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The present work reported the preparation of biocomposites based on poly(3-hydroxybutyrate) (PHB), plasticizer, and bacterial cellulose (BC) by melt processing and their testing by means of thermal properties (DSC), water absorption, and in vitro degradation. The surface of the biocomposites was analyzed via atomic force microscopy (AFM). In vitro degradation of the biocomposites was evaluated by weight loss and thermal properties (DSC) assessment after the immersion of the specimens in phosphate-buffered saline solution (PBS of pH 7.4) over 20 days. The results showed that the BC can reduce the PHB crystallinity and promote its degradation under PBS medium. Moreover, it was found that the water absorption increased as the percentage of BC increased.

The present paper reported the obtaining of an environmental friendly adsorbent based on sodium alginate, chitosan and glass bubbles. CaCl2 was used as crosslinking agent for sodium alginate favoring the interactions by physical bonds between the negative groups (-COO) of biopolymer and the Ca ions. The experimental study to determine the Cu(II) uptake using an atomic absorption spectrometer was conducted in the testing stand at the 1:50 and 1:100 ratios between the adsorbent mass and the amount of pollutant in solution. The number of cycles of regeneration of the adsorbent material was also evaluated. The characterization of alginate/chitosan/glass bubbles adsorbent by scanning electron microscopy (SEM) coupled with energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FTIR) showed that the Cu(II) was found out on the surface of adsorbent.

Anthropogenic microplastics (MPs) and nanoplastics (NPs) are ubiquitous pollutants found in aquatic, food, soil and air environments. Recently, drinking water for human consumption has been considered a significant pathway for ingestion of such plastic pollutants. Most of the analytical methods developed for detection and identification of MPs have been established for particles with sizes > 10 μm, but new analytical approaches are required to identify NPs below 1 μm. This review aims to evaluate the most recent information on the release of MPs and NPs in water sources intended for human consumption, specifically tap water and commercial bottled water. The potential effects on human health of dermal exposure, inhalation, and ingestion of these particles were examined. Emerging technologies used to remove MPs and/or NPs from drinking water sources and their advantages and limitations were also assessed. The main findings showed that the MPs with sizes > 10 μm were completely removed from drinking water treatment plants (DWTPs). The smallest NP identified using pyrolysis–gas chromatography–mass spectrometry (Pyr-GC/MS) had a diameter of 58 nm. Contamination with MPs/NPs can occur during the distribution of tap water to consumers, as well as when opening and closing screw caps of bottled water or when using recycled plastic or glass bottles for drinking water. In conclusion, this comprehensive study emphasizes the importance of a unified approach to detect MPs and NPs in drinking water, as well as raising the awareness of regulators, policymakers and the public about the impact of these pollutants, which pose a human health risk.

The aim of this paper is to obtain two types of bio-based membranes by electrospinning process: one based on polylactic acid (PLA), and PLA/polyhydroxybutyrate (PHB), and the second by coating the PLA/PHB membrane with chitosan (CS) and CS/activated coal (AC), respectively for removal of micropollutants from aqueous water. The designed bio-based electrospun membranes were analyzed through scanning electron microscopy (SEM), attenuated total reflectance (ATR) - Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), the removal of solid suspension and Pb (II) from aqueous water. The quality of filtrates was evaluated by physical-chemical methods, while the retaining of Pb (II) from wastewaters was reported.

In this study, lemon balm (Melissa officinalis L.) and dill (Anethum graveolens L.) essential oils (EOs) were encapsulated into collagen hydrolysates extracted from bovine tendons and rabbit skins, both mixed with chitosan (CS) by using the coaxial electrospinning technique for potential wound dressing applications. The morphology and chemical composition of the electrospun nanofibers were investigated using scanning electron microscopy (SEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The antimicrobial activity of the dill EO and lemon EO, as well as the electrospun samples loaded with essential oils was determined by disk diffusion assay against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29212, and Salmonella typhimurium ATCC 14028 bacterial strains, Candida albicans ATCC 10231 and Candida glabrata ATCC 90028 yeast strains, and Aspergillus brasiliensis ATCC 9642 fungal strain. In vivo biocompatibility testing of the collagen hydrolysate-chitosan/essential oil electrospun nanofibers was based on the determination of the hematological, biochemical, and immunological profile and the evaluation of the influence produced on the oxidative stress in white Swiss mice. The synergetic effect of dill and lemon balm EOs can improve the antimicrobial activity of collagen hydrolysate-chitosan nanofibers against the most important bacterial strains. The in vivo test results suggested a good biocompatibility of electrospun samples based on collagen hydrolysate extracted from bovine tendons or rabbit skin mixed with chitosan and containing dill and/or lemon balm essential oils as encapsulated bioactive compounds.

