ritnms
Not a member yet
1551 research outputs found
Sort by
Primena ISO 59020: okvir za ocenu cirkularnosti u sektoru upravljanja otpadom
No full textPrelazak na cirkularnu ekonomiju sve više se prepoznaje kao ključan za održivo upravljanje
resursima. Međutim, trenutne direktive EU u ovoj oblasti ostaju uglavnom fokusirane na stope
recikliranja, zanemarujući sistemske neefikasnosti i važnost prevencije i ponovne upotrebe. Ovaj rad
kritički proučava potencijal adaptacije postojećeg okvira cirkularne ekonomije na zahteve standarda
ISO 59020 za merenje i procenu cirkularnih performansi, i daje okvir praćenja cirkularnosti pri
upravljanju otpadom.
ISO 59020 uvodi obavezu merenja cirkularne ekonomije kroz jasno definisane granice
zasnovane na životnom ciklusu proizvoda. Standard zahteva transparentno praćenje i kvantitativno
izveštavanje tokova resursa, uključujući procenat ponovno korišćenih i recikliranih materijala. Sve
metrike se izračunavaju korišćenjem standardizovanih formula, omogućavajući objektivnu i
uporedivu ocenu cirkularnih performansi.
Posebnu vrednost okvir pruža kroz mogućnost proširenja analize opcionim metrikama za
energetske i vodene cikluse. Udeo obnovljivih izvora energije i stepen ponovne upotrebe vode pružaju
sveobuhvatniji uvid u ukupne performanse sistema i povezuju cilju cirkularne ekonomije sa
klimatskom politikom i efikasnim upravljanjem resursima. Komparativnom analizom rad pokazuje
da ISO 59020 ima značajne razlike u oceni cirkularne ekonomije u odnosu na konvencionalne metrike
EU, pre svega zahvaljujući uključivanju indirektnih indikatora za prevenciju i ponovnu upotrebu.
Zaključuje se da bi se uključivanjem principa standarda ISO 59020 u direktive EU eliminisale
osetljive tačke u merenju performansi cirkularne ekonomije, podstakle sistemske intervencije i
olakšalo odvajanje apsolutne potrošnje resursa od ekonomskog rasta. Ovaj pristup omogućio bi
stavljanje u fokus redizajn proizvoda, produženje veka trajanja robe i stvaranje inovativnih poslovnih
modela zasnovanih na uslugama umesto na vlasništvu
Evaluating the role of hydrochars as sustainable adsorbents for pollutant removal
No full textHydrothermal carbonization (HTC) produces biomass-derived hydrochar, a promising
adsorbent for environmental remediation. Lignocellulosic biomass serves as the primary
feedstock, and adsorption performance depends on biomass structure and HTC conditions,
especially carbonization temperature. This review highlights hydrochar’s adsorption
capabilities and modification strategies, including physical treatments to increase surface
area and chemical treatments to introduce oxygen-containing functional groups. Heteroatom
doping and acid-base modifications notably enhance the removal of metal ions and dyes.
Hydrothermal treatment is key to producing tailored hydrochars for specific applications.
