The Ca9La(PO4)5(SiO4)Cl2:Dy3+ (CLPSCl:Dy3+) powder phosphor with apatite structure has been successfully synthesized via high-temperature solid state method. Single phase in such phosphor was verified through X-ray diffraction (XRD) technique. The Dy ions concentration dependent luminescence properties including emission, excitation and lifetimes of Dy ions were characterized using photoluminescence (PL) spectroscopy. The results showed that CLPSCl:Dy3+ phosphor could efficiently assimilate the n-UV light and emit blue (~486 nm) and yellow light (~578 nm), originating from the f-f transitions of Dy3+. The critical Dy3+ quenching concentration (QC) was determined to be about 12 mol%. The concentration quenching mechanism was also determined to be dipole–dipole interaction.

The integration of flexible carbon-based materials and high capacity anode materials is an effective route to obtain superior flexible electrode materials. In this work, nickel sulfide nanoparticles were electrodeposited on a CNT thin film to form a paper-like composite (NS@CNT). As a binder-free flexible Li-ion battery anode, a record specific capacity to date of ∼845 mA h g−1 at a current density of 60 mA g−1 in terms of the mass of the composite has been achieved. The high capacities were mainly attributed to reversible conversion reactions of nickel sulfide and the capacitance effect of the nanostructured composite.

•Broad-band excited Ba10(PO4)6O:Eu2+,Tb3+/Li+ phosphors were prepared.•Efficient energy transfer from Eu2+ to Tb3+ in Ba10(PO4)6O were investigated.•Ba10(PO4)6O:Eu2+,Tb3+/Li+ have potential applications as blue-green emitting phosphors in w-LEDs.Developing color-tunable phosphors via the introduction of co-doping activators and sensitizers to the host with energy transfer processes has been a state-of-the-art topic for a long time. In this work, novel emission-tunable oxyapatites-type Ba10(PO4)6O:Eu2+,Tb3+/Li+ phosphors were prepared via a high temperature solid state reaction for the applications in white light emitting diodes (w-LEDs) with higher color rendering index. Tunable colors from blue to green can be realized in the Ba10(PO4)6O:Eu2+,Tb3+/Li+ by varying the relative ratios of Eu2+ to Tb3+, showing good absorption in the range of 230–400 nm. The energy transfer mechanism from Eu2+ to Tb3+ ions was demonstrated to be a quadrupole-quadrupole interaction by combining the Inokuti-Hirayama (IH) model and Reisfeld's approximation. Importantly, a prototype white lamp was packaged by mixing Ba9.83(PO4)6O: 0.03Eu2+, 0.07Tb3+, 0.07Li+ and commercial red phosphor CaAlSiN3: Eu2+, and the lamp exhibits a higher color rendering index (Ra = 92 and R9 = 56) and warm correlated color temperature of 4361 K for the actual application. Better luminescent properties compared to commercial Y3Al5O12:Ce3+-based w-LEDs, indicating that Ba10(PO4)6O: Eu2+, Tb3+/Li+ phosphors are emerging as potential phosphor-converted w-LEDs.

•Birnessite, a manganese dioxide with varying Mn(II)/Mn(III)/Mn(IV) ratios were synthesized.•The birnessite was used for tetracycline (TC) degradation under microwave induction.•Higher Mn(II) and Mn(III) resulted in faster TC degradation due to better microwave response of Mn.•LC–MS analyses revealed progressive removal of N, C, and H for the reaction intermediates.•The catalyst could be regenerated under microwave induction.Manganese dioxides (MOs) are excellent microwave absorbing materials and have been used as substrates or catalysts for enhanced degradation of organic compounds. In this study, we extended our research on using birnessite (Birn), a type of MOs, for the degradation of tetracycline (TC) in aqueous solution under microwave induction (MI). The Birns were fabricated to achieve different ratios of Mn(II)/Mn(III)/Mn(IV) in the crystal structure. Their physical and chemical characteristics were determined by X-ray diffraction, field-emission environmental scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray absorption fine structure spectra, and a microwave network analyzer. Their removal of TC under MI was evaluated under different physicochemical conditions. Lower solution pH, higher MI power, and higher Mn(II) and Mn(III) in the structure resulted in more TC removal. And the Birns are regenerable. LC–MS analyses confirmed the presence of degradation intermediates. The better performances of TC removal by Birns under MI was attributed to the high magnetic spin moment of Mn(II) and Mn(III) in the structure that has higher MI response.Download high-res image (128KB)Download full-size image

