Degradation of tris(2-chloroethyl) phosphate (TCEP) in aqueous solution by using pyrite activating persulfate to produce radicals.

Organophosphorus esters (OPEs), as one kind of emerging and toxic contaminant are ubiquitous in various environments. This study investigated the degradation of tris(2-chloroethyl) phosphate (TCEP) as a category OPEs by pyrite (FeS2)-activated persulfate (PS). The result shows that near-100% degradation of TCEP was achieved after 120 min in FeS2-PS system. The important role of Fe2+ in the activation mechanism was confirmed by the introduction of Fe2+ into the PS only system. Radical scavengers experiment and electron paramagnetic resonance (EPR) confirmed the presence of SO4·- and ·OH，which revealed that ·OH and SO4·- played major roles in TCEP degradation. The effect of various environmental factors, including pyrite and oxidant dosage, inorganic ions and pH were investigated. The result indicated that Fe3+ and Cl- can accelerate the degradation rate of TCEP and the reaction between TCEP and FeS2-PS favors acidic conditions (pH>9). In addition, due to the acidification of pyrite, this system can be applied with a wide pH range. Besides, two oxidation products, C4H9Cl2O4P and C2H6ClO4P were identified, which suggest that hydroxylation was probably the main mechanism. This study greatly improves our understanding on TCEP removal in FeS2-PS system.

Isolation and X-ray crystal structures of triarylphosphine radical cations.

Salts containing triarylphosphine radical cations 1(•+) and 2(•+) have been isolated and characterized by electron paramagnetic resonance (EPR) and UV-vis absorption spectroscopy as well as single-crystal X-ray diffraction. Radical 1(•+) exhibits a relaxed pyramidal geometry, while radical 2(•+) becomes fully planar. EPR studies and theoretical calculations showed that the introduction of bulky aryl groups leads to enhanced p character of the singly occupied molecular orbital, and the radicals become less pyramidalized or fully flattened.

Quantitative analysis of tris(2-carboxyethyl)phosphine by anion-exchange chromatography and evaporative light-scattering detection.

Tris(2-carboxyethyl)phosphine (TCEP) belongs to the trialkylphosphine class of reducing agents that are widely used in research and industry. In this paper, we discuss a sensitive high-performance liquid chromatography (HPLC) method equipped with an evaporative light scattering detector (ELSD) for the determination of TCEP in pharmaceutical samples containing therapeutic protein and stabilizing additives. TCEP was first completely oxidized with hydrogen peroxide to form TCEP oxide (TCEPO). Proteins and salts were removed from the sample by solid phase extraction. TCEPO concentrations were determined by anion exchange chromatography coupled with ELSD. Because of the 1:1 oxidation stoichiometry for the reaction, the concentration of TCEP in the sample is directly proportional to the measured concentration of TCEPO. A good linearity fit of ELSD response versus TCEPO concentration was observed over the range of 20-2000 µM. The specificity, precision, accuracy, and robustness of the method were evaluated and suitable for the quantitation of TCEP in biological samples. Moreover, selective treatment with peroxide prior to solid-phase extraction may be used to determine the mass balance of TCEP species or track the oxidation rate in pharmaceutical samples.

Copper loaded on sol-gel-derived alumina adsorbents for phosphine removal.

The hydride gas of phosphine (PH3) is commonly used for semiconductor and optoelectronic industries. The local scrubbers must immediately abate it because of its high toxicity. In this study, copper (Cu) loaded on the sol-gel-derived gamma-alumina (Al2O3) adsorbents are prepared and tested to investigate the possibility of PH3 removal and sorbent regeneration. Test results showed that during the breakthrough time of over 99% PH3 removal efficiency, the maximum adsorption capacity of Cu loaded on the sol-gel-derived gamma-Al2O3 adsorbent is 18 mg-PH3/g-adsorbent. This is much higher than that of Cu loaded on the commercial gamma-Al2O3 adsorbent--8.6 mg-PH3/g-adsorbent. The high specific surface area, narrow pore size distribution, and well dispersion of Cu loaded on the sol-gel-derived gamma-Al2O3 could be the reasons for its high PH3 adsorption capacity. The regeneration test shows that Cu loaded on the sol-gel-derived gamma-Al2O3 adsorbent can be regenerated after a simple air purging procedure. The cumulative adsorption capacity for five regeneration cycles is 65 mg-PH3/g-adsorbent, which is approximately double that of the Cu/zeolite adsorbent demonstrated in the literature.

Phosphine from rocks: mechanically driven phosphate reduction?

