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Enhanced Cu2+ adsorption ability of grape pomace hydrochar upon alkali modification
No full textGrape pomace hydrochar was evaluated as potential adsorbent of Cut from aqueous solution. In order to enhance the adsorption ability, obtained hydrochar was alkali modified using KOH and characterized by Fourier Transform Infrared spectroscopy and Scanning Electron Microscopy. Preliminary tests showed that adsorption capacity of hydrochar increased from 8.0 to 38.2 mg/g after alkali modification. It was found that KOH treatment increased the aromatic and oxygen-containing functional groups on hydrochar surface, which might affect the improvement of the Cu removal. The results suggest that KOH-modified hydrochar could be an effective adsorbent of Cu2+ from wastewaters
The valorization impact and methods for treatment of non ferrous secondary raw materials
No full textProizvodnja obojenih metala iz sekundarnih sirovina daleko je jeftinija od njihove proizvodnje iz primarnih sirovina, prvenstveno zbog manje potrošnje energije. Pored toga, reciklažom obojenih metala iz sekundarnih sirovina racionalnije se koriste prirodni resursi i smanjuje količina otpadnih materijala, čime se direktno štiti životna sredina. Sekundarne sirovine obojenih metala nastaju u procesu proizvodnje i prerade metala do njihove ugradnje u gotove priozvode i izbacivanjem tih proizvoda iz upotrebe usled njihove dotrajalosti ili tehnološke zastarelosti. U zavisnosti od vrste sekundarne sirovine, koriste se različiti postupci pripreme i metalurške prerade. Pojedine se veoma jednostavno recikliraju pretapanjem u metalurškim agregatima, dok druge moraju proći komplikovane operacije pripreme pre metalurške prerade.Production of non ferrous metals from secondary raw materials is far less costly than its production from primary raw materials, due to lower energy consumption. Besides, by recycling of non ferrous metals from secondary raw materials, the natural resources are saved and the amount of waste materials is reduced, directly protecting the environment. The secondary raw materials can originate in metal production and treatment, accompanied by their incorporation into the final product and its elimination due to amortization. The different methods of preparation and metallurgical treatment are used depending on secondary raw materials type. Some of them are very easy to be recycled by remelting in metallurgical furnace, while others must pass through complicated preparation before metallurgical treatment
Fluoride ion adsorption onto Al-alginate particles
No full textAntropogeni faktor uslovio je sve veće prisustvo fluoridnih jona u podzemnim vodama. Sa druge strane, povećana svest o štetnosti visokih koncentracija ovog polutanta u pijaćoj vodi, dovela je do strožijih standarda kada su ovi joni u pitanju. Zato se poslednje decenije vrše intenzivna ispitivanja novih metoda za uklanjanje fluoridnih jona iz otpadnih i pijaćih voda. U ovom radu je ispitana mogućnost upotrebe aluminijum alginatnih čestica, jeftinog i efikasnog adsorbenta, za uklanjanje fluoridnih jona. Detaljna karakterizacija primenjenog adsorbenta urađena je pre i nakon adsorpcije primenom FT-IR tehnike. Eksperimenti su izvedeni u šaržnom sistemu sa mešanjem, pri različitim polaznim koncentracijama adsorbenta i adsorbata. Dobijen rezultat od 11,40 mg F-/g Al-alginata ukazuje na visok kapacitet adsorbenta, a kinetički parametri pokazuju brzu kinetiku uklanjanja ispitivanog polutanta.Fluoride ions are increasingly present in the groundwater mainly due to the anthropogenic activity. On the other hand, increased awareness of harmful effects caused by high concentrations of F-in drinking water, leads to severe standards of water quality. Because of this, intensive researches of new methods for fluoride removal from water streams have been made in last decade. This paper examines the potential of aluminum alginate particles as a cheap and efficient biosorbent for F- removal. The adsorbent characterization before and after F- adsorption was performed using FT-IR technique. Adsorption experiments were conducted in a stirring batch mode, varying both concentration of adsorbate and adsorbent dose. Obtained result of 11,40 mg F-/g Al-alginate indicates a high adsorption capacity, while the kinetic parameters show fast removal kinetics
Ochratoxin A and zearalenone adsorption by the natural zeolite treated with benzalkonium chloride
No full textBenzalkonium chloride - BC (the mixture of alkylbenzyldimethylammonium chlorides containing the alkyl groups having chain lengths of C8 to C18 and benzyl functional group) was used as a surfactant for production of organozeolites (BZs). The natural zeolite - clinoptilolite was modified with three different levels (2, 5 and 10 mmol/100 g) of BC. FTIR spectroscopy, thermal analysis, zeta potential measurements, determination of the point of zero charge and BET were used to determine the quantity of the surfactant at the zeolitic surface. The main aim was to investigate adsorption properties of BZs towards ochratoxin A (OCHRA) and zearalenone (ZEN) under in vitro conditions. Results showed that adsorption of OCHRA and ZEN by BZs increased with increasing amounts of BC at the zeolitic surface but the adsorption mechanism was different. Adsorption of OCHRA by BZs followed nonlinear isotherms at pH 3 and 7, and higher adsorption capacity was observed at pH 3. This indicates that adsorption was dependent on the form of OCHRA in solution and that the sites at the uncovered zeolitic surface together with the surfactants contributed to OCHRA adsorption. Adsorption of ZEN by BZs showed linear isotherms at pH 3 and 7 and similar amounts were adsorbed at both pH values. This suggests that adsorption is practically independent of the form of ZEN in solution and that organic cations at the zeolitic surface are the active sites relevant for ZEN adsorption
