Study of viscosity of mono-, di-, and trialkylamines

Viscosities of several mono-, di-, and trialkylamines have been measured in the temperature range 298 to 333 K. It is observed that viscosities are highly dependent on shape, size, and association through H-bond or through dipole. Following the transition state theory, energy, Gibbs free energy, and entropy of activation of viscous flow have been calculated. The values of expansion energy for these liquids have also been calculated using free volume theory, and subsequently amines have been classified as volume-restrained or energy-restrained liquids. The group contribution method of Van Velzen, Cardozo, and Langenkamp for estimating viscosity has been examined with the present and literature data, and the new group contribution increments N _i and B _i for amines have been evaluated.     

Sulfur mustard destruction using ozone, UV, hydrogen peroxide and their combination

Numerous methods are used for destruction of sulfur mustard. Oxidation is one of those methods. There have been only limited data concerning application of the advanced oxidation technologies (AOTs) for mustard destruction available before. In this study sulfur mustard oxidation rate depending on kind of the oxidative system and process parameters used was assessed using selected AOT. The following were selected for mustard oxidation: ozone (O(3)), UV light (UV), hydrogen peroxide (H(2)O(2)); double systems: UV/O(3), UV/H(2)O(2), and O(3)/H(2)O(2); a triple system: O(3)/H(2)O(2)/UV and Fenton reaction. Effectiveness of the selected AOT methods has been evaluated and the most suitable one for mustard destruction was chosen. Using ozone in various combinations with hydrogen peroxide and UV radiation mustard can be destroyed much quicker comparing to the classical oxidizers. Fast mustard oxidation (a few minutes) occurred in those systems where ozone alone was used, or in the following combinations: O(3)/H(2)O(2), O(3)/UV and O(3)/H(2)O(2)/UV. When those advanced oxidation technologies are used, mustard becomes destroyed mainly in course of the direct oxidation with ozone, and reactions of mustard with radicals formed due to ozone action play a secondary role. Rate of sulfur mustard oxidation in the above mentioned ozone-containing oxidative systems decreases with pH value increasing from 2 to 12. Only when pH value of reaction solutions is close to pH 5, mustard oxidation rate is minimal, probably due to "disappearance" of radicals participating in oxidation in this pH. Sulfur mustard can be most effectively destroyed using just ozone in pH 7. In that case mustard destruction rate is only slightly lower than the rate achieved in optimal conditions, and the system is the simplest.     

Photo-assisted oxidation of an oily wastewater using hydrogen peroxide

The primary objective was to study the purification of an oily wastewater from a lubricant production unit using ultraviolet irradiation and hydrogen peroxide. The influence of hydrogen peroxide concentration, initial pH of the solution and of the addition of ferric ions on the chemical oxygen demand (COD) was examined. In each case, the concentration of the compounds contained in the oily wastewater was determined. It was shown that a 20-45% COD removal was achieved with 830-1660 mg l(-1) H(2)O(2). Gas chromatography-mass spectrometry analysis showed that the organic compounds of the wastewater decomposed to organic acids that were very resistant to photo-oxidation. Among these compounds, ethylene glycol remained almost unchanged by the attack from hydroxyl radicals. Acidic pH and Fe(III) addition enhanced significantly the photo-oxidation of the wastewater.     

Fabrication of tunnelling barriers by oxidation in hydrogen peroxide

One of the major experimental difficulties in electron tunnelling work is the preparation of very thin insulating barriers. This paper describes a method based on oxidation of the substrate in hydrogen peroxide. Good results have been obtained with gallium and tin, and the technique may be useful for other metals as well.     

Ametryn degradation in the ultraviolet (UV) irradiation/hydrogen peroxide (H2O2) treatment

Ultraviolet (UV) irradiation (253.7nm) in the presence of hydrogen peroxide (H(2)O(2)) was used to decompose aqueous ametryn. The concentrations of ametryn were measured with time under various experiment conditions. The investigated factors included H(2)O(2) dosages, initial pH, initial ametryn concentrations, and a variety of inorganic anions. Results showed that ametryn degradation in UV/H(2)O(2) process was a pseudo-first-order reaction. Removal rates of ametryn were greatly affected by H(2)O(2) dosage and initial concentrations of ametryn, but appeared to be slightly influenced by initial pH. Furthermore, we investigated the effects of four anions (SO(4)(2-), Cl(-), HCO(3)(-), and CO(3)(2-)) on ametryn degradation by UV/H(2)O(2). The impact of SO(4)(2-) seemed to be insignificant; however, Cl(-), HCO(3)(-), and CO(3)(2-) considerably slowed down the degradation rate because they could strongly scavenge hydroxyl radicals (OH) produced during the UV/H(2)O(2) process. Finally, a preliminary cost analysis revealed that UV/H(2)O(2) process was more cost-effective than the UV alone in removal of ametryn from water.     

