Antimicrobial activity of surface activated sorbents modified by metal ions.

Predmet istraživanja ove doktorske disertacije je površinska modifikacija materijala koji se koriste u antimikrobnom prečišćavanju vode. Promena površine materijala i prisustvo različitih funkcionalnih grupa važna je sa analitičkog aspekta i omogućava unapređenu primenu materijala. Materijali presvučeni filmom jona metala pokazuju dobro dezinfekciono svojstvo. U ovom radu, testirani su sorbenti različitog porekla (5 prirodnih, 3 modifikovana i 3 sintetička) i aktivirani sa Ag+-, Cu2+- i Zn2+- jonima, primenom procesa sorpcije u šaržnom sistemu. Ispitane su strukturne i površinske karakteristike prirodnih i modifikovanih materijala, određena je kinetika i mehanizam procesa sorpcije i desorpcije. Karakterizacija prirodnih i modifikovanih sorbenata izvršena je korišćenjem rendgenske difrakcione tehnike (XRD), rendgenske fotoelektronske spektroskopije (XPS) i skenirajućeg elektronskog mikroskopa (SEM). Za određivanje koncentracije jona metala korišćen je sistem indukovano spregnute plazme sa optičkom emisionom spektroskopijom (ICP-OES) i masenom spektrometrijom (ICP-MS)...The research topic of this doctoral thesis is focused on the surface modifications of materials used in antimicrobial water treatment. The surface change of the material and the presence of varying functional groups are of particular importance in an analytical aspect which allows for an improved application of the material, impregnated by a film of disinfecting metal ions. In this study, sorbents of a selected range of origin (5 natural, 3 modified and 3 synthetic) have been tested and activated by Ag+-, Cu2+- and Zn2+- ions, in a single batch sorption mode. The structural and surface characteristics of natural and modified materials have alsobeen investigated, followed by the kinetics and mechanisms of the sorption and the desorption processes. The characterization of native and modified sorbents was performed byX-ray diffraction technique (XRD), an X-ray photo electron spectroscopy (XPS) and a scanning electron microscope (SEM)..

SiO2 and TiO2 -Hybrid Material for Removal of As(V) and Pb(II) Ions from Aqueous Solution

The aim of this research was to investigate As(V) and Pb(II) adsorption behaviour onto mineral heterostructures based on the mixture of Si and Ti-oxides (MHO). Heavy metals are discharged into water bodies from various industries which cause environmental pollution and public health problems due to their toxicity, persistence, high solubility, and mobility [1]. The conventional methods of heavy metal decontamination include chemical precipitation, ion exchange, membrane separation and reverse osmosis [2]. However, the adsorption process for heavy metals removal has been investigated as a cost-effective method, usually easy to manage, maintain and consolidate within the entire wastewater treatment plant. The metal-oxide heterostructures with a high surface area and specific affinity for heavy metals adsorption from aqueous solutions have demonstrated a promising performance in practical engineering applications [3]. The most common hybrid adsorbents are consisted of metal-oxides combinations such as: iron oxides (maghemite: γ-Fe2O3, hematite: α-Fe2O3, magnetite: Fe3O4, goethite: α-FeOOH), manganese oxide (α-MnO2), zinc oxide (ZnO), titanium oxide (TiO2), aluminum oxide (γ-Al2O3), magnesium oxide (MgO) and cerium oxide (CeO2) [4-6]. In this study, synthesized SiO2 and TiO2-hybrid material for removal of As(V) and Pb(II) ions from aqueous solution was investigated. The adsorption experiment was conducted in a batch system, using the initial concentrations of 100 µg L-1, at appropriate pHi for selected ions (pHPb(II)=5 and pHAs(V)=6). The experimental optimization was performed by varying the parameters such as the mass of the adsorbent and pH of initial ion solution. The maximum removal efficiency of Pb(II) and As(V) was 99,8 and 52.2 %, respectively (experimental conditions: mads=10 mg, V=10 mL, t=24h and T=25 oC). The characterization of MHO adsorbent was carried out using the following techniques: X-ray diffraction (XRD), gas adsorption/desorption isotherms (BET), scanning electron microscopy (SEM) and the Fourier-transform infrared spectroscopy (FTIR). XRD patterns of the MHO sample have shown that the main contribution originates from the diopside phase, CaMgSi2 O6 (84.0 wt. %), while the other oxide-contributions comprised of a hexagonal structure of titanium oxides (anatase and rutile, in total 2.2 wt. %), and iron (titanium) oxides (hematite and titanomagnetite, in total 12.2 wt. %). The FTIR was used to analyze the functional groups present in MHO and recorded numerous vibrations and stretching of functional groups (dominantly Si-O-Si, Si-O-Al and Si-O-Ti bonds), which confirmed that the synthesized material consists of mineral oxides. The SEM analysis indicates a large number of uneven thin forms of nanoplatelets which is complementary confirmed by increased porosity and large surface size (SBET = 271.7 m2 g-1)

