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Removal of Pb(II) using alginate - immobilized Myriophyllum spicatum beads
No full textDirective 1999/31/EC requires that biowaste with more than 3% organic content isn't accepted for landfilling directing toward more efficient use of biological material from the landfill. Myriophyllum spicatum is an aquatic weed which grows on every continent except Antarctica and it is noted for its capability to cause different problems, so its growth must be controlled. Utilization of bio-waste in the bioeconomy can be achieved with biosorption. In this study was investigated M. spicatum/alginate (5: 1) biosorbent (MsA) for the removal of Pb(II) ions from aqueous solutions. MsA was characterized by Fourier transform infrared spectroscopy. The batch equilibrium was expressed by 5 isotherms and Redlich-Peterson isotherm model provided the best fit with the experimental data. Since, alginate-immobilized M. spicatum beads have superb Pb(II) uptake 200 mg/g they are appropriate cost-effective, environmental friendly biosorbent with potential application for continuous flow reactors. Managing and processing bio-waste must be deployed and integrated to meet the requirements of the sustainability
The assessment of maturation changes of humic coal organic matter - Insights from closed-system pyrolysis experiments
No full textThe artificial maturation changes of the humic coal organic matter (OM) from late diagenesis to the semianthracite stage of coalification were investigated using the closed-system pyrolysis. Two extracted coal samples, a subbituminous coal 26C (with a random vitrinite reflectance Rr = 0.42%) and a high volatile bituminous coal 30C (Rr = 0.56%), were pyrolysed during 4 hat two different temperatures, 250 degrees C and 400 degrees C. The applied petrographic and organic geochemical analyses showed that the humic coal OM is sensitive to the artificial thermal stress. A good correlation between the changes in petrographic characteristics and the derived liquid products was observed. The contents of all vitrinite macerals, as well as total vitrinite, increased during the thermal maturation. The abundance of liptinite macerals decreased during the maturation and they practically disappeared after 4 h of the pyrolysis at 400 degrees C. The total inertinite contents increased after the pyrolysis at 250 degrees C, yet to be decreased after the pyrolysis at 400 degrees C. The content of organic carbon increased from coals to the solid residues at 400 degrees C, whereas the contents of total hydrogen and sulphur decreased. The yields of gases, liquid products and solid residues at respective temperatures were very similar for both coals, regardless of the rank. As expected, the pyrolysis at 400 degrees C gave higher gas and liquid yields than at 250 degrees C. Regarding the liquid pyrolysates, more pronounced changes were observed in the distribution of aromatic compounds than in saturated biomarkers. The distributions of the aromatics indicate that apart from cracking and isomerisation (the formation of thermodynamically more stable isomers), the reactions of dehydrocyclization, condensation (the formation of more stable conjugated systems) and aromatization, as well as reactions involving H2S, elemental sulphur and reactive phenyl radicals released during the pyrolysis, also play an important role. It was shown that bentonitic clay plays a more important role in the subsequent aromatization of the OM than the initial maturity of the coal OM. n-Alkane parameters were useful at lower maturities (up to similar to 0.75% Rr), whereas sterane, naphthalene and phenanthrene maturity ratios are applicable at higher maturities (>0.75% Rr). Hopane parameters showed variable sensitivities over the investigated maturity range (0.5-1.8% Rr). The most sensitive maturity parameters in the wide range of the humic OM maturity (0.5-1.8% Rr) are vitrinite reflectance, phenylnaphthalene ratio, methylchrysene index 2 and a parameter proposed in this study, based on the distribution of methylfluorenes (MF): (2- + 3-MF) / (1- + 4-MF). Generally, maturity parameters based solely on the isomerisation reactions of alkylaromatics, which do not include alkylation/dealkylation processes, are more appropriate for the humic OM, particularly at higher maturities.info:eu-repo/grantAgreement/MESTD/Basic Research (BR or ON)/176006/RS/
Mineralogy and genetic characteristics of the Rudnik Pb-Zn/Cu,Ag,Bi,W polymetallic deposit (Central Serbia) - New occurrence of Pb(Ag)Bi sulfosalts
