摘要:

AbstractTwo series of size‐fractionated combusted residues, a bag‐house ash and a scrubber residue, from a municipal solid waste incinerator (MSWI) were prepared and extracted by means of sequential chemical extraction (SCE) procedures proposed by Tessier. Concentrations of water‐soluble phase, exchangeable phase, carbonated phase, Fe/Mn oxide phase, organic matter phase, and residual phase bound amphoteric metals (Pb and Zn) were obtained, and have been compared with those of single batch extraction of toxic characteristic leaching procedure (TCLP). In each size fraction of baghouse ash or scrubber residue, lead or zinc shows a common phenomena that the TCLP value is always lower than the content of the water‐soluble fraction. For lead, baghouse ash has a significant size‐dependent distribution on the water‐soluble phase to perform a size‐dependent test of lead in the TCLP test. The zinc TCLP data having less size dependence might be due to that neither the baghouse ash nor the scrubber residue has a size‐dependent distribution on the water‐s

ISSN:0009-4536    

DOI:10.1002/jccs.200400037

出版商:WILEY‐VCH Verlag    

年代:2004

数据来源: WILEY

摘要:

AbstractA mild chemical reduction method was developed to synthesize selenium nanoparticles. The observation of the particle growth within a five‐minute time frame at an elevated temperature is achieved, and it was evidenced by analyzing the particle sizes from electron micrographs. The samples at individual growth stages were taken after the reaction was quenched by cooling to stop further particle growth. The nucleation and growth processes dominate different reaction time regimes under the experimental condition. We demonstrate the size evolution of the selenium nanoparticles from 30 nm to about 200 n

ISSN:0009-4536    

DOI:10.1002/jccs.200400038

出版商:WILEY‐VCH Verlag    

年代:2004

数据来源: WILEY

摘要:

AbstractTwo‐center overlap integrals over Slater type orbitals (STOs) have been expressed in terms of the well‐known Mulliken's integralsBn(pt) using Rodrigues's formula for normalized associated Legendre functions. A computer program is written in Mathematica 4.0 for the evaluation of two‐center overlap integrals over STOs. Using this computer program, symbolic tables are presented for two‐center overlap integrals up to quantum numbers 1 ≤n,n′ ≤ 3, 0 ≤l,l′ ≤ 2, −2 ≤m,m′ ≤ 2. Numerical results of this work, for some quantum sets, have also been compared with prior literature and best agreement achieved with recent works of Barnett while some discrepancies were obtained with works of Özt

ISSN:0009-4536    

DOI:10.1002/jccs.200400039

出版商:WILEY‐VCH Verlag    

年代:2004

数据来源: WILEY

摘要:

AbstractThe electrochemistry of indium species was investigated at glassy carbon, tungsten and nickel electrodes in a basic 1‐ethyl‐3‐methylimidazolium chloride/tetrafluoroborate ionic liquid. Amperometric titration experiments suggest that In(III) chloride is complexed as [InCl5]2−in this ionic liquid. The electrochemical reduction of [InCl5]2−to indium metal is preceded by overpotential driven nucleations. The effective anodic dissolution of indium to indium(III) requires, however, the presence of sufficient chloride ions at the electrode surface. The electrodeposition of indium at glassy carbon and tungsten electrodes proceeds via three‐dimensional instantaneous nucleation with diffusion‐controlled growth of the nuclei. At the nickel electrode, the deposition proceeds via three‐dimensional progressive nucleation with diffusion‐controlled growth of the nuclei. Raising the deposition temperature decreases the average radius of the individual nuclei,r. Scanning electron microscopic and x‐ray diffraction data indicated that bulk crystalline indium electrodeposits could be prepared on nickel substrates within a temperature range be

ISSN:0009-4536    

DOI:10.1002/jccs.200400040

出版商:WILEY‐VCH Verlag    

年代:2004

数据来源: WILEY

摘要:

