Synthesis and characterization of composites of polyaniline and metal/organic frameworks based on Zn(II)-oxydicarboxylates

U ovoj tezi po prvi put su sintetisani kompoziti MOF-5, tipičnog predstavnika metalo-organskih mrežnih struktura (MOF), i polianilina (PANI), jednog od najvažnijih elektroprovodnih polimera. MOF-5 je mikroporozni, kristalni, elektroneprovodan materijal, velike specifične površine i poroznosti, koji se sastoji od Zn4O jedinica povezanih 1,4-benzendikarboksilatnim linkerima. PANI je konjugovani polimer koji egzistira u različitim kiselinsko-baznim i redoks oblicima i pokazuje visoku električnu provodljivost, ali ima malu specifičnu površinu. U prvom delu teze razvijena je efikasna sinteza čiste faze MOF-5, bazirana na korišćenju anhidrovanog cink acetata kao prekursora. Dodavanjem vode za in situ formiranje različitih cink acetata hidrata i karakterizacijom produkata nađeno je da optimalna količina vode za sintezu čistog kubičnog MOF-5 iznosi 0,250,5 molova vode po molu Zn2+. MOF-5 sintetisan pri molskom odnosu H2O/Zn2+ = 0,5 pokazivao je najveću specifičnu površinu SBET (1937 m2g1) i korišćen je za sinteze kompozita. PANI je sintetisan oksidativnom polimerizacijom anilina u prisustvu HCl i bez dodate kiseline. Kompoziti su okarakterisani brojnim fizičkohemijskim tehnikama. Sintetičkim postupkom, u kome je neprovodni oblik PANI rastvoren u DMF mešan sa MOF-5 u različitim masenim odnosima, dobijeni su mikroporozni kompoziti veoma velike SBET (najveća 2700 m2g1) i niske električne provodljivosti. Postupkom mehaničko-hemijske sinteze, u kome su elektroprovodni oblik PANI i MOF-5 mehanički sitnjeni u različitim masenim odnosima u prisustvu male količine hloroforma, dobijeni su mikroporozni kompoziti koji su pokazivali i elektroprovodljivost (najveća 1,0103 Scm1) i velike SBET (najveća 850 m2g-1). Kompoziti MOF-5/PANI predstavljaju obećavajuće kandidate za niz primena.In this thesis, for the first time, composites of MOF-5, a typical representative of metal-organic network structures (MOF), and polyaniline (PANI), one of the most important electrically conductive polymers, were synthesized. MOF-5 is a microporous, crystalline, non-conductive material, with a large specific surface area and porosity, consisting of Zn4O units connected by 1,4-benzenedicarboxylate linkers. PANI is a conjugated polymer that exist in various acid-base and redox forms and exhibits high electrical conductivity, but has small specific surface. In the first part of the thesis, efficient synthesis of pure phase MOF-5 was developed, based on the use of anhydrous zinc acetate as a precursor. By adding water for in situ formation of various zinc acetate hydrates and by characterization of the products it was found that the optimal amount of water for the synthesis of pure cubic MOF-5 is 0.250.5 moles of water per mole of Zn2+. MOF-5 synthesized at the H2O / Zn2+ = 0.5 molar ratio showed the highest specific surface area SBET of 1937 m2g-1 and was used for composite syntheses. PANI was synthesized by the oxidative polymerization of aniline in the presence of HCl and without added acid. Composites are characterized by a number of physicochemical techniques. Synthetic process in which the non-conductive form of PANI dissolved in DMF was mixed with MOF-5 in different mass ratios led to microporous composites of very high SBET (maximum 2700 m2g1) and low electrical conductivity. The process of mechano-chemical synthesis, in which the conductive form PANI and MOF-5 were mechanically crushed in different mass ratios in the presence of a small amount of chloroform, led to microporous composites that showed both electrical conductivity (maximum 1.0 103 Scm1) and large values of SBET (maximum 850 m2g-1). MOF-5/PANI composites are promising candidates for a range of applications

