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Application of cherry stones for the removal of brilliant green
No full textDyes, which are widely used in many industries, are often discharged into the water, without further
treatment, causing serious problems for human health and the natural ecosystems. Brilliant green (BG) is a
cationic dye, with genotoxic and carcinogenic properties and therefore needs to be separated from
wastewater. In this study, environmental and low-cost food industry waste, cherry stones, was mechanically
treated in order to obtain sorbent (CS) and analysed for the sorption of BG. Sorbent CS was characterized
by SEM-EDX and ATR-FTIR technique, while the pHsus and pHpzc were also evaluated. Characterization
results revealed that CS pose multilayer porous surface, rich in functional groups (dominantly carboxyl and
hydroxyl) with pHpzc close to 5, indicating plausible interaction with BG at pH values greater than this one.
Sorption experiments were conducted in a stirring batch system under isothermal conditions. The influence
of operating parameters such as pH, sorbent contact time and initial dye concentration on the sorption of
BG was investigated. The nonlinear forms of two adsorption isotherms (Langmuir and Freundlich) were
used to analyze the sorbent uptake capacity. The maximum sorption capacity obtained by Langmuir model
was found to be 189.05 mg/g (with adsorbent dosage 2 g/L, in BG concentration range 10 – 200 mg/L, pH
= 7, agitation speed 200 rpm and T=25 oC). Results from this study suggest that CS sorbent, as a renewable
resource which is, at the same time, waste from the food industry, have a potential to be applied for
removing BG dye from contaminated wastewater
Forensic science and fractal nature analysis
No full textForensic photography, also referred to as crime scene photography, is an activity that records the initial appearance of the crime scene and physical evidence in order to provide a permanent record for the court. Nowadays, we cannot imagine a crime scene investigation without photographic evidence. Crime or accident scene photographs can often be reanalyzed in cold cases or when the images need to be enlarged to show critical details. Fractals are rough or fragmented geometric shapes that can be subdivided into parts, each of which is a reduced copy of the whole. Fractal dimension (FD) is an important fractal geometry feature. There are many applications of fractals in various forensic fields, including image processing, image analysis, texture segmentation, shape classification, and identifying the image features such as roughness and smoothness of an image. Fractal analysis is applicable in forensic archeology and paleontology, as well. The damaged image can be reviewed, analyzed, and reconstructed by fractal nature analysis
Leaching of polymetallic Cu-Zn-Pb concentrate with sodium nitrate in sulphuric acid
No full textU radu su prikazani i diskutovani rezultati luženja polimetalnog sulfidnog Cu-Zn-Pb koncentrata rastvorom natrijum-nitrata i sumporne kiseline pri atmosferskom pritisku. Prikazan je hemijski i mineraloški sastav polaznog koncentrata i čvrstih ostataka nakon procesa luženja. Hemijske reakcije luženja i mogućnosti njihovog odvijanja analizirane su primenom termodinamičke analize na osnovu izračunatih Gibbsovih energija i analize E-pH dijagrama. Eksperimentalno je analiziran uticaj temperature i vremena na stepen izluženja korisnih metala iz sulfidnog koncentrata. Pokazano je da je moguće dobiti bakar, cink i železo u rastvoru u obliku sulfata, dok olovo u obliku anglesita (PbSO4) ostaje u čvrstom ostatku nakon procesa luženja. Železo se oksidiše u Fe (III) -sulfat, koji učestvuje u luženju sulfidnih minerala i prelazi u Fe (II) -sulfat.The results of polymetallic sulphide Cu-Zn-Pb concentrate leaching with sulphuric acid in the presence of sodium nitrate as an oxidizing agent, at atmospheric pressure, are presented and discussed. Chemical composition and phase ratio of the starting concentrate and solid residuals after the leaching process are shown. Chemical reactions of leaching and their thermodynamic probabilities are predicted based on the calculated Gibbs energies and analysis of E-pH diagrams. The influence of temperature and time on the leaching degree of the concentrate's components is experimentally determined. It is shown that it is possible to obtain copper, zinc and iron in a solute form, while lead in the anglesite (PbSO4) form remains in the solid residual after the leaching process. The iron is being oxidized to Fe(III)-sulphate, which takes part in a sulphide leached minerals and turns into Fe(II)-sulphate
Coating based on basalt protection metal structures
No full textU radu su prezentirani rezultati sinteze nove vrste vatrostalnih premaza na bazi bazalta za zaštitu metalnih konstrukcija u uslovima delovanja kavitacije. Polazni uzorci bazalta dobijeni su iz ležišta Vrelo - Kopaonik. Vatrostalni punioc na bazi bazalta dobijen je drobljenjem i mlevenjem izabranih uzoraka bazaltnih stena. Za karakterizaciju dobijenih uzoraka punioca korišćene su metode: rendgenska difrakciona analiza (XRD), skenirajuća elektronska mikroskopija (SEM) i optička mikroskopija. Istraživanjem su definisani sastavi premaza na bazi bazalta sa vezivom na bazi epoksi smole, organskim aditivima i organskim rastvaračem. Svojstva otpornosti zaštitnih premaza nanesenih na metalne površine ispitivana su primenom ultrazvučne vibracione metode sa stacionarnim uzorkom prema standardu ASTM G 32. Da bi se ocenila otpornost površine