Trivalent Ions Research Articles

Керамические радиационно стойкие сцинтилляторы для регистрации высокоэнергетического излучения

Complex oxides of Y3Al5O12, Gd(Nb,Ta)O4, (Zr,Hf,Y)O2, (Zr,Y)O2, activated with trivalent rare earth ions Nd3+, Eu3+ and Tb3+ have been studied in terms of their luminescent properties. These materials are promising scintillators with high radiation, chemical, and mechanical stability. The aim of the work was to develop ceramic radiation-resistant scintillators based on oxides activated by rare-earth ions. The study included: an evaluation of changes in the intensity and kinetics of luminescence decay from single crystal samples to ceramics; a study of the complete or partial replacement of light elements by heavier ones effect on the luminescent properties; a study of the possibility of using a sensitizer to increase the luminescence yield when luminescence is excited by an electron beam of medium energies.

Molecular Influences on the Quantification of Lewis Acidity with Phosphine Oxide Probes.

Gutmann-Beckett-type measurements with phosphine oxide probes can be used to estimate effective Lewis acidity with 31P nuclear magnetic resonance spectroscopy, but the influence of the molecular structure of a given probe on the quantification of Lewis acidity remains poorly documented in experimental work. Here, a quantitative comparison of triethyl (E), trioctyl (O), and triphenyl (P) phosphine oxides as molecular probes of Lewis acidity has been carried out via titration studies in MeCN with a test set of six mono- and divalent metal triflate salts. In comparison to E, the bulkier O displays a similar range of chemical shift values and binding affinities for the various test metal ions. Spectral linewidths and speciation properties vary for individual cation-to-probe ratios, however, confirming probe-specific properties that can impact the data quality. Importantly, P displays a consistently narrower dynamic range than both E and O, illustrating how electronic changes at phosphorus can influence the NMR response. Comparative parametrizations of the effective Lewis acidities of a broader range of metal ions, including the trivalent rare earth ions Y3+, Lu3+, and Sc3+ as well as the uranyl ion (UO22+), can be understood in light of these results, providing insight into the fundamental chemical processes underlying the useful approach of single-point measurements for quantification of effective Lewis acidity. Together with a study of counteranion effects reported here, these data clarify the diverse ensemble of factors that can influence the measurement of Lewis acid/base interactions.

A study of phase evolution, crystallographic and down-conversion luminescent behaviour of monoclinic Y4Al2O9:Dy3+ nanophosphors for white light applications

Undoped Y4Al2O9 and Dy3+ doped Y4Al2O9 nanophosphors have been synthesized through urea aided combustion approach. The monoclinic phase of undoped and Dy3+ doped Y4Al2O9 nanosamples are affirmed by the results of X-ray diffraction. Diffuse reflectance (DR) spectrum and an energy band gap (5.51 eV) value for optimized Y3.96Al2O9:0.04Dy3+ sample, calculated utilizing the Kubelka-Munk theory, demonstrated the good optical quality of nanosample. Transmission electron microscope confirms the nanosize particles with some agglomeration. The synthesized nanosamples are well excited at 348 nm, exhibited yellowish-band at 576 nm with 4F9/2 → 6H13/2 and bluish-band at 483 nm with 4F9/2 → 6H15/2 transition. Firstly, luminous intensity of trivalent dysprosium ion rises and then decreases, this was because of quenching of concentration (CQ). The dipole-dipole interaction between the nearest dopant ions is responsible for this concentration quenching. Bi-exponential fitting behaviour in the focused nanophosphors confirms that there are two coordinatively different luminous centres are present in the host material for the incoming dopant ions. The luminescence decay lifetime for 4F9/2 energy level was found to be around 1.522 ms for the optimized phosphor composition. The value of integrated Y/B ratio for the samples being close to one, they can be promising candidate for white light emitting nanophosphors. The obtained outcomes authenticate the ability of Y4Al2O9:Dy3+ nanophosphor to be utilized in WLED's and other lighting appliances.

Distinct Reactivity of Trimethylytterbium toward AlMe3 and GaMe3 : Synthesis of Donor-Stabilized Dimethylytterbium.