Massive amounts of industrial and agricultural water around the world are polluted by various types of contaminants that harm the environment and affect human health. Alginic acid is a very versatile green polymer used for heavy metal adsorption due to its availability, biocompatibility, low cost, and non-toxic characteristics. The aim of this paper was to prepare new low-cost hybrid composite beads using sodium alginate with treated montmorillonite and kaolin for the adsorption of copper (Cu) cations. Modified and unmodified clays were investigated by studying their morphology and elemental composition, functional groups, and mean particle size and particle size distribution. The characterization of alginate/clay hybrid composite beads was carried out by evaluating surface morphology (by scanning electron microscopy, SEM), crystallinity (by X-ray diffraction, XRD), and point of zero charge (pHpzc)(Zeta Potential Analyzer). Batch adsorption experiments of alginate/clay hybrid composite beads investigated the effect of metal concentration in the range of 1–4 mg L−1 on Cu(II) removal, adsorption kinetic for maximum 240 min, and Langmuir and Freundlich adsorption isotherms by using atomic absorption spectrometry. The pseudo-second-order kinetic model best fitted the adsorption for alginate/montmorillonite beads (R2 = 0.994), while the diffusion process was predominant for montmorillonite/kaolin beads (R2 = 0.985). The alginate/clay hybrid materials best fitted the Langmuir isotherm model.

Ferrous waste by-products from the metallurgical industry have a high potential for valorization in the context of the circular economy, and can be converted to value-added products used in environmental remediation. This research reviews the latest data available in the literature with a focus on: (i) sources from which these types of iron-based wastes originate; (ii) the types of ferrous compounds that result from different industries; (iii) the different methods (with respect to the circular economy) used to convert them into products applied in water and wastewater decontamination; (iv) the harmful effects ferrous wastes can have on the environment and human health; and (v) the future perspectives for these types of waste.

Polyvinylchloride (PVC) is a thermoplastic polymer widely used in large applications due to the excellent balance between cost and properties. Due to the environmental and human health concerns of consumption of petrochemical-based plasticizers, the use of bio-based plasticizers has been increasing. The new blends of PVC made with green plasticizers show attractive properties in terms of thermal stability, migration resistance, mechanical properties, etc. making them appropriate for the medical and industrial applications. This chapter reports the most recent and relevant studies concerning the synthesis and evaluation of bio-based plasticizers for PVC, with low toxicity and low migration levels.

Due to its valuable compounds, food waste has been gaining attention in different applications, such as life quality and environment. Combined with circular economy requirements, a valorization method for waste, especially banana waste, was to convert them into adsorbents with advanced properties. The banana waste, after thermal treatment, was used with high removal performances (100%) for the removal of heavy metals, such as Cr, Cu, Pb, and Zn, but their small particle size makes them very hard to recover and reuse. For this reason, a biopolymeric matrix was used to incorporate the banana waste. The matrix was chosen for its remarkable properties, such as low cost, biodegradability, low carbon footprint, and reduced environmental impact. In this research, different types of materials (simple banana peel ash BPA and combined with biopolymeric matrix, ALG–BPA, CS–BPA) were prepared, characterized, and tested. The materials were characterized by means of attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), optical microscopy (OM), scanning electron microscopy (SEM), and tested for the removal of metal ions from synthetic solutions using atomic absorption spectroscopy (AAS). The ALG–BPA material proved to be the most efficient in the removal of heavy metal ions from synthetic solution, reaching even 100% metal removal for Cr, Fe, Pb, and Zn, while the CS-based materials were the least efficient, presenting the best values for Cr and Fe ions with a removal efficiency of 34.14% and 28.38%, respectively. By adding BPA to CS, the adsorption properties of the material were slightly improved, but also only for Cr and Fe ions, to 37.09% and 57.78%.