No full textThe mineral aschamalmite, of heyrovskyite-like composition, but different in structure, from the Rudnik Pb–Zn/Cu,Ag,Bi,W polymetallic deposit in the central part of Serbia has been investigated. This polymetallic deposit includes over 90 hydrothermal and skarn-replacement orebody types, primarily hosted by Cretaceous sediments and occassionally by Oligocene dykes and sills of dacitic composition, and contact-metamorphic-metasomatic rocks. These rocks are host to an assemblage of pyrrhotite, colloform pyrite, chalcopyrite, galena, arsenopyrite, native bismuth and scheelite as well as minor pyrite, sphalerite, bismuthinite, argentopentlandite, and native silver. The chemical composition of the ore is very complex, where weight contents of valuable metals range as follows (%): Zn 0.49–4.49; Pb 0.90–5.66; Cu 0.08–2.18; WO3 0.05–1.18; Ag 0.005–0.030; Bi 0.005–0.081; and Cd 0.002–0.016. In reflected light, aschamalmite is optically anisotropic, with moderately high bireflectance ranging from slightly greenish to slightly gray. Electron-microprobe analysis gave an average crystallochemical formulae of (Pb5.82Ag0.20)Σ6.02Bi2.03(S8.93Te0.02Se0.01)Σ8.96. The strongest diffraction maximums of the X-ray powder pattern [d(in Å)(I)] are 3.419(100), 3.382(92), and 3.334(66). Monoclinic unit cell parameters are a=13.727(7); b=4.122(3); c=31.32(2) Å; β=90.72(5) o; and V=1771.8(1) Å3. Mineral assemblages and genesis of the Rudnik polymetallic deposit are discussed in detail and the sulfobismuthite mineralization has been compared with similar well-known global deposits
Obtaining fillers based on limestone from deposit Možura" – Ulcinj, for applications in various industries
No full textPaper presents results of investigations of the possibility of using “Možura”-Ulcinj limestone as filler in
various industries. Micronization, granulometric composition, oil and water absorption and degree of
whiteness were investigated, and chemical and thermal analyses were performed. Physico-chemical
properties of this sample classify it among high quality carbonate raw materials with high CaCO3 content
of 98.79%, with low contents of MgCO3 0.82% and SiO2 0.23%. Its quality satisfies requirements of
standards on using of calcium carbonate as filler in next industries: paints and coatings; rubber and
PVC; paper, glass ; foundry ; sugar industry production of mineral fertilizers and metallurgy
Vodeni korov Myrophyllum spcatum inkapsuliran alginatom kao biosorbentom za uklanjanje teških metala iz otpadnih voda - MsA-biosorb
No full textSynthesis of nano-crystalline NiFe2O4 powders in subcritical and supercritical ethanol
No full textNano-crystalline nickel ferrite has a broad range of applications due to its favourable magnetic properties. Those characteristics can be significantly influenced by the synthesis pathway including methods conducted in the presence of supercritical alcohols. Nano-crystalline NiFe2O4 powders were obtained in the reaction under subcritical and supercritical conditions of ethanol. Both high pressure synthesis routes resulted in powders with smaller primary particles and higher mesoporosity than co-precipitation method. Upon the annealing treatment the average crystallite size increased while material structure remained uniform, resulting in significantly enhanced magnetic properties, such as coercivity and remanence. It was found that synthesis under supercritical conditions provides higher conversion but also material with larger average crystallite size upon annealing. The time and temperature of annealing stage significantly influenced the morphology and magnetic properties of the obtained powders
Thermodynamic properties and microstructures of different shape-memory alloys
No full textThe results of a thermodynamic-properties calculation conducted using a general solution model (GSM) and an experimental investigation of the microstructures of different shape-memory alloys (SMAs) are presented in this paper. The investigated alloys belong to ternary systems Cu-Al-Zn and Cu-Mn-Ni and to quaternary system Ni-Cu-Fe-Mn. The examinations were conducted using light microscopy (LM) and scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM-EDX)
Using of the natural and Fe(III)-modified zeolite-alginate beads for adsorption of lead ions from water solutions
No full textIn this paper, adsorption of lead ions from water solutions by thenatural
(NZA) and Fe(III)-modified zeolite-alginate (FeA) beads was investigated.
