmade C-EcoForHome composter, supplemented with an inoculant, in processing biowaste generated at five educational institutions in Split. During the biowaste treatment, key parameters were monitored, including temperature, compost heap height, moisture content, dry and volatile matter, carbon and nitrogen content, pH, and electrical conductivity. The collected leachates were analysed for volume, pH, electrical conductivity, and turbidity. Pre-composts were subsequently matured in two soil types, where the same physicochemical parameters were assessed to evaluate further stabilisation. Fourier-transform infrared (FTIR) spectroscopy was used to evaluate compositional changes in the biowaste resulting from composting conditions, and to analyse the produced water-dominated leachates. The results showed that the C-EcoForHome composter effectively processed biowaste in institutional settings, producing stable pre-composts with only minor variations compared to the initial substrate composition. Anaerobic fermentation caused acidification, ion release, and partial stabilisation of organic matter, while soil maturation further contributed to drying and consolidation. Indoor small-scale biowaste treatment represents a sustainable, low-maintenance solution for biowaste management, producing nutrient-rich pre-compost suitable for soil amendment.
U ovom radu provedeno je mehaničko recikliranje niti za košnju u laboratorijskom dvopužnom ekstruderu. Procijenjen je utjecaj mehaničkog recikliranja na strukturu, toplinska svojstva i toplinsku postojanost materijala od kojeg su izrađene niti za košnju. Primjenom infracrvene spektroskopije s Fourierovom transformacijom (FT-IR) utvrđeno je da su niti izrađene odpoli(ε-kaprolaktama), odnosno poliamida 6 (PA6). Ekstrudiranje nije utjecalo na strukturu PA6. Toplinska svojstva niti za košnju određena su primjenom diferencijalne pretražne kalorimetrije (DSC). Rezultati su ukazali na to da je ekstrudiranje imalo utjecaj na pakiranje i slaganje lanaca, odnosno uzrokovalo početak kristalizacije PA6 iz taljevine pri višoj temperaturi. Utjecaj mehaničkog recikliranja na toplinsku postojanost niti za košnju istraživan je primjenom termogravimetrijske analize (TG). Temeljem vrijednosti karakterističnih parametara ( T onset i T max) može se zaključiti da mehaničko recikliranje ne narušava toplinsku postojanost PA6. Mehaničko recikliranje može biti potencijalno rješenje zbrinjavanja rabljenih niti za košnju.
Engineering education is increasingly focused on developing both digital skills and sustainability awareness. To meet modern workforce demands, engineers must be proficient in using digital tools while designing environmentally responsible processes. The “Process Design” course at the Faculty of Chemistry and Technology integrates COCO ( Cape-Open to Cape-Open ) and ChemSep simulation software to enhance students’ digital competencies and deepen their understanding of sustainable chemical engineering. These free tools allow simulation of chemical processes, thermodynamic calculations, and optimisation of energy-efficient designs, enabling environmentally conscious decision-making. COCO, built on the CAPE-OPEN standard, includes modules for flowsheeting, unit operations, and reaction modelling, while ChemSep is used for simulating distillation columns. Together, they enable students to assess environmental impacts and design more sustainable processes. For this purpose, a survey was conducted among students to assess the software’s usability and its role in developing technical and soft skills such as creativity, critical thinking, and teamwork. The results showed that students recognised the value of the opportunity to simulate real-world processes, particularly in the context of sustainability. They found the tools accessible and effective in bridging theoretical knowledge with practical application. Students also emphasised the need for increased practical exercises and the incorporation of more complex simulation tasks. The integration of COCO and ChemSep proved beneficial in preparing students to address sustainability challenges through practical and digital competencies in process design, offering a free and accessible alternative to commercial simulation software, which is often limited by high costs and licensing constraints.
