Synthesis and characterization of cobalt ferrite/ expanded vermiculite as a sorbent of nickel ions

The minerals with unique properties such as mica minerals have promising approach in environmental and industrial sphere. In this study, cobalt ferrite/expanded vermiculite (CoFe2O4/EV) composite was prepared by in-situ method. Both composite and base materials are characterized by FTIR, XRD and SEM techniques, while the CEC and point of zero charge (pHPZC) was also determined. The adsorption properties of CoFe2O4/EV and EV have been investigated in a batch system, for the Ni (II) sorption from water. Adsorption experimental results were fitted by kinetic and adsorption models, and resulted in ionic exchange mechanism with maximum adsorption capacity of 23.2mg g-1 (298 K)

Fabrication and characterization of manganese ferrite/expanded vermiculite as a magnetic adsorbent of nickel ions

Adsorbents based on magnetic materials are the subject of numerous researches. Beside good magnetism and functional surface, manganese ferrite is unstable and prone to form low mechanical strength agglomerates, which necessitate its deposition on the substrate surface. Expanded vermiculite outer surfac, is a useful medium for the deposition of nanoparticles whereas intercation layer is suitable for holding cation species (distance of 2:1 layers may be greater than 10 Å). Due to its relatively high surface area, cation exchange capacity and natural abundance of vermiculite, this mica mineral and its composites could be valorized as potentially low-cost adsorbents. In this study, manganese ferrite/expanded vermiculite (MnFe2O4/EV) composite was prepared by in-situ method. Deposited manganese ferrite particles on the surface of EV were formed in the solvothermal reaction using suitable reagents. Both composite and base material are characterized by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) specific surface area (SSA), cation exchange capacity (CEC) and pH point of zero charge (pHPZC) determination. The adsorption properties of MnFe2O4/EV and EV have been investigated in a batch system at pH close to the pHPZC for the removal of Ni (II) from water. Considering process parameters such as contact time, adsorbent dosage and temperature: adsorption type, isotherm parameters (Langmuir and Freundlich) and rate of adsorption parameters were determined. Results of the kinetic studies gave fine correlations with pseudo – second order and Weber – Morris model. Taking into consideration fact that EV had low CEC values and SSA, obtained composite have high adsorption capacity (more than 30 mg Ni g-1). Also, X-ray diffractograms showed alteration of biotite vermiculite (formed during solvothermal action) into phlogopite (formed after adsorption process and aging). The methodology applied in this work may be utilized for the fabrication of other ferrite spinels, perovskites and other oxide systems.Adsorbenti na bazi magnetičnih materijala su predmet brojnih istraživanja. Osim dobre magnetičnosti i funkcioncionalnoj površini, mangan ferit je nestabilan i teši formiranju aglomerata niske mehaničke čvrstine, čime se iziskuje njegova depozicija na površini supstrata. Spoljna površina ekspandovanog vermikulita je korisni medijum za depoziciju nanočestica dok interkalacioni sloj je podesan za zadržavanje katjonskih vrsta (rastojanje između slojeva može biti iznad 10 Å). Zahvaljujući relativno visokoj površini, kapacitetu katjonske izmene i prirodnoj zastupljenosti vermikulita, ovaj mineral liskuna i njegovi kompoziti mogu biti valorizovani kao potencijalni povoljni adsorbenti. U ovoj studiji, kompozit mangan ferita/eksapndovanom vermikulitu (MnFe2O4/EV) pripremljen je in-situ metodom. Deponovane čestice mangan ferita na površini EV formirane su u solvotermalnoj reakciji korišćenjem podesnih reagenasa. Kompozit kao i bazni materijal karakterizovani su: infracrvenom spektroskopijom sa Furijeovom transformacijom (FTIR), difrakcijom X-zraka na prahu (XRPD), skenirajućom elektronskom mikroskopijom (SEM), specifičnom površinom (SSA) određenom metodologijom po BET-u, kapacitetom katjonske izmene (CEC) i pH tačke nultog naelektrisanja (pHPZC). Adsorpciona svojstva MnFe2O4/EV i EV istražena su u šaržnom sistemu na pH vrednosti bliskoj pH tački nultog naelektrisanja za uklanjane Ni (II) iz vode. Uzimajući u obzir procesne parametre kao što su vreme kontakta, masa adsorbenta i temperatura određeni su: tip adsorpcije, izotermski parametri (Lengmir i Frojndlih) kao i parametri brzine adsorpcije. Rezultati kinetičkih studija dobro se korelišu pseudo – drugom redu reakcije i Veber – Morisovim modelom. Uzevši u obzir činjenicu da je uzorak EV imao malu vrednost CEC i nisku specifičnu površinu, dobijeni kompozit ima visok adsorpcioni kapacitet (preko 30 mg Ni g-1). Osim toga, difraktogrami X-zraka pokazali su alteraciju biotitskog vermikulita (formiranog solvotermalnom akcijom) u flogopit (formiran nakon adsorpcionog procesa i starenjem). Metodologija primenjena u ovom radu može biti iskorištena za proizvodnju drugih feritnih spinela, perovskita i ostalih oksidnih sistema.XII YuCorr International Conference, September 13-16, 2021, Tara Mountain, Serbia, [http://sitzam.org.rs/YUCORR/

