ritnms
Not a member yet
1551 research outputs found
Sort by
Composites of mica minerals and metal oxides for removal of metal ions from water
No full textPredmet istraživanja ove doktorske disertacije je priprema kompozita ekspandiranog vermikulita (neaktiviranog i kiselinski aktiviranog) i oksida metala kao i oksihidroksida metala, kao i njihova primena u adsorpciji jona metala: Ni2+, Pb2+, Cd2+, CrO42- kao i metaloida SeO32- ; adsorpciona svojstva ispitivana su kako na dobijenim materijalima tako i na polaznom uzorku. Navedeni materijali su izabrani zbog svoje dostupnosti u prirodi, niske cene, termičke stabilnosti kao i određenih fizičkih svojstava (magnetna svojstva).
Dosadašnja istraživanja ukazala su da feritni spineli među kojima su magnetit (Fe3O4), mangan ferit (MnFe2O4) i kobalt ferit (CoFe2O4) poseduju adsorpciona svojstva prema jonima metala. Osim toga svi pobrojani spineli poseduju feromagnetična svojstva čime predstavljaju veoma perspektivne potencijalne adsorbente. Međutim, njihov nedostatak je nestabilnost i velika težnja ka stvaranju aglomerata nepogodnih mehaničkih i hidrodinamičkih svojstava. Osim ovih oksida treba napomenuti da se u literaturi mogu pronaći i brojni primeri primene oksihidroksida, među kojima su getit i amorfni oksihidroksidi železa (AOŽ), kao adsorbenata brojnih polutanata. No i oni, kao i feritni spineli, spontano aglomerišu, čime se njihova primena kao adsorbenata značajno umanjuje. U cilju sprečavanja nastanka agregata i povećanja adsorpcionog kapaciteta neaktivirani ekspandirani vermikulit (Ver) korišćen je kao nosač feritnih spinela (Fe3O4, MnFe2O4 i CoFe2O4) i mešovitog oksida Cr2O3/Fe2O3. Kiselinski aktiviran ekspandirani vermikulit (AVer) korišćen je kao nosač oksihidroksida: getita (αFeO(OH)) i AOŽ.
Ispitivanja su pokazala da su specifična površina kao i kapacitet katjonske izmene (KKI) uzorka AVer znatno uvećani u odnosu na polazni uzorak Ver. Mineraloška analiza uzorka AVer utvrdila je znatnu alteraciju minerala vermikulita, prisutnog u uzorku Ver u nekoliko filosilikatnih minerala prisutnih u uzorku AVer. Sve ove promene čine uzorak AVer pogodnim adsorbentom katjona metala, kao i potencijalnim nosačem čestica oksida/oksihidroksida metala čime se mogu dobiti još bolji adsorpcioni materijali.
Nanošenje čestica feritnih spinela (MnFe2O4 i CoFe2O4) i mešovitog oksida železa (III) i hroma (III) na uzorak Ver izvršeno je metodom hidrotermalne koprecipitacije, dok je nanošenje magnetita (Fe3O4) na pomenuti liskun Ver izvršeno metodom koprecipitacije kroz tanak sloj nerastvarača na povišenoj temperaturi. Uzorci na kojima su nanešeni magnetit i mangan ferit pokazali su znatno veća feromagnetna svojstva od uzoraka na kojima su naneseni kobalt ferit i mešoviti oksidi železa (III) i hroma (III). Uzorak na koji je nanet MnFe2O4 pokazao je najbolja adsorpciona svojstva prema jonima Ni2+ , Pb2+ i Cd2+ uglavnom zbog visokog sadržaja lako izmenjivog jona Na+ u interkalacionom sloju kao i nešto većeg rastojanja između tetraedar-oktaedar-tetraedar (T-O-T) slojeva prisutnih liskuna.