Efficient wastewater treatment is essential for environmental protection and sustainable water resource management, particularly when dealing with complex wastewater streams. Hybrid processes that combine electrochemical and physicochemical methods are increasingly explored due to their potential to enhance pollutant removal efficiency and reduce operating costs. This study evaluates the performance of hybrid treatment methods for complex compost wastewater by integrating electrocoagulation (EC), zeolite and magnetic assistance using aluminium (Al) and iron (Fe) electrodes. The influence of different electrode materials on magnetically assisted hybrid treatment process was assessed with respect to key treatment indicators, including chemical oxygen demand (COD) and turbidity reduction, as well as electrode mass loss, surface morphology, suspension settling, and EC sludge amount. Energy consumption and electrode usage were also considered to evaluate process economics. The results show that the application of a magnetic field in Al electrode systems slightly improves COD and turbidity removal, enhances anodic dissolution, and contributes to a more homogeneous surface morphology. In contrast, Fe electrodes exhibit a partially opposite response – the magnetic field accelerates floc settling and increases EC sludge production but reduces pollutant removal efficiency due to decreased dissolution intensity. Ferromagnetic Fe electrodes respond more strongly to the magnetic field, promoting aggregation and compaction of Fe-hydroxide flocs and partial surface stabilisation, which leads to lower anode mass loss. Weakly paramagnetic Al electrodes, on the other hand, are not directly affected by the magnetic field, but experience an indirect influence through magnetohydrodynamic (MHD)-induced micro-mixing and improved mass transfer. This leads to more uniform and intensive dissolution and a slightly higher pollutant removal efficiency. These findings provide a deeper understanding of the interactions between electrochemical and magnetic effects in hybrid electrocoagulation and offer guidance for optimising electrode material selection and magnetic field parameters to achieve more efficient and sustainable treatment of complex wastewater.
Hrvatski geolog i mineralog Fran Tućan (1878. – 1954.) i Mijo Kišpatić (1851. – 1926.), njegov bivši profesor na Zagrebačkom sveučilištu, postavili su 1912. godine teoriju prema kojoj je crvenica nastala trošenjem vapnenaca i dolomita, dok je boksit nastao od nje. To su temeljili na Tućanovim mineraloškim i kemijskim analizama dalmatinskih i bosansko-hercegovačkih boksita, koje su pokazale da su kemijski slični u kiselini netopljivom ostatku krških karbonatnih stijena. Teoriju su većinom prihvatili hrvatski, a poslije i jugoslavenski znanstvenici, ali je danas dovedena u sumnju zbog najmanje tri konkurentne teorije. U radu se razmatra sadržaj i povijest Tućanove teorije, a usto se govori o povijesti iskorištavanja boksita i industrije aluminija u Hrvatskoj i Jugoslaviji.
Članak predstavlja hrvatski prijevod IUPAC-ova dokumenta Brief Guide to the Nomenclature of Organic Chemistry, koji pruža kratak pregled najvažnijih pravila nomenklature organske kemije prema preporukama IUPAC-a iz 2013. U članku su sadržane nadopune i korekcije hrvatskih izdanja IUPAC Nomenklatura organskih spojeva, preporuke SKTH-a (danas HDKI) iz 1985. i 1988., i Vodič kroz IUPAC-ovu nomenklaturu organskih spojeva, preporuke HKD-a i HDKI-a iz 2001., koja su prijevod odgovarajućih izdanja IUPAC-a iz 1979. i 1993. Svrha ovog prijevoda jest usklađivanje hrvatske nomenklature organske kemije s važećim preporukama IUPAC-a iz 2013.