The paper presents corrosion resistance testing results of three stainless steels that may be used in hydropower turbine blades manufacture. Two of these have a chemical composition close to that of some other stainless steels previously employed in producing these parts, being updated steel grades of the former ones. The third one is of a new conception, having a chemical composition close to that of a maraging steel. The three materials were produced in an induction furnace with cold copper crucible under vacuum and argon atmosphere in order to obtain improved mechanical and corrosion resistance characteristics as well as an inclusion � free structure. Quenching and tempering heat treatments were subsequently applied. Tests were carried out at room temperature in normally aerated 1N Na2SO4 and 3% NaCl solutions. Corrosion rates were calculated using the Tafel slope method. All steels have a passivation tendency in a chlorine-free aqueous medium. The newly conceived steel has a more pronounced anodic field as a result of a chromium content below 12%. However, the general corrosion behavior of this material is rebalanced by the content of about 10% Ni which leads to a mainly martensitic structure in quenched state. The corrosion rate values obtained for all samples enframe the three materials in highly and very highly corrosion resistant steels. Nevertheless it must be specified that in chlorine environments the overall corrosion rate is not a sensitive indicator of corrosion resistance performance due to the local depassivation process followed by corrosion pits.

The collagen hydrolysate (HC) and silver nanoparticles (AgNPs) effect on the mechanical, thermal, in vitro degradation, cytotoxicity and antifungal properties of polylactic acid (PLA) plast...

Photocatalysis has become common and nanomaterials having photocatalytic functions have been widely characterized. At present, among the many candidates for photocatalysis, TiO2 is almost t...

A nanocomposite (ION-CS) consisting of magnetite nanoparticles (ION) physically mixed with chitosan (CS) was synthesized by a green protocol in order to investigate the adsorption of hexavalent chr...

The goal of the present paper is to explore the properties of medium molecular-weight chitosan/polyvinyl alcohol blends mixed in volume ratios of 75:25, 50:50, and 25:75 obtained by solutio...

Cu-xFe3O4 nanocomposites with x = 5, 10, 15 and 20% have been obtained by powder metallurgy route starting from nanoscale magnetite and copper powders that were synthesized by co-precipitation. Both nanopowders and composite have been investigated for their structures, morphologies and physico-mechanical properties. Using high resolution microscopy methods, the structure of the initial powders and nanocomposite was investigated and the powder/grain size was evaluated. We demonstrated that the nanosized dimensions of both magnetite and copper powders obtained by co-precipitation has been preserved after sintering at 800 °C. It has been shown that both the copper matrix grains and the reinforcing Fe3O4 embedded in the matrix, have nanometric dimensions. Physico-mechanical properties of the nanocomposite have been studied in relation to crystalline structure and morphology. The electrical conductivity was determined, and the resistivity was calculated. Results showed the Cu-xFe3O4 nanocomposites were situated at the boundary between conductors and semiconductors, i.e. nanocomposites with 15–20% Fe3O4 were electric conductors, and nanocomposites with content of 5% Fe3O4 were semiconductors. The electrical behavior of nanocomposites in alternating current showed that Cu-xFe3O4 nanocomposites were good resistors too.

This research emphasizes the performance of some eco-friendly carbon materials as hydrochars (HC) obtained by the hydrothermal carbonization (HTC) process applied to walnut shell (WS) biowaste. These materials display promising properties that can be used for environmental applications such as emerging pharmaceutical pollutant retention from water sources. Thus, three hydrochars coded HCWS1, HCWS2, and HCWS3 were obtained using a dynamic autoclave in specific conditions—temperature of 220 °C, autogenous pressure, 1:10 biomass–water weight ratio—and for three different reaction times, 1 h, 6 h, and 12 h. The HCWSs were characterized by means of ATR-FTIR and SEM-EDS analyses and tested as possible adsorbents to assess the removal efficiencies of some emerging pharmaceutical pollutants (paracetamol and methylene blue) by UV–VIS spectrophotometry. Kinetic and adsorption studies were carried out. The best results were obtained for the HCWS3 hydrochar. Further perspectives include an activation step of the hydrochars and their testing on other emerging pharmaceutical pollutants.