Deponovanjem čestica oksihidroksida železa na uzorak AVer formirani su kompoziti koji poseduju poboljšana adsorpciona svojstva prema oksianjonima (CrO42- i SeO32- ) čime je povećana funkcionalnost adsorbenta. Nanošenje getita (α-FeO(OH)) na uzorak AVer izvršeno je metodom koprecipitacije kroz tanak sloj nerastvarača. Nanošenje AOŽ na isti uzorak (AVer) izvršeno je hidrolizom soli u prisustvu ksilena uz naknadnu dijalizu rastvornih proizvoda hidrolize. Nanošenjem getita i AOŽ znatno se povećao sadržaj hidroksilnih (-OH) funkcionalnih grupa na površini uzorka. Prisustvo hidroksilnih funkcionalnih grupa omogućilo je snažniju interakciju površine adsorbenta sa oksianjonima koji inače nemaju težnju da se spontano vezuju na materijale koji poseduju izmenjive katjone.
Skenirajućom elektronskom mikroskopijom sa emisionim poljem (FESEM, engl. Field Emission Scanning Electron Microscopy) ispitana je morfologija polaznih i pripremljenih uzoraka, a energetskom disperzionom spektroskopijom (EDS engl. Energy Dispersive Spectroscopy) određena je hemijska kompozicija površine testiranih uzoraka. Specifična površina uzoraka utvrđena je adsorpcijom/desorpcijom azota na tački ključanja pri atmosferskom pritisku (BET, engl. (Brunauer-Emmett-Teller)). Difrakcijom X-zraka na sprašenim uzorcima (XRPD, engl. X-ray diffraction on powdered samples) utvrđen je sastav mineralnih faza koje se javljaju u testiranim uzorcima. Infracrvenom spektroskopijom sa Furijeovom transformacijom (FTIR, engl. Fourier Transform Infrared Spectroscopy) utvrđeno je prisustvo molekulskih veza u ispitivanim uzorcima. Kapacitet katjonske izmene (KKI) i pH vrednost na tački nultog naelektrisanja (pHPZC, engl. pH point of zero charge) određeni su uravnotežavanjem posebnih proba, a zatim merenjem koncentracije metala i krajnje pH vrednosti, respektivno.
Adsorpciona svojstva dobijenih materijala ispitana su u šaržnom i protočnom sistemu. Kinetika adsorpcije opisana je modelima zasnovanim na brzini hemijske reakcije, među kojima se model pseudo drugog reda pokazao najboljim reakcionim modelom. Korelacijom dobijenih podataka iz modela pseudo drugog reda određene su energije aktivacije adsorpcionih procesa kao i vrednosti promena aktivacione entalpije, entropije i Gibsove energije. Pri opisivanju kinetike adsorpcije difuzionim modelima došlo se do veoma dobrih poklapanja eksperimentalnih podataka sa modelom unutarčestične difuzije (Veber – Morisov model), što je ukazalo na dvostepenu difuziju adsorbata (kako kroz granični difuzioni sloj tako i unutar čestica adsorbenata).
Ravnotežna adsorpcija polutanta veoma dobro je opisana modelom Frojndlihove adsorpcione izoterme, što je ukazalo na postojanje višeslojne adsorpcije na heterogenim adsorpcionim mestima na površini adsorbenta. I pored nešto lošijeg poklapanja eksperimentalnih rezultata sa Lengmirovom adsorpcionom izotermom, parametri ove izoterme su upotrebljeni za određivanje termodinamičkih parametara procesa adsorpcije (ΔGϴ, ΔHϴ i ΔSϴ). Uz ove parametre, određene su i vrednosti izosterične toplote adsorpcije čime su određeni sterni efekti između adsorbovanih vrsta odnosno intenzitet njihovih međumolekulskih interakcija.
Osim eksperimenata šaržne adsorpcije koji su izvršeni na svim testiranim adsorbentima, najbolji kandidati su testirani i u procesu kontinualne adsorpcije u koloni sa pakovanim slojem. Nakon zasićenja adsorbenta polutantima vršena je kontinualna desorpcija polutanata u istoj koloni. Rezultati ovih ispitivanja pokazala su da pripremljeni adsorbenti poseduju regenerativnu sposobnost te da se mogu koristiti do deset puta nakon čega moraju biti zamenjeni svežim adsorbentima.