Virusi (lat. virus – otrov) predstavljaju iznimno raznoliku skupinu bioloških entiteta s brojnom morfološkom i funkcionalnom raznolikošću. Nalaze se u gotovo svim ekosustavima na Zemlji – vodama tekućicama i stajačicama (jezerima, morima, rijekama), ispod površine Zemlje, u bilo kojoj vrsti tla, u pustinjama i u svemu što nas okružuje. Virusi predstavljaju jednu od najuspješnijih vrsta parazita na svijetu i izolirani su iz predstavnika svih poznatih skupina organizama od najmanje jednostanične bakterije do najvećeg sisavca. Dana 11. ožujka 2020. godine Svjetska zdravstvena organizacija proglasila je globalnu pandemiju bolesti uzrokovanu korona virusom (COVID-19) otkrivenim u prosincu 2019. u Wuhanu, Kina. COVID-19 treća je zoonotska epidemija 21. stoljeća. Na početku pandemije nije bilo dostupnog cjepiva ili specifičnih terapeutskih lijekova, a koristili su se “prenamijenjeni” lijekovi, koji su se prethodno rabili za liječenje sličnih virusnih oboljenja. Štoviše, tijekom pandemije COVID-19 porasla je upotreba lijekova poput antibiotika, analgetika, anti-karcinogenih lijekova, antidepresiva, antipiretika, antivirusnih lijekova itd. Kao rezultat pandemije i povećane upotrebe lijekova, zabilježene su povišene koncentracije farmaceutskih rezidua, posebice u otpadnim vodama koje se klasificiraju kao onečišćivala. Trenutačno postojeći sustavi odnosno postrojenja za pročišćavanje otpadnih voda nisu u mogućnosti u potpunosti ukloniti farmaceutske rezidue, uključujući mikrobiološke kontaminante, patogene i viruse. Sustavi za uklanjanje farmaceutika dijele se na fizikalne, kemijske i biološke procese obrade otpadnih voda. Da bi sustavi bili učinkoviti, potrebna je njihova nadogradnja. U literaturi postoji niz prijedloga za nadogradnju sustava za obradu otpadnih voda, međutim, niti jedan od naprednih procesa ne rješava stopostotno uklanjanje svih onečišćivala.
Hypolipidemic agents represent an important class of drugs used in the treatment of hyperlipoproteinemia. Statins are reversible, competitive inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, ezetimibe selectively inhibits intestinal and biliary absorption of cholesterol by blocking Niemann-Pick C1-like protein, while fibrates act as agonists of the peroxisome proliferator-activated receptor alpha nuclear receptor. Drug solubility is a critical parameter influencing bioavailability and therapeutic efficacy, particularly in orally administered formulations. This is of special importance for hypolipidemic agents such as simvastatin, atorvastatin, and fenofibrate, which are widely used in the treatment of hyperlipidemia. In this study, an HPLC method was developed and validated for determining the solubility of these three drugs. Method validation confirmed specificity, linearity, and precision. Solubility was assessed in four media of varying pH values (1.2, 4.5, 6.8, and 7.4) at 37 °C, employing a Zorbax Eclipse C18 column (5 µm, 150 × 4.6 mm), with a mobile phase consisting of acetonitrile and 0.1 % phosphoric acid, and UV detection at 242 nm. The results enabled solubility characterisation based on the dose number, which, in combination with literature-derived logP (partition coefficient) values, facilitated the Biopharmaceutics Classification System (BCS) categorisation of the investigated drugs. These findings provide valuable guidance for the design of new pharmaceutical formulations containing simvastatin, atorvastatin, or fenofibrate, as well as the optimisation of existing ones.
Cd, Cr, and Pb concentrations were analysed in 18 bottled drinking water samples from the Bosnia and Herzegovina (B&H) market, classified as natural spring water or still natural mineral water. Metal concentrations were determined using atomic absorption spectrometry with electrothermal atomisation in a graphite furnace. Cr was quantified in two samples, Pb in four samples, while Cd concentrations were below the limit of detection in all samples. All concentrations were below national regulatory limits. Health risks associated with Cr and Pb exposure through bottled water consumption were assessed for adolescents, adults, and pregnant women by calculating the hazard quotient (HQ), hazard index (HI), carcinogenic risk (CR), and total carcinogenic risk (TCR). Some exposure scenarios exceeded HQ and HI thresholds, suggesting potential non-carcinogenic effects, primarily due to Pb exposure. CR and TCR values across all exposure scenarios were below established thresholds, indicating generally acceptable or negligible carcinogenic risk. Given the limited sample set, the data on Cd, Cr, and Pb content, along with the health risk assessment, should be regarded as preliminary, serving as a starting point to guide future research. Considering the health implications of heavy metal exposure, continuous water-quality monitoring and a more comprehensive health risk assessment, including additional heavy metals and a larger sample set, are essential, as regulatory compliance does not necessarily imply the absence of health risks.