Future research should focus on combining physico-chemical modifications, deepening
understanding of adsorption mechanisms, and broadening hydrochar applications. These
efforts will advance the use of biomass hydrochars as effective, sustainable adsorbents for
pollution control while addressing waste management
Iron distribution in borehole RB-6/P 5D and the importance of integrated research in water supply
No full textOne key challenge in water supply systems is the aging of groundwater wells, due to clogging
and corrosion, driven by complex site conditions which require a multidisciplinary approach. This paper
focuses on determing the content of iron in lithostratigraphic units, and its distribution along the
lithological profile, particularly in aquifre, as a potential source of iron and the causative agent for the
clogging on the well screen. This paper also indicates on the activities on the definition of mechanism
of transport of iron from primary lithological medium and the processes by which iron minerals are
deposited onto the filter structure
Preparation, characterization, adsorption, and antibacterial assessments of silane-functionalized zeolites
No full textIn this work, the preparation and comparative analysis of two adsorbents based on silane-modified
natural and synthetic zeolite for adsorbing silver ions from aqueous solutions and the assessment of the
possibility of their application as antibacterial agents against two strains of bacteria was conducted. (3-
Aminopropyl) triethoxysilane (APTES) was employed for modification, the presence of which in the ob-
tained samples was verified by thermal and Brunauer-Emmett-Teller (BET) analysis, as well as infrared
spectroscopy. Kinetic analysis indicated that the silver adsorption process followed the Lagergren pseu-
do-second-order model, while the data fit best with the Freundlich isotherm, indicating multilayer adsorp-
tion on the heterogeneous surface. The maximum adsorption capacities for silver ions were measured at
89.49 mg/g for natural and 61.19 mg/g for synthetic beta zeolite. The higher silver binding capacity was
observed in natural zeolite, which led to the conclusion that the key role in silver binding was played by
exchangeable cations in the structure of this starting material and that the dominant mechanism was ion
exchange. Both materials exhibited good antibacterial properties against Gram-negative Escherichia coli
and the Gram-positive Staphylococcus aureus. These findings demonstrated the potential of APTES-
modified zeolites as efficient adsorbents for silver ion removal and as antibacterial agents, paving the way
for applications in water purification and antimicrobial technologies
Phase transformations kinetics in barium titanate synthesis by mechanochemical processing
No full textThis article presents the research results on a dry mechanochemical synthesis of barium titanate at a low temperature in which the reaction model and kinetics were determined during the activation of a powder mixture of titanium dioxide and barium oxide. The solid-state reaction achieved high degree of conversion (0.99). Successive analyses were conducted throughout the reaction, revealing the presence of both the starting powders and newly formed intermediate compounds. Phase transformations were monitored via X-ray diffraction, allowing the dynamics of the synthesis to be characterized. It was established that, for the given system, 440 min of mechanical activation in a high-energy vibration mill was required to complete the neutralization reaction and produce barium titanate. The reaction mixture composition was tracked by sampling at five intervals, confirming the presence of intermediate compounds and mapping the reaction pathway from the initial barium and titanium oxides to the final BaTiO3 product
The Influence of the Number of Pistons on the Pressure Pulsations and Vibration of the Axial Piston Pump Housing
No full textThe number of pistons in axial piston pumps plays a significant role in determining the performance characteristics of the pump. While increasing the number of pistons can improve capacity, stability, and flow, it also requires careful consideration of design complexity and operational efficiency. The optimal number of pistons will depend on the specific requirements of the application and the trade-offs that can be effectively managed. With multiple pistons operating together, the resulting pressure profile is smoother, reducing fluctuations that can affect system performance. This is crucial in applications where stable pressure is necessary, as it can improve the reliability and efficiency of the hydraulic system. Each piston contributes to the total displacement, resulting in an increase in flow rate. However, this must be balanced against the potential for increased internal friction and the complexity that can arise from multiple moving parts. The effect of the number of pistons on vibration and operating balance is another important factor. A well-balanced multi-piston pump can minimize pulsations and vibrations, resulting in smoother operation. This is essential for applications where excessive vibrations can lead to wear or system instability. To perform fast Fourier transforms (FFTs) on the measured signals, each signal was sampled at 4096 points per revolution (cycle). With five measured signals (four pressures and one vibration), this resulted in a total of (4 + 1) × 4096 = 20,480 data points per revolution and 204,800 data points for 10 consecutive revolutions
Beta zeolit funkcionalizovan aminosilanima: Novi pristup adsorpciji teških metala iz industrijskih otpadnih voda