Istrošeni adsorbenti su na kraju svog radnog veka korišćeni kao punioci polimernih matrica na bazi nezasićenih poliestarskih smola (NPS), a sve u cilju njihovog bezbednog deponovanja. Nastalim kompozitima testirana su mehanička svojstva kao i negorivost i utvrđeno je da kompoziti poseduju nešto lošija mehanička svojstva od uzorka NPS bez punioca. S druge strane, negorivost dobijenih kompozita je daleko veća od uzorka NPS bez punioca.
Prikazani rezultati iz ove teze ukazuju da dobijeni adsorbenti mogu imati i širu primenu u tretmanu otpadnih voda, a da se nakon upotrebe mogu koristiti kao punioci NPS, pružajući dobijenim kompozitima negorivost i mogućnost bezbednog deponovanja istrošenih adsorbenata.The subject of this doctoral dissertation is the preparation of a composite made from expanded vermiculite (both non-activated and acid-activated) and metal oxides or oxyhydroxides, and the examination of their adsorption properties towards metal ions: Ni2+, Pb2+, Cd2+, CrO42-, and the metalloid SeO32-, on the obtained materials and on the initial sample. The mentioned materials were chosen due to their abundance in nature, low price, thermal stability as well as certain physical properties such as ferromagnetism.
Previous research has shown that ferrite spinels, including magnetite (Fe3O4), manganese ferrite (MnFe2O4) and cobalt ferrite (CoFe2O4), possess adsorption properties towards metal ions. In addition, all listed spinels possess ferromagnetic properties, making them very prospective as potential adsorbents. However, their disadvantage is that they are unstable and tend to form agglomerates with unfavorable mechanical and hydrodynamical properties. Apart from these oxides, it should be noted that numerous examples of the oxyhydroxides application as adsorbents for numerous pollutants, can be found in the literature, including goethite and amorphous iron oxyhydroxides (AIO). However, they, like ferrite spinels, spontaneously agglomerate, which significantly reduces their use as adsorbents. In order to prevent the formation of aggregates and increase the adsorption capacity, inactivated expanded vermiculite (Ver) was used as a carrier for ferrite spinels (Fe3O4, MnFe2O4, CoFe2O4) and mixed oxide (Cr2O3/Fe2O3). In addition, acid-activated expanded vermiculite (AVer) was used as a carrier of oxyhydroxide: goethite (α-FeO(OH)) and AIO.
The specific surface area, as well as the cation exchange capacity (CEC) of the АVer sample is significantly increased compared to the Ver sample. Mineralogical analysis of the АВер sample determined a significant alteration of the mineral vermiculite, present in the Ver sample, into several phyllosilicate minerals present in the АВер sample. All these changes make the АВер sample a suitable adsorbent of metal cations, as well as a potential carrier of metal oxide/oxyhydroxide particles with better adsorption characteristics.
The deposition of ferrite spinels particles (MnFe2O4 and CoFe2O4) and mixed iron (III) and chromium (III) oxide on the Ver sample was carried out by the method of hydrothermal co-precipitation, while the forming of magnetite (Fe3O4) on the aforementioned mica was carried out by Ver; by co-precipitation method through a thin layer of non-solvent at elevated temperature. Samples on which magnetite and manganese ferrite were deposited showed significantly higher ferromagnetic properties than samples on which cobalt ferrite and mixed iron (III) and chromium (III) oxides were deposited. The sample on which MnFe2O4 was deposited showed the best adsorption properties for Ni2+, Pb2+ and Cd2+ ions, mainly due to the high content of the easily exchangeable Na+ ion in the intercalation layer, as well as the somewhat larger distance between the tetrahedral-octahedral-tetrahedral (T-O-T) layers of present micas.
Deposition of iron oxyhydroxide particles on the AVer samples formed composites that have improved adsorption properties towards oxyanions (CrO42- and SeO32-), which increased adsorbent functionality. The deposition of goethite (α-FeO(OH)) on the AVer sample was performed by co-precipitation through a thin layer of non-solvent. Precipitation of AIO on the same sample (АVer) was performed by salt hydrolysis in the presence of xylene with subsequent dialysis of the soluble hydrolysis products. Nano-coating of goethite and AIO significantly increased the content of hydroxyl (-OH) functional groups on the surface of the sample. The presence of hydroxyl functional groups enabled a stronger interaction of the adsorbent surface with oxyanions, which normally do not tend to spontaneously bind to materials that possess exchangeable cations.