Istraživanje je provedeno s ciljem utvrđivanja kvalitete i oksidacijske stabilnosti hladno prešanog ulja konoplje. U okviru ovog rada, na baznom uzorku hladno prešanog ulja konoplje ispitivani su sljedeći parametri: sastav masnih kiselina, nutritivni indeksi, sadržaj slobodnih masnih kiselina, peroksidni broj, sadržaj vode i netopljivih ostataka. Provedenim istraživanjem utvrđeno je da u ispitivanom uzorku ulja prevladavaju nezasićene masne kiseline (UFA) (89,91 %) u odnosu na zasićene masne kiseline (SFA) (10,07 %). Vrijednost omjera PUFA/SFA u ulju konoplje iznosila je 7,88, što ukazuje na to da se ulje konoplje može označiti kao proizvod visoke nutritivne vrijednosti. Vrijednost omjera ω-6/ω-3 u ispitivanom uzorku ulja konoplje iznosila je 2,85. Vrijednost AI indeksa u ispitivanom uzorku ulja konoplje iznosila je 0,07, vrijednost TI iznosila je 0,10 i vrijednost HH u ulju konoplje iznosila je 13,94. U ovom radu praćen je i utjecaj temperature od 63 °C na oksidacijsku stabilnost, odnosno na intenzitet primarne oksidacije, primjenom Schaal-Oven testa tijekom razdoblja do 96 h. Osim toga, ispitivan je utjecaj dodatka prirodnih antioksidansa eteričnih ulja mente, lavande, origana i bosiljka (0,20 %), kao i sintetskih antioksidansa butilhidroksianizola, butilhidroksitoluola i propil galata (0,01 %) na oksidacijsku stabilnost hladno prešanog ulja konoplje. Vrijednost peroksidnog broja ulja konoplje, bez dodatka i s dodatkom antioksidansa, rasla je s produljenjem vremena zagrijavanja. Nakon 96 h tretiranja povišenom temperaturom uzorci s dodatkom sintetskih i prirodnih antioksidansa imali su manje vrijednosti peroksidnog broja u odnosu na uzorak bez dodataka, što ukazuje na to da su u manjoj ili većoj mjeri zaštitili ulje konoplje od oksidacijskog kvarenja ovisno o vrsti antioksidansa. Iz skupine sintetskih, propil galat je najbolje očuvao ulje konoplje od kvarenja (45,52 mmol O₂ kg⁻¹). S druge strane, iz skupine prirodnih antioksidansa, najbolje antioksidativno djelovanje pokazalo je eterično ulje origana (97,26 mmol O₂ kg⁻¹).
This study presents the development of an automated system for the management and monitoring of water quality using the Python programming language, focusing on optimising chlorine dosage in water disinfection processes. The proposed module, named DriniChlor, utilises sensors to measure key water parameters such as temperature, dissolved oxygen, and turbidity. The collected data were analysed in real-time to determine the optimal chlorine dosage, ensuring maximum safety and efficiency. The integration of such technologies offers an innovative approach that not only improves water quality but also reduces operational costs and environmental impact. Results indicate that the system is effective in enhancing water treatment processes and is suitable for application in various treatment plants. This development represents a significant step toward the use of automated technologies for the sustainable management of water resources.
