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Nanofabrication and characterisation of magnetic Fe3O4 nanostructures for potential environmental and biomedical applications
No full textMagnetic iron oxide nanomaterials, which enable a multitude of uses, are given special focus in the fields of biomedicine and environmental protection. The detection, sorption, and/or degradation of inorganic (lead, chromium, arsenic, and cadmium), organic (dyes, pharmaceuticals, pesticides, phenols, and benzene), and biological (viruses and bacteria) pollutants can all be effectively accomplished with the use of magnetic nanoparticles. Magnetic iron oxide nanomaterials are in particular focus for use as hyperthermia media in cancer treatment and as magnetic resonance imaging (MRI) contrast agents. The possibility of magnetic separation of such materials, due to their essential properties under the influence of an external magnetic field, reduces production costs and also prevents the production and accumulation of toxic waste. Among the many metal oxide nanomaterials, magnetite (Fe3O4) and maghemite (γ-Fe2O3) are currently the only two magnetic materials approved by the US Food and Drug Administration (FDA) for human use as iron deficiency therapeutics and as contrast agents for MRI. Here, we synthesized nanoparticles of magnetite (Fe3O4) by the method of reduction-precipitation and characterized. Additionally, potential binding of brilliant green dye on Fe3O4 and construction of innovative magnetic composite was investigated. The physicochemical features were explored using X-ray diffraction (XRD),
Fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM). XRD analysis confirms formation of the crystal phase of magnetite. The presence of magnetite nanoparticles is shown by typical groups for the peaks of iron compounds at a lower wavelength (≤ 700 cm-1) that are characteristic of the Fe-O bond. Morphological analyzes with FESEM showed that magnetite is a composite of nanospheres and nanorods that provide a large surface area. Dye binding study was performed using UV visible and FTIR spectrometer
Postupci pripreme kvarcnog peska i njihov uticaj na životnu sredinu
No full textNečistoće iz rovnog kvarcnog pesku uklanjaju se odgovarajućim postupcima pripreme kao što su: prosejavanje, klasiranje, atricijsko čišćenje, gravitacijska, magnetska, elektrostatička i flotacijska koncentracija i odvodnjavanje. Koji će postupak biti izabran zavisi od sadržaja i vrste nečistoća, kao i od načina njihovog pojavljivanja. Postupci pripreme kvarcnog peska se mogu značajno poboljšati pravilnim pristupom i vođenjem samog postupka čime se daje veliki doprinos zaštiti životne sredine. Preduslovi za postizanje ovog cilja baziraju se na: smanjenju potrošnje vode i koncipiranju postupka tako da se upotrebljena voda reciklira i dalje koristi kao povratna voda, da se otpadna voda iz flotacijske koncentracije prečisti pre nego što se ispusti u okolinu i da se izvrši optimizacija potrošnje električne energije u svim fazama procesa
Recycling of glass waste into foam glass: A review
No full textWaste glass can be transformed into a foam by addition of suitable substance (foaming agent) which generated gaseous products by decomposition or reaction at temperatures above its softening temperature (corresponding to a viscosity of 106.6 Pas). This paper provides a concise overview of the latest research in the field of improving the glass foam production process. Some of the possibilities for reducing the environmental impact of glass foam production are also presented. Some of the new production techniques, new foaming agents as well as the possibility of including other solid waste in the composition of glass foams are presented. At the end, the glass foam produced in the Laboratory for glass and ceramics, Institute for Technology of Nuclear and other Mineral Raw Materials, was shown
Sequencing batch reactor systems for the treatment of wastewater
No full textReleasing untreated or inadequately treated effluents into recipients (rivers, lakes, and oceans) can endanger aquatic
ecosystems and drinking water sources. In order to eliminate harmful pollutants, wastewater must be treated, especially
industrial wastewater enriched with nutrients. Phosphorus contamination can occur through a variety of different routes,
such as wastewater treatment plant discharge (municipal and industrial), agricultural fertilizer losses from erosion,
drainage, etc. The establishment of suitable wastewater treatment techniques is essential. The subject of this paper is the
biological removal of nutrients (phosphorus) from wastewater, using unconventional methods of wastewater treatment -
sequencing batch reactors (SBR) systems. Their modifications and the advantages such processes offer, compared to the