The morphology of the initial and prepared samples was examined by field emission scanning electron microscopy (FESEM), while the chemical composition of the surface of the tested samples was determined by energy dispersive spectroscopy (EDS). The specific surface area of the samples was determined by adsorption/desorption of nitrogen at its boiling point on atmospheric pressure (BET method). X-ray diffraction on powdered samples (XRPD) determined the composition of the mineral phases that make up the tested samples. Fourier transform infrared spectroscopy (FTIR) was used to determine the presence of molecular bonds in the tested samples. The cation exchange capacity and the pH value at the point of zero charge were determined by equilibrating separate samples and then measuring the metal concentration and the final pH value, respectively.
Adsorption kinetics were described by models based on chemical reaction rates, among which the pseudo second-order model proved to be the best reaction model. By correlating the data obtained from the pseudo second-order model, the activation energies of the adsorption processes were determined, as well as the values of changes in activation enthalpy, entropy and Gibbs energy. When describing the kinetics of adsorption with diffusion models, there was a very good match of the experimental data with the intraparticle diffusion model (Weber – Morris model), indicating a two-stage diffusion of adsorbate (both through the boundary diffusion layer and inside the adsorbent particles).
Equilibrium adsorption of pollutants is very well described by the Freundlich adsorption isotherm model, which indicates the existence of multilayer adsorption on heterogeneous adsorption sites on the surface of the adsorbent. A better correlation of the experimental results with the Langmuir adsorption isotherm was used to determine the thermodynamic parameters (ΔGϴ, ΔHϴ and ΔSϴ) of the adsorption process. In addition to these parameters, the values of the isosteric heat of adsorption were also determined, which reveals the steric effects in between adsorbed species, that is, the intensity of their intermolecular interactions.
Apart from free adsorption experiments, which were performed on all tested adsorbents, the best candidates were additionally tested in the process of continuous adsorption in a column with a packed layer, and after saturation of the adsorbent with the pollutant, continuous desorption of the pollutant was performed in the same column. The results of these tests showed that the prepared adsorbents have a regenerative ability and that they can be used up to ten times, after which they must be replaced with fresh adsorbents.
At the end of their service life, spent adsorbents were used as fillers for polymer matrices based on unsaturated polyester resins (UPR), all with the aim of their safe disposal. The resulting composites were tested for mechanical properties, as well as fire retardancy, and it was determined that the composites have somewhat lower mechanical properties than the UPR sample without fillers. On the other hand, the fire retardancy of the obtained composites is much higher than the UPR sample without filler.
The presented results from this thesis indicate that the obtained adsorbents can be used in the treatment of waste water, and after their use they can be used as UPR fillers, providing the obtained composites with non-flammability while in the same time keeping spent adsorbents safe in UPR matrix
Development of Methodologies and Software for Design, Simulation and Optimization of Oil Hydraulic Cylinders of Large Dimensions and Power
No full textAs part of the research carried out in the field of processing systems and the production
process of oil-hydraulic cylinders of large dimensions and power, the specifics of fluid power transmission,
in the functioning of hydropower facilities, were analyzed. The research also includes the
optimization of the physical–mathematical model of non-stationary processes, which take place
inside the chamber of a large hydrocylinder. In parallel with the definition of the optimization model,
the work parameters that affect the process of fluid flow and piston movement were determined.