Optimization, Validation and Verification of ICP-MS Method for Determination of the Total Emission of Metals From Stationary Sources

Emisija zagađujućih materija u vazduh iz stacionarnih izvora zagađivanja se utvrđuje merenjem i/ili izračunavanjem emisionih parametara na osnovu rezultata merenja. U skladu sa održivim razvojem, teži se ka tome da se ove emisije smanje, ali je njihova neprekidna kontrola neophodna. Teži se da koncentracije metala koji se ispuštaju emisijom u životnu sredinu budu smanjene, pa je neophodno razvijati metode koje su dovoljno osetljive da detektuju i kvantifikuju niske koncentracije. Standardna referentna metoda za određivanje ukupne emisije As, Cd, Cr, Co, Cu, Mn, Ni, Pb, Sb, Tl i V iz stacionarnih izvora je SRPS EN 14385. Jedna od osnovnih karika u sistemu menadžmenta kvalitetom jeste obezbediti poverenje u kvalitet rezultata analize merenja. Ispravnost analitičkog merenja kontroliše se od ulaska uzorka u laboratoriju do samog izdavanja izveštaja o ispitivanju, sve u cilju dobijanja maksimalne pouzdanosti rezultata ispitivanja. Program obezbeđenja (QA) i kontrole kvaliteta (QC) uspostavlja se i realizuje da bi se obezbedila tačnost i preciznost (pouzdanost) dobijenih rezultata merenja. Cilj rada je optimizacija, validacija i verifikacija ICP-MS metode za određivanje metala iz emisije stacionarnih izvora. Da bi se obezbedili objektivni eksperimentalni dokazi da su ispunjeni posebni zahtevi za svaki analizirani metal, proces je uključivao (i) procenu mernih nesigurnosti, (ii) analizu dostupnih sertifikovanih referentnih materijala i (iii) merenje uzoraka za ispitivanje u okviru međulaboratorijskog poređenja. Dobijene vrednosti ICP-MS analize metala iz stacionarnih izvora ukazuju da je ponovljivost bolja od 5 % RSD, ponovljivost u PT šemi bolja od 10 % RSD, bias bolji od 10 % i granice detekcije u opsegu 0,05 i 10 μg kg−1 za analizirane metale.The emission of polluting substances into the air from stationary sources is determined by measurement and/or calculation of emission parameters based on measurement results. In line with sustainable development, efforts are made to reduce these emissions, but continuous monitoring remains essential. The aim is to decrease the concentrations of metals released into the environment through emissions, necessitating the development of methods sensitive enough to detect and quantify low concentrations. The standard reference method for determining the total emissions of As, Cd, Cr, Co, Cu, Mn, Ni, Pb, Sb, Tl, and V from stationary sources is SRPS EN 14385. A fundamental aspect of quality management systems is to ensure confidence in the quality of measurement results. The accuracy of analytical measurements is controlled from sample entry into the laboratory to the issuance of test reports, all with the goal of maximizing the reliability of test results. Quality assurance (QA) and quality control (QC) programs are established and implemented to ensure the accuracy and precision (reliability) of obtained measurement results. The objective of this work is the optimization, validation, and verification of the ICP-MS method for determination of metals emitted from stationary sources. To provide objective experimental evidence that specific requirements are met for each analyzed metal, the process includes (i) assessing measurement uncertainties, (ii) analyzing available certified reference materials, and (iii) measuring test samples within inter-laboratory comparison. The obtained values from ICP-MS analysis of metals from stationary sources indicate repeatability better than 5% RSD, repeatability in proficiency testing schemes better than 10% RSD, bias better than 10%, and detection limits in the range of 0.05 to 10 μg kg−1 for the analyzed metals.Procesing '24 : 37. Međunarodni kongres o procesnoj industriji : zbornik radova - Proceedings, 29-31. maj 2024, Beogra

