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Composites of carbons with metal oxides and metal sulfides have attracted a lot of interestas materials for energy conversion and storage applications. Herein, we report on novel N,O-dopedcarbon/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 electrochemicalbehavior. The composition and properties of C-(MOF-5/PANI) composites are dictated bythe 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 toS-containing counter-ions. XRPD revealed that ZnO and ZnS existed as pure wurtzite crystallinephases. PANI and MOF-5 acted synergistically to produce C-(MOF-5/PANI)s with high SBET (up to609 m2 g−1), electrical conductivity (up to 0.24 S cm−1), and specific capacitance, Cspec, (up to 238.2 Fg−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 etchingtreatment 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.

Ecotoxicity caused by neonicotinoid pesticides is largely due to oxidative stress on non-target species. Due to the fact that reactive radical species reach the environment, materials intended for pesticide removal should be applicable for the simultaneous removal of reactive radicals, as well. This work uses the spectroscopic, adsorptive and antioxidant responses from MFI, FAU and BEA zeolites as descriptors of their potential environmental importance. Different network structures and Si/Al ratios were correlated with excellent zeolite adsorption properties, as over 200 mg g1 of investigated neonicotinoids, acetamiprid and imidacloprid, was achieved in one cycle. Additionally, after two regeneration steps, over 450 mg g1 adsorbed pesticides were retained, in three adsorption cycles. Overall the best results were detected for the FAU zeotype in both tested applications, insecticide adsorption and radical-scavenging performance, with and without insecticides present. The proposed mechanism for adsorption relies on kinetic investigation, isotherm modelling and spectroscopic post-adsorption analysis and targets zeolite hydroxyl/siloxane groups as active sites for insecticide adsorption via hydrogen bonding. Neat, welldefined zeolite structures enable their prospective application in ecotoxic species removal.

Environmentaly friendly photoelectrochemical (PEC) materals are in the center of the research interest for sustainable solar-to-chemical energy conversion. Lately, bismuth vanadate (BiVO4) has attracted attention due to its visible light harvesting properties, band edge positions and lowcost synthesis method. However, BiVO4 has poor charge transfer properties due to the high rate of electron-hole recombination. It has been shown that metal doping efficiently boosts charge separation and hence increases PEC water splitting activity. Herein, we report physicochemical properties of hydrothermaly sinthesized 1%-, 2.5%- and 5%- Cu-doped BiVO4 powders for 8 h and 20 h. X-ray diffraction (XRD) study indicates that, depending on the degree of doping and synthesis time, material exists in monoclinic or tetragonal scheelite phase, but mixed phase composition was also possible. Monoclinic phase was formed in a case of pristine samples (synthesized for 8 h and 20 h) and 1% and 2.5% doped samples synthesized for 8 h. Tetragonal phase was observed in case of 5% and 1% doped samples synthesized for 8 h and 20 h, respectively. In the samples synthesized for 20 h and doped with 2.5% and 5% mixed phase was noticed. Scanning electron microscopy (SEM) reveals that samples with monoclinic phase consists of combination of worm-like and prismatic structures while tetragonal samples showed spherical shape. In case of samples with mixed phase a combination of prismatic and spherical shape was observed. Local structure was examined with Raman and Fourier Transformed Infrared (FTIR) spectroscopy. Optical properties were characterized with UV-Vis Diffuse Reflectance Spectroscopy (DRS) and Photoluminescence (PL) spectroscopy. Monoclinic phase has band gap in range 2.35 – 2.52 eV while samples with tetragonal phase has band gap in range 2.8 – 3 eV. Based on the results it can be concluded that band gap is dependent on the phase composition of samples. PL results indicate that monoclinic samples

Production of gasses such as hydrogen and oxygen on a large scale is of the great importance both in industry and in environmental protection. To achieve it, photoelectrochemical (PEC) water splitting has been regarded as promising method and the developement of new semiconductors holds a key role to the efficent application. Due to its great light harvesting ability, band edge positions and low-cost synthesis method, bismuth vanadate (BiVO4; BVO) has been intensively studied as a photoanode material for water splitting. To overcome limitations such as charge carriers recombination, material should be doped with different transition metal elements. In this work physicochemical properties of pristine and 1%-, 2.5%- and 5%- Cu-doped BVO powders, solvothermaly synthesized at 180°C for 20 h, were reported. X-ray diffraction (XRD) study indicates that, depending on the doping level, the material exists in monoclinic or tetragonal scheelite phase, but mixed phase composition was also observed. Pure monoclinic and tetragonal phase was formed in a case of pristine and 1% doped sample, respectively, while 2.5%- and 5%- Cu-doped BVO exhibit presence of both phases. Scanning electron microscopy (SEM) reveals that sample with monoclinic phase consists of irregular worm-like morphology, while morphology of tetragonal samples was mostly spherical. For 2.5%- and 5%- Cu-doped samples a combination of prismatic and spherical shape morphology was observed. Local structure of material was examined with Raman spectroscopy and the results were in accordance with XRD study where band positions well matched the phase composition. Optical properties were characterized with UV-Vis Diffuse Reflectance Spectroscopy (DRS) and Photoluminescence (PL) spectroscopy. The band gap of monoclinic samples was in range 2.4-2.5 eV, while band gap of sample with tetragonal phase has band gap was between 2.8 and 3 eV. Dual phase samples had two different band gaps that originate from presence of both phase

