Zhijun Luo

One-pot synthesis of visible-light-driven plasmonic photocatalyst Ag/AgCl in ionic liquid.

Plasmonic photocatalyst Ag/AgCl was prepared by in situ hydrothermal method with the contribution of 1-octyl-3-methylimidazolium chloride ([Omim]Cl), in which the [Omim]Cl ionic liquid acted not only as a precursor but also as a reducing reagent in the process of formation of Ag⁰. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and thermogravimetric and differential scanning calorimetry (TG-DSC). The photocatalytic activity of the composites were evaluated by degradation of methyl orange (MO) under visible light irradiation. The experimental results showed that the high activity and stability of Ag/AgCl photocatalysts under visible-light irradiation were due to their localized surface plasmon resonance (LSPR). Based on the characterization of the structure and photocatalytic performance, the LSPR was determined by synergetic effect of many factors, such as particle size of metallic Ag, contents of the Ag⁰ nanoparticles, and the extent of metallic Ag dispersing. A photocatalytic mechanism of the Ag/AgCl photocatalyst was also proposed.

Enhancement of hydroxyl radical generation of a solid state photo-Fenton reagent based on magnetite/carboxylate-rich carbon composites by embedding carbon nanotubes as electron transfer channels

A novel visible-light-driven solid state photo-Fenton reagent based on magnetite/carboxylate-rich carbon particles/carbon nanotubes (MCRCPs–CNTs) has been successfully synthesized by a simple one-pot hydrothermal carbonization (HTC) method using polyvinylpyrrolidone (PVP) as the CNT dispersant. By using PVP as the CNT dispersant, the CNT bundles are well dispersed and interwoven among the MCRCPs, such a structural feature is beneficial for efficient electron transfer. MCRCPs and CNTs play synergistic effects in the photocatalytic process. MCRCPs containing ferricarboxylate complexes act as the solid state photo-Fenton reagent, which realizes the solidification of iron ions and carboxylic acids at the same time. Without using H2O2, MCRCPs containing ferricarboxylate complexes can yield ˙OH under visible light irradiation. By using CNTs as fast electron transfer channels, the photoexcited electrons from the MCRCPs can be quickly trapped by O2 to form very reactive superoxide radical ions (O2˙−) and ultimately convert to hydroxyl radicals (˙OH). The enhanced generation of ˙OH gave the MCRCPs–CNTs advantages over magnetite/carboxylate-rich carbon spheres (MCRCSs) in the photodegradation of methylene blue (MB). In addition, the magnetic saturation (Ms) value is about 24 emu g−1. After the reaction ended, the MCRCPs–CNTs could be rapidly separated under an applied magnetic field.

3D nanostructured Ni(OH)2 microspheres as an efficient immobilization matrix of Ru(bpy)32+ for high-performance electrochemiluminescence sensor

The electrochemistry and electrochemiluminescence (ECL) of novel three-dimensional nanostructured Ru(bpy)(3)(2+)/Ni(OH)(2) microspheres were investigated for the first time. The negatively charged porous Ni(OH)(2) microspheres composed of Ni(OH)(2) nanowires were specifically designed to interact with Ru(bpy)(3)(2+). The large surface area and porous structure of Ni(OH)(2) microspheres enhance loading of Ru(bpy)(3)(2+) and mass transport of the model analyte, tripropylamine (TPA). Excellent ECL performance of the presented sensor was achieved including good stability and wide linear range from 7.7x10(-10) to 3.8x10(-3)M with the detection limit of 2.6x10(-10)M to TPA.

Feasibility of using basalt fiber as biofilm Carrier to construct bio-nest for wastewater treatment

Generally, biofilms developed for wastewater treatment readily detach from carrier medium once available thickness exceeds about 2 mm. Carrier media made of basalt fibers (BFs) could form ball-like aggregates (more than 10 cm in size, and called bio-nest). To demonstrate its feasibility for wastewater treatment, both reactors with and without BF carriers (RBF and RCO) were evaluated in terms of nutrient removal, oxygen mass transport and biological viabilities as well as biofilm adsorption characteristics. Therefore, oxygen microprofiles and confocal images for bio-nest as well as functional groups for biofilm-attached BF were performed on microsensor systems, confocal laser scanning microscopy (CLSM) and Fourier transform infrared (FTIR). Despite COD:N ratio, both reactors removed about 90% of COD, while only RBF reactor achieved high denitrification capabilities, with nitrogen removal efficiencies varying between 60.10 ± 0.45% and 82.07 ± 0.64%. Microprofile and confocal images showed that dissolved oxygen could reach the core with depth up to 50 mm, at which viable bacteria were detected. Characteristic peaks on FT-IR spectrum demonstrated that various functional groups of polysaccharide and proteins in EPS played a key role in aggregating biofilm-attached BFs into a bio-nest. Thus, BF provides a promising alternative to conventional carrier medium for wastewater treatment.

Controlled growth of BaMoO 4 hierarchical superstructures in functionalized ionic liquids

Dual-functionalized ionic liquids (ILs) containing both functionalized cation and anion offer scope for tuning of nucleation and growth steps to achieve crystallographic control. BaMoO4 crystals synthesized in alkyl methylimidazolium trifluoroacetate ([Cnmim]TA, n = 4, 8, 16) aqueous solution display the similar shuttle-like shape. The size of building blocks assembling into the hierarchical architectures has been influenced by the inhibiting effect of the imidazolium substituent alkyl chain. With the increase of imidazolium substituent alkyl chain length, the building blocks change from the truncated octahedron to the nanosheet. The single-crystalline BaMoO4 dendrites were prepared under the direction of [Omim]TA via the oriented attachment mechanism. BaMoO4 porous structures have been successfully synthesized in the [Omim]TA aqueous solution via the manipulation of the growth kinetics. Whether the resultant holes in the BaMoO4 structure are open or clogged depends upon variations in the molar ratio [Ba2+]/[Mo7O246–]. Shuttle-like BaMoO4 crystals made of nanosheets with the helical growth features have been successfully synthesized in the presence of [C16mim]TA. In addition, the amount of [C16mim]TA in the solution profoundly influences the morphology and size of the as-obtained products.