Me3 TACN (1,4,7-trimethyl-1,4,7-triazacyclononane)-stabilized trimethylytterbium was obtained via a salt-metathesis protocol employing [(Me3 TACN)YbCl3 ] and methyllithium. Complex [(Me3 TACN)YbMe3 ] seems not to engage in redox chemistry with potassium graphite and is thermally quite stable in the solid state. Treatment of trivalent [(Me3 TACN)YbMe3 ] with 3 equiv. of AlMe3 afforded divalent tetramethylaluminate complex [(Me3 TACN)Yb(AlMe4 )2 ]. The reaction of [(Me3 TACN)YbMe3 ] with GaMe3 in THF gave trivalent ion pair [(Me3 TACN)YbMe2 (thf)][GaMe4 ], which is susceptible to reduction with KC8 . The thermally very labile divalent [(Me3 TACN)YbMe(μ-Me)]2 is the first discrete donor adduct of a divalent dimethyl rare-earth-metal complex.

Er3+-doped Y4Al2O9 nanophosphors for advance display applications: Synthesis, crystal chemistry and down conversion photoluminescent investigation

A gel-combustion approach was positively used to synthesize a series of cool greenish light emitter Y4-xAl2O9:xEr3+ (x = 1–5 mol %) nanophosphors and their structural, vibrational, morphological and luminescent characteristics have been examined for display applications. Studies of X-ray diffraction and structural refinement show that synthesized nanophosphors are made up of a single phase with a monoclinical crystal structure having P21/c space group. Transmission electron microscope (TEM) image manifests occurrence of non-uniform agglomeration of particles in the dominion of nano region. Emission spectra entail strongest band located at 549 nm due to 4S3/2 → 4I15/2 transition of trivalent erbium ion, producing greenish light. Concentration quenching (CQ) was attributed to exchange interactions (quadruple-quadruple), with an optimum concentration at 3 mol %. The lifetime of 549 nm emission decreases with higher Er3+ addition. The CIE chromaticity coordinates of Y4-xAl2O9:xEr3+ (x = 1–5 mol %) nanosamples were found in the greenish area. These obtained results of Y4-xAl2O9:xEr3+ (x = 1–5 mol %) nanophosphors are supportive for the usage of prepared nanophosphors as green component in display fabrication and other lighting foundations.

Heptacoordinated lanthanide(III) complexes based on 2,6-bis(1H-benzo[d]imidazol-2-yl)pyridine ligands (bbp, bmbp and bdmbp): Computational calculations, luminescent properties and cytotoxic evaluation.

Two new series of heptacoordinated obtained of hydrated lanthanide(III) nitrates (Ln3+ = La, Nd, Sm, Eu, Gd, Tb and Dy) with 2,6-bis(1H-benzo[d]imidazol-2-yl)pyridine (bbp) and 2,6-bis(5,6-dimethyl-1H-benzo[d]imidazol-2-yl)pyridine (bdmbp) were synthesized and characterized by high-resolution mass spectrometry (HR-MS), elemental analysis (EA), melting point (MP), molar electrical conductivity (MEC), effective magnetic moment (EMM) and Fourier-transform infrared spectroscopy (FT-IR). The optical properties of complexes were evaluated by ultraviolet-visible (UV–Vis) absorption and emission spectroscopy in solution. Samarium(III), europium(III), and terbium(III) complexes exhibited luminescent properties and characteristic emission bands. IR and MEC studies indicated that only two of the three nitrate groups were coordinating with the lanthanide(III) ion in a bidentate manner and confirmed the presence of the third nitrate group outside the coordination sphere. EMM analyses indicated that the metal complexes present paramagnetism, except for those of lanthanum(III). The third series of these complexes with these same trivalent lanthanide ions derived from the ligand 2,6-bis(5-methyl-1H-benzo[d]imidazol-2-yl)pyridine (bmbp) were previously reported by our research group in this same research journal (10.1016/j.molstruc.2018.03.065). Therefore, the cytotoxic activity of the three series of complexes and their ligands against NIH-3T3, J774A.1 and HeLa cell lines was studied. Only the bdmbp-based complexes exhibited moderate cytotoxic activity versus the HeLa cell line compared to the other two cell lines, while the bbp- and bmbp-derived complexes exhibited weak cytotoxic activity against all three cell lines.