Copper matrix nanocomposites reinforced with magnetite nanoparticles were developed using powder metallurgy. Various processing parameters were taken into consideration, such as magnetite content, compaction pressure, sintering time and temperature. The nanopowder blends were compacted using various uniaxial pressures and sintered at 650 and 800 &deg, C in order to study the influence of processing parameters on morphology, structure, thermal, magnetic and mechanical properties. The structure and morphology of the nanocomposites analyzed by X-ray diffraction (XRD), bright field transmission electron microscopy (TEMBF) and scanning electron microscopy (SEM) showed that sintered composites retained the nanoscale characteristics of the initial Fe3O4 and Cu nanopowders. These nanocomposites have good cold-rolling deformability and Vickers micro-hardness. The Cu-xFe3O4 nanocomposites have thermal and magnetic properties that make them suitable for electronical applications.

Bionanocomposites including poly(lactic acid) (PLA), collagen, and silver nanoparticles (AgNPs) were prepared as biocompatible and stable films. Thermal properties of the PLA-based bionanocomposites indicated an increase in the crystallinity of PLA plasticized due to a small quantity of AgNPs. The results on the stability study indicate the promising contribution of the AgNPs on the durability of PLA-based bionanocomposites. In vitro biocompatibility conducted on the mouse fibroblast cell line NCTC, clone 929, using the 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed high values of cell viability (&gt, 80%) after cell cultivation in the presence of bionanocomposite formulations for 48 h, while the percentages of lactate dehydrogenase (LDH) released in the culture medium were reduced (&lt, 15%), indicating no damages of the cell membranes. In addition, cell cycle analysis assessed by flow cytometry indicated that all tested bionanocomposites did not affect cell proliferation and maintained the normal growth rate of cells. The obtained results recommend the potential use of PLA-based bionanocomposites for biomedical coatings.

The paper addresses environmental protection by valorizing an important agri-food waste category, namely fruit and vegetables with focusing on the main characteristics regarding consumption, waste quantities, and ways for valorizing these materials. Thus, vast research was undertaken in order to emphasize the main commodities and their potential application as adsorbents for organic and inorganic pollutants. The main methods or treatment techniques applied for the valorization of eco-materials as adsorbents were presented and the principal efficiency results were indicated. The advantages and disadvantages of using these eco-materials as adsorbents in wastewater treatment were revealed and future recommendations were established. According to the international statistics, the most purchased and consumed five commodities were studied regarding waste generations as potential conversion into eco-materials with an adsorbent role for water pollutants. Thus, the performances for adsorbents based on fruit wastes (such as citrus, banana, apples, grapes, mango) and vegetable wastes (such as potatoes, tomatoes, cabbage, carrots, cauliflower, and/or broccoli) were studied and highlighted in this research.

Two nanostructured hybrid materials are reported that include uncoated magnetic nanoiron oxides and magnetic nanoiron oxides treated with rose leaf extract. Atomic and molecular absorption ...

Nowadays, the polyolefins (polyethylene, polypropylene) are increasingly consumed in large amounts for many applications. This issue causes a concern regarding the environmental impact of the waste materials generated after the first use. Mechanical recycling of polyolefin wastes helps to conserve oil and gas resources and reduce the polymeric waste accumulation in environment. In this paper, the modification of some post-consumer polypropylene (rPP) properties coming from packaging processing is investigated by the use of styrene-isoprene-styrene triblock copolymers (SIS). Thus, SIS block copolymers up to 20 wt.% in content with respect to rPP were introduced into the melted polymeric matrix by means of a twin rolls under the processing temperature of 185-190 C. The mechanical, thermal and structural properties of rPP/SIS blends have been studied with regard both to the content of SIS from blends and of polystyrene (PS) from SIS. The obtained results showed that the used SIS block copolymers led to the decrease of the degree of crystallinity and to increase of crystallite sizes of blends, with SIS20-10% being the most pronounced effect. Although by introduction of SIS into rPP a slight decrease of tensile strength is recorded, a remarkable increase on elongation at break and impact strength of rPP/SIS blends are exhibited. The good mechanical properties were achieved even by using of 10 wt% SIS.