The operating and technological construction parameters of the hydraulic cylinder, which most
significantly affect the operation of the hydraulic cylinder, were defined, and the observed parameters
were optimized, based on which a prototype with improved characteristics compared to existing
solutions was realized
The effect of sintering temperature on cavitation erosion in glass-ceramics based on coal fly ash
No full textThe incombustible portion of coal that remains after burning is known as bottom or fly ash, and it has a detrimental influence on the environment. One of the possible alternatives for reducing the amount of ash deposited in landfills might be the production of useful glass-ceramic from vitrified fly ash. Glass-ceramic was synthesized using fly ash from the thermal power plant "Nikola Tesla" and fluxing additives. Sinter-crystallization of the parent glass resulted in glass ceramics. The glass was created by melting a combination of coal fly ash (CFA), Na2CO3, and CaCO3 at T= 1500 °C and quenching the melt in the air. Glass powders were sintered at temperatures 850 and 900 °C. The resulting glass-ceramics were characterized microstructurally, physically, and mechanically. The cavitation erosion of samples was evaluated. The cavitation rate was 0.015 mg/min for the sample sintered at 850 °C, and 0.0053 mg/min for the sample sintered at 900 °C. The leaching of heavy metals in glass-ceramic samples was determined using the Toxicity Characteristic Leaching Procedure. A low concentration of heavy metals in the leaching solution showed that heavy metals were successfully incorporated in the glass matrix and that obtained glass-ceramics are ecologically safe for usage. Both samples exhibit good resistance to cavitation erosion, suggesting their potential as possible replacements for structural ceramics commonly employed components of hydraulic machinery
Tokovi zagađujućih materija iz primarnih sirovina i mogućnost zatvaranja toka u ciklus
No full textУправљање загађујућим материјама добијеним из примарних сировина представља
изазов за очување животне средине. Надовезујући се на принципе циркуларне
економије, индустријске симбиозе и одрживог управљања ресурсима, дат је преглед
иновативних стратегија за затварање петље токова загађујућих материја и
промовисање отпорнијег и еколошки прихватљивијег индустријског екосистема. У
овом раду биће наведене различите методе за имобилизацију загађујућих материја
екстрахованих као споредних производа из минералних сировина и њихову
реинтеграцију у стабилне минерале. Концептом дизајнирања производа и процеса
имајући на уму могућност рециклирања и дуговечност уз примену чистијих
производних техника и коришћењем еколошки прихватљивих материјала. Поред
тога, напредак у рециклажним технологијама нуди обећавајуће методе за
екстракцију загађивача из отпадних токова и њихову поновну уградњу у минералне
матрице, ефикасно их имобилизирајући и спречавајући даље ширење у животну
средину. Кроз колаборативне мреже размене између индустрија, токови отпадних
сировина могу се пренаменити као инпути за друге процесе, затварајући петљу у
коришћењу ресурса и ублажавајући загађење. Превођењем загађујућих материја
назад у минерале кроз синергетска партнерства, индустријска симбиоза нуди пут
ка одрживом управљању ресурсима и ублажавању загађења. Кампање подизања
свести јавности и едукација потрошача такође играју кључну улогу у неговању
културе одрживости, оснажујући појединце да доносе информисане изборе и
подржавају предузећа која су посвећена управљању животном средином. У закључку,
овај рад наглашава хитну потребу за иновативним решењима за имобилизацију
загађивача екстрахованих из минералних сировина и њихову реинтеграцију назад у
одговарајуће минералне матрице. Комбинацијом чистијих производних техника,
технологија рециклаже, индустријске симбиозе и легислативне подршке, можемо
ефикасно затворити петљу на токове загађивача, минимизирати штету по
животну средину и промовисати одрживији индустријски екосистем. Како тежимо
ка циркуларној економији, имобилизација загађивача представља критичан корак у
постизању заједничког циља управљања животном средином и дугорочне
одрживости
Contribution of the Institute for Technology of Nuclear and Other Mineral Raw Materials to the SDGs – Towards International decade of Science for Sustainable Development
No full textScientific institutions could play a prominent role in solving global problems and attaining
Sustainable development goals (SDG). International Decade of Science for Sustainable Development
stipulates an opportunity to align research priorities and knowledge generation more effectively