•Ce3+ doped Sr2La8(SiO4)6O2 phosphors have been synthesized by facile sol-combustion method.•The concentration quenching mechanism was estimated to be dipole–dipole interaction.•This phosphor can generate apparent violent-blue emission.The Sr2La8(SiO4)6O2:Ce3+ powder phosphor with apatite structure has been successfully synthesized via a facile route of sol-combustion technique. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and photoluminescence (PL) spectroscopy were used to characterize the as-prepared samples. Sr2La8(SiO4)6O2:Ce3+ phosphor was composed of particles with average sizes range about 300 nm. The phosphor exhibited an absorption ranging from 220 to 390 nm in ultraviolet range and a broad blue-violet emission band peaked at 403 nm with a CIE coordinates of (0.167, 0.028). The concentration quenching mechanism was also determined to be dipole–dipole interaction.

Emission-tunable phosphors Ca9La(PO4)5(SiO4)F2:Ce3+,Tb3+ with apatite structure were synthesized by a solid-state reaction. The phase structure, photoluminescence (PL) properties, lifetimes and the PL thermal stability were investigated, respectively. The phosphor exhibited an asymmetric broad-band blue emission (Ce3+) with peak at 403 nm and the line-type green emission with peak at 543 nm (Tb3+). The varied color of the phosphors from blue to green can be achieved by properly tuning the relative ratio of Ce3+/Tb3+ through the energy transfer from Ce3+ to Tb3+ ions. The critical distance was calculated to be 8.78 Å by using the concentration quenching method. When the temperature turned up to 150 °C, the emission intensity of Ca9La(PO4)5(SiO4)F2:Ce3+,Tb3+ phosphor was 77% of its initial value at room temperature, which indicated the good thermal stability of the sample. All the properties indicate that the Ca9La(PO4)5(SiO4)F2:Ce3+,Tb3+ phosphor has potential application of color-tunable w-LEDs.

•Color-tunable blue–green La6Ba4(SiO4)6F2:Ce3+,Tb3+ phosphors were prepared.•The phase structures of the La6Ba4(SiO4)6F2 apatites compounds were analyzed.•Ce3+–Tb3+ energy transfer process and mechanism were discussed.A series of new luminescent emission-tunable phosphors La6Ba4(SiO4)6F2:Ce3+,Tb3+ with apatite structure have been synthesized by a high temperature solid-state reaction. X-ray diffraction, photoluminescence (PL) emission and excitation spectra, lifetime, as well as the effect of Tb3+ concentration were employed to characterize the resulting samples. The PL spectrum of La6Ba4(SiO4)6F2:Ce3+,Tb3+ phosphor contains both the asymmetric broad-band blue emission (Ce3+ ion) and the line-type green emission (Tb3+ ion). The increased Tb3+ concentration induced the emitting colors to shift from blue to green region by the naked eye. Meanwhile, the energy transfer between Ce3+ and Tb3+ is thoroughly investigated, and the energy-transfer efficiency from Ce3+ to Tb3+ ion is also calculated. The results indicated that these phosphors could be considered as double emission phosphors for n-UV excited white light-emitting diodes.

Single-crystal X-ray diffraction structural data of four Fe-Mg tourmalines with different Fe contents from Xinjiang, Sichuan, and Yunnan Provinces, China, were collected at room temperature and −100°C. The intrinsic dipole moments of polyhedra and the total intrinsic dipole moment of the unit cell were calculated. By comparing the intrinsic electric dipole moments of the X, Y, Z, T, and B site polyhedra, it is found that the T site polyhedron makes the greatest contribution to the total intrinsic dipole moment. The pyroelectric coefficients of four Fe-Mg tourmalines were experimentally determined, and the influence of intrinsic dipole moments on their pyroelectric properties was investigated. The experimental results show that, compared with the case at room temperature, the intrinsic dipole moments change with the total Fe content at −100°C in a completely different way. With the decrease of temperature, the total intrinsic dipole moments of tourmaline decrease. Over the same temperature interval, the pyroelectric coefficients increase with the increase in intrinsic dipole moment.

Yb3+/Er3+ codoped CaY4F14 materials with tunable upconversion (UC) emission were prepared by a high temperature solid-state method. Based on the UC luminescence properties investigations, it was found that, under 980 nm excitation, CaY4F14:Yb3+,Er3+ showed green–yellow–red upconversion luminescence by changing the composition of the Yb3+-Er3+ dopants. It was also found that the green and red emissions originated from the two photon processes, and the ground-state absorption (GSA), excited-state absorption (ESA) and energy transfer (ET) processes between Er3+/Yb3+ ions were involved in the upconverted emission mechanism. The measured lifetimes show a strong dependence on Yb concentration.Highlights▶ Yb3+/Er3+ codoped CaY4F14 materials with tunable upconversion (UC) emission were prepared. ▶ CaY4F14:Yb3+, Er3+ showed green–yellow–red upconversion luminescence by changing the composition of the Yb3+-Er3+ dopants. ▶ Measured lifetimes show a strong dependence on Yb concentration.