uzorka na dejstvo kavitacije ispitivana je površina uzorka pre i za vreme testiranja. Površine uzoraka snimane su na skenirajućem elektronskom mikroskopu u cilju praćenja i analize morfologije oštećenja površine. Za ocenu oštećenja površine uzoraka primenjena je kompjuterska analiza slike prema programu Image Pro Plus. Dobijeni rezultati ispitivanja pokazali su visoku otpornost slojeva premaza na dejstvo kavitacije, sa malim gubicima mase, malim oštećenjima površine premaza i kavitacionom brzinaom 0,1 mg/min.The paper present the results of the synthesis of a new refractory coating based on basalt for the protection of metal construction under conditions of cavitation. Initial basalt samples obtained from the locality Vrelo - Kopaonik. The basalt based refractory filler was obtained by crushing and grinding selected samples of basalt rock. XRD, SEM and optical microscopy methods were used to characterize the obtained filler samples. The research defined the composition of basalt -based coating with epoxy resinbased binder, organic additives and organic solvent. The resistance properties of protective coatings applied to metal surface were investigated using the ultrasonic vibration method with a stationary sample according to the ASTM G 32 standard. To evaluate the resistance of the sample surface to the action of cavitation, the sample surface was examined before and during testing. The surface of the samples was monitored by scanning electron microscopy in order to analyze the morphology of surface damage. Computer image analysis according to the Image Pro Plus program was applied to assess the damage to the sample surface. The obtained test results showed high resistance of the coating layers to the effect of cavitation, with small mass losses, small damage to the coating surface and a cavitation rate of 0,1 mg/min
Single-stage production of miscanthus hydrochar at low severity conditions and application as adsorbent of copper and ammonium ions
No full textIn the framework of bio-circular economy, miscanthus biomass was valorized through a single-stage, low severity hydrothermal carbonization process. The produced hydrochars were characterized using elemental and spectroscopic methodologies. It was determined that as the temperature increased so did the C content (47.9 and 68.9% for the samples prepared at 180 and 260 degrees C, respectively), whereas the O content decreased (from 44.2 to 25.5%, respectively). The adsorption behaviour of the hydrochars was investigated in the adsorption of Cu2+ and NH4+ and MIS-180 was determined as the optimum sample, achieving qmax values of 310 and 71 mg g-1, respectively. Isotherm and kinetic analysis indicated the higher number of O-containing functional groups of MIS-180 as the main reason for its higher adsorption capacities. Furthermore, Cu2+ adsorption followed the 2ndorder kinetic model, whereas NH4+ adsorption followed the 1st-order kinetic model, due to the different mechanisms involved, inner-sphere and outer-sphere complex formation, respectively
The chitosan-based bioactive composite coating on titanium
No full textThis paper describes a promising electrophoretic deposition (EPD) approach for developing composite coatings based on chitosan with the additional components of hydroxyapatite, graphene, and gentamicin on titanium substrate. Bioactive properties were investigated in vitro by immersing the coatings in simulated body fluid (SBF) at 37 degrees C. The newly formed biomimetic layer on the top of the deposited chitosan-based coatings on Ti was confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and electrochemical measurements, while coatings' bioactivity was proved by alkaline phosphatase activity assay in MRC-5 and L929 tested cell lines. The biocompatibility towards MRC-5 and L929 cell lines was investigated by dye exclusion test (DET) implying the non-cytotoxic effect of coatings. Gentamicin release studies were monitored during 21-day by high-performance liquid chromatography coupled with mass spectrometry, indicating rapid release of gentamicin (approximate to 40%) in the first 48 h and more than 60% after 14 days
Deashing and desulfurization of subbituminous coal from the East field (Bogovina Basin, Serbia) - Insights from chemical leaching
No full textThe study is focused on the determination of the most effective chemical leaching process for the simultaneous demineralization/deashing and desulfurization of subbituminous coal from the Bogovina Basin. Coal was treated for 30 min, at different temperatures, using variable concentrations of hydrochloric, nitric, acetic and citric acids; hydrogen peroxide, mixture of hydrogen peroxide and nitric acid (pH 2), as well as by the stepwise leaching process (nitric acid + mixture of hydrogen peroxide and nitric acid, pH 2). The changes in mineral composition, caused by the chemical leaching, are followed using X-ray diffraction, whereas alterations of coal organic matter are tracked by Fourier-transform infrared spectroscopy and the content of fixed carbon. Inorganic acid leaching, regardless of the temperature and acid concentration, enabled the successful deashing of coal, whereas the percent of desulfurization was insufficient. The organic acid leaching was not satisfactory for both, deashing and desulfurization. Leaching by H2O2 and H2O2/HNO3 mixture (pH 2) resulted in moderate desulfurization, but the ash reduction was low. The most suitable method for the simultaneous effective ash (78 wt.%) and the sulfur (66 wt. %) removal from Bogovina coal is the two-step leaching, combining 10 vol. % HNO3 and mixture of 35 vol. % H2O2/10 vol. % HNO3 of pH 2 at 60 degrees C