A comparison was performed between Co-Ni thin films and template-assisted nanowires arrays obtained by electrochemical co-deposition. To reduce the effects of anomalous deposition and increase the Ni content in the deposit, an electrolyte with three times more Ni than Co in atomic ratio was chosen. Electrochemical deposition was performed at constant potentials chosen in the range from E = &minus, 0.8 to &minus, 1.2 V vs. Ag/AgCl. Cyclic voltammetry, chronoamperometry, and charge stripping techniques were used to characterize and compare the electrochemical behavior of Co-Ni films and nanowires. Morphological and compositional characterization was performed by scanning electron microscopy (SEM/EDAX) to assess the influence of the deposition potential on the growth of film and nanowires. A comprehensive analysis of the deposit growth rates for thin films and nanowires is presented taking into consideration the hydrogen evolution and anomalous deposition. The comparative study of the composition of film and nanowires obtained at different deposition potentials has shown that deposition of nanowires with a film-like composition takes place at more positive potential than thin film.

International audience; The paper presents a study concerning the characterisation of EN 1.4136 stainless steel heat-treated by means of concentrated solar energy in orde to improve some mechanical properties. In addition to the standard chemical composition, this steel was alloyed with nickel (Ni 1.5%wt) and copper (Cu 0.30%wt). Nickel was added to increase corrosion strength in acids, oxidising or non-oxidising environments, also facilitating an improved tenacity of the material. The addition of copper allows an increasing atmospheric corrosion strength (for copper content over 0.20%), at the same time intensifying the austenitising effect of nickel. The obtained steel was subjected to a solution heat treatment (hyper-hardening) with a heating time up to a austenitisation temperature (T A = 1050°C) for 20 (lot A) and for 33 min (lot B), respectively. The maintaining duration for austenitisation was 7 (lot A) and 21 min (lot B), respectively, followed by cooling in water. After the heat treatment in the solar furnace, the specimens were analysed from the structural point of view as well as to their behaviour when subjected to tribological stress, in accordance with the operational requirements for these types of steels. The analysed characteristics were the dynamic friction coefficient (CoF), the wear rates and the hardness (HRC) tests. Based on the collected data, a specific characterisation was made for EN 1.4136 stainless steel heat-treated in a solar furnace. By applying the thermal treatments in the solar furnace, the hardness values have been increased (of about 55%) and the average wear rates have decreased compared to the base material.

The need to recycle and develop nanomaterials from waste, and use them in environmental applications has become increasingly imperative in recent decades. A new method to convert the mill scale, a waste of the steel industry that contains large quantity of iron and low impurities into a nanoadsorbent that has the necessary properties to be used for water purification is presented. The mill scale waste was used as raw material for iron oxide nanopowder. A thorough characterization was performed in each stage of the conversion process from the mill scale powder to magnetic nanopowder including XRD (X-ray diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy), BET (Brunauer, Emmett and Teller) and magnetization properties. Iron oxide nanoparticles were approximately 5–6 nm with high specific surface area and good magnetic properties. These are the necessary properties that a magnetic nanopowder must have in order to be used as nanoadsorbents in the heavy metal removal from waters. The iron oxide nanoparticles were evaluated as adsorbents for the removal of Cu, Cd and Ni ions.