Viscosity of binary mixtures. I. mono-, di-, and tri-n-butyl and -n-octylamine with cyclohexane

Viscosities for six binary mixtures of n-butylamine, di-n-butylamine, tri-n-butylamine, n-octylamine, di-n-octylamine, and tri-n-octylamine with cyclohexane have been measured at 303.15 K with an Ubbelohde suspendedlevel viscometer. Deviations of viscosities from a rectilinear dependence on mole fraction are attributed to H-bonding and to the size of alkylamine compounds. The application of the Eyring's theory of activation energy is examined. The free volume theory of Prigogine-Flory-Patterson (PFP) and the experimental excess enthalpy have been used to estimate excess viscosity ln = (ln / ₁ ⁰ – x ₂ ln ₂ ⁰ / ₁ ⁰ ) and corresponding free volume, enthalpy, and entropy contributions for five binary mixtures of tri-n-alkylamine: triethyl, tripropyl, tributyl, trihexyl, and trioctylamine with cyclohexane. A comparison of experimental and theoretical excess viscosities indicates a failure of the PFP theory when two components of the mixture differ considerably in size. The size difference contribution to excess viscosity is related to (V ₂ ^*1/2 – V ₁ ^*1/2 ), where V ₁ ^* and V ₂ ^* are hard-core volumes of two components of the mixture.     

Olive mill wastewater degradation by Fenton oxidation with zero-valent iron and hydrogen peroxide

The degradation of olive mill wastewater (OMW) with hydroxyl radicals generated from zero-valent iron and hydrogen peroxide has been investigated by means of chemical oxygen demand (COD) and phenolic compounds analyses. The effects of the H2O2 dose, the pH and the organic matter concentration have been studied. The optimal experimental conditions were found to have continuous presence of iron metal, acid pH (2.0-4.0), and relatively concentrated hydrogen peroxide (9.5M). Coloration of OMW disappeared and phenolic compound decreased to 50% of initial concentration after 3h reaction time. The application of zero-valent Fe/H2O2 procedure permitted high removal efficiencies of pollutants from olive mill wastewater. The results show that zero-valent Fe/H2O2 could be considered as an effective alternative solution for the treatment of OMW or may be combined with a classical biological process to achieve high quality of effluent water.     

Simultaneous determination of mono-, di-, and tributyltin in sediments by isotope dilution analysis using gas chromatography--ICPMS

A mixed spike containing 119Sn-enriched monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) was prepared by direct butylation of 119Sn-enriched tin metal using a 1:3 molar excess of butyl chloride with iodide and triethylamine as catalysts. The isotopic composition of the different tin species in the spike solution was determined by gas chromatography- ICPMS after aqueous ethylation using sodium tetraethylborate. Reverse isotope dilution analysis was used for the characterization of the spike by means of natural MBT, DBT, and TBT standards. No species transformation was evident during derivatization from the reverse isotope dilution experiments based on the measured isotope ratios both before and after spiking. The mixed spike was applied to the simultaneous analysis of MBT, DBT, and TBT in certified reference materials, PACS-2 and CRM 646, with satisfactory results.     

Simultaneous determination of mono-, di-, and triglycerides in multiphase systems by online Fourier transform infrared spectroscopy

Glycerides are of significant value for industry as ingredients with different purposes in food or cosmetics. The analysis of glycerides is mainly performed by gas chromatography (GC) or high-pressure liquid chromatography (HPLC), which demonstrate limitations in dealing with multiphase systems. In this article, an in situ differentiation between mono-, di-, and triglycerides in multiphase systems by Fourier transform infrared (FT-IR) spectroscopy is demonstrated. The enzymatic esterification of glycerol with lauric acid was analyzed as a model system. The reaction was carried out in a bubble column reactor containing four phases (two liquid phases of glycerol and lauric acid, air as gaseous phase, and a heterogeneous catalyst as solid phase). As a feasibility study, a chemometric model was generated for the pure components only. The quantities of lauric acid and the three products (mono-, di-, and trilaurin) were simultaneously determined over the course of the reaction with acceptable errors (1.8-12.5%) with regard to the calibration effort. This technology has the potential to give accurate results, particularly in unstable emulsion systems containing fats, oils, or emulsifiers, which are currently afflicted by analytical errors caused by the challenge of accurate sampling.     

