The negative ion chemistry of nitric oxide in the gas phase

Nitric oxide is not only an important biological molecule with varied indispensable physiological roles but also shows interesting chemical reactivity both in gas-phase and solution phase. Even though it is a small molecule with an extremely low electron affinity, the reactivity of NO in the gas-phase is not just limited to electron-transfer or adduct formation. NO can behave both as an electrophile with closed-shell anions or as a radical with open-shell anions. Its reactivity with open-shell anions is characteristic and varied leading to interesting rearrangements. Nitric oxide anion undergoes spin-forbidden proton transfer with strong acids. Also, the ability of NO to serve both as one-electron or three-electron donor ligand can result in adduct formation or substitution reactions with transition metal complexes.     

Effect of pH, inorganic ions, organic matter and H2O2 on E. coli K12 photocatalytic inactivation by TiO2: Implications in solar water disinfection

The effect of different chemical parameters on photocatalytic inactivation of E. coli K12 is discussed. Illumination was produced by a solar lamp and suspended TiO₂ P-25 Degussa was used as catalyst. Modifications of initial pH between 4.0 and 9.0 do not affect the inactivation rate in the absence or presence of the catalyst. Addition of H₂O₂ affects positively the E. coli inactivation rate of both photolytic (only light) and photocatalytic (light plus TiO₂) disinfection processes. Addition of some inorganic ions (0.2 mmol/l) like HCO₃⁻, HPO₄²⁻, Cl⁻, NO₃⁻ and SO₄²⁻ to the suspension affects the sensitivity of bacteria to sunlight in the presence and in absence of TiO₂. Addition of HCO₃⁻ and HPO₄²⁻ resulted in a meaningful decrease in photocatalytic bactericidal effect while it was noted a weak influence of Cl⁻, SO₄²⁻ and NO₃⁻. The effect of counter ion (Na⁺ and K⁺) is not negligible and can modify the photocatalytic process as the anions. Bacteria inactivation was affected even at low concentrations (0.2 mmol/l) of SO₄²⁻ and HCO₃⁻, but the same concentration does not affect the resorcinol photodegradation, suggesting that disinfection is more sensitive to the presence of natural anions than photocatalytic degradation of organic compounds. The presence of organic substances naturally present in water like dihydroxybenzenes isomers shows a negative effect on photocatalytic disinfection. The effect of a mixture of chemical substances on photocatalytic disinfection was also studied by adding to the bacterial suspension nutrient broth, phosphate buffer and tap water.     

On the effects of competition between agent-based double auction markets

Real market institutions, stock and commodity exchanges for example, do not occur in isolation. The same stocks and commodities may be listed on multiple exchanges, and traders who want to deal in those goods have a choice of markets in which to trade. While there has been extensive research into agent-based trading in individual markets, there is little work on this kind of multiple market scenario. Our work seeks to address this imbalance in the context of double auction markets. This paper examines how standard economic measurements, like allocative efficiency, are affected by the presence of multiple markets for the same goods, especially when the markets are competing for traders. We find that while dividing traders between several small markets typically leads to lower efficiency and worse convergence than grouping them into one large market, competition between markets for traders, can reduce these losses.     

Adsorption of phosphate and nitrate anions on ammonium-functionnalized mesoporous silicas

Surface modified mesostructured silica materials represent potential adsorbents offering an opportunity to remediate several important water pollutants. In the present work, ammonium-functionnalized MCM-41, MCM-48 and SBA-15 mesoporous silica materials were synthesized via post-synthesis grafting and co-condensation. Their efficiency to remove nitrate and phosphate anions in aqueous solutions was investigated. The adsorbent materials showed high adsorption capacities reaching 46.5 mg NO₃⁻/g and 55.9 mg H₂PO₄⁻/g under the operating conditions explored. The mesoporous silica materials functionalized via post-synthesis grafting method exhibited higher performances in terms of percentage pollutant removal and adsorption capacities if compared to their analogs synthesized according to the co-condensation strategy.     

