applications in environmental analysis

... preparation techniques are received increasing attention in the past few decades since they are critical in an analytical procedure Along with the trend in miniaturization in analytical chemistry, microextraction ... stirred aqueous sample containing the analytes of interest After extraction, the extraction droplet is withdrawn back into the microsyringe and introduced to instrument for analysis directly SDME ... especially in trace analysis [6] The quality of sample preparation largely determines the success of an analysis from complex matrix Despite advances in instrumental techniques, complete non-invasive...

Ngày tải lên: 09/09/2015, 10:18

... thicker coating However, the main drawback of this technique is that the introduction and desorption of extracting membrane in the GC injection liner is quite complicated PC-HFME was developed in our ... worldwide against insects, fungi and weeds They are increasingly used instead of organochlorine and organophosphorous pesticides due to their lower environmental persistence However, since they ... 1.7 ml/min The following temperature program was employed: initial temperature of 60 °C for min; increased at 10 °C/min to 260 °C, held for The injector temperature was 270 °C and all injections...

Ngày tải lên: 14/09/2015, 11:45

... Embedding) and are used mainly in intracellular sensing [23] In this kind of nanosensor, the fluorescent dye is encapsulated within an inert matrix that protects the dyes from interferences in the ... simultaneously identifying pathogens (like cholera toxin or ricin) in water The FRET principle was also used to build a maltose biosensor [20,21] The sensing mechanism involved using semiconductor ... of concentric cylinders a few nanometres in diameter and up to hundreds of micrometres in length These cylinders have interlinked hexagonal carbon rings They were discovered in 1991 by the Japanese...

Ngày tải lên: 20/03/2014, 13:05

... transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage and retrieval system, without permission in writing ... remediation, (4) waste minimization/recycle Each contribution has either a theoretical significance or practical utility or both Interfacial Applications in Environmental Engineering is an invaluable resource ... Uddin and Sakata, in the final chapter, consider the recycling of halogen-containing polymers, notably PVC A thermal degradation of PVC-based waste will generate a range of chlorine-containing...

Ngày tải lên: 11/08/2014, 12:21

... increase in N2 , CO2 , and H2 O concentrations The former reflects an increase in the conversion of NO and C3 H6 reactants; the latter indicates an increase in product formation To gain an insight into ... was placed in the IR beam path inside the IR reactor cell, and the others were broken down into flakes and placed in the close vicinity of the IR beam path The MS determined the changes in the concentration ... vicinity of the catalyst sample in the infrared reactor cell, as shown in the inset of Figure One-hundred-mg catalysts were pressed into three to four thin disks, each weighing 25 mg, by a hydraulic...

Ngày tải lên: 11/08/2014, 12:21

... observed that the increase in Cu loading in the PILC-based catalysts resulted in an increase in CuO aggregates (Table 3) In a study of the reducibility and catalytic activity in propane oxidation ... species in Cu-MFI-based catalysts resulted in a substantial increase in propane conversion as well selectivity to CO2 This fact would explain the decided decrease in NO conversion with increasing ... but in this case the corresponding maximum appeared at 523 K It was observed that increasing the copper loading increased NOx conversion until the copper loading reached 116% ion exchange in the...

Ngày tải lên: 11/08/2014, 12:21

... the Π bonding in the majority spin and the LUMO is the Π antibonding in the minority spin (b) SO (singlet, C 2v ) (c) SO (singlet, C 3v ) TM Copyright n 2003 by Marcel Dekker, Inc All Rights ... are shown in Figure 1a From the frontier orbital point of view [20], these single-particle orbitals should be considered the most active ones in most kinds of chemical reactions, including surface ... in engine-out exhaust affected the reactivity of the three-way catalysts It was demonstrated that by increasing the sulfur concentration in gasoline from zero to 0.03 wt%, one observed lowering...

Ngày tải lên: 11/08/2014, 12:21

... determine exactly whether it is via adsorbing and cracking sulfides in the feed or via adsorbing and cracking those in the gasoline produced For FCC, most cracking reactions take place at the instant ... 2003 by Marcel Dekker, Inc All Rights Reserved Gasoline Desulfurization via Catalytic Cracking 79 Cracking of Sulfides in FCC Gasoline over a Catalyst of Gasoline Tracking Desulfurization USY ... obtained from on-line pulse-reaction chromatography Ten grams of thiophene/n-heptane or the gasoline distillate was pumped into the reactor within Sulfides in the liquid product collected in the...