In this study, sodium alginate film (Alg) was coated with electrospun collagen glue (Col) extracted from rabbit skin waste, loaded with different commercial antimicrobial agents (chitosan, AG425K and ZnONPs) and investigated in terms of morphological, structural and biological properties. The coated nanostructures were characterized using scanning electron microscopy coupled with the energy-dispersive X-ray (SEM/EDS), Attenuated Total Reflectance Fourier-Transform Infrared spectroscopy (ATR FT-IR), and Atomic Force Microscopy (AFM) tests. The cytotoxicity was investigated on murine L929 fibroblasts using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide salt (MTT) and lactate dehydrogenase (LDH) assays. Microbiological tests were performed against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and Candida albicans ATCC 27853 standard strains. In vitro cell culture tests showed a good cytocompatibility of the coated nanostructured systems, except the sample loaded with ZnONPs, which exhibited a highly cytotoxic effect. Alg-Col-ZnONPs nanostructure inhibited the growth and multiplication of the Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 bacterial strains. The results of new coated nanostructures may be useful for the development of sustainable biomaterials in a circular economy, with bioactive properties for medical wound dressings.

This paper assessed the collagen glue (Col) from rabbit skin for use as a raw material in combination with different water-based dispersants of antimicrobial agents such as ZnO NPs, TiO2 NPs doped with nitrogen and Ag NPs (TiO2-N-Ag NPs), and chitosan (CS) for the production of biocompatible and antimicrobial nanofibers. The electrospun nanofibers were investigated by scanning electron microscopy (SEM), attenuated total reflectance in conjunction with Fourier-transform infrared spectroscopy (ATR-FT-IR) analyses and antioxidant activity. The biocompatibility of electrospun nanofibers was investigated on cell lines of mouse fibroblast NCTC ((clone L929) using MTT test assays. Antimicrobial activity was performed against Escherichia coli and Staphylococcus aureus bacteria and Candida albicans pathogenic fungus. Electrospun antimicrobial nanofibers based on collagen glue achieved reduction in the number of viable microorganisms against both fungi and bacteria and exhibited multiple inhibitory actions of fungal and bacterial strains. The electrospun nanofibers showed average dimension sizes in the range of 30&ndash, 160 nm. The results indicated that both Col/TiO2-N-Ag NPs and Col/CS formulations are suitable for cell proliferation and may be useful for producing of nonactive wound dressings.

Removing heavy metals from wastewaters is a challenging process that requires constant attention and monitoring, as heavy metals are major wastewater pollutants that are not biodegradable and thus accumulate in the ecosystem. In addition, the persistent nature, toxicity and accumulation of heavy metal ions in the human body have become the driving force for searching new and more efficient water treatment technologies to reduce the concentration of heavy metal in waters. Because the conventional techniques will not be able to keep up with the growing demand for lower heavy metals levels in drinking water and wastewaters, it is becoming increasingly challenging to implement technologically advanced alternative water treatments. Nanotechnology offers a number of advantages compared to other methods. Nanomaterials are more efficient in terms of cost and volume, and many process mechanisms are better and faster at nanoscale. Although nanomaterials have already proved themselves in water technology, there are specific challenges related to their stability, toxicity and recovery, which led to innovations to counteract them. Taking into account the multidisciplinary research of water treatment for the removal of heavy metals, the present review provides an updated report on the main technologies and materials used for the removal of heavy metals with an emphasis on nanoscale materials and processes involved in the heavy metals removal and detection.

This paper is focused on obtained two catalysts such as TiO2 nanoparticles and Fe3O4/SiO2/TiO2 nanocomposite for adsorption and photocatalytic degradation of methylene blue (MB) dyes from aqueous solution. The morphology, structure and chemical proprieties of synthesized materials were investigated by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), N2 adsorption-desorption isotherms and Zeta potential. The photocatalytic degradation of methylene blue under UV light in the presence of different synthesized catalysts was analyzed with Spectrometer UV-Vis. The photocatalytic degradation of methylene blue was studies by focusing of photoactivity performance of Fe3O4/SiO2/TiO2 in comparation with TiO2. An attempt has been made to study the effect of process parameters through amount of the catalysts and initial concentrations of methylene blue. In all cases was found that the kinetics of the MB photocatalytic degradation under UV light was fitted to the Langmuir–Hinshelwood. Even if the photocatalytic degradation study revealed that Fe3O4/SiO2/TiO2 and TiO2 degraded about 90 % of methylene blue within 60 min, the magnetic nanocomposite Fe3O4/SiO2/TiO2 serves as better catalyst compared with TiO2 nanoparticles. An important role in the photocatalytic degradation of MB is adsorption characteristic of TiO2 and Fe3O4/SiO2/TiO2 surface. The photocatalytic performance of Fe3O4/SiO2/TiO2 remained greater than TiO2 after 4 cycles of use.