Interactions between chlorpheniramine (CP), an antihistamine drug used to treat allergy, and 2:1 phyllosilicates were studied under batch kinetic and different solution conditions to investigate the effect of charge density of the substrates on CP removal from solution. The CP removal by Na-montmorillonite was instantaneous, with a very large rate constant and a fast rate, reaching a capacity of 0.64 mmol/g, compared to its cation exchange capacity of 0.85 mmolc/g. In contrast, CP removal by talc was 10 times lower at 0.06 mmol/g. Stoichiometric desorption of exchangeable cations accompanying CP removal by Na-montmorillonite confirmed cation exchange as the dominant interaction mechanism. Solution pH had a minimal effect on CP removal by Na-montmorillonite until pH 11. On the contrary, a slight increase in CP removal by talc was observed as the solution pH increased, due to increased negative charges on the pH-dependent surfaces of talc. Interactions between CP and Na-montmorillonite occurred on both external and interlayer sites, resulting in a d-spacing expansion from 12.5 Å to 15.2 Å. In contrast, interactions between CP and talc were only limited to the external surfaces. It was the charge density that ultimately controlled the amount of CP removal by 2:1 phyllosilicates. Thus, montmorillonite offers a superior option for the removal of cationic drugs from aqueous solution.Graphical abstractHighlights► Charge density played an important role on chlorpheniramine (CP) adsorption and retention. ► Cation exchange was the dominant mechanism for CP adsorption on high charge density clays. ► At high adsorption, CP intercalated into the interlayer of montmorillonite. ► Molecular simulation resulted in interactions between N and the negatively charged mineral surfaces.

Three kinds of salt solutions including NaCl, CaCl2 and MgCl2, were used to modify the expansion of vermiculite. X-ray diffraction results indicate that vermiculites have been successfully modified by salt solutions. The d(002) reflection spacings of Na-vermiculite, Ca-vermiculite and Mg-vermiculite corresponding to different salt solution modifications are 1.223 nm, 1.474 nm and1.448 nm, respectively. Expansion ratio experiment results show that the as-obtained vermiculite modified by NaCl solution can lower the beginning expansion temperature, while the vermiculites modified by CaCl2 and MgCl2 solutions can show high expansion ratio. The combined thermogravimetric-differential thermal analysis and infrared spectroscopy analysis reveal that electrostatic attraction force between interlayer cations and interlayer water plays the key factor in the expansion ratio of vermiculite. Compared with Ca and Mg cations, the electrostatic attraction force between Na cation and interlayer water is weak and Na-vermiculite has less interlayer water than that of Ca-vermiculite and Mg-vermiculite.The figure illustrates the relationship between K% and expansion temperature of Na-vermiculite (A), Ca-vermiculite (B), and Mg-vermiculite (C). Where K% represents the increased percentage of expansion ratio; Km-v represents the expansion ratio of modified vermiculite; Kv represents the expansion ratio of the original vermiculite without modification.Highlights► Salt solution modification method is originally used for expansion of vermiculite. Na-vermiculite has low beginning expansion temperature at 500 °C. ► Ca-vermiculite and Mg-vermiculite have high expansion ratio at high temperature.

Tourmalines with different Fe content have been analyzed by using Raman spectra polarized parallel to b and c-axis at −195 °C, 25 °C, 250 °C, and 450 °C and infrared spectroscopy at 25 °C, 150 °C, and 250 °C, respectively. The Raman spectra show that the intensities of both the stretching bands of FeO5(OH) and the deformation bands of [BO3]3− in b direction increase with the total Fe content, and the spectra polarized along c direction of [Si6O18]12− ring and [OH]− shift to lower frequencies. With increasing temperature, the stretching bands of FeO5(OH) in c direction shift to higher frequencies. Meanwhile, the deformation vibration bands of [Si6O18]12− ring enhance significantly, and the asymmetric stretching bands of [Si6O18]12− ring merge into a broad one. The deformation bands of [BO3]3− and the asymmetric stretch bands of [Si6O18]12− ring are weakened at (bb) polarization. The intensities of infrared absorption peak of tourmalines are weakened, and some peaks shift to lower frequencies with the increase of the total Fe content. With the increase of temperature, most infrared absorption peaks shift to lower frequencies. The variation of the Raman and infrared spectra of tourmalines with temperature and Fe content indicate that more replacement of Fe for Mg in Y–O5(OH) octahedron, leads to the deformation of Y–O5(OH) octahedron, and further the deformation of [BO3]3− polyhedron and [Si6O18]12− ring which are connected with Y–O5(OH) octahedron. Further, Mg(Fe)(OH) bonds extend with increasing temperature, leading to the deformation of [SiO4] tetrahedra connected with Y octahedra.

