Oxygen functional groups on MWCNT surface as critical factor Boosting T-2 relaxation rate of water protons: towards improved CNT-based contrast agents

Purpose: Salicyl (Sal) – among other oxygen functionalities – multi-walled carbon nanotubes (MWCNTs) and their nanohybrids are investigated as promising contrast agents (CA) in magnetic resonance imaging (MRI) or drug delivery platforms, due to their unique properties. The preliminary results and the literature reports were the motivation to endow high r2 relaxivities, excellent dispersibility in water, and biocompatibility to superparamagnetic MWCNTs nanohybrids. It was hypothesized that these goals could be achieved by, not described in the literature yet, two-stage oxygen functionalization of MWCNTs. Results: Two structurally different MWCNT materials differing in diameters (44 and 12 nm) and the iron content (4.7% and 0.5%) are studied toward the functionalization effect on the T2 relaxometric properties. MWCNT oxidation is typically the first step of functionalization resulting in “first generation” oxygen functional groups (OFGs) on the surface. Until now, the impact of OFGs on the relaxivity of MWCNT was not truly recognized, but this study sheds light on this issue. By follow-up functionalization of oxidized MWCNT with 4-azidosalicylic acid through [2+1] cycloaddition of the corresponding nitrene, “second generation” of oxygen functional groups is grafted onto the nanohybrid, ie, Sal functionality. Conclusion: The introduced OFGs are responsible for an almost 30% increase in the relaxivity, which leads to remarkable r2 relaxivity of 951 mM−1s−1 (419 (mg/mL)−1s−1), the unprecedented value reported to date for this class of CAs. Also, the resulting nanohybrids express low cytotoxicity and superb diffusion after subcutaneous injection to a mouse

A Method for Determination of Metals in Hybrid Metal Oxide/Metal-Carbon Nanotubes Catalysts

Carbon nanotubes (CNTs), due to their special structure and unique properties, are still one of the most interesting materials for scientists. Recently, carbon nanotubes were proposed as a new type of carbon support for catalysts. Fe, Pt, Ni, Co, and other metals anchored to CNTs are used in various reactions. Due to the fact that production processes are usually unpredictable and the total amount of metal/metal oxide deposited on the CNTs may only be estimated, the methods for examining the chemical composition are necessary. In this study, fast and simple inductively coupled plasma atomic emission spectrometry (ICP-AES) with slurry nebulization was proposed for metal content determination in hybrid CeZrO2/CNT, Ni-CeZrO2/CNT, and Ni/CNT materials. Slurries were prepared by 30 min ultrasonication of appropriate amount of investigated material in 1% Triton X-100 solution. Optimal range of slurry concentration and optimal RF plasma power were established (40–400 mg L−1, 1.2 kW, resp.). Obtained results proved that this method may be applied for determination of Ce, Zr, and Ni in hybrid CNT-based materials

Zinc Sorption Studies on Pectin-Based Biosorbents

The previously-obtained and characterized hybrid pectin-based beads containing agar-agar and guar gum, as well as sole pectin beads (P, for comparison) were examined for zinc ions sorption and desorption properties. The sorption kinetics and equilibrium in the studied system was described by two kinetic models (pseudo-first- and pseudo-second-order) and two isotherms (Langmuir and Freundlich), respectively. The desorption kinetics and equilibrium was also investigated by applying various inorganic acids (nitric, hydrochloric, and sulfuric acid) of various concentrations. In the case of guar gum additive, no significant change in sorption capacity compared to sole pectin beads was observed (q: 37.0 ± 2.6 and 34.7 ± 2.0 mg/g, respectively). Addition of agar-agar significantly decreased the sorption capacity to 22.3 ± 1.0 mg/g, but stripping of zinc(II) ions from this biosorbent was complete even with very diluted acids (0.01 M). Total desorption of zinc from sole pectin and pectin-guar gum beads required acid solution of higher concentration (0.1 M). Sorption rates for all biosorbents are roughly the same and maximum sorption is achieved after 4–5 h. Obtained results and the advantage of our sorbent’s shape formation ability, make the pectin-based biosorbents interesting alternative for zinc(II) ions removal

Mało energochłonna utylizacja zasolonych wód kopalnianych w zintegrowanym systemie membranowo – wyparnym