New photocatalytic membranes based on polylactic acid (PLA)/TiO2 hybrid nanofibers deposited on fiberglass supports were prepared and tested for the removal of ampicillin from aqueous solutions. The electrospinning technique was used to obtain hybrid nanofibers that were deposited on three types of fiberglass with different structures, resulting in three distinct photocatalytic membranes namely fiberglass fabric plain woven-type membrane, fiberglass mat-type membrane, and fiberglass fabric one-fold edge-type membrane. The results of the photocatalytic tests showed that the highest efficiency of ampicillin removal from aqueous solution is obtained with the fiberglass fabric plain woven-type membrane. Although it has been shown that the rate of photocatalytic degradation of ampicillin is high, being practically eliminated within the first 30 min of photocatalysis, the degree of mineralization of the aqueous solution is low even after two hours of photocatalysis due to the degradation of PLA from the photocatalytic membrane. The instability of PLA in the reactive environment of the photocatalytic reactor, evidenced by morphological, mineralogical and spectroscopic analyzes as well as by kinetic studies, is closely related to the structure of the fiberglass membrane used as a support for PLA/TiO2 hybrid nanofibers.

The paper had as purpose the fabrication and characterization of magnetic nanoparticles covered with TiO2 for applications in environmental field. The research consisted in investigating the properties of magnetic iron nanooxides, synthesized from ferric and ferrous chloride and then covered with TiO2, with minimum costs and high efficiency in industrial wastewater treatment. The iron nanoparticles were obtained by co-precipitation method and the titan dioxide was obtained by sol-gel method. After covering the nanoparticles with TiO2, the samples were characterized by X-Ray diffraction (XRD) and scanning electron microscopy (SEM).

The paper presents results of researches carried out to establish the causes that led to the cracking of forgings made of manganese low alloy steel microalloyed with boron. The researches includes analysis of samples taken from the forgings in the cracked surface area and also analysis of a sample from forged material. The following methods and techniques were used for investigation:metallographic analysis by optical microscopy;visual macroscopic examination by scanning electron microscopy (SEM) at low magnification, using scanning electron microscope;examination by scanning electron microscopy on the material cracks area and its adjacent area;investigation of material by X-ray microanalysis in energy dispersive (EDAX) for its characterization, in terms of microcomposition

The paper presents the investigations made on samples taken from the related rotor blade of an hospital cooling equipment.The failure analysis was made in order to find if the failure appear because the metallic material used or was functional problem.The objectives of our analysis and techniques used are described below:determining the chemical composition by optical emission spectrometry;determining the hardness of the material;metallographic analysis by optical microscopy;micro compositional and microstructural analysis by scanning electron microscopy (SEM) and by microanalysis, energy dispersive X-ray (EDAX). Research has highlighted the quality of piece elaboration and casting, which led to a long life of its use.

The paper emphasizes the importance of use the nano-iron oxides as treatment materials for wastewaters decontamination, having in mind the size of these compounds and specific surface area suitable for retaining toxic metals such as chromium or cadmium presented as major pollutants for industrial wastewaters. Also, the magnetic properties of the nano-iron oxides offer the possibility of a fast removal of these from the system, after wastewaters treatment. The obtaining of some core-shell composites with nano-iron oxides as core represent an advantage because of the dissolving tendency of the nano-iron oxides under acidic conditions, the situation being common to the industrial wastewaters.

