Optimization of hydrothermal carbonization process of grape pomace and application of obtained hydrochar

Predmet ovog rada je razvoj i optimizacija procesa hidrotermalne karbonizacije komine grožđa i ispitivanje mogućnosti upotrebe dobijene hidročađi kao adsorbensa olova iz vodenih rastvora. U cilju optimizacije procesa, ispitan je uticaj reakcione temperature na transformaciju biomase, primenom različitih fizičko-hemijskih metoda karakterizacije dobijenih proizvoda karbonizacije na 180, 200 i 220 °C. Hidrotermalno indukovane strukturne promene u dobijenim hidročađima su okarakterisane ispitivanjem fizičko-hemijskog sastava, gorivnih karakteristika, kao i primenom termogravimetrijske, morfološke i spektroskopske analize, dok je u procesnim vodama određen sadržaj neorganskih elemenata, urađena spektroskopska analiza, analiza sadržaja pojedinačnih organskih komponenti i ispitan antioksidativni potencijal. Dobijeni rezultati su pokazali da između dobijenih hidročađi postoje bitne strukturne razlike. Utvrđeno je da hidrotermalna degradacija hemiceluloze i celuloze, uzrokovana povećanjem temperature karbonizacije u najvećoj meri indukuje strukturne promene biomase tokom konverzije. Hidročađ koja poseduje značajan energetski potencijal, povećan sadržaj ugljenika i aromatičnost, kao i mogućnost re-adsorpcije pojedinih neorganskih elemenata dobijena je karbonizacijom na 220 °C. Takođe, povećanje reakcione temperature dovodi do porasta sadržaja fenola, polifenolnih jedinjenja i organskih molekula u procesnim vodama, dok istovremeno uzrokuje opadanje antioksidativne aktivnosti, ukupnog sadržaja antocijana i organskih kiselina. Mogućnost upotrebe hidročađi kao biosrbenta ispitana je sa aspekta adsorpcije Pb2+ jona iz vodenih rastvora. Kako bi se izabrao uzorak sa najboljim adsorpcionim kapacitetom izvršena su preliminarna ispitivanja procesa adsorpcije Pb2+ jona primenom hidročađi dobijenih na tri pomenute reakcione temperature. Dobijeni rezultati su ukazali da hidročađ dobijena na 220 °C pokazuje najbolji adsorpcioni kapacitet (27,8 mg/g), pa je stoga ova hidročađ izabrana za detaljna ispitivanja procesa adsorpcije Pb2+ jona...The subject of this work was the development and optimization of hydrothermal carbonization of grape pomace and investigation of potential applications of the obtained hydrochar as adsorbent of lead from aqueous solutions. In order to optimize the process, influence of the reaction temperature on transformation of biomass was investigated using different physico-chemical characterization methods of the products obtained at 180, 200 and 220 °C. Hydrothermal induced structural changes in hydrochars were elucidated by examination of physico-chemical composition, fuel characteristics, using thermogravimetric, morphological and spectroscopic analysis. IR spectroscopy, analysis of inorganic, as well as organic compounds, and antioxidant assays, were used for process waters characterization. The results showed significant structural differences between the obtained products. It has been found that degradation of hemicellulose and cellulose, caused by temperature increase, governs the most significant structural changes in biomass during carbonization. The formation of hydrochar with significant energy potential, increased carbon content and the best adsorption ability, but decreased H/C ratio was achieved at 220 °C. Also, at higher temperature an increase in total phenolic and organic content in process waters was observed, while total antioxidative capacity, anthocyanin and organic acid content simultaneously decreased. Application of the obtained hydrochars was tested via adsorption of Pb2+ ions from aqueous solution. In order to select material with the best adsorption ability, preliminary studies of Pb2+ sorption using hydrochars obtained at three aforementioned reaction temperatures were performed. Obtained results indicated that hydrochar produced at 220 °C exhibited the best adsorption potential (27.8 mg/g), and therefore this sample was chosen for further investigations of Pb2+ removal..

Supplementary material for the article: Šoštarić, T. D.; Petrović, M. S.; Pastor, F. T.; Lončarević, D. R.; Petrović, J. T.; Milojković, J. V.; Stojanović, M. D. Study of Heavy Metals Biosorption on Native and Alkali-Treated Apricot Shells and Its Application in Wastewater Treatment. Journal of Molecular Liquids 2018, 259, 340–349. https://doi.org/10.1016/j.molliq.2018.03.055

Supplementary material for: [https://doi.org/10.1016/j.molliq.2018.03.055]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2152]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/2970