No full textOvaj rad istražuje adsorpcionu efikasnost modifikovanog sintetskog β-zeolita za uklanjanje jona teških metala (Cu2+ i Pb2+) iz vodenih rastvora. U cilju poboljšanja njegovih adsorpcionih svojstava ispitivana je modifikacija β-zeolita sa (3-aminopropil) trietoksisilanom. Dobijeni eksperimentalni rezultati ukazuju na povećanje kapaciteta vezivanja Cu2+ i Pb2+ jona sa 19,1 mg/g i 23,4 mg/g na 43,4 mg/g i 65,6 mg/g nakon modifikacije β-zeolita , respektivno. Adsorpcija jona metala prati kinetički model pseudo-drugog reda, sa visokom korelacijom (R² > 0,99), što ukazuje na hemisorpciju kao mehanizam vezivanja
Chemical stability and fertilizer efficiency of bioglass and biochar on rose plantings biochar on rose plantings
No full textDeclines in soil quality and low efficiencies of applied fertilizers has limited agricultural
productivity worldwide, inducing necessity for sustainable orientated soil amendments. Glass-matrix-based
fertilizers are promising “green technologies” thanks to the controlled release of nutrients due to their
engineered chemical durability in a wide solubility range. Beside mentioned inorganic soil support, biochar was
found to be an effective organic soil amendment that enhances nutrient/water retention as well as microbial
activity, making it a promising tool for sustainable agriculture. In this paper, we have tested two possible “green
soil amendments”: polyphosphate glass (PG) and plum stone biochar (PS) in a 2% citric acid solution, as well as
their use as fertilizers on two-year-old rose plantings. The results have shown quick dissolution of PG: nearly
90% for 48 h at 20 °C that steady increase up to 97% at the 480 h; under the same operating parameters, 7.6%
of PS was dissolved increasing to 8% at final investigated time. Higher temperatures resulted in higher
dissolution rate. The data obtained within the scope of this study indicates that tested fertilizers have a positive
effect on rose plant growth, not only promoting bud formation but also extending the flowering period of roses
Exploring the adsorption potential of hydrochars: a mini review
No full textThe hydrothermal carbonization (HTC) process provides biomass-derived hydrochar, a material that exhibits great potential as adsorbents for environmental pollution remediation. For the preparation of these materials a different feedstock including corn cob, grape pomace, Miscanthus, Paulownia leaves, and spent mushroom substrate can be utilized. The adsorption performances of hydrochars are significantly influenced by structural characteristics of the biomass, as well as the applied hydrothermal conditions, primarily the carbonization temperature. This overview outlines the performance, modifications, and potential applications of biomass hydrochar. It discusses diverse modifications, physical (to increase surface area) and chemical (to add oxygen-containing functional groups) that can further enhance the adsorptive properties of tested materials. Summarizing previous findings, it can be concluded that heteroatom doping and acid-base treatments significantly facilitate and enhance the removal of metal ions and dyes. Accordingly, the study emphasizes the critical role of hydrothermal treatment as a key process for producing biomass-derived hydrochar that can be tailored for specific adsorption applications.
In general, three main research directions are recommended: integrating physico-chemical modification techniques, gaining a deeper understanding of adsorption mechanisms, and expanding the applications of biomass hydrochar. These directions present promising opportunities for the continued development and application of biomass hydrochar as an effective and sustainable adsorbent for environmental purification while simultaneously solving the problem of waste generation
Recycling and reduction of plastic waste in the European Union and Serbia: The regulatory framework and mechanisms
No full textIn the contemporary context of ecological and economic challenges, the management of plastic waste constitutes a pivotal legal and socio-economic issue of paramount importance for the preservation and protection of the environment and public health. This study examines the legal and economic aspects of plastic-waste management within the European Union, with particular emphasis on identifying deficiencies in the existing legislative framework of the Republic of Serbia. Drawing on comparative practices from EU Member States, especially the implementation of deposit‐refund schemes and eco‐taxes that obligate producers to assume full responsibility for plastic waste, the study proposes legal and economic instruments aimed at reducing plastic waste and incentivizing recycling in Serbia. Statistical data reveal that, in 2022, EU citizens generated an average of 36.1 kg of plastic packaging waste per capita, of which 14.7 kg was recycled. Between 2012 and 2022, per‐capita generation of plastic packaging waste increased by 7.6 kg, while recycled quantities rose by only 4.0 kg. Despite a relatively high recycling rate, this remains insufficient, given the ongoing growth in plastic‐waste generation. The EU’s target is to recycle 55 % of plastic packaging waste by 2030, and certain single‐use plastic products will be banned as of 1 January 2030. In Serbia, 67 355 tonnes of non‑hazardous plastic waste were generated in 2023, of which 56 513 tonnes were successfully recycled. Plastic has been identified as one of priority sectors in the European Commission’s New Circular Economy Action Plan for a Cleaner and More Competitive Europe (COM/2020/98) and its governance is integral to the European Green Deal’s sustainable‑development agenda. Particular attention has been devoted to the issue of plastics through EU Directive 2019/904, commonly known as the Single Use Plastics Directive. This Directive has received partial transposition under Serbia’s Packaging Waste Act; nevertheless, comprehensive alignment with EU standards remains outstanding. The recommendations put forward in this study aim to strengthen the legislative framework, enhance regulatory oversight, and establish economic incentives, thereby achieving further increases in recycling rates and minimizing the harmful impacts of plastic waste