Chemical oxidation of chlorinated non-aqueous phase liquid by hydrogen peroxide in natural sand systems

This study explored the Fenton-like oxidation of trichloroethylene (TCE) existing as dense non-aqueous phase liquid (DNAPL) in natural silica sand (iron=0.04 g/kg) and the sand from an aquifer (iron=2.01 g/kg). Glass bead containing no iron mineral was used as the control. Batch oxidation experiments were conducted to assess interactions between oxidant and TCE DNAPL. Column experiments were performed to evaluate dynamics of TCE and H(2)O(2) during oxidation. The pH was not altered. In the batch system, a single application of 3% H(2)O(2) to the aquifer sand oxidized 40% of the added TCE DNAPL in 1 h, which was four times of that by dissolution with the gas purge procedure. This demonstrated the ability of mineral-catalyzed Fenton-like reaction to directly oxidize TCE in non-aqueous liquid. In the column experiments, after passing 7 pore volumes (PVs) of 1.5 and 3% H(2)O(2) solution, the residual TCE in aquifer sand column was 12.0 and 2.6% of the initial added, respectively. On the other hand, 28.4% of the added TCE still remained in the silica sand column by 7 PVs of 3% H(2)O(2). The distribution of TCE in column and effluent indicated the occurring of direct oxidation of TCE DNAPL and the increased solubilization, which probably due to size reduction of DNAPL droplets, followed by water-phased TCE oxidation.     

蚕丝纤维/金属酞菁活化双氧水催化氧化酸性橙的研究

合成了四磺酸基钴酞菁(CoPcS),采用基质辅助激光解析电离飞行时间质谱(MALDI-TOF-MS)、紫外-可见光谱(UV-Vis)和傅里叶变换红外光谱(FT-IR)对其进行表征,然后通过三聚氯氰改性将其负载到蚕丝纤维(SF)上,制得了新型蚕丝纤维负载钴酞菁催化剂(CoPcS-SF)。以H2O2为氧化剂,考察了CoPcS-SF对酸性橙Ⅱ(AO2)的催化氧化性能,结果表明,在中性条件下,CoPcS-SF能高效催化氧化AO2,反应60min后AO2的去除率可达97%以上,并且具有较好的重复使用性。考察了pH值、电解质NaCl和温度对CoPcS-SF催化性能的影响,结果表明,CoPcS-SF在pH值3～9较宽范围内均具有较高催化活性;NaCl对催化AO2有促进作用;催化活性随反应温度升高而增强。FT-IR和气质联用(GC-MS)对AO2的降解产物分析表明,AO2的主要产物为顺丁烯二酸、反丁烯二酸和丁二酸等小分子可生物降解脂肪酸。     

Landfill leachate treatment with ozone and ozone/hydrogen peroxide systems

In the search for an efficient and economical method to treat a leachate generated from a controlled municipal solid waste landfill site (Jebel Chakir) in the region of greater Tunis in Tunisia, ozone alone and ozone combined with hydrogen peroxide were studied. The leachate was characterised by high COD, low biodegradability and intense dark colour. A purpose-built reactor, to avoid foaming, was used for the study. It was found that ozone efficacy was almost doubled when combined with hydrogen peroxide at 2g/L but higher H(2)O(2) concentrations gave lower performances. Enhancement in the leachate biodegradability from about 0.1 to about 0.7 was achieved by the O(3)/H(2)O(2) system. Insignificant changes in pH that may due to buffering effect of bicarbonate was found. A small decrease in sulphate concentrations were also observed. In contrast, chloride concentration declined at the beginning of the experiment then increased to reach its initial value. Estimates of the operating costs were made for comparison purposes and it was found that the O(3)/H(2)O(2) system at 2g/L H(2)O(2) gave the lowest cost of about 3.1TND( approximately 2.3USD)/kgCOD removed.     

Treatment of petroleum-hydrocarbon contaminated soils using hydrogen peroxide oxidation catalyzed by waste basic oxygen furnace slag

The contamination of subsurface soils with petroleum hydrocarbons is a widespread environmental problem. The objective of this study was to evaluate the potential of applying waste basic oxygen furnace slag (BOF slag) as the catalyst to enhance the Fenton-like oxidation to remediate fuel oil or diesel contaminated soils. The studied controlling factors that affect the removal efficiency of petroleum hydrocarbons included concentrations of H₂O₂, BOF slag dosages, types of petroleum hydrocarbons (e.g., fuel oil and diesel), and types of iron mineral. Experimental results indicate that oxidation of petroleum hydrocarbon via the Fenton-like process can be enhanced with the addition of BOF slag. Results from the X-ray powder diffraction analysis reveal that the major iron type of BOF slag/sandy loam system was iron mineral (e.g., α-Fe₂O₃ and α-FeOOH). Approximately 76% and 96% of fuel oil and diesel removal were observed (initial total petroleum hydrocarbon (TPH) concentration = 10,000 mg kg⁻¹), respectively, with the addition of 15% of H₂O₂ and 100 g kg⁻¹ of BOF slag after 40 h of reaction. Because BOF slag contains extractable irons such as amorphous iron and soluble iron, it can act as an iron sink to supply iron continuously for Fenton-like oxidation. Results demonstrate that Fenton-like oxidation catalyzed by BOF slag is a potential method to be able to remediate petroleum-hydrocarbon contaminated soils efficiently and effectively.     