Amino-modified hollow alumina spheres: effective adsorbent for Cd2+, Pb2+, As(V), and diclofenac removal
No full textA simple sol-gel method and external gelatinization method of hollow alumina spheres synthesis were developed in this study. The spheres were modified with polyethyleneimine (PEI) producing PEI-Al2O3 via (3-glycidyloxypropyl)trimethoxy-silane, GLYMO, linker. Characterization results, obtained using XRD and SEM microscopy revealed spherical geometry with a hollow core of PEI-Al2O3 adsorbent. Introduction of a large number of the amino group, 6.9 mmol g(-1), contributes to achieving high adsorption capacities, q(m), of 95.6, 124.9, 61.3, and 125.9 mg g(-1) for Cd2+, Pb2+, As(V), and DCF, respectively, which is obtained by using the Langmuir model. Thermodynamic studies indicated feasible adsorption and higher spontaneity with temperature increase. The kinetic study conveniently modeled using pseudo-second-order (PSO) and Weber-Morris kinetic model, as well as single resistance mass transfer model, indicated a change of the contribution of diffusional processes during adsorption with a dominance of intra-particle diffusion. The fixed-bed column adsorption data, fitted using Bohart-Adams, Clark, Yoon-Nelson, and Thomas models, showed lower capacity in comparison to batch study, and thus clear potential applicability of PEI-Al2O3 was deduced even at a high loading of feed water
Chemical durability of sintered glass-composite prepared from glass cullet and waste foundry sand
No full textIn this study, the glass-composite was prepared using glass cullet and waste foundry sand as raw materials. The powder technology route was employed. The mixtures containing 10-50 wt% of the sand were sintered at T = 750 degrees C for t =1h. XRD and DTA analyses were performed. The chemical durability of the resulting glass-composite was determined by leaching test in HCl, H2SO4, NaOH and distilled water at T = 95 degrees C for t =1h. It was shown that the sintering process carried out without the crystallization of the glass matrix. The lowest chemical durability was determined in alkali solution of glasscomposite
The Embryotoxic Potential and Photocatalytic Degradation of Thiophanate-Methyl
No full textPesticides are substances designed to protect plants
from various types of diseases and pests [1]under UV irradiation
is studied using synthesized Zinc oxide (ZnO.
Synthetic organic pesticides, in addition to the high
efficiency, have led to frequent adverse environmental
impact, as a consequence of their high accumulation
and toxicity. Due to the increased pollution of water
with mixture pesticides, it is necessary to use different
processes for their removal and degradation. Therefore,
oxidative processes have been developed, commonly
named as Advanced Oxidation Processes (AOPs).
Among them, special attention was attributed to photocatalysis,
as a process that enables the degradation
of difficult-to-decompose organic molecules under the
action of UV radiation in the presence of catalysts [2].
In this study the photocatalytic degradation of thiophanate-
methyl (TM) in the presence of the TiO2 Degussa
P-25 catalyst was investigated. Different experimental
conditions were varied, such as the concentration of
the pesticide solution, the mass of the catalyst and the
influence of the anions (chloride, sulphate, nitrate, etc.).
The pesticide concentration in the reaction system was
monitored based on the decrease in system absorbance
using a Shimadzu 1800 UV spectrophotometer. For optimized
conditions of complete photodegradation, the
environmental acceptability of the defined degradation
process was examined. The toxic effect of the TM solution
before and after degradation was examined using
the embryotoxicity test with Danio rerio, in order to
prove the reduction of toxicity and the success of the
degradation process [3]which raises the issue of potential
influence of different formulation types on herbicide
toxicity. The present study evaluated the toxicity and
teratogenic effects of the active ingredient clomazone
and its two formulations (Rampa® EC and GAT Cenit
36 CS, both containing 360 g a.i./l of clomazone.
Comparing the obtained results of the influence of
ions on the processes of photocatalysis, it was noticed
that all ions have catalytic effects on the kinetics of the
degradation process of TM. The presence of sulphates
and carbonates had the greatest catalytic effect, while
hydrogen phosphates and bicarbonates showed the lowest
catalytic capacity.
The optimal experimental conditions were obtained
using 0,2 g/L of TiO2 and 5 mg/L of TM solution. In
addition, the embryotoxicity test followed the analytical
examination. Comparison of results obtained in embryotoxicity
assay testing of the initial solution, partly
and completely degraded samples confirmed suitability
of applied degradation method. Increase in toxicity,
compared to the initial solution, was registered in partly
degraded sample. This observation can be attributed to
increase in concentration of carbendazim (TM metabolite)
more toxic than parent substance. Finally, completely
degraded sample caused no mortality or adverse
effects in D. rerio embryos after 120 h exposure. Toxicity
of samples, in decreasing order is half degraded >
initial >completely degraded sample.
Based on the obtained results it can be concluded
that used photocatalytic degradation process can be successfully
applied in pesticide contaminated water management