Polyethylenimine-functionalized magnetic amorphous carbon fabricated from oil palm leaves as a novel adsorbent for Hg(II) from aqueous solutions

PEI (polyethylenimine) functionalized magnetic amorphous carbon thin film nano composite (Fe₃O₄-PEI-ACTF NC), was successfully synthesized and characterized by High Resolution Transmission Electron Microscope (HR-TEM), X-ray diffraction (XRD), Fourier-transform infrared spectrometer (FTIR), and Thermo gravimetric analysis (TGA). The synthesized nano composite Fe₃O₄-PEI-ACTF was developed as a highly efficient adsorbent for Hg(II) from aqueous samples. Effect of pH, contact time, adsorbent dose, initial concentration and temperature were investigated and optimized through batch adsorption technique. Besides, good magnetic performance of Fe₃O₄-PEI-ACTF NC makes it easily recovered from water with magnetic separation at low magnetic field. The adsorption kinetic data described well with the pseudo-second-order model and the equilibrium data fitted well to Langmuir isotherm model. The maximum adsorption capacity was 714?µg/g of Hg(II). Thermodynamic studies (ΔG°?<?0, ΔH°?>?0, ΔS°?>?0) implied an endothermic and spontaneous adsorption process in nature. Furthermore, the excellent reproducibility indicated that Fe₃O₄-PEI-ACTF NC has a promising application for removing heavy metals from aqueous environments due to high adsorption capacity and easily and quick separation.     

Removal of Ni (II), Mn (II) and Zn (II) from crude yellow cake aqueous solution by cross-linked chitosan and polyvinyl alcohol

The removal of Ni (II), Mn (II) and Zn (II) from crude yellow cake onto chitosan cross-linked by Epichlorohydrin (CS-ECH) and polyvinyl alcohol (PVA) were investigated in nitrate solutions. The influence of contact time, pH, temperature and initial metal concentrations on the adsorption processes were investigated using batch modes. Langmuir and Fruindlish models were used for investigation of adsorption isotherm. The results showed that the equilibrium adsorption behavior of metal ions onto CS-ECH and PVA could be fitted to Langmuir model. The total maximum adsorption capacity of CS-ECH and PVA were calculated, and the results indicate the higher values of CS-ECH than PVA, due to the properties of chemical structure of CS-ECH. The adsorption kinetics parameters were also tested using pseudo-first-order, pseudo-second-order models, and interparticle diffusion models. The results indicate the adsorption processes of metal ions on both CS-ECH and PVA followed the pseudo-first-order and the pseudo-second-order models which meaning the mixed adsorption, except the adsorption of Mn (II) on PVA is only described by the pseudo-second-order equation. The results indicate the adsorption processes of metal ions followed the pseudo-second-order models for both CS-ECH and PVA. Otherwise, the values of thermodynamic parameters (ΔH^o_ads, ΔS^o_ads, and ΔG^o_ads) of metal ions removal by CS-ECH and PVA exhibit the spontaneity, and exothermicity of adsorption processes.     

Base-catalyzed oxidation of poly (ethylene glycol) by alkaline permanganate: Part I. Kinetics and mechanism of formation of coordination intermediate complex

A spectrophotometric investigation has been applied to study the kinetics of oxidation of poly (ethylene glycol) (PEG) as a synthetic polymer by alkaline permanganate at a constant ionic strength of 1.0 mol.dm^?3. The reaction was found to proceed through two distinct measurable stages. The first stage was relatively fast and corresponding to the formation of coordination polymer intermediate complexes involving blue hypomanganate (V) and/or green manganate (VI) transient species. The influence of variable factors on the oxidation rates such as the concentration of permanganate ion and PEG substrate concentrations as well as the pH and ionic strength have been examined. Under the pseudo-first-order reaction conditions of [PEG] ? [MnO₄^?], the experimental results showed a first-order dependence in [MnO₄^?] and fractional first-order kinetics in each of [PEG] and alkali concentration. The oxidation process was of base-catalyzed nature where the oxidation rates were increased with increasing the alkali concentration. The observed first-order rate constant was found to be 1.1 ×10^?3 s^?1 with deprotonation constant of 0.72 dm³ mol^?1 at 45 °C. Blue hypomanganate (V) was detected for the first time by using a conventional spectrophotometer. The oxidation process has proceeded without the intervention of a free-radical mechanism. Colloidal manganese (IV) and the acid derivatives of PEG were identified as final oxidation products. The activation parameters of the second-order reaction have been calculated and found to be ΔH^≠ = 40.66 kJmol^?1; ΔS^≠ = ? 145.41 Jmo^l?K^?1 and ΔG^≠ = 83.99 kJmol^?1. A plausible reaction mechanism for oxidation based on the evaluated activation parameters and in good consistent with the observed kinetic data was suggested and discussed.     