International audience; Maghemite nanoparticles (γ-Fe2O3) were synthesized in order to be used as magnetic adsorbent for two heavy metals, Pb(II) and Zn(II), from aqueous solutions. γ-Fe2O3 was prepared from magnetite nanoparticles and was tested for single and binary aqueous solutions. Efficiency removal (%) for single solutions appears only after 10 minutes and was higher than 80%. In case of binary solutions, same results regarding efficiency removal were registered after 60 minutes, being almost 90% for Pb(II) and only 70% for Zn(II). In this case, the experimental data for single solutions were correlated with the Langmuir, Freundlich and Dubinin- Radushkevich adsorption models in order to evaluate the adsorption capacity of the magnetic adsorbent. Level of the metals concentration removed with these types of particles can be assumed as satisfactory. The maximum adsorption capacity was found at 19.23 mg/g for Zn(II) and 9.89 mg/g for Pb(II) in case of single solution (at 25°C) according to the Langmuir model. The results obtained in case of Dubinin-Radushkevich model indicate a good adsorption in terms of ion-exchange process. Also, recovery for Pb(II) and Zn(II), after acidic washing, was studied. The results suggest that magnetic nanomaterial can be used as efficient adsorbents of heavy metals also from aqueous environments. © 2016 Gh. Asachi Technical University of Iasi. All rights reserved.

Synthesis and characterization of iron oxide nanoparticles coated with a large molar weight dextran for environmental applications are reported. The first experiments involved the synthesis of iron oxide nanoparticles which were coated with dextran at different concentrations. The synthesis was performed by a co-precipitation technique, while the coating of iron oxide nanoparticles was carried out in solution. The obtained nanoparticles were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction spectrometry, Fourier transform infrared spectroscopy and superconducting quantum interference device magnetometry. The results demonstrated a successful coating of iron oxide nanoparticles with large molar weight dextran, of which agglomeration tendency depended on the amount of dextran in the coating solution. SEM and TEM observations have shown that the iron oxide nanoparticles are of about 7 nm in size.

A sodium alginate/cellulose/n-clay composite was prepared as potential adsorbent for removal of Pb(II) from wastewater. The results showed that obtained adsorbent used for 4 mg L-1 initial concentration of Pb(II) in wastewater after 90 min adsorption time led to 90% removal efficiency and the adsorption capacity of the prepared composite was 0.11 mg .g-1. The isotherms and kinetics of adsorption revealed that the equilibrium adsorption and kinetics were well-described by the Langmuir model and pseudo-second-order kinetics, respectively.

The toxicity of heavy metals for the environment can be solved by using the adsorption properties of magnetic nanomaterials. These types of nanomaterials can remove pollutants, especially from wastewaters. This study was conducted to determine whether two magnetic nanomaterials can be used as adsorbents for heavy metals (Cr, Cd, Cu, Zn, and Ni) from aqueous solutions under acidic conditions. Qualitative and quantitative elemental information and structural and surface characteristics before and after use as adsorbents were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The obtained data showed a good correlation with the Langmuir adsorption model using the two magnetic nanomaterials in aqueous solutions. The crystalline structure of the Fe₃O₄ powder was identified with XRD. The TEM images of Fe₃O₄ nanoparticles indicated a good dispersion of particles of 85.5 nm. The SEM analysis for Fe₃O₄–PAA (magnetite covered with sodium alginate) showed spherical particles of magnetite wrapped into the polymer with dimension of ∼200 nm. According to the adsorption Langmuir model, the removal efficiency for uncoated Fe₃O₄ decreased in order: Cr(VI) > Cu(II) > Zn(II) > Ni(II) > Cd(II). For the Fe₃O₄–PAA nanocomposite (45% w/w Fe in a mass of polymer), the adsorption phenomena appears as follows: Cr(VI) > Cd(II) > Cu(II) ∼ Zn(II) > Ni(II). Langmuir parameters indicated a favorable monolayer adsorption at pH 2.5. The nanocomposite Fe₃O₄–PAA can be used as an adsorbent with the same performance as uncoated Fe₃O₄ but with the advantage of stability under conditions where industrial wastewaters have an acidic pH.

The paper refers at adsorption studies using the maghemite nanoparticles as adsorbent for removal of the hexavalent chromium from aqueous synthetic solutions. Adsorption reached at equilibrium within 10 minutes and was registered as maximum at pH 2.54. The adsorption data were analyzed and fitted by Langmuir isotherm. Investigation methods for characterization of the nanoparticles were X-ray diffraction, scanning and transmission electron microscopy. Also, in order to evaluate the hexavalent chromium concentration the atomic and molecular absorption spectrometry were used. Key words: adsorption, chromium removal, maghemite