Treating waste with waste: Adsorption of anionic dyes in wastewater with surfactant-modified phosphogypsum.

Phosphogypsum (PG) is a solid waste generated during the wet process of phosphoric acid production. The environmental-friendly disposal and recycling of PG is vital in the field of environmental solid waste treatment. In this study, PG is used for adsorbent of dyes in wastewater to achieve the goal of recycling waste with waste. Surfactant-modified phosphogypsum (ODBAC@PG) was prepared using octadecyl dimethyl benzyl ammonium chloride (ODBAC) as modifier. ODBAC@PG exhibits high adsorption capability for anionic dyes (methyl blue (MeB) and indocyanine carmine (IC)). The pseudo-second-order kinetic model fits the kinetic experimental data for the adsorption of two organic anionic dyes. Langmuir adsorption isotherm fits the adsorption characteristics of MeB and IC on ODBAC@PG, exhibiting a monolayer adsorption pattern. Thermodynamic parameters indicate the spontaneous and exothermic properties of MeB and IC on ODBAC@PG. MeB and IC have antagonistic effects on each other in binary adsorption system. High adsorption capacity after six cycles of experiments demonstrates the high reusability of ODBAC@PG. The nature for the adsorption includes electrostatic interaction, hydrogen bond and hydrophobic interaction. Using ODBAC@PG for dyes wastewater treatment can accomplish the goal of treating waste with waste and turning waste into treasure.

Visible-light photoelectric response in semiconducting quaternary oxysulfide FeOCuS with anti-PbO-type structure.

A novel quaternary oxysulfide, FeOCuS has been successfully synthesized with a tetragonal anti-PbO-type structure and a visible-light bandgap of about 1.37 eV. Driven by only a 0.4 V bias voltage under simulated AM 1.5 G illumination, a high photocurrent density of 3.89 mA cm-2 has been achieved, revealing the potential optoelectronic applications.

Determination of capsaicinoids by magnetic solid phase extraction coupled with UPLC-MS/MS for screening of gutter oil.

Capsaicinoids, including capsaicin, dihydrocapsaicin and N-vanillylnonanamide have been identified as characteristic markers for gutter oil. In this study, the nanocomposite of graphene oxide-Fe3O4 (GO-Fe3O4) was synthesized by a co-precipitation method, and applied to magnetic solid phase extraction (MSPE) process. The capsaicin, dihydrocapsaicin and N-vanillylnonanamide extracted in gutter oil were analyzed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Under the optimized pretreatment conditions, the limit of detection (LOD) and limit of quantification (LOQ) are 0.15 and 0.4 µg L-1, respectively. The linear range is 0.4-200 µg L-1, and the correlation coefficients (R2) are over 0.996 for all three compounds. The recoveries range from 81.2% to 103.3% for soybean oil and 71.2% to 84.3% for rapeseed oil. The values of matrix effect range in 87.6%-105.5% and 83.4%-110.6% and the intra-day RSDs range from 2.8%-4.6% to 4.8%-6.1% for soybean oil and rapeseed oil, respectively. The adsorbent can be reused for multiple times with no appreciable loss of adsorption capability. The present methodology has high potential for screening of gutter oil in food samples, thus having importance for food safety monitoring.

Graphene oxide-Fe3O4 nanocomposite magnetic solid phase extraction followed by UHPLC-MS/MS for highly sensitive determination of eight psychoactive drugs in urine samples.

Graphene oxide-Fe3O4 (GO-Fe3O4) nanocomposite was synthesized by a facile chemical co-precipitation method. The GO-Fe3O4 was used as magnetic sorbent to extract the eight psychoactive drugs from urine samples. The analytes are morphine (MOR), 6-monoacetylmorphine (6-MAM), amphetamine (AMP), methamphetamine (MAMP), codeine, cocaine, dolantin and benzoylecgonine (BZE), which were determined by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). This method has high selectivity for the target analytes. The limit of detection (LOD) and limit of quantification (LOQ) were 0.02-0.2 µg L-1 and 0.05-0.5 µg L-1, respectively. The Mandel's fitting test revealed good linearity within all linear ranges. The linear ranges were calculated as 0.05-1000 µg L-1 for AMP, MAMP, cocaine and dolantin; 0.1-1000 µg L-1 for 6-MAM and codein; and 0.5-1000 µg L-1 for MOR and BZE. The recoveries ranged in 80.4-105.5%. The intra-day and inter-day RSDs are in the range of 2.7-13.1% and 3.9-13.7%, respectively. Magnetic solid phase extraction (MSPE) with GO-Fe3O4 provides a convenient, rapid and green sample pretreatment method for extracting the target psychoactive drugs from urine. This methodology can be used for simultaneous or individual detection of eight major psychoactive drugs with high sensitivity. This method has high potential in clinical and forensic areas for psychoactive drugs analysis.

Tunable assembly of vanadium dioxide nanoparticles to create porous film for energy-saving applications.

Nanoparticle-assembled vanadium dioxide (VO2) films have been easily prepared with the assistance of cetyltrimethylammonium vanadate (CTAV) precursor which exhibits self-assembly properties. The obtained VO2 film has a micro/nano hierarchical porous structure, so its visible-light transmittance is significantly improved (∼25% increased compared to continuous film). The VO2 particle density as well as the film porosity can be facilely controlled by adjusting experimental parameters such as dip-coating speed. Accordingly, film optical properties can also be tuned to a large extent, in particular the visible transmittance (Tvis) and near-infrared switching efficiency (ΔTnir). These VO2 nanoparticle-assembled films prepared by this novel method provide a useful model to research the balance between Tvis and ΔTnir.

Ultrafast coloring-bleaching performance of nanoporous WO3-SiO2 gasochromic films doped with Pd catalyst.

The gasochromic performance and durability of WO(3)-based films can be improved by doping SiO(2) particles within WO(3) matrix forming nanoporous supporting network and dispersing Pd catalyst inside films with enhanced catalytic activity. Nanoporous WO(3)-SiO(2) composite films loaded with Pd catalyst were prepared by sol-gel dip-coating process and served as an active chromogenic layer to fabricate a double-glazed gasochromic device. The structure, morphology, optical properties and gasochromic performance of WO(3)-SiO(2) films were fully investigated. The WO(3)-SiO(2) films exhibit excellent gasochromic performance with ultrafast coloring rate of 14.8% per second (%/s) (WO(3): 2.84%/s) and bleaching rate of 44.1%/s (WO(3): 7.18%/s). The transmittance changed between 17.8 and 74.6% during coloring-bleaching cycles, and totally reversibility and stability were achieved.