Wen-Churng Lin

Liquid–liquid equilibria of alkane (C10–C14)+octylbenzene+sulfolane

Equilibrium tie line data have been determined at (323.15, 348.15, and 373.15) K for the ternary liquid–liquid equilibria (LLE) of three alkane + sec-butylbenzene + sulfolane systems, where the alkanes studied are decane, dodecane, and tetradecane. The relative mutual solubility of sec-butylbenzene is higher in decane + sulfolane than in dodecane + sulfolane or tetradecane + sulfolane mixtures. The tie line data were correlated with the UNIQUAC and NRTL models. The calculated values based on the UNIQUAC model were found to be better than those based on the NRTL model; the average root-mean-square deviation between the phase composition obtained from experiment and that from calculation was 0.00385 for UNIQUAC compared to 0.00566 for NRTL. The values of selectivity and distribution coefficients were derived from the equilibrium data.

Liquid–liquid equilibria of alkane (C10/C12/C14)+1,4-diisopropylbenzene+sulfolane at 323.15, 348.15 and 373.15 K

Abstract Tie line data have been determined at 323.15, 348.15 and 373.15 K for the ternary liquid–liquid equilibria (LLE) of alkane (C10/C12/C14)+1,4-diisopropylbenzene+sulfolane systems. The addition of 1,4-diisopropylbenzene to sulfolane is found to increase the solubility of alkanes in the order of n-decane>n-dodecane>n-tetradecane and the relative mutual solubility of 1,4-diisopropylbenzene is higher in n-decane+sulfolane than in n-dodecane+sulfolane or n-tetradecane+sulfolane mixtures. The tie line data were correlated with the well-known UNIQUAC and NRTL models. The calculated equilibrium mole fractions based on the UNIQUAC model are better than those based on the NRTL model. The values of selectivity and distribution coefficient were derived from the equilibrium data.

Dual donor–π–acceptor type organic dyes for efficient dye-sensitized solar cells

A series of novel triphenylamine (TPA)-based dyes that use double linkers between the electron donor and the electron acceptor are synthesized, characterized, and applied as photosensitizers for dye-sensitized solar cells. The dyes contain N-methylpyrrole (NMP) (MTPA-2 dye) and styrene (St) (STPA-2 dye), respectively, linkers on TPA. These linkers are expected to generate effective π-conjugation forming donor–π–acceptor (D–π–A) links. The photovoltaic performance of the dyes depends on the linker type. For the dual-St-π-linked dye, the charge transfer from the excited dye molecules to the conduction band of TiO2 is improved, making the efficiency of the corresponding devices higher than those of dye-based devices with NMP linkers and no linkers. The device with the dye bearing positions of C3 and C4 on NMP linkers has the lowest conjugation effect and efficiency. In particular, the STPA-2 dye shows a broad incident-photon-to-current conversion efficiency response with a signal of up to 700 nm, covering most of the ultraviolet-visible light region. Device efficiencies of 5.43% and 7.56% for dye-sensitized devices using the STPA-2 dye and the cis-RuL2(NCS)2 (N3) dye, respectively, were fabricated using the same method and measured under AM 1.5 irradiation.

Preparation and Application of Titanate Nanotubes on Methylene Blue Degradation from Aqueous Media

Titanate nanotubes were synthesized at various hydrothermal temperatures and reaction times by the hydrothermal process and used as photocatalyst. BET analysis was conducted in order to find out the surface area of these as-prepared samples and it was found that the surface area increases with rise in temperature till 130 oC. Synthesized as-prepared titanate nanotubes were applied on methylene blue degradation from aqueous media by UV irradiation. It was observed that dye removes ~99% from the aqueous media at a titanate nanotubes dose of 2 g/L.