Characterization of raw peach stones and its biochar by SEM, FTIR and Raman spectroscopy

Growing industrialization and non-renewable resource depletion have a huge impact on alternative clean up technologies development, inducing investigation of the renewable, low-cost waste materials. Recently, lignocellulosic waste biomass, generated at a large scale by different industries, appeared as an attractive feedstock worldwide, due to its abundance, availability, multi-functionality and low cost. Since the fruits production has increasing trend all over the world, generation of lignocellulosic waste such as fruit stones (that represent approximately 1/5 of the total fruit mass) became a great environmental threat. In order to minimize negative impact on the environment, avoid greenhouse gasses emissions and help in resource depletion by its renewable nature, it is necessary to explore its performances regarding its wide application potential. Thermo-chemical conversion of lignocellulosic biomass in oxygen limited conditions, in order to get biochar, has received a lot of attention recently. The biochar production requires lower energy inputs and less expensive technology compared to activated carbon (estimation is that production cost of activated carbon are six times higher than biochar costs). In this paper, waste peach stones biomass was effectively converted into biochar at 500 °C under inert (Ar) atmosphere. Pyrolysis was performed in Nabertherm 1300 muffle furnace for residence time of 1.5 h, with a heating rate of 10 °C/min, while Ar was circulated through the sample at a rate of 100 mL/min. The raw biomass (PS) and obtained biochar (PS-B) with particle size 0.1 mm < dp < 0.5 mm, were characterized by Scanning Electron Microscopy (SEM), Fourier transform infrared spectrometry (FTIR) and Raman spectrometry to understand physicochemical changes which have been occurred after pyrolysis. SEM analysis revealed the increased surface area due to the visible augmentation of pores and roughness. FTIR analysis showed that many bands present in native biomass cannot be observed in biochar, due to the conversion or removal of the most of the functional groups. Prominent bands have confirmed presences of aromatic compounds in biochar: at 1592 cm−1 (C=C bond stretching derived from aromatic rings in the lignin), 1030 cm-1 (alcohol C-O stretching vibration) and in the region 900 to 700 cm−1 (originating from aromatic compounds). These finding are in accordance with results from Raman analysis, where D and G bands (at 1350 cm-1 and 1580 cm-1 respectively), indicate the presence of poly-aromatic hydrocarbons. Thermo-chemically modified biomass like this has a great application potential: as a pollutants sorbent, biofuel, soil amendment, biocarriers, and in construction and electronic industries

Supporting information for: Water-Tuned Tautomer-Selective Tandem Synthesis of the 5,6-Dihydropyrimidin-4(3 H )-ones, Driven under the Umbrella of Sustainable Chemistry