Low temperature UV/ozone oxidation formation of HfSiON gate dielectric

Physical and electrical properties of hafnium silicon oxynitride (HfSi_xO_yN_z) dielectric films prepared by UV ozone oxidation of hafnium silicon nitride (HfSiN) followed by annealing to 450 °C are reported. Interfacial layer growth was minimized through room temperature deposition and subsequent ultraviolet/ozone oxidation. The capacitance–voltage (C–V) and current–voltage (I–V) characteristics of the as-deposited and annealed HfSi_xO_yN_z are presented. These 4 nm thick films have a dielectric constant of 8–9 with 12 at.% Hf composition, with a leakage current density of 3×10⁻⁵ A/cm² at V_fb+1 V. The films have a breakdown field strength >10 MV/cm.     

Simultaneous electroanalysis of peroxyacetic acid and hydrogen peroxide

The electrochemical behavior of peroxyacetic acid (PAA) in the presence of hydrogen peroxide (H2O2) has been investigated using cyclic voltammetry and hydrodynamic techniques [rotating disk electrode (RDE) voltammetry and rotating ring-disk electrode (RRDE) voltammetry]. The results have been analyzed aiming at simultaneous electroanalysis of both species. Glassy carbon and gold electrodes were used for this investigation. It was found that the reduction of PAA, as well as H2O2, is highly sensitive to the electrode material; for example, at 100 mV s-1, the reduction peak potentials of PAA were 0.2 and -1.1 V at gold and glassy carbon electrodes, respectively. The well-separated steady-state limiting currents were obtained using a gold electrode for the reduction of both PAA and H2O2 and also a well-defined one for the oxidation of H2O2. On the basis of the RDE experiments, good calibration curves were obtained for both species over a wide range of their concentrations, for PAA and H2O2 in the range of 0.36 to 110 and 0.11 to 34 mM, respectively. The simultaneous and selective electroanalysis of PAA and H2O2 in their coexistence is demonstrated for the first time.     

Gold nanoparticles/graphene oxide composite for electrochemical sensing of hydroxylamine and hydrogen peroxide

It has been discovered that the complex formed by cetyltrimethyl ammonium bromide (CTAB) and graphene oxide (GO) is highly stable in aqueous solution and adhesive to the glassy carbon electrode (GCE) surface in our previous research. In this work, the film of CTAB/GO complex was directly formed on GCE and gold nanoparticles were facilely incorporated into the matrix of CTAB/GO complex at the same time. Scanning electron microscopic (SEM) investigation shows that gold nanoparticles were distributed uniformly on the sheets of graphene. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometry were used to investigate the electrochemical behaviors of AuNP/CTAB/GO. The obtained AuNP/CTAB/GO presents excellent catalytic capabilities towards the oxidation of hydroxylamine (HA) and the reduction of H₂O₂. The oxidation current of HA and the reduction current of H₂O₂ are linear with their concentrations in the range of 10～1000 μM and 1.0～5000 μM, respectively. The detection limits for HA and H₂O₂ are 3.5 μM and 0.67 μM, respectively. The mechanism of the oxidation of HA on AuNP/CTAB/GO modified GCE was also studied.     

Studying the effect of temperature on the copper oxidation process using hydrogen peroxide for use in multi-step chemical mechanical planarization models

Given that the mechanism responsible for removal during copper chemical mechanical planarization (CMP) is generally accepted to be based on the cyclic oxidation of copper and the subsequent removal of copper oxide, this study characterizes the copper oxide growth process as a function of temperature in aqueous hydrogen peroxide solutions. A copper oxidation model was proposed based on cation migration to adequately represent measured copper oxide growth profiles as a function of temperature. The two parameters extracted to fit the oxidation profiles, W and V, in the proposed model are related to activation energy of cation migration and the potential developed across the oxide film, respectively. The potential was found to be 0.95 V and did not vary with temperature. The activation energy was found to be 0.84 ± 0.01 eV and increased slightly with temperature. This slight increase, on the order of 2 to 3 kcal, has been previously reported and attributed to an increase in activation energy of cation solution in the oxide. The oxidized copper formation rates calculated suggest that the typical oxide thicknesses involved during the cyclic oxide growth and removal mechanism in copper CMP are between 7 and 12 Å. Though the oxidation model parameters are extracted from copper oxidation experiments on the minute time scale, there are a number of experimental, physical, and theoretical arguments that suggest the model represents the actual physical system and is applicable to the sub-second timescales involved during the oxidation processes in copper CMP.