AbstractA turbidimetric technique based on a reaction between Hg(II) and melamine is described for the measurement of melamine content of wastewater of a petrochemical company. The present technique is rapid and simple, uses a small amount of reagent and is set up with low‐cost equipment, making this system economically viable. The experimental conditions such as volume of reagent, pH of buffer, stirring time, stirring speed, ionic strength, etc. were optimized and used in plotting the calibration curve. The linear dynamic range was 1–70 mg/L with a limit of detection of 0.3 mg/L. Repeatability of the proposed method is good, and the relative standard deviation (RSD%) is less than 1.5%. Interferences studies showed that the common compounds existing in wastewater have no negative effect on the efficiency of the method at relatively high concentrations. Finally, the proposed method has been successfully used in determination of melamine in wastewater of Urmia Petrochemical Comp

ISSN:0009-4536    

DOI:10.1002/jccs.200400041

出版商:WILEY‐VCH Verlag    

年代:2004

数据来源: WILEY

摘要:

AbstractTreatment of Pd(PPh3)4with phenylchlorothionoformate, PhOC(S)Cl, in dichloromethane at −20 °C produces the phenyloxythiocarbonyl complex [Pd(PPh3)2{η1‐C(S)OPh}(Cl)],1. The31P{1H} NMR spectrum of1shows the dissociation of either the chloride or the triphenylphosphine ligand to form complex [Pd(PPh3)2(η2‐SCOPh)][Cl],2or the dipalladium complex [Pd(PPh3)Cl]2(μ,η2‐SCOPh)2,3. Continuous stirring of the dichloromethane solution of1at room temperature for 4 h forms the dipalladinum complex [Pd(PPh3)Cl]2(μ,η2‐SCOPh)2,3as the final product. Respective reactions of1and Et2NCS2Na or dppa {bis(diphenylphosphino)amine} gives complex [Pd(PPh3){η1‐C(S)OPh}(η2‐S2CNEt2)],4or [Pd(PPh3){η1‐C(S)OPh}(η2‐dppa)][Cl],5. Complex1is determined by single‐crystal X‐ray diffraction and crystallized in the monoclinic space group P21withZ= 4. The cell dimensions of1are as follows:a= 9.5613(1)

ISSN:0009-4536    

DOI:10.1002/jccs.200400042

出版商:WILEY‐VCH Verlag    

年代:2004

数据来源: WILEY

摘要:

AbstractA new route to synthesize silver nanoparticles via vapor‐solid reaction growth (VSRG) is reported. Employing AgCl to react with (Me3Si)4Si in a sealed tube (433–673 K) generates silver particles (diameter ≥ 10 μm). Addition of polydimethylsiloxnae (PDMS) to the reaction dramatically reduces the particle size (diameter 60–1200 nm). Moreover, formation of silver nanorods and nanocubes was discovered in some reaction conditions. Adding PDMS and varying the reaction temperature were the key factors influencing the Ag parti

ISSN:0009-4536    

DOI:10.1002/jccs.200400043

出版商:WILEY‐VCH Verlag    

年代:2004

数据来源: WILEY

摘要:

AbstractTreatment of Pd(PPh3)4with N,N‐dimethylthiocarbamoyl chloride, Me2NC(=S)Cl, in dichloromethane at −20 °C produces complex [Pd(PPh3)2(η1‐SCNMe2)(Cl)] (1). In solution state, complex1shows the intramolecular dissociation of the chloride or intermolecular dissociation of the triphenylphosphine ligands to form η2‐thiocarbamoyl complex [Pd(PPh3)2(η2‐SCNMe2)][Cl](2) or the bridging η2‐thiocarbamoyl dipalladium complex [Pd(PPh3)Cl]2(μ,η2‐SCNMe2)2(3). Treatment of1with MeOCS2K yields [Pd(PPh3){η1‐C(SMe)(NMe2)}(η2‐S2CO)] (5a). The Fischer‐type carbene‐complex5ais formed via methyl migration of the methyldithiocarbonate to thiocarbamoyl ligand. Complex1reacts with EtOCS2K resulting in the formation of η2‐dithiocarbonate complex [Pd(PPh3)(η1‐SCNMe2)(η2‐S2COEt)] (4b) and carbene‐complex [Pd(PPh3){η1‐C(SEt)(NMe2)}(η2‐S2CO)] (5b) with ratios of 10:1 from the integration of31P{1H} NMR spectra. By continuously stirring the mixtures4band5bin CH2Cl2solution for 2 h, complex5bwas formed as the final product. Complex [Pd(η1‐SCNMe2)(η2‐Phen)(Cl)] (6) or [Pd{η1‐SC(O)NMe2}Pd(Cl)](μ,η2‐SCNMe2)‐(μ,η2‐dppm)2(7) is accessible by the reaction of1with phen (1,10‐phenanthroline) or dppm {bis(diphenylphosphino)methane} in dichloromethane at room temperature. All of the complexes are identified by spectroscopic methods and complexes1,3,5a, and7are determined by single‐crystal X‐ray diffraction. The complexes1and3crystallize in the monoclinic space group P21/n and P21/c withZ= 4, respectively, whereas5aand7belong to the triclinic space group P&1bar; withZ= 2. The cell dimensions are as follows: for1,a= 12.8248(1) Å,b= 18.6358(2) Å,c= 14.9692(1) Å, β = 105.1513(4)°; for3,a= 9.8782(1) Å,b= 11.7238(1) Å,c= 20.7353(2) Å, α = 103.9126(5)°, β = 97.8453(3)°, γ = 104.9669(5)°; for5a,a= 16.3638(2) Å,b= 9.3374(1) Å,c= 15.7117(2) Å, β = 98.2957(6)°; for7,a= 12.