Plesni i mikotoksini u zrnu kukuruza posle berbe

Incidence of toxigenic fungi (molds) and concentration of mycotoxin aflatoxin B1 (AFB1), deoxynivalenol (DON), zearalenone (ZON) and fumonisin (FB1) were studied in the maize grains collected immediately after harvesting in 2012. A total of 29 maize samples were analyzed and the highest incidence was determined for fungal species of Rhizopus (56.41%), Aspergillus (43.66%) and Fusarium (14.97%) genera. Significantly lower incidence was obtained for species of genus Penicillium (3.31%), and especially for species of genera Acremonium (1.38%), Alternaria (0.75%) and Cladosporium (0.14%). Among toxigenic fungi Aspergillus flavus (36.69%) was the most common species of Aspergillus genus, whereas the Fusarium verticillioides with 14.69% of incidence was the predominant species of Fusarium genus. In all studied maize samples, the presence of AFB1, ZON and FB1 mycotoxins was established, except for DON which was established in 75.86% samples. AFB1 was detected in average concentration of 13.95 μg kg-1 for 44.83% of samples, and average concentration higher than 40 μg kg-1 for 55.17% of samples. The average concentrations of DON which was detected was 235 μg kg-1, while it was 98.38 μg kg-1 and 3590 μg kg-1 for the presence of ZON and FB1, respectively. Moderate positive correlation was obtained between concentrations of AFB1 and FB1 (r=0.35), while weak positive correlation was established between concentrations ZON and DON (r=0.02).Učestalost toksigenih gljiva (plesni) i koncentracija mikotoksina aflatoksina B1 (AFB1), deoksinivalenola (DON), zearalenona (ZON) i fumonizina B1 (FB1) je proučavana u uzorcima zrna kukuruza prikupljenim odmah posle berbe u 2012. godini. U ispitivanih 29 uzoraka najveću zastupljenost imaju vrste iz rodova Rhizopus (56,41%), Aspergillus (43,66%) i Fusarium (14,97%). Značajno niža učestalost ustanovljena je za vrste roda Penicillium (3.31%), a posebno za vrste iz rodova Alternaria (0,75%) i Cladosporium (0,14%). Među toksigenim vrstama, A. flavus (36,69%) je bila najučestalija vrsta iz roda Aspergillus, dok je F. verticillioides sa prisustvom od 14,69% bila dominantna vrsta roda Fusarium. U svim ispitivanim uzorcima kukuruza ustanovljeno je prisustvo mikotoksina AFB1, ZON-a i FB1 (100%), osim DON-a koji je bio prisutan u 75,86% uzoraka. AFB1 je detektovan u prosečnoj koncentraciji od 13,95 μg kg-1 u 44,83% uzoraka i u prosečnoj koncentraciji od više od 40 μg kg-1 u 55,17% uzoraka. Prosečna koncentracija DON-a je bila 235 μg kg-1, ZON-a 98,38 μg kg-1 i FB1 3590 μg kg-1. Srednja pozitivna korelacija ustanovljena je između koncentracija AFB1 i FB1 (r=0,35), dok je slaba pozitivna korelacija utvrđena između koncentracija ZON-a i DON-a (r=0,02)

EFFECT OF ANTIMONY DOPING ON PROPERTIES OF BARIUM TITANATE CERAMICS

Nanopowders of pure and antimony doped barium titanate were synthesized by polymeric precursors method. Sintering was performed at 1300 oC for 8 h. XRD analysis showed formation of cubic crystal structure in all nanopowders and tetragonal in ceramics. The influence of antimony concentration on structure change and microstructure development was analyzed. The significant dielectric properties modification as a consequence of antimony doping was noticed. The electrical resistivity measurements pointed out that antimony concentration influenced on materials change from insulator to semiconductor