The selective synthesis of 5,6-dihydropyrimidin-4(3H)-one scaffold (precursor of dihydrouracil) was a very difficult synthetic challenge that, so far, has not been achieved. For the first time, in this paper, green, selective and high-yields approach to 40 novel 5,6-dihydropyrimidin-4(3H)-ones (DHPMs) by one-pot reaction of aldehydes, Meldrum's acid and isothioureas under solvent-free conditions, in the presence of water, since an additive is presented. In the majority of cases, introduced methodology gave an unprecedented tautomer-selective fashion toward targeted compounds with excellent tautomeric purity (>99.9%), which reached 100% in few cases. The molecular structure of the five compounds has been determined by X-ray crystallography. In each one of them, very short length for the corresponding N2-C1 bond was noticed, making them especially interesting from a structural standpoint. This experimental fact can imply a highly localized electron π density in this part of each heterocyclic ring. The obtained experimental results, which are determined from NMR and ESI-MS study, indicate that this Biginelli-type reaction smoothly proceeds in a one-pot mode, pointing to the three-step tandem process, proceeding via the Knoevenagel, aza-Michael, and retro-Diels-Alder reactions. The presented strategy also had the following advantages: reduction amount of waste, excellent values of green chemistry metrics (cEF, EcoScale and GCIS), and it is the first eco-friendly strategy toward the DHPMs scaffold. © Copyright 2018 American Chemical Society.Supplementary data for the article: [https://dx.doi.org/10.1021/acssuschemeng.8b03127]Related to: [http://vinar.vin.bg.ac.rs/handle/123456789/7886

Double catalytic effect of (PhNH3)2CuCl4 in a novel, highly efficient synthesis of 2-oxo and thioxo-1,2,3,4-tetra-hydopyrimidines

An innovative route for the construction of 2-oxo and thioxo-1,2,3,4-tetrahydropyrimidines was delineated through a multicomponent reaction under Biginelli conditions, starting from different aromatic aldehydes, β-ketoesters and urea or thiourea. Proper choice of copper complex (PhNH3)2CuCl4, as a novel homogeneous catalyst, enables facile, efficient, and inexpensive reaction under mild experimental conditions. Moreover, we present the first application of this complex salts in organic synthesis ever. The obtained products are of high purity, and can be easily isolated from the reaction mixture in good to excellent yields. Also, compared to the classical Biginelli reaction conditions, the present method has the advantages in higher yields and experimental and work-up simplicity. To illustrate the joint catalytic action of the Cu2+ and phenylammonium ions, two key steps of Biginelli reaction were examined using the M06 functional. [Projekat Ministarstva nauke Republike Srbije, br. 172011 i br. 172016

Regioselectivity in Cyclofunctionalization of Olefinic Alcohols with Benzeneselenenyl Halides at Different Temperatures

The regioselectivity in cyclofunctionalization of some acyclic olefinic alcohols with benzeneselenenyl halides (PhSeCl and PhSeBr) at different temperatures (−78°C, 0°C and room temperature) is investigated. It has been found that Δ4‐ and Δ5‐ alkenols are converted into five‐ and/or six‐membered cyclic phenyl selenoethers, the yield of which decreases with increasing reaction temperature. PhSeCl has been found to be more efficient than PhSeBr in the cyclization reactions

Photocatalytic deposition of gold on nanocrystalline TiO2 films

Nanocrystalline TiO2 films were prepared on glass supports by the dip coating technique using colloidal solutions consisting of 45 angstrom TiO2 particles as a precursor in order to probe the feasibility of exploiting solid state photocatalytic reactions for efficient deposition of gold. The reduction of Au3+ ions was maintained by photoirradiation of unmodified TiO2 films with metal ions being attached directly to the surface of TiO2. Absorption spectrum as well as atomic force microscopy measurements revealed presence of gold grains in the nanosize regime. Conductivity of deposited gold was measured in the temperature range from 45 to 295 K

Synthesis, Characterization, Antioxidant Activity of β-diketonates, and Effects of Coordination to Copper(II) Ion on their Activity: DNA, BSA Interactions and Molecular Docking Study