Evidence of Eu(III) Dual Binding in a PVC‐Based Electrochemical Sensor with N,N,N’,N’‐Tetrapentyl Diglycolamide (TPDGA) as the Ionophore: Potentiometric and Luminescence studies

AbstractThe present investigation deals with the development of a polyvinyl chloride (PVC) based potentiometric sensor for Eu(III) containing N,N,N’,N’‐tetrapentyl diglycolamide (TPDGA) as ionophore, 2‐nitrophenyl octylether (NPOE) as plasticizer and sodium tetraphenylborate (NaTPB) as ionic additive. The membrane with 8.7 % TPDGA, 29.7 % PVC, 59.0 % NPOE, 2.5 % NaTPB exhibited a linear response behaviour from 1.5×10−6 m to 1.1×10−2 m Eu(III) with a slope of 23.4±0.3 mV/decade and a limit of detection (LOD) of 1.2×10−6 m. The sensor showed fast response times (<5 s) and a lifetime of two months. It showed good tolerance for monovalent/divalent interfering ions and moderate/poor tolerance for trivalent ions. The membrane was characterized using photoluminesce (PL) spectroscopy which suggested NPOE can alter the nature of species in the membrane and evidence the presence of two species. The membrane can be used as an indicator electrode for the potentiometric titration of Eu(III) and in the estimation of europium in the synthetic and laboratory bearing waste which compared well with the x‐ray fluorescene (XRF) results.

An Electrolyte-Gated Graphene Field-Effect Transistor for Detection of Gadolinium(III) in Aqueous Media

In this work, an electrolyte-gated graphene field-effect transistor is developed for Gd3+ ion detection in water. The source and drain electrodes of the transistor are fabricated by photolithography on polyimide, while the graphene channel is obtained by inkjet-printing a graphene oxide ink subsequently electro-reduced to give reduced graphene oxide. The Gd3+-selective ligand DOTA is functionalized by an alkyne linker to be grafted by click chemistry on a gold electrode without losing its affinity for Gd3+. The synthesis route is fully described, and the ligand, the linker and the functionalized surface are characterized by electrochemical analysis and spectroscopy. The as functionalized electrode is used as gate in the graphene transistor so to modulate the source-drain current as a function of its potential, which is itself modulated by the concentration of Gd3+captured on the gate surface. The obtained sensor is able to quantify Gd3+ even in a sample containing several other potentially interfering ions such as Ni2+, Ca2+, Na+ and In3+. The quantification range is from 1 pM to 10 mM, with a sensitivity of 20 mV dec-1 expected for a trivalent ion. This paves the way for Gd3+ quantification in hospital or industrial wastewater.

Synthesis of a new pyrimidine-based sorbent for indium(III) removal from aqueous solutions – Application to ore leachate

A new sorbent (TcTDG, pyrimidine derivative, with high content of N-based reactive groups and S-based sites) was successfully synthesized by the polycondensation of thiocarbazide and 2-thiobarbituric acid through reaction with formaldehyde. The material is characterized by FTIR, SEM and SEM-EDX analyses, titration, elemental analysis, BET, and TGA. After interacting with In(III), the FTIR spectrum of TcTDG shows the modification of the environment of N- and S-based reactive groups. The sorption of In(III) is first studied in synthetic solutions with TcTDG micro-particles through the evaluation of pH effect (optimum at pH 4), the uptake kinetics (equilibrium achieved in 20–30 min), the sorption isotherms and the selectivity properties from equimolar solution of different metal ions. The sorption capacity significantly decreases when increasing the temperature from 15 to 50 °C: In(III) sorption onto TcTDG is exothermic. Maximum sorption capacity at room temperature and at pH 4 reaches up to 1.87 mmol In g−1; the isotherm is equally fitted by the Langmuir and the Sips equations. Indium is fully eluted from metal-loaded sorbent using 0.3 M HCl solution (equilibrium reached in 20–30 min). The pseudo-first order rate equation fits well experimental kinetic profile; although the resistance to intraparticle diffusion plays a significant role in the control of In(III) sorption. The sorbent is highly stable at recycling: the FTIR spectrum is restored after five cycles and desorption remains complete along the cycles; after five re-uses, the sorption efficiency decreases by less than 4%. The study is extended to more complex solutions: first, with multi-component synthetic equimolar solutions before investigating the application of TcTDG to metal recovery from acidic leachate of ore sample (from Eastern Central Desert, Egypt). The sorbent shows a marked preference for In(III) at pH 4 against mono-, di- and tri-valent metal ions in synthetic solutions, the preference is also appreciable but the selectivity coefficient (SCIn/metal) is weaker for rare metals (between 3 and 6, vs. 10–35 for other metal ions). In the case of acidic leachate, the pH control to 4 leads to substantial precipitation of huge amounts of iron and the co-precipitation of other metal ions. The sorption capacity for In(III) (and Ga(III)) is significantly reduced by the complexity of the effluents; although the sorbent maintains a preference for these trivalent metal ions. The new sorbent shows promising sorption properties, although complementary investigation is required for optimizing the practical application of this material (conditioning, larger number of recycling steps, etc.).