The aim of this study was to determine the existence of differences in the quality of cold-pressed sesame oils from different producers in Bosnia and Herzegovina. By comparing samples of sesame oil, one of which was produced in the laboratory and the other four purchased on the market, the research aimed to identify the highest quality oil most suitable for consumption. The analyses included fatty acid profiles, free fatty acid content, saponification and peroxide values, moisture content, insoluble impurities, chlorophyll, carotenoids, and total phenolic content, along with measurements of colour parameters. The results showed higher levels of unsaturated fatty acids (UFA) compared to saturated fatty acids (SFA), with the highest UFA content (84.94 %) recorded in sample US1, which also had the best nutritional profile (the highest content of monounsaturated fattyacids-MUFA, the lowest atherogenic index-AI and thrombogenic index-TI, and the highest hypocholesterolemic/hypercholesterolemic index-HH). Linoleic acid was the most abundant polyunsaturated fatty acid (PUFA). Sample US1, freshly pressed, had the lowest free fatty acid content (0.41 %) and peroxide value (0.00 mmol O2 kg(-1)), indicating superior quality. The values of the saponification number ranged from 182.60 to 188.43 mg KOH g(-1), with the US5 sample having the lowest moisture content (0.02 %), while samples US1 and US2 had the least insoluble impurities. The content of chlorophyll and carotenoids varied, with the US2 sample having the highestcarotenoid content (25.58 mgkg(-1)), and the US5 sample the highesttotal phenolic content (1962.32 mg kg(-1) GAE). Principal component analysis (PCA) highlighted sample US1 as optimal due to its favourable fatty acid profile and colour. The results showed that sample US1 had the highest lightness (L*) and yellow colour intensity (b*), while samples US2 and US5 were darker with lower yellow colour index (YI) values, indicating variations in colour stability.
Biocatalysis is gaining increasing importance as a scientific discipline in the field of asymmetric synthesis of pharmaceutical compounds and specialised chemicals, and has shown significant progress in industrial applications in recent years. For biocatalytic processes to be successfully developed, optimised, and integrated into industrial synthesis, they must be examined from multiple perspectives, e.g., from protein engineering for the design of new enzymes, through organic chemistry in planning synthetic pathways, to reaction engineering for process design and optimisation. This paper focuses specifically on halohydrin dehalogenases (HHDHs), a group of enzymes with great potential that, despite their promise, remain insufficiently explored. HHDHs catalyse the ring-opening reactions of epoxides in the presence of various nucleophiles, leading to the formation of new C-C, C-O, C-S, and C-N bonds, and the synthesis of beta-substituted alcohols. This property makes HHDHs valuable enzymes for the production of important compounds such as drugs, agrochemicals, and fine chemicals. Despite the justified significant interest shown by the scientific and industrial community toward this group of enzymes, which has consequently led to the implementation of HHDH-catalysed reactions in pharmaceutical production, the kinetic characteristics of this group remain largely unknown. Challenges such as various enzyme inhibitions and decreased operational stability under synthetically relevant conditions are still poorly explored. Since addressing these issues through detailed kinetic studies is crucial for expanding the practical applications of HHDH in synthetic processes, this review paper is conceived as a discussion of recent and relevant research on the kinetic characteristics and limitations of this group of enzymes, collected over several years of practical experience and laboratory work with HheC from Agrobacterium radiobacter and its variants, primarily in the synthesis of fluorinated beta-azido alcohols and beta-hydroxy nitriles.
Additive manufacturing, commonly known as 3D printing, is increasingly being used in chemical engineering to fabricate complex components, optimise industrial processes, and develop new materials. While polymer technologies dominated the early stages of industrial application of additive manufacturing, the growing need for materials with high mechanical strength, chemical resistance, and thermal stability has driven development toward metals, ceramics, and composites. This paper provides an overview of key additive manufacturing processes that enable the use of metal and other materials. It also analyses potential applications in chemical engineering, such as the fabrication of reactors, heat exchangers, catalytic supports, and porous membranes. Particular emphasis is placed on the challenges associated with post-processing and the optimisation of manufacturing parameters to achieve the chemical and mechanical properties necessary for laboratory and industrial applications. The development of additive manufacturing with metal and other materials in this area enables faster, more environmentally friendly, and more functionally advanced manufacturing of industrial and laboratory components, opening up new possibilities for engineering and scientific applications.