Heterogeni prirodni materijali mineralne strukture kao efikasni adsorbenti za uklanjanje Pb2+ jona iz vode

Cilj istraživanja ovog rada bio je ispitivanje mogućnosti primene prirodnih nemodifikovanih materijala kao adsorbenata za efikasno uklanjanje Pb2+ jona iz vode. Korišćena su dva materijala čiji sastav čini smeša oksida SiO2, Al2O3 i Fe2O3. Na osnovu teksturne klasifikacije uzoraka, analizirani materijali spadaju u peskovitu ilovaču i ilovasti pesak. U okviru rada izvršena je karakterizacija materijala primenom rendgenske difrakcione analize (engl. X-Ray Difraction, XRD) i infracrvene spektroskopije sa Furijeovom transformacijom (engl. Fourier- Transform Infrared Spectroscopy, FTIR). Proces adsorpcije Pb2+ jona na prirodnim materijalima ispitan je u šaržnom sistemu, variranjem mase adsorbenta i pH vrednosti rastvora. Peskovita ilovača i ilovasti pesak pokazali su visoku efikasnost za uklanjanje Pb2+ jona iz vode, bez prethodne hemijske modfikacije. Efikasnost uklanjanja jona olova uz pomoć peskovite ilovače i ilovastog pesaka iznosi 88,2 % i 80,2 %, pri optimalnim uslovima (Ci (Pb2+)=100 μg L-1, mads=10 mg i pH=5). Dobijeni rezultati pokazuju i potvrđuju da se prirodni materijali na bazi oksida metala mogu koristiti kao efikasni adsorbenti za uklanjanje katjonskih oblika teških metala iz vode.The aim of this study was to examine the possibility of using natural unmodified materials as adsorbents for efficient removal of Pb2+ions from aqueous solution. Two raw materials composed of SiO2, Al2O3 and Fe2O3, were analyzed. According to the textural classification the tested materials belong to sandy loam and loamy sand. In this research, X-ray diffraction analysis (XRD) and Fourier-Transform infrared spectroscopy (FTIR) were used for structural characterization of the materials. The process of adsorption of Pb2+ ions onto natural materials was conducted in a batch system. In order to determine optimal conditions, the mass of the adsorbent and the pH value of the solution were varied. Sandy loam and loamy sand have shown high efficiency for removing Pb2+ions from aqueous solution, without previous chemical modification. The efficiency of removal of lead ions on sandy loam and loamy sand is 88.2% and 80.2%, respectively, under optimal conditions (Ci(Pb2+)=100 μg L-1, mads=10 mg and pH 5). This study confirms that natural materials based on metal oxides can be used as effective adsorbents toremove cationic species of heavy metals from water systems

Natural radioactivity in the soil samples of Subotica, Serbia

The activity concentrations of 40K, 226Ra and 232Th from 23 locations of the territory of Subotica were determined by gamma ray spectrometry. Based on the results obtained the value of absorbed gamma dose rate in air was calculated. Mean values of activity concentrations were found to be 277 Bq kg-1 for 40K, 18 Bq kg-1 for 226Ra and 18 Bq kg-1 for 232Th. The total absorbed gamma dose rate varied between 20 and 44 nGy h-1. The mean value 31 nGy h-1 is lower than the world average value

COMPARATIVE ANALYSIS OF Pb2+ SEPARATION USING NATURAL AND SYNTHETIC SILICATE MATERIALS

In this study, the adsorption capacity and removal efficiency of lead using various metal-oxide materials from aqueous solution have been analyzed. Two SiO2-based materials, natural (loam) and synthesized (metal-oxide heterostructures – MOH) were investigated. The characterization of these samples was performed using X-ray powder diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Adsorption tests were performed in a batch system by varying the mass of tested materials. The highest adsorption capacity for Pb2+ was achieved using 5 mg of MOH (166.6 µg g-1), while the removal efficiency using the optimal mass (10 mg) of MOH and loam was 99.3 and 94.2 %, respectively. Based on the obtained results, it was concluded that the synthetic material has higher adsorption capacity and removal efficiency than the natural material for the selected ion