Natural rock and mineral samples released trace amounts of phosphine during dissolution in mineral acid. An order of magnitude more phosphine (average 1982 ng PH3 kg rock and maximum 6673 ng PH3/kg rock) is released from pulverized rock samples (basalt, gneiss, granite, clay, quartzitic pebbles, or marble). Phosphine was correlated to hardness and mechanical pulverization energy of the rocks. The yield of PH3 ranged from 0 to 0.01% of the total P content of the dissolved rock. Strong circumstantial evidence was gathered for reduction of phosphate in the rock via mechanochemical or "tribochemical" weathering at quartz and calcite/marble inclusions. Artificial reproduction of this mechanism by rubbing quartz rods coated with apatite-phosphate to the point of visible triboluminescence, led to detection of more than 70 000 ng/kg PH3 in the apatite. This reaction pathway may be considered a mechano-chemical analogue of phosphate reduction from lightning or electrical discharges and may contribute to phosphine production via tectonic forces and processing of rocks.

Characterization and ultrafiltration of semiconductor indium phosphide (InP) wastewater for recycling.

This research work investigated the physical and chemical properties of a new type of wastewater produced from the semiconductor industry. The wastewater generated from indium phosphide (InP) wafer backgrinding and sawing processes was characterized in term of its particle size distribution (PSD), zeta potential, suspended and dissolved solids, total organic carbon, and turbidity. The wastewater contained high concentration of fine InP dusts with a size ranging from 0.07 - 1.44 mm. In spite of its high concentration of suspended solids resulting in high turbidity up to 371 NTU, the wastewater contained very low organic matters (TOC < 2.2 mg l(-1)) and other inorganic impurities (SO4(2-) < 0.21 mg l(-1) and Na+ < 0.16 mg l(-1)). Based on the experimental data collected, the treatment technologies using chemical precipitation and ultrafiltration were applied to the wastewater. Both processes could effectively remove InP particles from the wastewater, however the coagulants in chemical precipitation introduced other ionic contents into the process resulting in difficulties of water recycling in the later stage. In comparison, ultrafiltration was more promising for InP wastewater treatment and recycling. Based on the results of this study, a full-scale UF system was built in a local semiconductor plant and it has successfully reclaimed water from the InP wastes for the past six months without any quality issue being raised.

Two- versus three-dimensional quantum confinement in indium phosphide wires and dots.

The size dependence of the bandgap is the most identifiable aspect of quantum confinement in semiconductors; the bandgap increases as the nanostructure size decreases. The bandgaps in one-dimensional (1D)-confined wells, 2D-confined wires, and 3D-confined dots should evolve differently with size as a result of the differing dimensionality of confinement. However, no systematic experimental comparisons of analogous 1D, 2D or 3D confinement systems have been made. Here we report growth of indium phosphide (InP) quantum wires having diameters in the strong-confinement regime, and a comparison of their bandgaps with those previously reported for InP quantum dots. We provide theoretical evidence to establish that the quantum confinement observed in the InP wires is weakened to the expected extent, relative to that in InP dots, by the loss of one confinement dimension. Quantum wires sometimes behave as strings of quantum dots, and we propose an analysis to generally distinguish quantum-wire from quantum-dot behaviour.

Phosphine fumigation of stored in-shell peanuts for the control of A. flavus. link/A. parasiticus speare growth and aflatoxin production

Amendoim em casca recém-colhido com conteúdos de umidade na faixa de 12,8 a 16,9, foi trilhado e ensacado em sacarias de poliestireno trançado. Em um armazém, duas pilhas, de 40 sacos cada uma, foram formadas sendo que uma delas foi fumigada com fosfina durante 7 dias aplicando-se 3,0 g/m inicialmente e após 24 horas. Aspergillus flavus/A. parasiticus näo foram detectados na pilha tratada, imediatamente após o tratamento. Aflatoxinas foram encontradas no topo (20 mg/kgB1, 16mg/kbB2) e na base (24 mg/kg B1, 5mg/kg B2) da pilha näo fumigada. Um mês após a fumigaçäo, a percentagem de gräos infectados com A. flavus/A. parasiticus foi aproximadamente de 8 a 3 vezes superior na base e no meio da pilha näo fumigada em relaçäo as camadas correspondentes da pilha näo tratada (270 mg-600 mg/kg B1, 18-92 mg/kg B2). Por outro lado contaminaçäo com aflatoxinas foi evidenciado na camada superior da pilha tratada (340 mg/kg B1 e 51 mg/kg B2) e da näo tratada (1200 mg/kg B1, 220 mg/kg B2). Os resultados indicam que a fosfina pode afetar o desenvolvimento de A. flavus/A. parasiticus e produçäo de aflatoxinas em amendoim armazenado em sacarias com teores de umidade acima dos limites recomendáveis em armazém. Estudos adicionais devem ser realizados para esclarecer alguns pontos que ficaram em dúvida

Rabbit gastric lipase in biocatalytic resolution of 2-hydroxyalkyldiphenylphosphines.

Kinetic resolution of 2-hydroxyalkyldiphenylphosphines 4 by acylation with isopropenyl acetate was carried out under rabbit gastric lipase (RGL) catalysis to give optically active 4 and the corresponding acetate, the enantioselectivity factors E ranging from 10 to 20. 1-(2-Naphthyl)ethanol and 2-[N-(ethoxycarbonyl)amino]1-butanol 7 were also resolved.