towards sustainability. Institute for Technology of Nuclear and Other Mineral Raw Materials
(ITNMS) contributes to various SDGs through its project activities, concentrating on those that cover
a range of socio-technical systems or the areas of application as well as those that promote
transversal directions for system change. This paper aimed to comprehensively present Institutes’
scientific projects in coordination with the set of 17 officially ratified goals of sustainable
development. Obtained results are categorized according to several parameters: project realization
period, institution position in the project (leader or participant), and type of the project (international
or national). The Institute scientific activities possesses’ good alignment with several SDGs,
particularly: SDG 12 (Responsible consumption and production) and SDG 9 (Industry, innovation,
and infrastructure), but also directly or indirectly with SDG 2 (Zero hunger) and SDG 3 (Good health
and well-being). Additionally, ITNMS project activities contribute to the Planet, Prosperity, People
and Partnership UN pillars of sustainable development. With consideration of the guidelines of
International Decade of Science for Sustainable Development and Strategy for scientific and
technological development of the Republic of Serbia, ITNMS may effectively contribute to the
solutions for current scientific and technological problems in a way that promotes sustainable
development and various SDGs in future
Efikasnost mineralnih sirovina u prečišćavanju rudarskih otpadnih voda koje su kontaminirane Pb, Cd, Zn, U
No full textZagađivanje čovekove sredine i mere za njihovo saniranje predstavlja jednu od najvećih briga današnjeg čovečanstva. Dosadašnje aktivnosti čoveka bila su usmerena ka naučnim i tehničkim dostignućima kako bi se unapredila industrijska proizvodnja na svim nivoima ne obazirući se uvek na segmente životne sredine. Posledice takvog ponašanja, danas se odražavaju na kvalitet tri osnovna faktora životne sredine a to su zemljište, voda i vazduh. Procesi oštećenja, uništenja posebno površinskih i podzemnih voda predstavljaju danas veliki problem mnogih zemalja u svetu, posebno ako se ima u vidu njihova direktna uloga u zdravlju i bezbednosti ljudi. Danas se u Srbiji godišnje u recipijente ispusti oko 400 miliona m3 otpadnih voda od toga preko 150 miliona m3 iz industrije a gde značajni deo preko 80 miliona m3 iz rudarstva. Rudarstvo kao značajna privredna grana u Srbiji u poslednjih nekoliko godina beleži značajno povećanje proizvodnih kapaciteta tako i generisanja kontaminiranih otpadnih voda posebno kada su u pitanju polimetalični rudnici. Otpadne vode iz rudarstva nastale kao nusprodukt procesnih aktivnosti najčešće u sadrže u sebi sadrže hemijske zagađivače a jednim manjim delom biološke zagađivače. Karakteristike rudarskih otpadnih voda značajno variraju u zavisnosti od ležišta tj. mineralne sirovine koja se eksploatiše kao i primenjene tehnologije i stepena prerade. Poslednjih nekoliko godina intenzivno se vrši proučavanje „in situ“ tehnologije polupropustljivih reaktivnih barijera (PRB) od prirodnih mineralnih sirovina na bazi zeolita i apatita kao punioca u tehnologiji prečišćavanja otpadnih voda. Polupropustljive reaktivne barijere sa odgovarajućim puniocima mogu uspešno da rešavaju širok spektar zagađivača kao što su metali, radionuklidi, hloridi i organski zagađivači,. Polupropustljive barijere predstavljaju brzo, ekonomično i efikasno rešenje za probleme kontaminacije površinskih i podzemnih voda u rudarstvu. U radu je ispitivana efikasnost prirodnih mineralnih sirovina na bazi zeolita i apatita kao reaktivnih materijala za „in situ“ prečišćavanje površinskih i podzemnih voda kontaminiranih Pb, Zn, Cd i U pri različitim pH vrednostima sredine
Photodegradation of thiophanate-methyl under simulated sunlight by utilization of novel composite photocatalysts