ISSN:0009-4536    

DOI:10.1002/jccs.200400044

出版商:WILEY‐VCH Verlag    

年代:2004

数据来源: WILEY

摘要:

AbstractFlash pyrolysis of raw and tetralin treated coal samples were carried out in nitrogen atmosphere. Two representative coal samples from Lakhra coalmines labeled Lakhra‐3 (L3) and Lakhra‐6B (L6B) were pyrolyzed in their raw state and after treatment with tetralin. Initial experiments were carried out at 700 °C with 2 milligrams of 80 mesh size samples. The main hydrocarbon products detected from both samples were methane, ethylene, ethane, propane, butane, pentane, benzene, toluene and xylene (BTX). The ratio of the total hydrocarbon yield from L3 and L6B raw samples is 1:1.49, respectively, while the relative yield of aliphatic C1‐C5straight chain products to BTX are 7.65:5.49. Theses differences in product yields clearly indicate the compositional variation between the two samples. The total hydrocarbon yield (C1‐C5+BTX) of tetralin swollen L3 coal and L6B coal was larger than the raw coal at all temperatures, and larger by 50.6% and 32.6%, respectively, at 700 °C. The treatment of coal samples has a more pronounced effect on BTX yield than C1‐C5aliphatic hydrocarbons. BTX yield of tetralin treated L3 coals at 700 °C was 3.5 times higher while for L6B coal the BTX yield was 2.1 times higher than the raw samples. These significant increases in hydrocarbons yields can be explain in terms of the suppression of the cross‐linking reactions of coal fragments due to the penetration of tetralin in to the micropores of coal, as well as the effective H radicals transfer from tetralin to coal fragments du

ISSN:0009-4536    

DOI:10.1002/jccs.200400045

出版商:WILEY‐VCH Verlag    

年代:2004

数据来源: WILEY

摘要:

AbstractA highly sensitive, selective and rapid method for the determination of mercury based on the rapid reaction of mercury(II) with 5‐(p‐aminobenzylidene)‐rhodanine (ABR) and the solid phase extraction of the colored chelate with C18disks has been developed. In the presence of pH = 3.5 sodium acetate‐acetic acid buffer solution and Emulsifier‐OP medium, ABR reacts with mercury(II) to form a red chelate of a molar ratio 1:2 (mercury to ABR). This chelate was enriched by the solid phase extraction with C18disks and eluted the retained chelate from the disks with dimethyl formamide (DMF). The enrichment factor of 50 was achieved. In the DMF medium, the molar absorptivity of the chelate is 1.16 × 105L.mol−1.cm−1at 540 nm. Beer's law is obeyed in the range of 0.01˜3 μg/mL in the measured solution. The relative standard deviation for eleven replicated samples of 0.01 μg/mL level is 1.83%. This method was applied to the determination of mercury in tobacco and tobacco additives

ISSN:0009-4536    

DOI:10.1002/jccs.200400046

出版商:WILEY‐VCH Verlag    

年代:2004

数据来源: WILEY