16Mn(T/S 52K)螺旋缝埋弧焊钢管的H2S环境开裂性能

通过对16Mn(t／S52K)螺旋缝埋弧焊钢管在含H2S气田使用中所发生的破裂事故及实验室检测数据的分析，阐明了16Mn(T／S52K)螺旋缝埋弧焊钢管，其管体虽然能满足抗SSC要求，但由于锰、碳含量较高，具有淬硬倾向，不良的焊接行为，易产生对SSC敏感的马氏体组织。且管体和焊接热影响区对HIC十分敏感。因此不适宜用于输送含H2S天然气。     

Synthesis and characterization of Schiff base ligand as a carrier and its application for construction of new Mn(II) sensors and their use in petroleum water samples

The ligand (PBABMDP: 2,2′-((1E,1′E)-(1,3-phenylene bis(azanylylidene)) bis(methanyly-lidene))-diphenol was synthesized in a reasonable yield from 2-hydroxybenzaldehyde and m-phenylenediamine and studied using IR, mass, and ¹H NMR spectroscopy. PBABMDP has been used as a neutral carrier to make a new carbon paste (CPS) and screen-printed sensors (SPS) that are highly selective to Mn(II) ions. They revealed linear concentration ranges from 1.0 × 10^-7 to 1.0 × 10^-1 mol L^-1 for CPS (sensor I) and from 3.7 × 10^-8 to 1.0 × 10^-1 mol L^-1 for SPS (sensor II), respectively, with Nernstian slopes of 29.01 ± 0.97 and 29.96 ± 0.57 mV decade^-1. For sensor I and sensor II, the detection limit, and the response time of the sensors were: 1.0 × 10^-7 and 3.7 × 10^-8 mol L^-1 and 9 and 6 s, respectively. Without observe a divergence, the paste may be used for more than 95 or 182 days and the sensors can be used between 4.0 and 7.5 pH and 3.0 to 8.5 pH. For sensor I and II, the isotherm coefficient of the sensors was 0.000105 and 0.000168 V/^oC. The proposed sensors were applied to the determination of Mn(II) ions in real petroleum water samples. The results achieved using this potentiometric method and those obtained with AAS were well agreed.     

基于PRMS准则的煤层气资源/储量划分与评估

介绍了基于国际通用准则"石油资源管理系统"(PRMS)的各级煤层气资源/储量的定义及分类要求,从资产所有权、政府监管与项目审批条件、井控程度、测试程度、基础设施和销售市场、开发与生产时间以及经济参数这7个方面详细分析煤层气各级储量的划分依据。结合煤层气地质条件和工程条件、现行经济条件、操作条件以及政府相关政策等,初步制定了煤层气3P储量和条件储量的确定原则并进行实例分析,为合理评估煤层气储量提供重要参考。     

Three years of monitoring of PCDD/F,DL-PCB and NDL-PCB residues in bovine milk from Lombardy and Emilia Romagna regions (Italy): Contamination levels and human exposure assessment

In the three-years period 2012–2014, 160 cow milk samples from farms located in Lombardy and Emilia Romagna regions (Italy) were analyzed during the implementation of the Italian National Residues Monitoring Plan to assess the presence of PCDD/F, DL-PCB and NDL-PCB residues. The obtained contamination data were combined with cow milk consumption data from the Italian national dietary survey to estimate PCDD/F, DL-PCB and NDL-PCB human dietary exposure through the consumption of whole, semi skimmed and skimmed bovine milk. The exposure assessment was carried out separately for children, teenagers, adults and elderly. Average contamination levels of the analyzed samples were found to be 1.26 pg WHO-TEQ/g fat for the sum of PCDD/Fs and DL-PCBs and 9.30 ng/g fat for the sum of the 6 NDL-PCB indicators. PCB 126 was found to be the main contributor to the total WHO-TEQ. Using the upper bound approach, the estimated mean dietary intakes ranged from 0.07 pg WHO-TEQ/kg bw per day to 0.39 pg WHO-TEQ/kg bw per day for the sum of PCDD/Fs and DL-PCBs and considering exposure from whole milk. NDL-PCB mean dietary intakes resulted between 0.52 ng/kg bw per day and 2.86 ng/kg bw per day for consumption of whole milk. Children and teenagers were found to be the most exposed groups. This is the first time that Italian consumers exposure to NDL-PCBs is assessed using contamination data of cow milk produced in Italy.