改性竹炭对含铅废水吸附处理的效果研究

研究了商用竹炭和改性竹炭对含铅废水的吸附处理的实验条件及效果。结果表明,对一定质量浓度及一定量含铅废水处理时,只要条件和吸附剂竹炭的投放量合适,铅的去除率均可达99.9%以上。以我国饮用水卫生标准中铅含量≤0.05mg/L为标准,根据废水中铅的含量,给出了吸附处理所需吸附剂投料量的估算方法和实验验证结果,为竹炭在含铅废水处理中的应用提供理论依据。     

Ethylene oxide pollution evaluation Part II: Sampling on HBr-treated charcoal tubes

Summary Air sampling of ethylene oxide on HBr-treated charcoal tubes followed by capillary GC analysis of the 2-bromoethanol produced allows pollution control evaluation for concentrations ranging from 0.2 to 20 mgm⁻³. The adequacy of the method is assessed taking into account ambient temperature and relative humidity.     

Absorption method for rapid decontamination of solutions of ethidium bromide and propidium iodide

Summary An activated charcoal filter has been used to remove ethidium bromide (EB) in water, various buffers, CsCl solutions and ethanol. In all cases studied, ethidium bromide was undetectable in the eluted liquid (contamination less than 0,5 g/ml in a fluorescence detection assay performed in the presence of 10 g/ml HeLa cell DNA). Since EB can be destroyed by heating at temperatures above 262°C, the contaminated charcoal filters can be easily incinerated thus providing a simple and cheap decontamination procedure which can be extended to other suspected mutagens such as propidium iodide (PI) which is commonly used in flow cytometric DNA analysis.     

Evaluation of CSC Charcoal for Production of Dry Combustion Plasma

Evaluation of CSC charcoal by standard thermoanalytical techniques shows that the dry material contains ⪞ 99% carbon having calorific value of about 16.32 mJ/kg; its hydrogen and ash contents are insignificant. On admixture with small amount of K₂CO₃ (seed for generation of combustion plasma) its combustion characteristics remain more or less unaltered though the combustion rates are greatly enhanced. This revised version was published online in July 2006 with corrections to the Cover Date.     

Monoionic montmorillonites treated with Congo-Red

The adsorption of the anionic dye congo-red (CR) by Na-, Cs-, Mg-, Al- and Fe-montmorillonite was studied by simultaneous DTA-TG. Thermal analysis curves of adsorbed CR were compared with those of neat CR. The oxidation of neat CR is completed below 570°C. Thermal analysis curves of adsorbed CR show three regions representing dehydration of the clay, oxidation of the organic dye and dehydroxylation of the clay together with the oxidation of residual organic matter. The oxidation of the dye begins at about 250°C with the transformation of organic H atoms into water and carbon into charcoal. Two types of charcoal are obtained, low-temperature and high-temperature stable charcoal. The former gives rise to an exothermic peak in the second region of the thermal analysis and the latter in the third region. The exchangeable metallic cation determines the ratio between the low-temperature and high-temperature stable charcoal, which is formed. With increasing acidity of the exchangeable metallic cation higher amounts of high-temperature stable charcoal are obtained. It was suggested that aromatic compounds p bonded to the oxygen plane of the clay framework are converted into charcoal, which is burnt at about 550-700°C. With increasing surface acidity of the clay more species of CR are protonated. Only protonated dye species can form p bonds with oxygen plane and are converted to high-temperature stable charcoal during the thermal analysis. The thermal behavior of the dye complex of Cu-montmorillonite is different probably due to the catalytic effect of Cu. This revised version was published online in July 2006 with corrections to the Cover Date.     

微波辐射在制备竹节活性炭中的应用研究

研究了以竹节废料为原料，采用微波辐射氯化锌法制备优质活性炭的可行性．探讨了微波功率．活化时间及氯化锌浓度对产品各项指标的影响．得到了微波辐射氯化锌法制备活性炭的最佳工艺：微波功率350W、活化时间5min、氯化锌浓度40%．用此工艺制得的活性炭碘吸附值1088．4mg／g、亚甲基蓝脱色力22．0ml/0．1g．得率39．2％．该工艺所需活化时间为传统方法的1／36，产品活性炭亚甲基蓝脱色力为国家一级标准的1．83倍(GB/T13496.10-1999)．微波辐射法所制活性炭比传统方法所制活性炭具有更加发达的孔隙结构，且孔隙的分布更加均匀．     