Przedstawiono rozwiązanie, w którym woda zasolona poddawana jest wstępnemu uzdatnianiu metodą nanofiltracji (NF) a następnie zatężaniu metodą wyparną lub w zintegrowanym układzie elektrodializa – odwrócona osmoza i dalszemu odparowaniu z krystalizacją chlorku sodu. Na przykładzie solanki z KWK Budryk wykazano, że uzysk soli, dzięki samemu zastosowaniu nanofiltracji, można zwiększyć z obecnej wartości 72,01% do 87,35%, a po dalszym usprawnieniu, polegającym na oczyszczaniu chemicznym, do 91,11% a nawet 99,1%. Wstępne uzdatnianie solanki metodą nanofiltracji, prowadzone w sposób opracowany przez Autorów w warunkach dużego przesycenia siarczanem wapnia z częściową recyrkulacją retentatu i kontrolowaną krystalizacją gipsu, daje możliwość zastosowania mało energochłonnych rozwiązań zatężania solanki. Na przykładzie solanki Budryk wykazano, że zużycie energii w procesie jej utylizacji można zmniejszyć z obecnych 888,7 kWh/t soli do 433,7-451,2 kWh/t soli, w przypadku zatężania solanki mało energochłonną metodą wyparną lub do 396,8 kWh/t soli w przypadku zatężania solanki w zintegrowanym układzie: elektrodializa – odwrócona osmoza. Proponowane rozwiązanie ma zostać przebadane w instalacji pilotowej w ramach projektu NANOS, finansowanego w programie TANGO2

Solvent-Impregnated Sorbents for Tantalum from Niobium Separation Using a Fixed-Bed Column

Reactor-grade niobium steel is used as a construction material for nuclear reactors. In this case, the presence of tantalum, which is characterized by a 20 times higher active cross section for capturing thermal neutrons than the cross section of niobium (181Ta: 21.3 barn), cannot exceed 100 ppm. Analytical methods for quality and new separation method development control need very pure niobium matrices—niobium compounds with a low tantalum content, which are crucial for preparing matrix reference solutions or certified reference materials (CRMs). Therefore, in this paper, a new, efficient method for separating trace amounts of Ta(V) from Nb(V) using extraction chromatography with the use of sorbents impregnated with methyl isobutyl ketone MIBK solvent is proposed. Various types of MIBK-impregnated sorbents were used (AG® 1-X8 Anion Exchange Resin, AMBERLITE™ IRC120 Na Ion Exchange Resin, SERVACEL® Cellulose Anion Exchangers DEAE 52, active carbons of various grain size, carbonized blackcurrant pomace, carbonized chokeberry pomace, bentonite, and polyurethane foam in lumps). The highest tantalum removal efficiency was determined using active coal-based materials (>97%). The separation effectivity of tantalum from niobium was also determined in dynamic studies using a fixed-bed column with MIBK-impregnated active carbon. Solutions of various Nb:Ta weight ratios (1:1, 100:1, 1000:1) were used. The most impressive result was obtaining 70 mL of high purity niobium solution of tantalum content 0.027 ppm (in relation to Nb) with 88.4% yield of niobium from a solution of Nb:Ta, weight ratio 1000:1 (purge factor equaled 35,000). It proves the presented system to be applicable for preparation of pure niobium compounds with very low contents of tantalum

Zinc Ion Removal on Hybrid Pectin-Based Beads Containing Modified Poly(Methyl Methacrylate) Waste

A new hybrid sorbent in the form of round beads containing modified poly(methyl methacrylate) (PMMA) waste immobilized in pectin and crosslinked with calcium ions was prepared. A previously obtained and characterized powdered poly(methyl methacrylate)–based sorbent was used. Batch and column studies on the new material’s sorption-desorption properties were performed. Two kinetic models (pseudo-first- and pseudo-second-order) and three isotherms (Langmuir, Langmuir bisite and Freundlich) were used to describe the results. Breakthrough and elution curves were also obtained. Nitric, hydrochloric, and sulfuric acid of various concentrations were used in the desorption studies. Higher sorption affinity of zinc(II) ions to hybrid sorbent than to pectin alone, reflected by higher values of the Langmuir and Freundlich model parameters, was observed. The maximum sorption capacities, calculated based on the best-fitted models, were 50.2 mg/g (Langmuir bisite) and 42.2 mg/g (Langmuir) for hybrid and only pectin beads, respectively. The stripping of Zn ions using 0.1 M solutions of mineral acids was similarly effective in the case of both sorbents. The mass balance calculated for the column studies showed about 100% recovery of zinc in a sorption-desorption cycle. By applying the hybrid sorbent under the studied conditions it is possible to purify Zn in water to the level permitted by law and concentrate Zn(II) ions by about 60 times

Long Term and Large-Scale Continuous Studies on Zinc(II) Sorption and Desorption on Hybrid Pectin-Guar Gum Biosorbent