standard activated sludge (AS) treatment that is the most often used, will be presented. Enhanced biological phosphorus
removal methods that employ various microorganisms have been observed from the perspective of the method's
effectiveness. Of all applied treatments for phosphorus removal, the most effective and the most often used was the
accumulation of polyphosphates in the biomass itself. The purpose of this paper is to offer a brief review and theoretical
essentials of environmental engineering techniques that can be applied in real industrial wastewater treatment plants
Directions and challenges of the circular economy: Movement of municipal solid waste in city of Paraćin
No full textThis paper aims to show a short economic analysis of the profitability of recycling management on the territory of Paraćin
municipality. Consumption habits of modern society and socioeconomic conditions have made it difficult to implement
sustainable waste management strategies. Industry, economics, sociocultural and political activities must work together
to solve the multifaceted problem of waste management. The municipality of Paraćin is located in the central part of the
Republic of Serbia, Pomoravlje region. Annually, this municipality generates about 18,000 t of waste, while the mass of
recyclable waste is approximately 7,000 t. This small industrial city have been constantly facing with an insufficient
number of available bins and containers for the disposal of Municipal Solid Waste (MSW). Moreover, this city has been
challenging by an increasing number of illegal dumps along the roads. Together with surrounding municipalities, the local
government was planning to create Regional Recycling Center and Landfill with all necessary operations. Sorting of the
waste at the source of its origin, and adequately disposing it in containers intended for different types of waste, would
provide precisely insight into the movement of recyclable waste. In addition, with these actions by the local community,
it could produce a habit among citizens for proper deposition and disposal of household waste and reduce the negative
impact on the environment. This article shows the categories of waste and their percentages, as well as the resulting
amount of recyclable waste, which should be a starting point for establishing a recycling center with surrounding
municipalities
The effect of gamma irradiation on the synthesis, microbiological sterility, and improvement of properties of PMMA-Al2O3 composite used in dental prosthesis manufacturing
No full textPolymethyl methacrylate (PMMA) is a polymer material widely used in dental applications due to its excellent biocompatibility, stable physicochemical properties, easy manipulation, and low cost. The combination of biocompatible polymers and ceramics has great potential for the development of materials in the dental industry with improved mechanical properties. The addition of Al2O3 nanoparticles to PMMA can significantly improve its compressive and flexural strengths and wear resistance. Since this material is used in dental applications, it requires a high degree of product sterility. This can easily be achieved with gamma radiation treatment. Gamma radiation not only ensures the sterility of the product but can also affects changes in numerous material properties.The aim of this paper is to determine the influence of different doses of gamma radiation on the microbio-logical purity and changes in the mechanical and thermal properties of the PMMA/Al2O3 composite as well as the microstructural and color changes. It was found that the dose of radiation of 25 kGy is sufficient for complete sterilization of the product. This radiation dose improves the mechanical properties of the material and thermal stability. On the other hand, the dose of 25 kGy does not affect the morphology of the exposed sample and has small effect on the color change
Influence of the Type and the Amount of Surfactant in Phillipsite on Adsorption of Diclofenac Sodium
No full textModified phillipsite samples were prepared with two different amounts (monolayer and bilayer coverage) of surfactants octadecyldimethylbenzylammonium chloride (O) and dodecylamine (D). Composites were characterized by Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR), thermal analysis and determination of zeta potential, and subsequently tested for removal of diclofenac sodium (DCF). Drug adsorption experiments were performed under different initial DCF concentrations and different contact times. In order to investigate the influence of the chemical structure of surfactants used for modification of phillipsite on the preparation and properties of composites and DCF adsorption, experimental data were compared with previously published results on DCF adsorption by composites containing phillipsite and the same amounts of surfactants cetylpyridinium chloride (C) and Arquad((R))2HT-75 (A). DCF adsorption isotherms for O and D composites showed a better fit with the Langmuir model with maximum adsorption capacities between 12.3 and 38.4 mg/g and are similar to those for C and A composites, while kinetics run followed a pseudo-second-order model. Composites containing either benzyl or pyridine functional groups showed higher adsorption of DCF, implying that surfactant structure has a significant impact on drug adsorption. Drug adsorption onto O, D, C and A composites was also confirmed by FTIR-ATR spectroscopy and zeta potential measurements