A practical synthesis of highly functionalized aryl nitriles through cyanation of aryl bromides employing heterogeneous Pd/C: in quest of an industrially viable process

Preparation of aryl nitrile 2a through classical Rosenmund-von Braun reaction of aryl bromide 1a resulted in a poor yield (61%) due to a high reaction temperature (165 °C) and a lack of efficient procedure for separating 2a from a large quantity of heavy metal waste (Cu salts). To address these issues, a practical synthesis of multifunctional aryl nitriles through cyanation of aryl bromides has been developed with heterogeneous Pd/C used as the catalyst. Treatment of aryl bromides 1 with Zn(CN)₂ in the presence of Pd/C, Zn, ZnBr₂ and PPh₃ in DMA provided aryl nitriles 2 involving those carrying sterically demanding electron-rich substituent in good yields and in highly reproducible manner. The activity of Pd/C is highly dependent on the properties of the Pd/C. Oxidic thickshell type catalyst Pd/C D5 was found to furnish the highest rate acceleration and yield. The use of heterogeneous Pd/C might anchor and disperse Pd over the solid support of the catalyst, at least in the initial stage of the reaction, to assure the formation of monomeric Pd complex without precipitating to inactive Pd black. The use of a slightly excess of Zn(CN)₂ (0.6 equiv) and air oxidation of phosphine ligand, after end of the reaction, converted Pd species to insoluble phosphine-free Pd cyanides, from which Pd was recovered in high yield through simple filtration followed by usual recovery process involving combustion.     

Kinetic of Patent Blue VF Adsorption from Aqueous Solution on Activated Bone Charcoal

The effect of temperature of activation on bone charcoal, used as adsorbent for the removal of Patent Blue VF from water solutions was studied. The adsorbent was characterized by FTIR, XRD, SEM and EDS. The kinetic of adsorption of dye was carried out at 10 °C and 45 °C. Carbonization temperature (600–1000 °C) of the adsorbent has significant effect on the removal of dye from water solutions. The first order kinetic, Elovich, Bangham, parabolic diffusion and power function equations were found to fit the kinetic data. Activation energies of adsorption (Δ≠) have higher values for the charcoal activated at high temperatures and the other thermodynamic parameters like ΔH≠, ΔS≠ and ΔG≠ were also found.     

Preconcentration and decomposition of perfluorinated carboxylic acids on an activated charcoal cartridge with sodium biphenyl reagent and its determination at microg L(-1) level on the basis of flow injection-fluorimetric detection of fluoride ion

Perfluorinated surfactants of heptafluorobutylate and pentadecafluorooctanoate ions were adsorbed on an activated charcoal cartridge and decomposed with sodium biphenyl (SBP) reagent to form inorganic fluoride ion. The fluoride ion thus formed was determined by flow injection analysis (FIA) using quercetin-Zr complex as a fluorimetric reagent, where λ_ex and λ_em were 422 and 491 nm, respectively. The limit of detection for fluoride ion by the FIA system was developed to 1.1 × 10⁻⁶ M (signal to noise ratio of three), when 50% (v/v) tetrahydrofuran (THF) was used as a dissolving solvent for quercetin. The perfluorinated surfactants in the sample solution were quantitatively adsorbed on the cartridge containing 100 mg of activated charcoal and were decomposed with 0.5 mL of sodium biphenyl reagent after drying thoroughly by flowing through dry nitrogen gas. The fluoride ion formed was recovered with 3 mL of purified water as an eluent, and it was determined by the fluorimetric flow injection system. The blank fluorescence signal accompanied during the adsorption/decomposition on the cartridge was reduced by washing the activated charcoal with acetone. The blank signal was also observed from dimethoxyethane, which was used in sodium biphenyl reagent. When 600 mL sample solution was used and 200 times enrichment was applied, the heptafluorobutylate and pentadecafluorooctanoate ions at the concentrations of 2.1 μg L⁻¹ were quantitatively recovered as fluoride ion, and the limit of detections for the perfluorinated surfactants were 0.3 and 0.3 μg L⁻¹ for the two perfluorinated surfactants, respectively (3 sigma of the blank signal).     

Ethylene oxide pollution evaluation part I: Sampling with active charcoal tubes

Summary Air sampling of ethylene oxide on active charcoal tubes followed by GC analysis is a frequently proposed method. This paper studies just to what extent it can be used, defining its limitations (concentration range, influence of ambient temperature and relative humidity), which are seldom taken seriously into account. This method proves inadequate to determine low pollution levels, i.e. around 2 mg m⁻³.