It was shown that chitosan and hydroxy-aluminum pillared montmorillonites were excellent materials for the removal of dyes and metal ions from effluent of dying and finishing. Chitosan, a natural biopolymeric cation, is also a promising candidate to modify montmorillonite as absorbent. Chitosan/hydroxy-aluminum pillared montmorillonite nanocomposites are expected to play a multiplex role in wastewater treatment. In this study, the nanocomposite was synthesized by incorporating hydroxy-aluminum pillared montmorillonite into chitosan solution prepared by dissolving the chitosan into diluted acetic acid. The ratio of chitosan to the cationic exchange capacity of the montmorillonite was about 1:1, 2:1, 3:1, 4:1 and 6:1, respectively. The nanocomposites were characterized by XRD (X-ray diffraction), SEM (scanning electron microscopy) and FT-IR (Fourier transform infrared spectroscopy). The experimental results indicated that the presence of hydroxy-aluminum cation was in favor of the chitosan intercalation and the interlayers of montmorillonites was intercalated with the bilayers of chitosan sheets. The nanocomposites can be used in absorption of organic and metal ions from dying and finishing effluent.

•A novel composite of nanoscale zero-valent iron/montmorillonite was prepared•The intercalation makes NZVI well dispersed and more stable in the interlayer•The reduction rate of Cr(VI) was 16 times higher than traditional reaction•NZVI/Cr (VI) redox reaction occurred in the interlayer of MMT.Composite of nano-zero-valent iron and montmorillonite (NZVI/MMT) was prepared by inserting NZVI into the interlayer of montmorillonite. The unique structure montmorillonite with isolated exchangeable Fe(III) cations residing near the sites of structural negative charges inhibited the agglomeration of ZVI and result in the formation of ZVI particles in the montmorillonite interlayer regions. NZVI/MMT was demonstrated to possess large specific surface area and outstanding reducibility that encourage rapid and stable reaction with Cr (VI). Besides, the intercalation also makes NZVI well dispersed and more stable in the interlayer, thereby improving the reaction capacity by 16 times. The effects of pH value, initial concentration of Cr (VI) and reaction time on Cr (VI) removal have also been investigated in detail. According to PXRD and XPS characterization, NZVI/Cr (VI) redox reaction occurred in the interlayer of MMT. The study of NZVI/MMT is instrumental to the development of remediation technologies for persistent environmental contaminants.

Super hydrophobic copper wafer was prepared by means of solution immersion and surface self-assembly methods. Different immersion conditions were explored for the best hydrophobic surface. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and water contact angle measurements were used to investigate the morphologies, microstructures, chemical compositions and hydrophobicity of the produced films on copper substrates, respectively. Results show that the super hydrophobic surface is composed of micro structure of Cu7S4. The films present a high water contact angle larger than 150°, a low sliding angle less than 3°, good abrasion resistance and storage stability. The molecular dynamics simulation confirms that N-dodecyl mercaptan molecules link up with Cu7S4 admirably, compared with Cu, which contributes to the stable super hydrophobic surface.

In this study, spent activated carbon (AC) saturated with caramel was regenerated by using yeast and NaOH. The efficiency of regeneration was evaluated under parameters such as amount, treatment time, temperature, pH value, stirring temperature of yeast and NaOH concentration. The optimum condition for AC regeneration was 8 h for yeast treatment time, 35°C for 0.075% yeast culture temperature, a pH value of 6 for the yeast dealing with the spent AC, 90°C for NaOH stirring temperature of AC and 6% NaOH for washing after the spent AC was treated by yeast. Under these conditions, methylene blue (MB) adsorption was 213 mg·g−1 in comparison with 60 mg·g−1 of spent AC. The micro structure and surface area of the regenerated AC were characterized by scanning electron microscope (SEM) and N2 sorption, respectively. The pore size distributions of virgin and regenerated AC were analyzed by means of H-K equation, resulting in a mean pore diameter of 1.28 nm and a pore volume of 1.13 cm3·g−1. This study provides data for theoretical support of the AC regeneration technology.