Distribucija plesni i mikotoksina u silaži od zrna kukuruza u silo-trenču

In this study the mycological and mycotoxicological contamination of maize silage samples collected from the bottom (BL), middle (ML) and top (TL) layer in the silage trench silo was studied. Mycological testing of the silage contamination showed the presence of five potential toxigenic fungi of the genera, Aspergillus, Fusarium, Mucor, Penicillium and Rhizopus with their total number ranging from 1 to 10 x 103 CFU g-1. Also, four mycotoxins were detected as followed, aflatoxin B1 (AFB1), zearalenone (ZON), deoxynivalenol (DON) and fumonisin B1 (FB1). Mycotoxins AFB1 and FB1 were detected as 100% positive in all the samples tested. An average concentration of AFB1 was 2.31 μg kg-1, 2.51 μg kg-1 and 2.81 μg kg-1 in BL, ML and TL respectively, while the concentration of FB1 was 1292.00 μg kg-1, 1298.00 μg kg-1 and 1902.00 μg kg-1 in BL, TL and ML respectively. Average concentration of toxin ZON in positive samples was 15.69 μg kg-1 in BL and 30.68 μg kg-1 in ML, while its presence in the samples taken from the top layer was not detected. An average concentration of DON toxin in positive samples were in the range of 41.71 μg kg-1 for TL, 79.20 μg kg-1 for ML, while it was 97.00 μg kg-1 for BL. There was no statistically significant correlation between moisture content and total number of moulds and concentrations of certain mycotoxins. However, statistically highly significant correlations between the total number of moulds and AFB1 concentration (r = 1.0), ZON (r = 0.99) and FB1 (r = 0.91) were established, while weak correlation was obtained in the case of DON and total mould counts (r = 0.54).U radu je ispitivana mikološka i mikotoksikološka kontaminacija uzoraka silaže od zrna kukuruza sakupljenih iz donjeg (DS), srednjeg (SS) i gornjeg (GS) sloja silaže u silo-trenču. Mikološkim ispitivanjima kontaminacije silaže ustanovljeno je prisustvo pet potencijalno toksigenih rodova plesni, Aspergillus, Fusarium, Mucor, Penicillium i Rhizopus sa ukupnim brojem od 1-10 x 103 CFU g- 1. Takođe, detektovana su i četiri mikotoksina kao što su aflatoksin B1 (AFB1), zearalenon (ZON), deoksinivalenol (DON) i fumonizin B1 (FB1). Mikotoksini AFB1 i FB1 detektovani su kao 100% pozitivni u svim ispitivanim uzorcima. Prosečna koncentracija AFB1 bila je 2,31 μg kg-1 za GS, 2,51 μg kg-1 za DS i 2,81 μg kg-1 za SS, dok je prosečna koncentracija FB1 bila 1292,00 μg kg-1 za DS, 1298,00 μg kg-1 za GS i 1902,00 μg kg-1 za SS. Prosečna koncentracija ZON toksina u pozitivnim uzorcima je 15,69 μg kg-1 za DS i 30,68 μg kg-1 za SS, dok njegovo prisustvo nije detektovano u uzorcima iz gornjeg sloja. Prosečna koncentracija DON toksina u pozitivnim uzorcima bila je od 41,71 μg kg-1 za GS, 79,20 μg kg-1 za SS do 97,00 μg kg-1 za DS. Nije utvrđena statistički značajna korelacija sardžaja vlage sa ukupnim brojem plesni i koncentracijom pojedinih mikotoksina. Međutim, utvrđena je statistički veoma značajna korelacija između ukupnog broja plesni i koncentracije AFB1 (r = 1,0), ZON (r = 0,99) i FB1 (r = 0,91), a nešto manja u slučaju DON i ukupnog broja plesni (r = 0,54)

Liquid-phase microextraction in a single hollow fibre - determination of mass transfer coefficient

In this study, the mass transfer coefficient of two local anesthetics in liquid-phase microextraction (LPME), which is performed in a single hollow fibre, was investigated. Previously developed mathematical model has been applied for the determination of the overall mass transfer coefficient based on the acceptor phase, KA, in an unsteady-state LPMEPhysical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Supplementary material for the article: Mihajlović, M.; Petrović, J.; Maletić, S.; Isakovski, M. K.; Stojanović, M.; Lopičić, Z.; Trifunović, S. Hydrothermal Carbonization of Miscanthus × giganteus: Structural and Fuel Properties of Hydrochars and Organic Profile with the Ecotoxicological Assessment of the Liquid Phase. Energy Convers. Manage. 2018, 159, 254–263. https://doi.org/10.1016/j.enconman.2018.01.003

Supplementary material for: [https://doi.org/10.1016/j.enconman.2018.01.003]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2100

The effects of the „Stomp“ herbicide application on the microbial prevalence in the soil.

Agricultural production has benefited a lot from herbicides; however, the use of herbicides caused many environmental problems. Herbicide application can affect the biodiversity of an ecosystem by killing non-target organisms. Microorganisms in the soil are important factors for plant growth; they represent the biological factor of soil fertility. Herbicides can have a beneficial effect on the development of some microorganisms and a negative on others, leading to depletion of microbial diversity in soil. The objective of this work is to determine microbial activity in the soil and to isolate herbicide-resistant bacteria after the use of the “Stomp” herbicide. Agar plate method was used for the determination of microbial prevalence in the soil. The results showed an increase in the total number of bacteria, ammonifiers, fungi, and actinomycetes. Nine isolates, mostly Gram-positive spore- forming rods, showed an ability to grow in the mineral salt medium with different concentrations of “Stomp” herbicide. Isolates G1/1 and G1/2, showed high level of tolerance at the initial pendimethalin concentration of 25 mg/l. Those isolates have the potential to be used to decontaminate herbicide affected ecosystems

Assessment of computed tomography simulators used in radiotherapy treatment planning in Serbia, Croatia, and Bosnia and Herzegovina

The purpose of this work was to evaluate computed tomography simulators used in radio-therapy treatment planning in Serbia, Croatia, and Bosnia and Herzegovina. A survey of quality assurance programmes of 24 computed tomography simulators in 16 facilities was conducted. A dedicated CT-to-ED phantom was scanned at 120 kV and 140 kV, to obtain CT-to-ED conversion curves as well as CTDIvol. Thoracal phantoms were scanned in the standard and extended field of view to evaluate the dosimetric effect on treatment planning and delivery. The mean age of the measured scanners was 5.5 years. The mean water HU value was –6.5 (all scanners, all voltages) and air HU value was –997. Extended field of view computed tomography data differ from the standard field of view and differences between conversion curves have significant dosimetric impact. The CTDI data showed a large range of values between centers. Better quality assurance of computed tomography simulators in all countries is recommended. The CT-to-ED curve could be used as default at one voltage and per manufacturer. Extended field of view imaging can be used, but treatment planning should be avoided in the regions out of the standard field of view