Composite materials consisting of the silver salt of dodecatungstophosphoric acid and HBEA zeolite are developed in order to give materials of superior adsorption properties for aqueous pesticide removal. Two-step impregnation and an ion-exchange method with variable constituent mass ratios were employed as synthesis procedures. One of the study goals was to optimize the composite preparation for efficient elimination of glyphosate pesticide and to investigate the modulation of antioxidant activity in the presence of pesticide. Based on comprehensive results, we propose mechanisms for simultaneous glyphosate removal and antioxidant activity. Spectroscopic analysis shows that the applied two-step impregnation method results in advanced composite materials with evenly distributed active sites for glyphosate adsorption and radical-scavenging activity. The original Krishnamurti isotherm is successfully used to fit pesticide adsorption data, pointing to co-operative adsorption of glyphosate on partly saturated adsorbents sites. The amount of glyphosate adsorbed from water suspension was 378 mg per gram of composite material, the highest value reported for glyphosate removal to date.

The oscillatory Briggs‐Rauscher (BR) reaction was applied on solid insoluble materials i. e. bentonite clays. Under the same BR experimental conditions, the addition of identical masses of bentonite of different origin resulted in different effects on oscillatory time duration (τ): no influence, quenching, or prolongation. It was found that the following bentonite properties: montmorillonite/beidellite ratio; cation exchange capacity; principal exchange cation; extent of iron leaching in acidic environment of BR reaction; and specific surface area of clay were not exclusively responsible for observed behavior. On the other hand, the influence of added mass, for all investigated clays, resulted in the same behavior pattern. The increase of the mass of added clay increased τ up to the certain maximal value (τmax, mmax) characteristic for each clay. Further increase of mass resulted in quenching. Therefore, (τmax, mmax) pair can be regarded as the “fingerprint” characteristic of bentonite useful for identification of its origin. Furthermore, the addition of naturally occurring and non‐toxic clay in an oscillatory reaction can offer a versatile approach to tune the oscillation dynamics of nonlinear chemical systems.

Series of alkylammonium modified smectites with different alkylammoinum/clay ratios was synthesized (H series). The obtained organoclays were used as precursors for carbon-clay composite materials (C series). Both set of materials were characterized by X-ray diffraction (XRD), point of zero charge (pH(PZC)), N-2 adsorption-desorption isotherms, Raman spectroscopy and electron paramagnetic resonance (EPR) analysis. XRD analysis of organomodified clays confirmed incorporation of HDTMA(+) into interlamellar space of smectite. Series of carbonized clays showed constant d(001) value of 1.4 nm. The pH(PZC) of two series differed indicating that carbonization changed the profile of pH dependent sites on the clay surface. Textural properties of the H series decreased throughout the series, while in the C series the most developed porous structure was obtained for sample where HDTMA(+) loading was equal to cation exchange capacity. Raman spectroscopy showed that amorphous carbon was formed during carbonization process. The obtained materials were used as modifiers of carbon paste electrode and investigated using electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry. The comparison of electrochemical behavior of H series and C series showed the importance of interlamellar species for charge transfer process. The investigation of influence of composition of carbon paste and form of added carbon showed that performance of carbon-clay based electrodes depended on synergy of different factors.

Potassium tungstophosphate is supported on BEA zeolite by in situ synthesis for glyphosate removal. Spectroscopic measurements identified hydrogen bonding as a primal interaction of potassium salt and BEA zeolite. Composites are evaluated for glyphosate herbicide removal and adsorption process is analyzed using two isotherm models. Obtained adsorption capacities for all prepared composites lay between 45.2 and 92.2 mg of glyphosate per gram of investigated composite. Suspension acidity revealed that glyphosate is adsorbed mainly in the zwitter-ion form at the composite surface while the amount of potassium salt in the composites is crucial for the adsorption application. Exceptional adsorption behavior is postulated to come from a high degree of homogeneity among surface active sites which is confirmed by different experimental methods. Temperature programmed desorption of glyphosate coupled with mass spectrometer detected one broad, high-temperature peak which represents overlapped desorption processes from active sights of similar strength. Introduction of potassium tungstophosphate affects active sites present in BEA zeolite for glyphosate desorption and significantly increases the amount of adsorbed pesticide in comparison to BEA zeolite. Supporting of potassium tungstophosphate on BEA zeolite via in situ synthesis procedure enables the formation of highly efficient adsorbents and revealed their perspective environmental application.