Experiments were performed for different initial concentrations and results
showed improving adsorption properties of the starting materials (natural
(NZ) and Fe(III)-modified zeolite (FeZ)) after modification with alginate.
Also, for both adsorbents, direct relation between initial concentration and
adsorbed amount of lead was observed. Much higher adsorption of lead was
obtained by FeA than NZA. Results also showed that presence of alginate,
beside improving adsorption properties have a positive influence on physical
properties of starting samples. After immobilization of the starting samples
with alginate no falling apart of the beads was noticed and there was no water
turbidity
Mineralogy and genetic features of the Cu-As-Ni-Sb-Pb mineralization from the Mlakva polymetallic deposit (Serbia) — New occurrence of (Ni-Sb)-bearing Cu-arsenides
No full text(Ni-Sb)-bearing Cu-arsenides are rare minerals within the Mlakva and Kram mining sectors (Boranja ore field) one of the less-known Serbian Cu deposits. (Ni-Sb)-bearing Cu-arsenides were collected from the Mlakva skarn-replacement Cu(Ag,Bi)-FeS polymetallic deposit. The identified phases include β-domeykite, Ni-bearing koutekite and (Ni-Sb)-bearing α-domeykite. (Ni-Sb)-bearing Cu-arsenides are associated with nickeline, arsenical breithauptite, chalcocite, native Ag, native Pb and litharge. Pyrrhotite, pyrite, chalcopyrite, cubanite, bismuthinite, molybdenite, sphalerite, galena, Pb(Cu)-Bi sulfosalts and native Bi, as well as minor magnetite, scheelite and powellite are associated with the sulfide paragenesis. The electron microprobe analyses of the (Ni-Sb)-bearing Cu-arsenides yielded the following average formulae: (Cu2.73,Ni0.17,Fe0.03,Ag0.01)∑ 2.94(As0.98,Sb0.05,S0.02)∑ 1.06–β-domeykite (simplified formula (Cu2.7,Ni0.2)∑ 2.9As1.1); (Cu3.40,Ni1.40,Fe0.11)∑ 4.91(As1.94,Sb0.13,S0.02)∑ 2.08–Ni-bearing koutekite (simplified formula (Cu3.4Ni1.5)∑ 4.9As2.1); and Cu1.97(Ni0.98,Fe0.03)∑ 1.01(As0.81,Sb0.22)∑ 1.03–(Ni–Sb)-bearing α-domeykite (simplified formula Cu2NiAs). The Rietveld refinement yielded the following unit-cell parameters for β-domeykite and Ni–bearing koutekite: a = 7.1331(4); c = 7.3042(5) Å; V = 321.86(2) Å3, and a = 5.922(4); b = 11.447(9); c = 5.480(4) Å; V = 371.48(5) Å3, respectively. Ore geology, paragenetic assemblages and genesis of the Mlakva deposit are discussed in detail and the Cu-As-Ni-Sb-Pb mineralization has been compared with similar well-known global deposits
Modified local diatomite as potential functional drug carrier-A model study for diclofenac sodium
No full textDiatomite makes a promising candidate for a drug carrier because of its high porosity, large surface area, modifiable surface chemistry and biocompatibility. Herein, refined diatomite from Kolubara coal basin, which complied with the pharmacopoeial requirements for heavy metals content and microbiological quality, was used as a starting material. Inorganic modification of the starting material was performed through a simple, one-step procedure. Significant increase in adsorbent loading with diclofenac sodium (DS) was achieved after the modification process (similar to 373 mg/g) which enabled the preparation of comprimates containing therapeutic dose of the adsorbed drug. Adsorption of DS onto modified diatomite resulted in the alteration of the drug's XRD pattern and FTIR spectrum. In vitro drug release studies in phosphate buffer pH 7.5 demonstrated prolonged DS release over 8 h from comprimates containing DS adsorbed on modified diatomite (up to 37% after 8 h) and those containing physical mixture of the same composition (up to 45% after 8 h). The results of in vivo toxicity testing on mice pointed on potential safety of both unmodified (starting) and modified diatomite. All these findings favor the application of diatomite as a potential functional drug carrier