An evaluation of a new instrument to measure organisational safety culture values and practices

The main aim of this research is to evaluate a safety culture measuring instrument centred upon relevant organisational values and practices related to the safety management system. Seven dimensions that reflect underlying safety meanings are proposed. A second objective is to explore the four cultural orientations in the field of safety arising from the competing values framework. The study sample consisted of 299 participants from five companies in different sectors. The results show six dimensions of organisational values and practices and different company profiles in the organisations studied. The four cultural orientations proposed by the competing values framework are not confirmed. Nevertheless, a coexistence of diverse cultural orientations or paradoxes in the companies is observed.     

含阴离子官能团物质与蒙脱土的相互作用研究

通过研究不同电荷状态的含阴离子官能团物质与蒙脱土(MMT)复合物的插层情况来研究阴离子官能团与MMT的相互作用,利用FT-IR、XRD和NMR等手段对反应产物进行表征,以确定阴离子官能团与MMT的作用机理和作用位点。试验结果表明,羧酸基团与MMT有很强的相互作用。羧酸基团与MMT发生作用的位点是(—COO-)上的羰基(—CO),它与MMT上的(—OH)或Al3+发生作用。     

离子色谱法测定湖泊水体中的阴离子

本实验建立了湖泊水体中阴离子(F-、Cl-、NO-3、SO2-4)的测定,采用抑制电导离子色谱法,分离和检测出水样中的阴离子.色谱条件为IonPac AS9-HC阴离子分离柱(4 mm×250 mm),IonPac AG9-HC阴离子保护柱(4 mm×50 mm).以流速为1 mL/min、流动相为9.0 mmol/L Na2CO3及36.0 mmol/L H2SO4,实验所得RSD值分别为3.64、2.58、4.99、3.46,平均回收率分别为104.5%、100.8%、101.8%、104.4 %,线性良好,具有很好的重现性和较低的检出限.     

利用赤泥去除水中污染物的研究进展

赤泥作为一种大宗矿业固体废弃物,含有丰富的金属氧化物/金属氢氧化物,同时具有丰富的孔隙结构和较高的比表面积.经过简单改性处理后,可以作为一种低成本的水处理材料有效地去除水体中的污染物,同时实现以废治废的目的,具有良好应用前景.近些年来,利用赤泥去除水中污染物的研究受到了广泛关注,本文分析了赤泥的来源、组成和性质,介绍了...     

铁炭微电解法对处理含盐硝基苯废水的实验研究

对不同的盐分在铁炭微电解降解硝基苯过程中的作用机理进行了研究。在铁炭微电解的条件下,以硝基苯为研究对象,选择盐分为参数,在降解过程中,一定时间下取样检测浓度,并计算硝基苯降解率。铜离子、氯离子能促进硝基苯的去除;钙离子对硝基苯的去除率无明显作用;六价铬离子和磷酸根离子对硝基苯的去除有抑制作用;低浓度的硫酸根离子可促进硝基苯的降解,高浓度的硫酸根离子则会减弱对硝基苯降解的促进作用。铁炭微电解过程中盐分对硝基苯的降解率影响很大。     

钙离子对胶磷矿和白云石可浮性的影响研究

以白云石-胶磷矿体系为研究对象, 在无机阴离子存在的条件下, 研究了钙离子对胶磷矿和白云石浮选行为的影响。试验结果表明: F^-存在的条件下, Ca²⁺对两种矿物的可浮性影响并不大; 而CO₃^2-存在的条件下, 在强碱性环境中, Ca²⁺的加入使两种矿物的可浮性趋于一致。同时, 在Ca²⁺体系中, 当pH≈7时, SO₄^2-对胶磷矿的抑制效果较好; 在pH=5~7时, PO₄^3-对两种矿物有明显的选择性抑制作用。F^-和CO₃^2-混合体系中, Ca²⁺对两种矿物的浮选均有一定的活化作用, Ca²⁺对胶磷矿的活化作用要优于白云石。