Background: In order to make some progress in discovering the more effective way to eliminate ROS which cause the oxidative stress in organism in humans and bearing in mind the fact that ethyl-2-hydroxy-4-aryl(alkyl)-4-oxo-2-butenoates (β-diketonates) belong to a class of biologically active compounds, series of β-diketonates were synthesized, characterized, and tested to evaluate there antioxidant activity. Further, to investigate how coordination to copper(II) ion affects the activity of β-diketonates, appropriate complexes were synthesized and characterized. Methods: All complexes were characterized by UV-Vis, IR, and EPR spectroscopy, MS spectrometry, and elemental analysis. Fluorescence spectroscopic method was used for investigations of the interactions between biomacromolecules (DNA or BSA) and compound 2E. Viscosity measurements and molecular docking study were performed to confirm the mode of interactions between DNA and BSA and compound 2E. Results: Scavenging activity on DPPH radical revealed that compounds 2A, 2B, and 2E possess largest free radical scavenging, comparable to standard while results of superoxide anion scavenging activities of tested samples showed that maximum scavenging activity (IC50=168.92 µg/mL) was found for 2E, very similar to standard ascorbic acid, followed by 2B and 2G. Results of the interactions between biomacromolecules and 2E indicated that 2E has the affinity to displace EB from the EB-DNA complex through intercalation [Ksv = (3.7 ± 0.1) × 103 M-1], while Ka value obtained via titration of BSA with 2E [Ka = (4.2 ± 0.2) × 105 M-1], support the fact that the significant amount of the drug could be transported and distributed through the cells. Conclusions: All β-diketonates exhibited better scavenging activities than their corresponding copper complexes. Among all the tested compounds, 2E gave the highest reducing power, even higher than standard ascorbic acid, while reducing power for compounds 2A and 2B was also good but lower than standard. DNA and BSA binding study for 2E showed that this compound has the potential to be used as medicament. © 2021 Bentham Science Publishers

Synthesis, characterization, anticancer evaluation and mechanisms of cytotoxic activity of novel 3-hydroxy-3-pyrrolin-2-ones bearing thenoyl fragment: DNA, BSA interactions and molecular docking study

In order to make a progress in discovering a new agents for chemotherapy with improved properties and bearing in mind the fact that substituted 3-hydroxy-3-pyrrolin-2-ones belong to a class of biologically active compounds, series of novel 1,5-diaryl-4-(2-thienylcarbonyl)-3-hydroxy-3-pyrrolin-2-ones were synthesized and characterized by spectral (UV–Vis, IR, NMR, ESI-MS), X-ray and elemental analysis. All compounds were examined for their cytotoxic effect on human cancer cell lines HeLa and MDA-MB 231 and normal fibroblasts (MRC-5). Four compounds, 3-hydroxy-1-(p-tolyl)-4-(2-thienylcarbonyl)-5-(4-chlorophenyl)-2,5-dihydro-1H-pyrrol-2-one (D10), 3-hydroxy-1-(3-nitrophenyl)-4-(2-thienylcarbonyl)-5-(4-(benzyloxy)phenyl)-2,5-dihydro-1H-pyrrol-2-one (D13), 3-hydroxy-1-(4-nitrophenyl)-4-(2-thienylcarbonyl)-5-(4-(benzyloxy)phenyl)-2,5-dihydro-1H-pyrrol-2-one (D14), and 3-hydroxy-1-(4-chlorophenyl)-4-(2-thienylcarbonyl)-5-(4-(benzyloxy)phenyl)-2,5-dihydro-1H-pyrrol-2-one (D15), that showed the highest cytotoxicity against malignant cells and the best selectivity towards normal cells were selected for further experiments. Results obtained by investigating mechanisms of cytotoxic activity suggest that selected 3-hydroxy-3-pyrrolin-2-one derivatives in HeLa cells induce apoptosis that is associated with S phase arrest (D13, D15, and D10) or unrelated to cell cycle distribution (D14). Additionally, to better understand their suitability for potential use as anticancer medicaments we studied the interactions between biomacromolecules (DNA or BSA) and D13 and D15. The results indicated that D13 and D15 have great affinity to displace EB from the EB-DNA complex through intercalation [K sv = (3.7 ± 0.1) and (3.4 ± 0.1) × 10 3 M −1 , respectively], an intercalative mode also confirmed through viscosity measurements. K a values, obtained as result of fluorescence titration of BSA with D13 and D15 [K a = (4.2 ± 0.2) and (2.6 ± 0.2) × 10 5 M, respectively], support the fact that a significant amount of the tested compounds could be transported and distributed through the cells. In addition, by DNA and BSA molecular docking study for D13, D14 and D15 is determined and predicted the binding mode and the interaction region. © 2019 Elsevier Inc.Peer-reviewed version of the article (Accepted Manuscript or postprint) available at: [https://vinar.vin.bg.ac.rs/handle/123456789/8186