Determination of nickel, cobalt and chromium in a soda-lime glass by using LIBS based on pulses IR laser

This work presents a study of the applicability of laser-induced breakdown spectroscopy (LIBS), based on Infrared Transversally Excited Atmospheric CO2 pulsed laser (TEA CO2), to determine nickel, cobalt, and chromium in a window glass samples. Estimated limits of detection (LODs) for Ni, Co, and Cr, were 2.1, 3.2, and 0.4 ppm, respectively. In addition, two main plasma parameters, electron number density and temperature, were determined to characterize the laser-induced plasma. The electron number density (Ne) was determined from the measured Stark width of the Al I 396.15 nm line, and the intensity ratio of two atomic iron lines (342.71 nm and 344.06 nm) was used to determine the excitation temperature (Texc). The obtained values were Ne= 8.3·1016 cm-3 and Texc= 7700 K.The book of abstracts available at: [http://www.socphyschemserb.org/media/physical-chemistry-2022/abstracts.pdf

Permanent disposal of Cs ions in the form of dense pollucite ceramics having low thermal expansion coefficient

A promising method for removal of Cs ions from water and their incorporation into stable crystal structure ready for safe and permanent disposal was described. Cs-exchanged X zeolite was hot-pressed at temperature ranging from 800 to 950 °C to fabricate dense pollucite ceramics. It was found that the application of external pressure reduced the pollucite formation temperature. The effect of sintering temperature on density, phase composition and mechanical properties was investigated. The highest density of 92.5 %TD and the highest compressive strength of 79 MPa were measured in pollucite hot-pressed at 950 °C for 3 h. Heterogeneity of samples obtained at 950 °C was determined using scanning electron microscopy. The pollucite hot-pressed at 950 °C had low linear thermal expansion coefficient of ∼4.67 × 10−6 K−1 in the temperature range from 100 to 1000 °C. © 201

Electrochemical Sensing of Cadmium and Lead Ions in Water by MOF-5/PANI Composites

For the first time, composites of metal-organic framework MOF-5 and conjugated polymer polyaniline (PANI), (MOF-5/PANI), prepared using PANI in its conducting (emeraldine salt, ES) or nonconducting form (emeraldine base, EB) at various MOF-5 and PANI mass ratios, were evaluated as electrode materials for the electrochemical detection of cadmium (Cd2+) and lead (Pb2+) ions in aqueous solutions. Testing of individual components of composites, PANI-ES, PANI-EB, and MOF-5, was also performed for comparison. Materials are characterized by Raman spectroscopy, scanning electron microscopy (SEM) and dynamic light scattering (DLS), and their electrochemical behavior was discussed in terms of their zeta potential, structural, morphology, and textural properties. All examined composites showed high electrocatalytic activity for the oxidation of Cd and Pb to Cd2+ and Pb2+, respectively. The MOF/EB-1 composite (71.0 wt.% MOF-5) gave the highest oxidation currents during both individual and simultaneous detection of two heavy metal ions. Current densities recorded with MOF/EB-1 were also higher than those of its individual components, reflecting the synergistic effect where MOF-5 offers high surface area for two heavy metals adsorption and PANI offers a network for electron transfer during metals’ subsequent oxidation. Limits of detection using MOF/EB-1 electrode for Cd2+ and Pb2+ sensing were found to be as low as 0.077 ppm and 0.033 ppm, respectively. Moreover, the well-defined and intense peaks of Cd oxidation to Cd2+ and somewhat lower peaks of Pb oxidation to Pb2+ were observed at voltammograms obtained for the Danube River as a real sample with no pretreatment, which implies that herein tested MOF-5/PANI electrodes could be used as electrochemical sensors for the detection of heavy metal ions in the real water samples

Optical spectroscopy of plasma induced by irradiation of animal bone with TEA CO2 laser