Stable Lead Isotope Compositions in Coal, Coal Ash and Coal Fly Ash From Serbia

The Republic of Serbia predominantly produces electricity in thermal power plants (TPP) Nikola Tesla (A i B), Kolubara and Kostolac. They are supplied from Kolubara basin mines (Nikola Tesla (A i B), Kolubara) which produces three quarters of Serbian lignite (about 70%), with the mean annual production about 30 million tons of coal and from Kostolac basin (TE Kostolac) which produces 30% of lignite in Serbia. Coal combustion residuals include bottom ash, fly ash and slag. Environmental pollution by coal ash and fly ash has been intensively studied taking into account high content of potentially hazardous elements such as As, Pb, Cd and Cr. Tracking lead sources in environmental studies has usually been performed by stable lead isotopes. The pres- ence, pathways and environmental impact of coal ash and fly ash can be identified using Pb isotopic compositions. In this study, isotopic compositions for 12 coal samples from Kolubara and Kostolac major coal mines and 12 fly ash samples from thermal power plants Kolubara (A and B), Kostolac (A and B), Nikola Tesla TENT (A3, A2, and B1) were determined. Samples were digested in mineral acids mixture. Lead conc- entration and stable Pb isotopes were measured by inductively coupled plasma mass spectrometry (ICP-MS). The results obtained might be useful in monitoring of Pb poll- ution from the examined sources, as well as in emission control.Međunarodna naučna konferencija Održivi razvoj i zelena ekonomija : Knjiga apstrakata ; 19-21 April 2022, BeogradInternational Scientific Conference Sustainable Development and Green Economy : Book of Abstracts ; 19-21st April 2022, Belgrad

Ispitivanje adsorpcionih svojstava ilovače za uklanjanje jona olova i arsena iz vodenih rastvora

Olovo i arsen predstavljaju značajnu grupu neorganskih polutanata koji su prisutni u životnoj sredini, pre svega u vodenim sistemima, pa je njihovo uklanjanje veliki tehničkotehnološki izazov. Zbog toga se sve više pažnje posvećuje razvoju pristupačnih, efikasnih i ekološki prihvatljivih adsorbenata. Prirodni materijali na bazi oksida metala (SiO2, Al2O3, Fe2O3), poput ilovače, predstavljaju efikasne adsorbente za uklanjanje katjonskih i anjonskih vrsta iz vodenih rastvora. U ovom radu adsorpciona svojstva ilovače ispitivana su u šaržnom sistemu, promenom pH vrednosti početnog rastvora, dok su masa adsorbenta, vreme i temperature procesa bili konstantni. Značajnu ulogu u odvijanju adsorpcionog procesa ima pH vrednost rastvora, stoga se eksperiment zasnivao na određivanju efikasnosti procesa pri vrednosti pH rastvora 4, 5 i 6. Strukturne karakteristike ilovače su određene primenom rendgenske difrakcione analize (engl. X-Ray Difraction, XRD), infracrvenom spektroskopijom sa Furijeovom transformacijom (engl. Fourier-Transform Infrared Spectroscopy, FTIR) i skenirajuće elektronske mikroskopije (engl. Scanning electron microscopy, SEM). Koncentracija jona nakon procesa adsorpcije određena je pomoću indukovano spregnute plazme sa masenom spektrometrijom (engl. Inductively Coupled Plasma Mass Spectrometry, ICP-MS). Maksimalna efikasnost uklanjanja jona olova postignuta je na pH vrednosti 5 (94,2 %), dok je za jone arsena optimalna pH vrednost bila 6 (35,1 %).Lead and arsenic represent an important group of inorganic pollutants that can be found in the environment, primarily in aquatic systems. Their removal from water systems is a big environmental problem, but also a significant technological challenge. Therefore, an increasing attention is paid to the development of widely available, efficient and environmentally friendly adsorbents. Natural metal oxide-based materials (SiO2, Al2O3, Fe2O3), such as loam, are effective adsorbents for removal of cationic and anionic species. The adsorption experiments were performed in a batch system, varying the pH value of the initial solution, while the mass of adsorbent, time and temperature were constant. The influence of pH value has a leading influence to the adsorption process so the process efficiency was determined at the pH values set at: 4, 5 and 6. The structural characteristics of the loam was performed using X-ray diffraction analysis (XRD), Fourier-Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM). The concentration of ions after their removal was determined using inductively coupled plasma mass spectrometry (ICP-MS). The maximum removal of lead ions was obtained at pH 5 (94.2%), while for arsenic ions, it was at pH 6 (35.1%)