Designing Heterovalent Substitution with Antioxidant Attribute for High‐Performance Sn‐Pb Alloyed Perovskite Solar Cells

AbstractAll‐perovskite tandem solar cells are promising for breaking through the single‐junction Shockley–Queisser limit, and that potentially raises interest in configuring efficient Sn‐Pb alloyed narrow‐bandgap perovskite solar cells (PSCs). However, the Sn‐Pb alloyed perovskites are commonly plagued by uncontrollable crystallization dynamics and severe p‐doping levels. Herein, an effective additive molecule is designed with heterovalent substitution and antioxidant functions, whereby an organic metal coordination compound of tris(2,4‐pentanedionato)gallium (TPGa) is employed to upgrade the quality of perovskite films. Ga3+ substitution obviously boosts the formation energy of Sn vacancies and heals the trap states. Meanwhile, the crystal structure evolution process is improved by the anchoring effect of 2,4‐pentanedionato. The PSCs incorporating these improvements deliver not only a power conversion efficiency of 21.5% but also outstanding stability, as demonstrated by retaining 80% of the initial efficiency for over 1500 h. In addition, 23.14%‐efficient all‐perovskite tandem solar cells are further obtained by pairing this PSC with a wide‐bandgap (1.74 eV) top cell. This study supports the feasibility of doping trivalent ions into the Sn‐Pb alloyed perovskites to compromise the self‐p‐doping effect and highlights the importance of acetylacetone for passivating defects and hindering oxidation.

Structural, optical and radiation shielding parameters of sodium aluminium borate glasses modified with chromium oxide

Samples of nominal composition xCr2O3. (60-x)B2O3.5Al2O3.35Na2O: x = 0 (Cr0), 0.1 (Cr0.1), 0.2 (Cr0.2), 0.4 (Cr0.4), 0.6 (Cr0.6), 0.8 (Cr0.8), and 1 (Cr1) mol% were prepared via the traditional melt quenching route. Structural FTIR absorption spectra of the prepared glasses reveal distinct absorption bands which are characteristic of both triangular BO3 and tetrahedral BO4 groups within their varying wavenumber vibrational sites. The dopant chromium ions are observed to have no distinct variations on the FTIR spectra because of low dopant percent. Optical absorption characterization indicates that the undoped glass shows only UV absorption which is related to originating from unavoidable trace ferric ions present as impurities in the used chemicals. The Cr2O3-doped glasses reveal additional UV absorption at about 370-385 nm correlated with the hexavalent state of chromium, producing this distinct charge transfer band. Additionally, two visible bands are identified at about 420-400 nm and 580-640 nm originating from trivalent chromium ions with distorted octahedral coordination. Optical parameters including band gap, refractive index, molar refraction, and reflection losses were calculated together with optical dielectric properties, electronic and molar polarizability. In terms of radiation shielding capacity, increasing Cr2O3 mol% of the sample encoded Cr1 that possessed the highest mass (μm) and linear (μ) attenuation coefficients, but the lowest half value layer (HVL) at low and high incident photon energy, results showed that Cr1 can be used in optical and radiation shielding safety.