To evaluate the impact of meteorological conditions on air quality in the vicinity of the Prudinec/Jaku & scaron;evec landfill in Zagreb, daily concentrations of particulate matter (PM10), hydrogen sulphide (H2S), and ammonia (NH3), monitored over a five-year period (2020-2024), were analysed. Under meteorological conditions in which the mixing layer height (MLH) falls below 1,000 m, an inversion layer forms above the city, suppressing vertical air mixing and leading to atmospheric stability and pollutant accumulation. The results showed that nearly 80 % of stable conditions occurred during the cold season (autumn and winter) of the study period. During these stable episodes, 88 % of all daily PM10 limit exceedances and 70 % of H2S exceedanceswere recorded. Comparable PM10concentrationswere measured atseveral monitoringstationsacrossZagreb, suggesting that the landfill is not a dominant source of PM10 pollution. The seasonal pattern of H2S concentrations at the landfill showed higher levels during winter, opposite to the pattern observed at the nearby Central Wastewater Treatment Plant of the City of Zagreb (CUPOVZ). This behaviour indicates the landfill is most likely a specific local source of H2S. NH3 concentrations were higher during the warm season both near the landfill and at CUPOVZ, suggestingdifferentdominantemission sources. The differingseasonal patterns of PM10, H2S, and NH3 indicate thatthese pollutants originate from distinct dominant emission sources. In the south-eastern part of Zagreb, agriculture and livestock farming are likely among the main contributors to NH3 emissions.
Detoxification of toxic species has become an increasingly important topic worldwide because these pollutants contribute significantly to environmental contamination. Industrialisation and population growth have led to pollution containing mixtures of metals and organic compounds, such as chromate, copper, arsenate, and aromatic compounds commonly found in wood-preserving pesticides. Such contamination can be controlled using macromolecules synthesised through various chemical reactions. In supramolecular chemistry, calix[4]arene macromolecules are particularly widespread because of their versatility in numerous applications. In this review, we summarise the synthesis reactions of macrocyclic compounds and their usefulness in extracting toxic metals through different supramolecular cavities. Most of the study was conducted using aqueous solutions of the molecules. The results demonstrated that macromolecules can effectively remove hazardous materials from the environment. These molecules are expected to play an even greater role in future toxin removal, as they can serve as building blocks for the design of novel compounds.
The conversion of vegetable oils into high-value epoxidised derivatives has gained increasing relevance as industries seek renewable and safer alternatives to petroleum-based materials; however, conventional acid-catalysed systems remain limited by corrosiveness, difficult separation, and environmental concerns. Addressing these challenges, this study evaluates the epoxidation of palm cooking oil via an in situ peracid mechanism using sodium hydroxide (NaOH) as a base catalyst and hydrochloric acid (HCl) as an acid catalyst, with the aim of elucidating their comparative performance and reaction behaviour. The reactions were conducted using formic acid and hydrogen peroxide under controlled conditions, with catalyst loadings varied to assess their influence on oxirane formation. Samples were collected at 10-minute intervals for titrimetric quantification of oxirane oxygen. Kinetic modelling was applied to determine rate constants and to interpret the mechanistic differences between the catalytic systems. NaOH achieved the highest relative conversion to oxirane (RCO), reaching 59.96 % at 40 min, compared with 50.12 % for HCl, while FTIR analysis confirmed the successful formation of epoxide functionalities in both pathways. These findings highlight the potential of base-catalysed epoxidation as a greener and operationally safer route for producing epoxidised vegetable oils suitable for downstream polymer applications.
In this work, trimmer lines were mechanically recycled using a laboratory-scale twin-screw extruder. The influence of mechanical recycling on the material's structure, thermal properties, and thermal stability was evaluated. Fourier transform infrared spectroscopy (FT-IR) confirmed that the trimmer lines were composed of poly(e-caprolactam), or polyamide 6 (PA6). Mechanical recycling did not affect the structure of PA6. The thermal properties of the trimmer lines were analysed by differential scanning calorimetry (DSC). The results indicated that extrusion influenced chain packing and rearrangement, leading to crystallisation of PA6 from the melt at a higher temperature. The effect of mechanical recycling on the thermal stability of the trimmer lines was investigated using thermogravimetric analysis (TG). Based on the characteristic parameter (T-onset and T-max) values, it can be concluded that mechanical recycling did not deteriorate the thermal stability of PA6. Mechanical recycling can be a potential solution for recycling of used trimmer lines.