Ability of Deep Eutectic Solvent Modified Oat Straw for Cu(II), Zn(II), and Se(IV) Ions Removal
No full textIn the proposed study, agro-waste biomass oat straw (OS) was considered a potential adsorbent for Cu(II), Zn(II), and Se(IV) removal from aqueous solutions. In order to obtain material with better adsorption abilities, the OS was modified by a deep eutectic solvent (DES). Structural changes caused by the applied modification route were considered by pHpzc, SEM, FTIR, and DSC/TG analysis. These methods discovered that lignocellulosic biomass degradation and material functionalization were achieved by DES treatment. Preliminary adsorption tests showed an over fourfold increase in capacity upon modification. The kinetic parameters implied that adsorption on modified material followed the pseudo-second-order kinetic model. Different isotherm models were applied to experimental data, while the Sips isotherm model best describes the equilibrium of the adsorption process on the tested modified material. According to this isotherm model, the maximum achieved adsorption capacities of Cu(II), Zn(II), and Se(IV) were 48.21, 55.06, and 87.85 mg/g, respectively. The summarized experimental results revealed that the adsorption process of selected cations on modified OS was predominantly caused by chemisorption, while, in addition to chemisorption, electrostatic forces were also responsible for Se(IV) removal. Desorption test showed that the prepared material could be reused for at least 3 cycles, with minimal efficiency loss. Briefly, this study reinforces that DES-modified agro-waste biomass could be used as a promising adsorbent for cations and oxyanions from wastewater
Recycling of flat glass for glass foam production
No full textOpen loop glass recycling is a process where the glass is recycled into a new product. Glass recycling helps reduce landfill waste. Glass takes up significant space in landfills and does not decompose. In many countries, landfills are filling up faster than we can create new ones. Recycling glass reduces the volume of waste, and increases the lifespan of landfills. One of examples of open loop recycling of glass is glass foam produciton. Glass foam production is a process that involves the creation of a light-weight glass material with a foam-like consistency. This type of glass is made by mixing a foaming agent with glass powder and heating to temperatures where decomposition of a foaming agent and sintering of glass happens. This results in the creation of a material that is light, strong, and has thermally-insulating properties. Milled flat glass was mixed with sugar beet factory lime, a CaCO3 – rich waste wich has role of a foaming agent, in order to enter 5% CaCO3 in mixture and pressed at 20 MPa in hydraulic press. Raw pellets were sintered at 800 °C for 30 min. In obtained glass foam phase composition, pore size distribution, compressive strength and thermal conducitivity were determined. Glass foam is emerging as a flexible, cost-effective, and sustainable material that can be utilized in numerous applications to promote sustainable development. Its features such as high insulation capacity, lightweight, and durability make it an ideal material for a wide range of industries
Mg/Fe-modified hydrochar with promoted adsorption performances
No full textThis study examined Mg/Fe-pyro-hydrochar produced from grape pomace as potential sorbent for Cu2+
ions. Obtained results show that the Mg/Fe-modification increases the adsorption capacity for five times.
To evaluate the effectiveness of produced sorbent, Langmuir, Freundlich, Sips and Redlich-Peterson
isotherm models were applied to batch adsorption results. According to applied models Cu2+ adsorption at
equilibrium fitted the Sips isotherm model, with a maximum achieved capacity of 75 mg/g. Spectroscopic
analysis reveal that oxygenated active sites and aromatic groups on pyro-hydrochar surface participate in
Cu2+ions binding. In general, preliminary findings from this paper offers perspective to effective utilization
of waste biomass as an efficient adsorbents for Cu2+ ions removal