Enhanced emission intensity in (Li+/Ca2+/Bi3+) ions co-doped NaLa(MoO4)2: Dy3+phosphors and their Judd-Ofelt analysis for WLEDs applications

In the present study, we have synthesized a series of Dy3+ ion doped NaLa(MoO4)2phosphors by the conventional solid-state method at 750 °C for 4h. All the compounds were crystallized in the tetragonal scheelite type structure with space group (I41/a, No.88). The morphology and functional group were confirmed by the field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared(FTIR)spectroscopy. Upon near-Ultraviolet (n-UV) excitation, the PL spectra exhibit the two characteristic emissions of Dy3+ ions, blue (4F9/2 → 6H15/2) at 487 nm and yellow (4F9/2 → 6H13/2) at 574nm respectively. The optimum concentration of Dy3+ionis 3 mol% and then quenching occurred due to multipolar interaction. Further, enhanced the emission intensity by co-doping with monovalent (Li+), divalent (Ca2+) and trivalent (Bi3+) ions. Among them, Li+ ion co-doped samples are shown maximum intensity (50 times) more than Dy3+ doped phosphors as relaxation of parity restriction of electric dipole transition because of local distortion of crystal field around the Dy3+ ions. In addition, by incorporation of Eu3+ ions into NaLa(MoO4)2:Dy3+system, tuned the emission color from white to red, owing to energy transfer from Dy3+ to Eu3+ ions. The intensity parameters (Ω2, Ω4) and radiative properties such as transition probabilities (A T), radiative lifetime (τ rad), and branching ratio were calculated using the Judd-Ofelt theory. CIE color coordinates, CCT values indicates that these phosphors exhibit an excellent white emission. The determined radiative properties, CIE and CCT results revealed that the Dy3+-activated NaLa(MoO4)2phosphors are potential materials for developing white LEDs, and optoelectronic device fabrications.

Commentary: Clinical profile, demographic distribution, and outcomes of ocular siderosis: Electronic medical record-driven big data analytics from an eye care network in India.

Commentary: Clinical profile, demographic distribution, and outcomes of ocular siderosis: Electronic medical record-driven big data analytics from an eye care network in India.

Studies of energy transfer process between Gd3+ and Eu3+ ions in oxyfluoride sol-gel materials

In this work, the series of silicate xerogels co-doped with Gd3+ and Eu3+ ions have been synthesized via a sol-gel method and further processed into nano-glass-ceramic materials. The mutual molar ratio of trivalent metal ions' acetates in samples’ compositions was gradually modified as follows: La3+:Gd3+:Eu3+ = (0.95-x):x:0.05, x = 0.05, 0.25, 0.45, 0.65, and 0.90; hence the molar ratio of Gd3+:Eu3+ (RGd/Eu) was set from 1 through 5, 9, 13 up to 18. XRD measurements confirmed the amorphous nature of fabricated xerogels, but their heat-treatment successfully triggered the crystallization of hexagonal LaF3 fraction with an average size of about ∼10 nm, which was additionally confirmed by HR-TEM microscopy. Additionally, it was found that the LaF3 phase crystallized in a whole range of proposed La(CH3COO)3:Gd(CH3COO)3 molar ratio, and Gd3+ ions played only the role of dopant and replaced La3+ cation in the fluoride crystal lattice. The optical characterization of prepared sol-gel samples involved the registration of absorption, excitation and emission spectra, along with the luminescence decay analysis from the 6P7/2 (Gd3+) and the 5D0 (Eu3+) excited states. For nano-glass-ceramics defined by RGd/Eu = 13 and 18, the unexpected prolongation of the τ(6P7/2):Gd3+ lifetimes was denoted, compared with samples singly-doped with Gd3+. The changes in photoluminescence behavior of studied samples are strongly dependent on the nature of the fabricated sol-gel samples, the established molar ratios of La3+:Gd3+:Eu3+, and the tendency of cation-exchange in LaF3 nanocrystal lattice by Gd3+ and Eu3+ ions.

Effect of monovalent, divalent, and trivalent ions codoped with LaOCl: Eu3+ phosphors and its Judd-Ofelt analysis for display device applications

In this work, Lanthanum oxychloride LaOCl: Eu3+ (0–9 mol%) was synthesized using a conventional solid-state approach over the course of relatively low temperature (400 °C) and a shorter duration of 1 h. To investigate the phase purity of phosphors, crystallographic studies were performed using PXRD, which revealed the tetragonal structure with space group P4/nmm (No. 129). Morphological investigations were made using FESEM which unveils the agglomeration of phosphors. Photoluminescence spectra reveals that, the intensity of the 5D0→7F2 transition (618 nm), which increases with an increase in Eu3+ concentration (1–9 mol%), rises to a maximum of 7 mol% before quenching causes it to fall. The reason behind the quenching concentration of Eu3+ ions at 7 mol% was dipole-quadruple interaction which is determined using the Van Uitert equation. To improve luminescence efficiency metal ions like Li+, Na+, K+, Ca2+, and Bi3+ were exploited, among these LaOCl: Eu3+ co-doped with Li+ ion exhibit the highest PL intensity (39 times that of Eu3+). The Commission International de I'Eclairage (CIE) chromaticity coordinates of LaOCl: Eu3+ co-doped with Li+ phosphor is (0.590, 0.346) which is close to commercial red light-emitting phosphors. These phosphor materials were mixed with PVA and developed a flexible phosphor polymer composite, which can be used for flexible display device applications. Spectral parameters like J-O intensity parameters are used to analyze optical materials, these parameters were determined with the help of luminescence spectra.