Stabilization of Fly Ash Matrix Using Calcium-Oxide, Hydroxide and Carbonate

Sagorevanjem uglja u termoelektranama nastaju velike količine letećeg pepela koji u svom sastavu sadrži teške metale i metaloide čije izluživanje može naruštiti stanje životne sredine u ve- likoj meri. Cilj ovog rada jeste optimizacija procesa stabilizacije matrice letećeg pepela upotrebom oksida, hidroksida i karbonata kalcijuma, kao i ispitivanje stepena desorpcije (izluživanje) ele- menata u desorpcionim rastvorima. Stabilizacijom letećeg pepela omogućila bi se njegova dalja upotrebe u građevinskoj industriji ili u svrhu adsorbenta. Kako bi se dobili optimalni uslovi korišćeno je nekoliko različitih stabilizatora (CaO, Ca(OH)2 i CaCO3) u različitim koncentracijama (5% i 7%). Variraran je i sastav desorpcionog rastvora (dejonizovana voda i 4% i 8% sirćetna kiselina) kao i odnos letećeg pepela i desoprcionog rastvora (1:10 i 1:30). Koncentracija jona teških metala i metaloida (V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Pb) određivana je metodom masene spektrometrije sa indukovano spregnutom plazmom (ICP- MS). Za obradu podataka rađena je multivarijaciona statistička analiza (korelaciona analiza, ana- liza glavnih elemenata i klasterska analiza). Korišćen je statistički softver MINITAB.Combustion of coal in thermal power plants produces large amounts of fly ash, which contains heavy metals and metalloids, and their leaching can greatly damage the environment. The aim of this paper is to optimize the process of stabilization of the fly ash matrix using calcium oxide, hydroxide and carbonate, as well as to examine the degree of desorption (leaching) of elements in desorption solutions. Stabilization of fly ash would enable its further use in the construction industry or as an adsorbent. In order to obtain optimal conditions, several different stabilizers (CaO, Ca(OH)2 and CaCO3) were used in different concentrations (5% and 7%). The composition of the desorption solution (deionized water and 4% and 8% acetic acid) is also variable, as is the ratio of fly ash to the desorption solution (1:10 and 1:30). The concentration of heavy metal ions and metalloids (V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Pb) was determined by the method of Inductively coupled plasma mass spectrometry (ICP-MS). Multivariate statistical analysis (correlation analysis, principal component analysis (PCA) and cluster analysis (CA)) was performed for data processing. MINITAB statistical software was used.36. Međunarodni kongres o procesnoj industriji - PROCESING ′23 : zbornik radova ; 1-2. jun, Šaba

The Removal of Ni2+ and Cd2+ -ions onto Synthetic Mineral Based Composite Functionalized by Polyethylenimine

This study presents the synthesis of porous cordierite- based ceramics and its surface activation by polyethylenimine/nano-CeO2 for the heavy metal removal. The synthesis was carried out by the addition of following powders: MgO, Al2O3, and SiO2 in 2:2:5 molar ratios, respectively. The oxide(s) mixture was further processed in two sequential stages: i) ball milled in the ethanol for 40 minutes and palletized under the pressure of 3 t/cm2, as a pre-sintering process, and ii) the pallets were further sintered for 2h in the air atmosphere at 1350 oC, under a heating rate of 20 oC/min. The sintered mineral composite was crashed and sieved, and mixed with 20 wt % of nanocellulose, as a pore forming agent. Nanocellulose mixture was pressed into pallets under 5 t/cm2 and sintered at 700 oC, under a heating rate of 5 oC/ min. The obtained synthetic cordierite was further tested as the adsorbent activated by polyethylenimine/ nano-CeO2 for the removal of Ni2+ and Cd2+ -ions. The adsorption isotherms, kinetics models, and thermodynamic parameters were also analyzed, manifesting that the adsorption is a spontaneous and endothermic process. The phase composition of the pristine and activated cordierite was analyzed by the X-ray diffraction method (XRD), Fourier transformation infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). This work has shed light on the mechanism of heavy metals removal from the aquatic medium using the novel hybrid (nano)synthesized material