No full textThis work aimed to investigate the influence of modified titanium(IV) oxide by different nanosized particles on photocatalytic capacity to decompose the chosen organic pollutant under simulated sunlight. For that purpose, rutile-phased titanium(IV) oxide (r-TiO2) was decorated with iron vanadate (FeVO4/r-TiO2) and vanadium-substituted goethite (Fe1-xVxOOH/r-TiO2). The obtained composites were characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X ray powder diffraction, Brunauer-Emmett-Teller, Fourier transform infrared spectroscopy – attenuated total reflectance and ultraviolet–visible diffuse reflectance spectroscopy techniques. Both synthesized photocatalysts showed higher photoactivity than the base r-TiO2 for the degradation of the target contaminant - thiophanate-methyl (2.5 h vs. 5 h). During the tests, parameters like the irradiation time, catalysts amount, and pesticide concentration were systematically investigated. Furthermore, photocatalysts were applied in multicycle degradation tests for examining their effectiveness during exploitation time. Monitoring of the removal rate was performed both by UV/visible spectrometry and high-performance liquid chromatography (HPLC). In order to prove completion of fungicide degradation chemical oxygen demand was measured in the course of the photocatalytic experiment. The final concentration of the observed contaminant in treated samples was under the prescribed legislative level. The fabricated materials displayed great reliability, durability and photocatalytic activity representing good potentials for implementing this process in real wastewater treatment plants
Toxic dye removal by thermally modified lignocellulosic waste in a three-phase air-lift reactor: Kinetic insights
No full textThis paper investigates the influence of the air flow rate in a three-phase air-lift reactor on the sorption of toxic dye, Brilliant green, onto a promising and efficient sorbent, sour cherry stone biochar. In order to gain a comprehensive insight into the sorbent/sorption behaviour, sour cherry stone biochar was characterized by Fourier transform infrared spectroscopy with attenuated total reflection, pH of the suspension, point of zero charge, scanning electron microscopy with energy-dispersive X-ray spectroscopy and X-ray diffraction. The experiments were performed in an air-lift reactor using airflows of 2.50 and 5.55 dm3 h-1. The experimental data of sorption kinetics experiments were fitted by non-linear form of pseudo-first and, pseudo-second models as well as the Weber-Morris model based on intraparticle diffusion. The overall sorption rate was found to be limited by the Brilliant Green mass transport rate to the sorbent at a lower airflow and thus mixing intensity, while it was kinetically controlled at a higher rate following the pseudo-second order kinetic model. Furthermore, sorption at lower air flow was delayed by mass transfer resistance through the liquid boundary layer surrounding sorbent particles. Presented results clearly indicate that airflow intensity plays a significant role in the overall sorption kinetics and support possible application of the applied biochar for efficient Brilliant Green sorption
Effects of Microplastics and Nickel on Soil-Medicinal Plant System: Risks to Food Security and Human Health
No full textSoil contamination with microplastics and nickel caused changes in Cd, Cr, Ni, and Pb
phytoavailability in soil and their uptake by medicinal plant Capsella bursa-pastoris. Extreme
environmental conditions increased the health risks and hazard to the food web and public health based on
the bioavailable soil fractions
Novel photocatalyst for advanced photocatalytical degradation of methyl orange
No full textA significant reduction in environmental quality inevitably affects global health. Traces of various
organic molecules have been detected in all spheres of life, raising concerns about the continued
functioning and survival of various plant and animal species [1]. Wastewater, with all its
constituents, has a negative impact when discharged into a recipient without prior treatment.
Different techniques were utilized for water purification, while advanced oxidation techniques
gave the best solutions [2]. The aim of this work is to examine the efficiency of the newly
synthesized photocatalyst Y-TiO2 for the degradation of methyl orange (MO) dye in aquatic
environments. The fabricated catalyst was subjected to structural and morphological
investigations. During the photocatalytic tests, process parameters such as pollutant
concentration, catalyst mass, radiation source distance, and added hydrogen peroxide (HP)
concentration are varied. The best results were obtained at a dye concentration of 10 ppm in a
system with 0.10 g of catalyst. With the addition of HP at a concentration of 0.015 mg/l, the time
required for complete dye degradation was 45 min, compared to 65 min in the system without
HP. The analytical measurements of the degradation process was monitored by UV/Vis
spectroscopy, and the calculated efficiency was 95%. The obtained results show the great power
of the synthesized photocatalyst to decompose the anionic dye under the influence of simulated
solar radiation