Natural and Modified Silica-Based Materials as Carriers for NSAIDs
No full textIn the last two decades several representatives of natural silica-based materials (clays, zeolites, and diatomites) have emerged in biomedical applications due to their favorable physicochemical and functionality-related characteristics along with good biocompatibility. The possibility of their use in drug delivery as carriers for NSAIDs, as one of the most widely prescribed drugs, is particularly interesting since it would overcome some of the therapy-related side effects and improve patience compliance.This chapter gives an overview of natural silica-based materials' characteristics relevant for their pharmaceutical use, along with various examples of their structure modification in order to obtain materials with improved functional properties as potential drug carriers. A review on application of these materials in drug delivery of NSAIDs is presented including evaluation of techniques used for drug silica based carrier characterization in addition to investigation of their biopharmaceutical performances
Mineralogy and crystallochemical characteristics of heu-type minerals from zeolitic tuff deposits of Serbia
No full textThe results of perennial research of several Serbian zeolitic tuffs enriched with HEU-type minerals are presented in this paper. There are several recognized zeolitic tuff deposits containing HEU-type minerals: Zlatokop, Igros, Beocin, Toponica and Slanci, but their comparative mineralogical and crystallochemical features have not been studied in detail so far. These zeolitic tuff deposits are spatially and genetically connected to volcanic and pyroclastic rocks of marine and lake environments of Senonian and Eocene, and Neogene age, respectively. As a result of devitrification and diagenesis process of volcanic glass within zeolitic tuffs hypocrystalline porphiry and vitroclastic textures occur. The studied zeolitic tuffs are mainly composed of heulandite occuring in a form of needle-to plate-like crystals of 0.1 do 100 mu m in length, associated with other silicates. Depending on the type and content of exchangeable cations as well as the thermal stability of these raw materials, clinoptilolite-Ca and heulandite-Ca can be distinguished. The values of cation exchange capacity and surface area capacity range from 96 to 166 meq/100 g, and from 8.0 to 10.5 meq/100 g, respectively. HEU-type minerals can be distinguished either by a Si/Al ratio or arrangement of extra framework cations within the crystal structure of these minerals
Lignocellulosic Waste Material - from Landfill to Sorbent and Fuel
No full textThe most important source of renewable energy in Serbia represents biomass (60.3 %) with total potential of 3.405 million toe. Almost half of this amount (1.67 million toe) represents agricultural and industrial waste, with further negligible revalorization. Various investigations have demonstrated that agricultural byproducts have promising capacities to remove a variety of pollutants, which might increase the sustainability of their life cycle. This paper investigates the possible use of lignocellulosic waste material (LCW), originating from food industry as biosorbent for heavy metals, and later as a solid fuel. For this purpose we have used peach stone particles (PS) obtained by mechanical activation of this LCW as Cu(II) sorbent. The physical and chemical characteristics of PS reveal its complex structure which was confirmed by SEM, and FTIR analysis. PS behavior on pyrolysis process was studied by dynamic thermo gravimetric and derivate thermo gravimetric analysis. Results show that this lignocellulosic waste can be applied as sorbent and as a fuel. This approve that this agricultural waste can be a resource more than a waste and that it does not need to be disposed of in the costly and inefficient way, which is especially important in developing economies, like Serbian
Zatvaranje životnog ciklusa otpadne biomase hidrotermalnom karbonizacijom
No full textOtpadna lignocelulozna biomasa ima izvanredan potencijal kao sirovina za održivu
proizvodnju energije i drugih biomaterijala. Međutim, zbog inferiornih fizičko-hemijskih
svojstava u odnosu na ugalj, biomasa ne predstavlja idealnu sirovinu za industrijsku primenu
i neophodna je njena modifikacija. Hidrotermalna karbonizacija je termo-hemijski postupak
konverzije vlažne otpadne biomase na povišenoj temperature i autogenom pritisku u hidročađ
i procesnu vodu. Dobijena hidročađ, po prirodi slična uglju, može biti primenjena kao
zamena za fosilni ugalj, sekvestraciju ugljenika, adsorbent različitih polutanata, dodatak za
poboljšanje plodnosti zemljišta i dr. Procesna voda, bogata rastvorenim organskim
materijama predstavlja pogodan supstrat za sintezu bitnih hemikalija i proizvodnju biogasa.