In situ Hydrothermal Oxidation of Ternary FeCoNi Alloy Electrode for Overall Water Splitting

Exploring noble metal‐free catalyst materials for high efficient electrochemical water splitting to produce hydrogen is strongly desired for renewable energy development. In this article, a novel bifunctional catalytic electrode of insitu‐grown type for alkaline water splitting based on FeCoNi alloy substrate has been successfully prepared via a facile one‐step hydrothermal oxidation route in an alkaline hydrogen peroxide medium. It shows that the matrix alloy with the atom ratio 4:3:3 of Fe:Co:Ni can obtain the best catalytic performance when hydrothermally treated at 180°C for 18 h in the solution containing 1.8 M hydrogen peroxide and 3.6 M sodium hydroxide. The as‐prepared Fe0.4Co0.3Ni0.3‐1.8 electrode exhibits small overpotentials of only 184 and 175 mV at electrolysis current density of 10 mA cm−2 for alkaline OER and HER processes, respectively. The overall water splitting at electrolysis current density of 10 mA cm−2 can be stably delivered at a low cell voltage of 1.62 V. These characteristics including the large specific surface area, the high surface nickel content, the abundant catalyst species, the balanced distribution between bivalent and trivalent metal ions, and the strong binding of in‐situ naturally growed catalytic layer to matrix are responsible for the prominent catalytic performance of the Fe0.4Co0.3Ni0.3‐1.8 electrode, which can act as a possible replacement for expensive noble metal‐based materials.

Luminescence Properties of Fe2+:ZnSe Single Crystals Grown via a Traveling Heater Method

The luminescence properties of iron-doped ZnSe (Fe2+:ZnSe) single crystals grown via a traveling heater method have been studied via photoluminescence (PL). Nine emission bands were identified in the PL spectra of Fe2+:ZnSe single crystals and their origins were also discussed. The near-infrared emission bands seen at 820 nm and 978 nm can be attributed to the emission bands formed by the background Fe or other impurity-related defect complexes in Fe2+:ZnSe single crystals, rather than by doped transition-metal-related defects. With the increase in temperature, the PL intensity increased slightly and reached a maximum near room temperature for bound excitons (430–490 nm), but the PL intensity decreased significantly for impurity-defect emission bands (500–720 nm), indicating the occurrence of a thermal quenching effect. The excitation wavelength-dependent PL spectra showed that PL intensity first increased and then decreased with an increase in the excitation wavelengths, and the maximum PL intensity of the bound excitons was obtained at 364 nm. In addition, the X-ray photoelectron spectroscopy (XPS) results showed that both bivalent and trivalent iron ions were found, but bivalence was the dominant charge state for iron atoms in the iron-doped ZnSe single crystals, meaning that they are suitable for developing mid-infrared gain medium applications.

New and effective photocatalysts for removal of mordant black 17 and Congo red pollutants: In3+ and Sb5+ doped and codoped TiO2 semiconductor