The application of laser-induced breakdown spectroscopy (LIBS) for the elemental analysis of pig shoulder bone samples is reported. Measurements were performed using a compact laboratory-made TEA CO2 laser with low pulse energy. The recorded spectra consisted of well-defined lines of atoms and single charged ions of Ca, Mg, P, and other constituent elements, with a good signal-to-noise ratio suitable for spectrochemical analysis. Based on the ICP quantitative analysis of the bone sample, the limits of detection of LIBS analysis were estimated for Mg (16 ppm) and Na (940 ppm). Plasma parameters, temperature, and electron number density were determined by measuring Stark widths and relative intensities of the C and Mg ionic and atomic spectral lines.The book of abstracts available at: [http://www.socphyschemserb.org/media/physical-chemistry-2021/abstracts.pdf

Carbonization of MOF-5/Polyaniline Composites to N,O-Doped Carbon/ZnO/ZnS and N,O-Doped Carbon/ZnO Composites with High Specific Capacitance, Specific Surface Area and Electrical Conductivity

Composites of carbons with metal oxides and metal sulfides have attracted a lot of interest as materials for energy conversion and storage applications. Herein, we report on novel N,O-doped carbon/ZnO/ZnS and N,O-doped carbon/ZnO composites (generally named C-(MOF-5/PANI)), synthesized by the carbonization of metal–organic framework MOF-5/polyaniline (PANI) composites. The produced C-(MOF-5/PANI)s are comprehensively characterized in terms of composition, molecular and crystalline structure, morphology, electrical conductivity, surface area, and electrochemical behavior. The composition and properties of C-(MOF-5/PANI) composites are dictated by the composition of MOF-5/PANI precursors and the form of PANI (conducting emeraldine salt (ES) or nonconducting emeraldine base). The ZnS phase is formed only with the PANI-ES form due to S-containing counter-ions. XRPD revealed that ZnO and ZnS existed as pure wurtzite crystalline phases. PANI and MOF-5 acted synergistically to produce C-(MOF-5/PANI)s with high SBET (up to 609 m2 g−1), electrical conductivity (up to 0.24 S cm−1), and specific capacitance, Cspec, (up to 238.2 F g−1 at 10 mV s−1). Values of Cspec commensurated with N content in C-(MOF-5/PANI) composites (1–10 wt.%) and overcame Cspec of carbonized individual components PANI and MOF-5. By acid etching treatment of C-(MOF-5/PANI), SBET and Cspec increased to 1148 m2 g−1 and 341 F g−1, respectively. The developed composites represent promising electrode materials for supercapacitors

Safe trapping of Cs radionuclides in sintered matrix of zeolites

Cesium aluminosilicate phases are of the great interest as possible host for Cs immobilization in radioactive waste management. The possibility to use zeolite as a host material for radioactive Cs immobilization was investigated. Cs-exchanged forms of clinoptilolite and 13X which were prepared by ion-exchange treatment were compacted. The powders compacts of exchanged zeolites were thermally treated at 1200 °C. The XRD analysis showed that Cs was successfully immobilized after heat treatment by formation of stable cesium-aluminosilicate ceramic forms. Thermal and mechanical properties of the sintered samples were investigated. From the perspective of these characteristics, Cs-exchanged zeolite (clinoptilolite and 13 X) can be considered as a potential material for safe waste disposal