Ovaj rad pruža uvid u osnovne reakcione mehanizme, kao najvažnije primene dobijenih
proizvoda.Waste lignocellulosic biomass has outstanding potential as a raw material for sustainable
production of energy and other biomaterials. However, due to inferior physical and chemical
properties in relation to coal, biomass is not an ideal raw material for industrial application,
and its modification is necessary. Hydrothermal carbonization is a thermo-chemical process
for the conversion of wet, waste biomass at elevated temperature and autogenous pressure
into the hydrochar and process water. The obtained coal-like hydrochar, can be applied as a
fossil coal substitute, for carbon sequestration, as an adsorbent for various pollutants, soil
fertility, etc. On the other hand, process water, rich in dissolved organic matter, is a suitable
substrate for synthesis of essential chemicals and the biogas production. This paper provides
an insight into the basic reaction mechanisms, as the most important applications of the
obtained products
Thermal analysis application on the phase equilibria investigation of the alloys in the Bi- Cu0.75Ni0.25 section of the Bi-Cu-Ni system
No full textHigh toxicity of lead and damaging effects on the environment resulted in its prohibited
use in electronic materials (RoHS Directive from 1 July 2006 in the EU). Therefore, great
effort has been made on the development of new Pb-free soldering and brazing materials
[1-5]. The Bi–Cu–Ni ternary system belongs to the group of potential Cu-Ni-based
advanced lead-free solder materials for high temperature application [6-8]. The results of
phase equilibria investigation of the alloys selected in the Bi-Cu0.75Ni0.25 section from
bismuth corner with molar ratio Cu:Ni = 3:1, are presented in this paper. The investigations
were performed using DTA/DSC experimental methods, while thermodynamic calculation
was done according to the CALPHAD method using PANDAT software. The results of the
DTA/DSC heating measurements of the chosen samples in the Bi-Cu0.75Ni0.25 section,
including liquidus temperatures and other phase transition temperatures are presented in
graphical abstract. The phase diagram of the investigated Bi-CuNi section has been
calculated using PANDAT software and is presented in graphical abstract, together with
experimentally determined DTA/DSC points. It could be noticed that calculated phase
diagram is in good agreement with DTA/DSC experiments
Exergy analysis for aluminothermic processing of waste materials
No full textThe analysis of material and energy balance can be done using concept of exergy, which is
a measure of available energy in the system [1]. Exergy losses indicate the place of
degradation in the process; thus, it implies improving of selected process.
The aluminothermic reduction process is an attractive method for immobilization of
hazardous waste, and for utilization of valuable elements from the waste [2]. The exergy
calculation relies on the material and energy balance calculation and standard chemical
exergy of the elements. For the purpose of material, energy, and exergy balance calculation
discrete non-commercial software was developed [3]. The waste materials used in these
calculations are Electric-arc furnace dust (EAFD, mostly Fe and Zn oxides) and the Mill
scale (mostly Fe oxides) [4].
Calculated exergy efficiency for aluminothermic processing of waste was 94.6%. All the
heat released by exothermic reactions was used for producing the iron, the slag and the
crude ZnO dust. Comparing to the conventional carbothermic reduction process in the DC
electric-arc furnace with the same materials (for which exergy efficiency was 56.5%) this
is much higher. The irreversible exergy losses of the aluminothermic process are 398.2
kWh/t of produced iron. The further processing of slag and dust is required, as well as in
the case of the carbothermic reduction process, so that the real value of exergy efficiency
of the process will be somewhat lower than the calculated