Refined diatomite from the Kolubara coal basin (Serbia) was inorganically functionalized through a simple, one-pot, non-time-consuming procedure. Model drug ibuprofen was adsorbed on the functionalized diatomite under optimized conditions providing high drug Loading (similar to 201 mg g(-1)). Physicochemical characterization was performed on the starting and modified diatomite before and after ibuprofen adsorption. Dissolution testing was conducted on comprimates containing the drug adsorbed on the modified diatomite (composite) and those containing a physical mixture of the drug with the modified diatomite. The antihyperalgesic and the antiedematous activity of ibuprofen from both composites and physical mixtures were evaluated in vivo employing an inflammatory pain model in rats. Functionalization and subsequent drug adsorption had no significant effect on the diatomite ordered porous structure. Two forms of ibuprofen most likely coexisted in the adsorbed state - the acidic form and a salt/complex with aluminium. Both comprimate types showed extended ibuprofen release in vitro, but no significant influence on the duration of the ibuprofen effect was observed upon in vivo application of the composite or physical mixture. However, both the composite and the physical mixture were more effective than equivalent doses of ibuprofen in pain suppression in rats. This potentiation of the ibuprofen antihyperalgesic effect may result from the formation of the drug complex with the carrier and can be of clinical relevance.

A thorough discussion on the Comments on the article "Adsorption of strontium on different sodium-enriched bentonites", by Sanja R. Marinovic, Marija J. Ajdukovic, Natasa P. Jovic-Jovicic, Tihana M. Mudrinic, Bojana N. Nedic-Vasiljevic, Predrag T. Bankovic and Aleksandra D. Milutinovic-Nikolic published in the Journal of the Serbian Chemical Society, Volume 82, Issue 4, Pages: 449-463 (2017), given as Letter to the Editor by S. K. Milonjic, is provided in this letter. The authors of the commented paper have considered all the comments, and responded to each of them, point by point.

Heteropoly acid (HPA) was supported on BEA zeolite by optimized synthesis method yielding samples containing different amounts (20 to 50 wt%) of 12-phosphotungstic acid (HPW). The prepared supported HPW samples were subjected to different post-synthesis procedures including calcination and ultrasonication resulting in BEA-HPW (BPW) hybrid materials. These BPW samples were characterized using SEM, N-2-sorption and electrical conductivity measurements. They were subsequently used for the preparation of composites with carbonized polyaniline synthesized in the presence of 5-sulfosalicylic acid, and studied as electrode materials for phenols sensing in acidic, neutral and alkaline media. Linear dependence of current on p-nitrophenol concentration in acidic media was obtained enabling evaluation of limit of detection. Composite electrode gave response to p-nitrophenol presence in alkaline media as well, while no response was recorded in neutral media. The work demonstrates benefits of using novel composite based on BPW hybrid materials and carbonized polyaniline for sensing of phenols in aqueous environmental samples.

Ispitan je mehanizam visoko temperaturskih faznih transformacija cezijum (Cs) izmenjenih zeolita tipa LTA i klinoptilolita (CLI). Analizirane su osobine dobijenih faza u pogledu termalne stabilnosti i otpornosti na luţenje jona cezijuma. Rezultati pokazuju da su dobijene stabilne kristalne alumosilikatne strukture polucita (CsAlSi2O6) i faze CAS (CsAlSi5O12) koje mogu biti matrice za imobilizaciju Cs jona..., The mechanism of high-temperature phase transformation of cesium (Cs) exchanged zeolites such as LTA and clinoptilolite (CLI) was investigated. Thermal stability of obtained phases and their resistance to Cs ion leaching was also analysed. It was shown that the obtained stable, crystalline alumosilicate structures of pollucite (CsAlSi2O6) and CAS phase (CsAlSi5O12) can be used as matrices for Cs ion immobilisation...

An optimized synthetic route for obtaining heteropoly acid (HPA) species supported on BEA zeolite was applied, and different samples, comprising 20 to 50 wt% of 12-phosphotungstic acid (HPW) were prepared. The as-synthesized supported HPW were subjected to different post-synthesis routes, which involved calcination and ultrasound treatment. Characterization of these materials was performed by means of Scanning Electron Microscopy, zeta potential measurements, Infrared Spectroscopy and X-ray Powder Diffraction analysis. Results suggest strong interaction of HPW with the support and revealed that ultrasound treatment resulted in better dispersion of active phase and thus homogeneous morphology of the samples. The zeta potential was found to be dependent on the preparation procedure and HPW content in these materials, while higher HPW loadings induced its agglomeration. Catalytic activity of the synthesized materials was investigated in an ethanol dehydration reaction, where lower HPW loadings induced higher ethanol conversion. Acid sites distribution and accessibility for ethanol molecules were found to be more essential for catalytic activity than HPW loadings, i.e., amount of active sites present in these hybrid materials.