Pectin-guar gum biosorbent was tested for zinc(II) ions removal in column process. Sorption–desorption experiments were performed in laboratory and at larger scale. The breakthrough and elution curves were obtained for various conditions. The Bed Depth Service Time model was tested for utility in data estimation. Possibility of sorbent reuse and its lifetime was examined in 20 repeated sorption–desorption cycles. Finally, tests were repeated for real wastewater from galvanizing plant, giving satisfactory results. The effectiveness of Zn(II) sorption happened to be dependent on process parameters; tests have proved that it increased with increasing bed height and with decreasing flow rate or grain size. For an initial zinc concentration of 30 mg/L, even 2096 mL of zinc solution could be purified in small scale experiment (2 g of fine grain sorbent and flow rate 60 mL/h) or 5900 L in large-scale (16 kg of large grain sorbent and flow rate 45 L/h). This allowed for 40-fold or 49-fold zinc increases in concentration in one sorption–desorption cycle. The most successful results are meant that at least 20 sorption–desorption cycles could be performed on one portion of biosorbent without loss of its effectiveness, large-scale tests for real wastewater from galvanizing plant gave satisfactory results, and that the form and mechanical stability of our sorbent is suitable for column usage with flow rates applicable in industry

Hybrid Pectin-Based Sorbents for Cesium Ion Removal

In this paper, beads-shaped hybrid sorbents composed of pectin and Prussian blue were prepared. Various ratios of pectin and Prussian blue in hybrid sorbents were tested. Obtained sorbents had high and roughly constant sorption capacity in a broad pH range (4–10), in which also the swelling index and stability of sorbents were satisfactory. The preliminary sorption studies proved that almost 100% of cesium removal efficiency may be achieved by using the proper sorbent dose. The sorption capacity of the hybrid sorbent with a 1:1 ratio of pectin to Prussian blue equaled q = 36.5 ± 0.8 mg/g (dose 3 g/L, pH = 6, temp. = 22 ± 1 °C, t = 24 h). The obtained results showed that the prepared hybrid pectin-based sorbents are promising for cesium ions removal

Fast and Simple Analytical Method for Direct Determination of Total Chlorine Content in Polyglycerol by ICP-MS

The fast and simple method for total chlorine determination in polyglycerols using low resolution inductively coupled plasma mass spectrometry (ICP-MS) without the need for additional equipment and time-consuming sample decomposition was evaluated. Linear calibration curve for 35Cl isotope in the concentration range 20–800 µg/L was observed. Limits of detection and quantification equaled to 15 µg/L and 44 µg/L, respectively. This corresponds to possibility of detection 3 µg/g and determination 9 µg/g of chlorine in polyglycerol using studied conditions (0.5% matrix-polyglycerol samples diluted or dissolved with water to an overall concentration of 0.5%). Matrix effects as well as the effect of chlorine origin have been evaluated. The presence of 0.5% (m/m) of matrix species similar to polyglycerol (polyethylene glycol—PEG) did not influence the chlorine determination for PEGs with average molecular weights (MW) up to 2000 Da. Good precision and accuracy of the chlorine content determination was achieved regardless on its origin (inorganic/organic). High analyte recovery level and low relative standard deviation values were observed for real polyglycerol samples spiked with chloride. Additionally, the Combustion Ion Chromatography System was used as a reference method. The results confirmed high accuracy and precision of the tested method

EGFR-Targeted Cellular Delivery of Therapeutic Nucleic Acids Mediated by Boron Clusters

New boron carriers with high boron content and targeted cancer-cell delivery are considered the first choice for boron neutron capture therapy (BNCT) for cancer treatment. Previously, we have shown that composites of antisense oligonucleotide and boron clusters are functional nanoparticles for the downregulation of expression of epidermal growth factor receptor (EGFR) and can be loaded into EGFR-overexpressing cancer cells without a transfection factor. In this study, we hypothesize that free cellular uptake is mediated by binding and activation of the EGFR by boron clusters. Proteomic analysis of proteins pulled-down from various EGFR-overexpressing cancer cells using short oligonucleotide probes, conjugated to 1,2-dicarba-closo-dodecaborane (1,2-DCDDB, [C2B10H12]) and [(3,3′-Iron-1,2,1′,2′-dicarbollide)−] (FESAN, [Fe(C2B9H11)2]−), evidenced that boron cage binds to EGFR subdomains. Moreover, inductively coupled plasma mass spectrometry (ICP MS) and fluorescence microscopy analyses confirmed that FESANs-highly decorated B-ASOs were efficiently delivered and internalized by EGFR-overexpressing cells. Antisense reduction of EGFR in A431 and U87-MG cells resulted in decreased boron accumulation compared to control cells, indicating that cellular uptake of B-ASOs is related to EGFR-dependent internalization. The data obtained suggest that EGFR-mediated cellular uptake of B-ASO represents a novel strategy for cellular delivery of therapeutic nucleic acids (and possibly other medicines) conjugated to boron clusters