Degradation of dye crystal violet released from the textile industry

Textile industry wastewater is a significant source of pollution, often containing hazardous organic dyes like Crystal Violet (CV). Photocatalytic degradation using semiconductor materials such as titanium dioxide (TiO2) presents a promising solution for wastewater treatment due to its effectiveness in breaking down organic pollutants under UV irradiation. This study investigates the efficiency of TiO2 as a catalyst for the photodegradation of CV removed from textile wastewater. Experimental trials were conducted in a batch reactor under UV irradiation, with CV (20 ppm) and varying concentrations of TiO2 catalyst. Results revealed a significant reduction in CV concentration with increasing catalyst dosage (to 0.1 g/L) and irradiation time. The optimal conditions for maximum degradation efficiency were determined, highlighting the potential of TiO2 photocatalysis for textile wastewater treatment. Furthermore, the kinetics of CV degradation were analyzed to understand the reaction mechanism and rate. The degradation of the dye (20 ppm) was 98% for 95 min with 0.1 mg/L TiO2. This research contributes to developing sustainable and efficient methods for treating textile wastewater, addressing environmental concerns associated with dye pollution.31st International Conference Ecological Truth and Environmental Research : Sokobanja, Serbia, 18-21 June 2024

Ultrasound and shacking-assisted water-leaching of anions and cations from fly ash

Two mechanical extraction techniques were used for the extraction of environmentaly interesting components of coal fly ash: shaking, during which the extraction process lasted from 6 up to 24 h, and sonication that lasted from 15 up to 60 min, using water as extractant. The concentration of anions in fly ash extracts was determined by ion chromatography, while atomic absorption spectrometry was used for determination of: As, Pb, Cd, Ni, Cr, Zn, Cu, Fe, Mn and Al. The ultrasonication yielded slightly higher amounts of extracted anions as well as Pb, Al, Mn and Fe cations, while shaking-assisted extraction was more efficient for the Cr, As, Zn and Ni ions. The changes in pH value, particle size distribution within colloid solution, zeta potential and conductivity during ultrasound-assisted extraction were measured in order to explain changes that occur on the surface of fly ash particles contacting water and different processes (adsorption, ion exchange and flocculation) that develop under natural conditions. Principal Component Analysis was used for assessing the effect of observed process parameters. It is essential to evaluate quantity of these elements leachable from coal fly ash into the surface waters in natural conditions in order to prevent contamination of the environment

Radionuclides and heavy metals in soil around the coal-fired power plant "Kostolac"

Ovaj rad je fokusiran na određivanje koncentracije aktivnosti radionuklida (210Pb, 238U, 235U, 226Ra, 232Th i 40K) i koncentracije teških metala (Pb, Mn i Zn ) u površinskom sloju zemljišta okoline termoelektrane "Kostolac A". Tehnike koje su korišćene za analizu pomenutih radionuklida i teških metala su gamaspektometrija i atomska apsorpciona spektrometrija, redom. Srednje vrednosti koncentracija aktivnosti ispitanih radionuklida, izražene u Bq/kg, iznosile su: 76,7 za 210Pb; 67,2 za 238U; 4,1 za 235U; 29 za 226Ra; 50,1 za 232Th i 611 za 40K. Srednje vrednosti koncentracija teških metala, izražene u mg/kg, iznosile su: 28 za Pb; 775,4 za Mn i 105,5 za Zn. Rezultati ove studije su ukazali da rad termoelektrane nema značajan negativan uticaj na okolinu u pogledu sadržaja radionuklida i teških metala.This study is focused on determination of the activity concentration of radionuclides (210Pb, 238U, 235U, 226Ra, 232Th i 40K) and concentration of heavy metals (Pb, Mn i Zn) in surface layer of soil around coal-fired power plant "Kostolac A". The techniques used to analyze of mentioned radionuclides and heavy metals are gamma spectometry and atomic absorption spectrometry, respectively. The mean values of activity concentrations of investigated radionuclides, expressed as Bq/kg, were: 76.7 for 210Pb, 67.2 for 238U, 4.1 for 235U, 29 for 226Ra, 50.1 for 232Th and 611 for 40K. The mean concentrations of heavy metals, expressed as mg/kg, were 28 for Pb, 775.4 for Mn and 105.5 for Zn. The obtained results indicated that operation of the coal fired power plant has no significant negative impact on the surrounding environment with regard to the content of investigated radionuclides and heavy metals12. Savetovanje Održivi razvoj Braničevskog okruga i energetskog kompleksa Kostolac : Maj 31., Kostolac, 2018