The incorporation of trivalent (In3+) and pentavalent (Sb5+) ions into nano-sized TiO2 structure critically improved the visible light absorption and the photodegradation characteristics toward mordant black 17 and Congo red (CR) dyes as model organic pollutants. The X-ray diffraction (XRD) proved that pure TiO2 and Ti0·97In0·03O2 powders have a single tetragonal anatase phase structure while Ti0·97Sb0·03O2 and Ti0·94In0·03Sb0·03O2 compositions possess mixed phases of anatase and brookite. The sacnning electron microscope (SEM) images displays that Ti0·94In0·03Sb0·03O2 powder has fine and homogenous particles. The transmission electron microscope (TEM) images confirmed that Ti0.94In0·03Sb0·03O2 powder hasthe lowest mean particles size of 20 nm. The visible light response of TiO2 is significantly enhanced owing to addition of Sb5+ and In3/Sb5+ions. The calculated band gap energies of TiO2, Ti0·97In0·03O2, Ti0·97Sb0·03O2 and Ti0·94In0·03Sb0·03O2 samples are 3.35, 3.21, 2.97 and 2.91 eV, respectively. The engineering of the optical characteristics powerfully boosted the photocatalytic charcteristics of Ti0·97Sb0·03O2 and Ti0·94In0·03Sb0·03O2 catalysts under natural sunlight irradiation. Both samples exhibit photocatalytic efficiencies of 89 and 97% toward 30 ppm mordant black 17 solution under sunlight irradation in 60 min, respectively. As well, Ti0·97Sb0·03O2 and Ti0·94In0·03Sb0·03O2 catalysts show high photo-degradation efficiencies of 81 and 86% toward 15 ppm CR after sunlight irradation for 80 min. The enhanced degradation properties of the nanocrystalline Ti0·94In0·03Sb0·03O2 catalyst may be related to high separation of charge carriers, oxygen vacancies generation and good visible light response. For three cycles, Ti0·94In0·03Sb0·03O2 catalyst reveals high photodegradation activity within 89–97% for 30 ppm mordant black 17 dye under the same circumstances, demonstrating good photostability.

Turning Recycled Cardboard Container-Derived Lignin-Containing Cellulose Nanofibrils into a Robust Gas Barrier UV-Shielding Film

Self-standing cellulose nanofibril (CNF) films are regarded as one of the promising alternatives to current petroleum-based packaging materials mostly due to their ability to form dense self-assembled structures exhibiting high gas barrier properties. Nonetheless, one of the major obstacles to the commercialization of these materials in packaging applications is the high cost of raw materials and production energy. In this study, we created self-standing films of lignin-containing cellulose nanofibrils (LCNFs) derived from a recycled old corrugated cardboard (OCC) pulp that costs less than bleached softwood Kraft (BSK) pulp and requires half as much energy for refining to obtain the same quality of material. The low zeta potential (−3.83 mV) of OCC-derived LCNFs (OCC-LCNFs) resulted in aggregation of the fibrils in aqueous suspension, leading to considerable unpredictability in oxygen permeability (OP) values (coefficient of variation 36%). The addition of 3 wt % (based on the dry weight of LCNFs) carboxymethyl cellulose lowered the coefficient of variation to 16% with an average OP of 1478 (cc.μm/m2.atm.day) at 80% relative humidity. Because the OP was higher than that of the CNF film made from BSK-derived CNF (BSK-CNFs), we demonstrated that ionic crosslinking with trivalent aluminum ion or covalent crosslinking with polyamide epichlorohydrin decreased the OP by 30% at 23 °C and 80% relative humidity while also significantly enhancing the tensile strength and modulus. In addition, the presence of lignin in OCC resulted in a relatively lower water vapor permeability value in OCC-LCNF films compared to BSK-CNF films. Moreover, OCC-LCNF films showed complete UV-shielding (200–400 nm) property. Overall, this work provides a new opportunity to exploit a recycled and inexpensive source of CNFs to produce robust gas barrier materials for packaging applications.

Covalent organic polymers with azido group for efficient recovery of gold from gold-bearing waste

BackgroundGold is a rare precious metal. Efficient and selective adsorption of Au(III) is of great significance for gold recovery. MethodsA covalent organic polymer with azido group (N3-COP) was synthesized utilizing enaminone covalent organic polymer and Ts-N3 as raw materials. Significant FindingsThe adsorption capacity of N3-COP for gold ions was up to 1220 mg·g−1 under the condition that the adsorption process took place at room temperature and at a pH value of 4. The results of adsorption thermodynamic and adsorption kinetic experiments illustrated that the adsorption process of N3-COP for the trivalent gold ion is consistent with the Langmuir adsorption model and Quasi second-order adsorption model. Additionally, this adsorbent has high adsorption selectivity when it is used to adsorb trivalent gold ion from effluent containing gold (III), cadmium (II), nickel (II), cobalt (II), and copper (II) ions. This adsorbent also has good reusability for it maintains excellent adsorption performance after five consecutive adsorption operations.