Enhanced Supercapacitor Performance Using Electropolymerization of Self-Doped Polyaniline on Carbon Film

In this work, we electrochemically deposited self-doped polyanilines (SPANI) on the surface of carbon-nanoparticle (CNP) film, enhancing the superficial faradic reactions in supercapacitors and thus improving their performance. SPANI was electrodeposited on the CNP-film employing electropolymerization of aniline (AN) and o-aminobenzene sulfonic acid (SAN) comonomers in solution. Here, SAN acts in dual roles of a self-doped monomer while it also provides an acidic environment which is suitable for electropolymerization. The performance of SPANI−CNP-based supercapacitors significantly depends upon the mole ratio of AN/SAN. Supercapacitor performance was investigated by using cyclic voltammetry (CV), galvanostatic charge and discharge (GCD), and electrochemical impedance spectroscopy (EIS). The optimal performance of SPANI−CNP-based supercapacitor exists at AN/SAN ratio of 1.0, having the specific capacitance of 273.3 Fg−1 at the charging current density of 0.5 Ag−1.

Synthesis of Titania Nanotubes and its Application on Oxalic Acid Removal from Aquatic Environment

Titania nanotubes were synthesized after the protonation and calcination of titanate precursors prepared at different hydrothermal temperatures. Calcination of the titanate precursors at various temperature, governs the TiO2 nanotubes formation. It was observed that sample prepared at 130°C and calcination at 500°C forms only anatase, but at 800°C, both anatase and rutile formed. The as-prepared titania nanotubes were used as photocatalyst in order to degrade organic contaminant, oxalic acid from aqueous solution by UV irradiation. 78 % oxalic acid was removed from the aqueous media at the nanotubes dose of 2 g L-1, in 120 min.

Synthesis, Characterization and Photocatalytic Activity of Copper (II)-Doped Titanium Dioxide Powders

Different concentration of copper (II) doped TiO2 photocatalyst powders were synthesized through the sol-gel method and characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET)-specific surface area, transmission electron microscopy (TEM), and Ultraviolet–Visible (UV-Vis) spectroscopy. Cu2+-doping in the TiO2 promotes the particle growth, decreases the specific surface areas of powders, extends the absorption to visible light regions, and exhibits the vis-photocatalytic activity for methylene blue (MB) degradation. Appropriate content of Cu2+-doping is an effective means to improve the photocatalytic activity of TiO2 for MB degradation under visible light irradiation.

Crosslinked Polymer Ionic Liquid/Ionic Liquid Blends Prepared by Photopolymerization as Solid-State Electrolytes in Supercapacitors

A photopolymerization method is used to prepare a mixture of polymer ionic liquid (PIL) and ionic liquid (IL). This mixture is used as a solid-state electrolyte in carbon nanoparticle (CNP)-based symmetric supercapacitors. The solid electrolyte is a binary mixture of a PIL and its corresponding IL. The PIL matrix is a cross-linked polyelectrolyte with an imidazole salt cation coupled with two anions of Br− in PIL-M-(Br) and TFSI− in PIL-M-(TFSI), respectively. The corresponding ionic liquids have imidazolium salt cation coupled with two anions of Br− and TFSI−, respectively. This study investigates the electrochemical characteristics of PILs and their corresponding IL mixtures used as a solid electrolyte in supercapacitors. Results show that a specific capacitance, maximum power density and energy density of 87 and 58 F·g−1, 40 and 48 kW·kg−1, and 107 and 59.9 Wh·kg−1 were achieved in supercapacitors based on (PIL-M-(Br)) and (PIL-M-(TFSI)) solid electrolytes, respectively.

Effect of Iron (III)-Doping on the Photocatalytic Activity of Titanium Dioxide Catalysts for Methylene Blue Degradation

Iron-doped TiO2 photocatalyst powders were prepared by the sol–gel method and characterized by Brunauer–Emmett–Teller (BET)-specific surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Ultraviolet–Visible (UV-Vis) spectroscopy. Fe3+ doping in the TiO2 decreases the crystal grain size, increases the specific surface areas of powders, extends the absorption to visible light regions (400~500 nm), and lowers the photocatalytic activity for methylene blue (MB) degradation under UV irradiation. The photocatalytic degradation of MB in water was investigated as a function of the Fe3+ content in TiO2. It was found that under the irradiation of visible light, a small amount of Fe3+ dopant in TiO22 powders could obviously enhance the photocatalytic activity. When the Fe3+ content was in the range of 0.03–0.1 mol%, the photocatalytic activity of the samples was higher than that of undoped TiO2. Appropriate content of Fe-doping is an effective means to improve the photocatalytic activity of TiO2 for MB degradation under visible light irradiation.