The bio-nanocomposite of montmorillonite and natural biopolymer chitosan (C-MM) was synthesized. Intercalation of chitosan in form of monolayer into the interlamellar space of montmorillonite was confirmed by XRD and IR analysis. The adsorption of textile dyes: Acid Yellow 99 (AY99), Acid Orange 10 (AO10) and Reactive Black 5 (RB5) onto C-MM was investigated. The adsorption was performed with the respect to adsorption time, pH and initial dye concentration. The kinetics of adsorption obeyed pseudo-second-order of kinetics and was the most efficient in acidic pH. Langmuir model best described the adsorption of AY99 and AO10, while RB5 adsorption isotherm was best fitted with Freundlich model.

Bentonites from three different deposits (Wyoming, TX, USA and Bogovina, Serbia) with similar cation exchange capacities were sodium enriched and tested as adsorbents for Sr2+ in aqueous solutions. X-Ray diffraction analysis confirmed successful Na-exchange. The textural properties of the bentonite samples were determined using low-temperature the nitrogen physisorption method. Significant differences in the textural properties between the different sodium enriched bentonites were found. Adsorption was investigated with respect to adsorbent dosage, pH, contact time and the initial concentration of Sr2+. The adsorption capacity increased with pH. In the pH range from 4.0-8.5, the amount of adsorbed Sr2+ was almost constant but 2-3 times smaller than at pH approximate to 11. Further experiments were performed at the unadjusted pH since extreme alkaline conditions are environmentally hostile and inapplicable in real systems. The adsorption capacity of all the investigated adsorbents toward Sr2+ was similar under the investigated conditions, regardless of significant differences in the specific surface areas. It was shown and confirmed by the Dubinin-Radushkevich model that the cation exchange mechanism was the dominant mechanism of Sr2+ adsorption. Their developed microporous structures contributed to the Sr2+ adsorption process. The adsorption kinetics obeyed the pseudo-second-order model. The isotherm data were best fitted with the Langmuir isotherm model.

Three different bentonites with similar cation exchange capacities were investigatedas adsorbents for Sr2+ionsin aqueous solutions.Textural properties of thebentonite samples were determined using low-temperature N2 physisorption method.Adsorption was carried out with respect to contact time. It was found that adsorption capacity of all adsorbents towards Sr2+ ions was similar.It was shown that ion exchange mechanism is the dominant mechanism of Sr2+ ions adsorption on the Na-enriched bentonites.Adsorption dynamics obeyed pseudo-second-order kinetics model for all bentonites.

Diatomite 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 (~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 favour the application of diatomite as a potential functional drug carrier.

Bentonite from locality Mečji Do was acid treated, characterized and denoted as MDA. The obtained material was used to modify glassy carbon electrode (GCE). The GCE was covered either with a suspension of MDA and Nafion (perfluorinated resin solution), or with the same suspension mixed with Carbon Black Vulcan XC72, Cabot Corporation (CB). Thus the influence of the presence of CB on the electrochemical performance of the modified bentonite based electrodes was examined. The electrochemical properties of the electrodes were tested by cyclic voltammetry in 0.1 M H2SO4 aqueous solution containing 10 mM of phenol, at the scanning rate of 10 mV/s in the potential range from -0.3 V to 1.1 V. The anodic oxidation of phenol led to the formation of insulating polymeric film on modified bentonite based electrode. As a consequence, rapid decrease of the current of phenol oxidation was observed. The composite electrode prepared with CB powder exhibited better performance than its counterpart without CB. Better performance was reflected in the stability of the electrodes regarding electrode fouling during the phenol electrooxidation process and better mechanical durability of the modified bentonite based electrodes.

The silver acid salts AgxH3-xPW12O40 (Ag(x)WPA), where Ag content is x = 1 up to x = 2.5, were synthesized and characterized by Fourier transform infrared and micro-Raman spectroscopy, powder X-ray diffraction and differential thermal and thermogravimetric analysis and nitrogen adsorption. The properties of the prepared salts are compared with those of the parent acid. Regarding the structural, textural and thermal and solubility characteristics, these salts are between salts of group A, with small metal ions, and B group salts with large metal ions. The acid salts are two phase mixtures of soluble acid and insoluble neutral salt, like other alkaline acid salts of H3PW12O40 for x lt 2. The catalytic properties of the acid salts have been studied for the vapor-phase dehydration of ethanol, carried out in a conventional flow-type reactor at 300 degrees C. The acid salts exhibited stable catalytic activity, a little bit lower than tungstophosphoric acid for ethylene production from ethanol.