Ngày tải lên: 11/08/2014, 12:21

... recorded in this study Exchange with the zeolitic indigenous Naϩ ions and siting within the aluminosilicate framework must necessitate some weakening of the ion–dipole interactions between the in- going ... with cations in external solution An increase in exchange temperature enhanced HM removal by reducing the solvation coating and kinetic diameter of the ingoing HM cation, facilitating exchange ... Dekker, Inc All Rights Reserved 98 Keane linked by sharing rings of 12 tetrahedra (free diameter ϭ 0.7–0.8 nm); (2) the less accessible sodalite units, which are linked through adjoining rings...

Ngày tải lên: 11/08/2014, 12:21

... effective in the gold heap leachate solutions by selectively reducing mercury levels from an initial concentration of 34.5 ppm to 0.014 ppm within 10 minutes and to 0.008 pm within 15 minutes [20] In ... is initially titrated into aqueous divalent heavy metal solutions The pH decline associated with the precipitation of the divalent metals (M2ϩ) is explained by the following reaction involving ... Stoichiometric Stoichiometric 10% dose increase 10% dose increase 10% dose increase Stoichiometric Stoichiometric Stoichiometric 10% dose increase 10% dose increase 10% dose increase Stoichiometric Stoichiometric...

Ngày tải lên: 11/08/2014, 12:21

... strong inhibitory effect of water content can be interpreted as water-aided interruption of inter- and intramolecular contacts in the soil upon oil sorption An increase in K d when increasing the ... which could be interpreted as a limiting saturation in the instantaneous sorption The data for sample I lie slightly below the three points observed for sample III, indicating a retarding effect ... main interaction is then with mineral surfaces, which may cause consequent partitioning; therefore, the reduction in soil clay contents results in an inhibitory effect on the oil sorption to mineral...

Ngày tải lên: 11/08/2014, 12:21

... driven mainly by hydrogen binding interactions, e.g., the presence of certain surface functionalities: O, OH, and Cl can act as nucleation sites and/ or adsorption sites, resulting in the formation ... of a constant flow is energy demanding, and flow disruptions/plugging can impair an effective processing of contaminant streams A significant improvement in existing activated carbon–based VOC treatments ... of an activated carbon was intimately linked to the surface acidity of the adsorbent [92] Carbon materials in their pristine form are hydrophobic in nature but, following oxidative treatment, can...

Ngày tải lên: 11/08/2014, 12:21

... given data point and the two data points preceding and following the central point Average effective pQ values can then be calculated by averaging the values obtained from twice solving two equations ... adjacent data points) This suggests two possible methods for improving the accuracy in estimating pQ values with these methodologies: (1) increasing the number of data points by decreasing the quantity ... averaging the values tended to minimize extreme estimates of Q a behavior The procedure of solving Eq (9) twice with three consecutive data points and averaging the results will be used in this...

Ngày tải lên: 11/08/2014, 12:21

... Destroying VOCs 217 to water vapor, and supporting Pt on a hydrophobic support such as a fluorinated carbon can reduce the inhibiting effect of water, but inhibition is still observed [13] In combination ... expected to be at a minimum The oxidation activity was maintained after many thousands of pulses, indicating that lattice oxygen was the active species Second, analysis of the TAP data indicated that ... catalyst in flowing 4% water/air over the temperature range 100–600°C is shown in Figure The results indicated that even at 600°C no change in the initial U O phase occurred Some thermal broadening...

Ngày tải lên: 11/08/2014, 12:21

... has been viewed in terms of an E1 elimination mechanism, where the chlorine component interacts with the catalyst with electron withdrawal, weakening the C– Cl bond and inducing intermediate carbocation ... predominant in the case of the trichlorobenzenes, in keeping with the deactivating effect of the additional Cl substituent The attractive feature of catalytic hydrodechlorination in terms of treating ... hydrodechlorination over incineration Incorporation of catalytic hydrodehalogenation units in distillation/separation lines is envisaged with a HCl recovery unit, where HCl absorption into an aqueous...

Ngày tải lên: 11/08/2014, 12:21

... potential gradient that has formed from band bending (Fig 2) This band-bending phenomenon assists in separating the eϪ /hϩ pairs and in reducing recombination rates For TiO2, the surface holes oxidize ... with the resulting arrays being distinguisable by different-size particles and different interparticular spacing In Figure 8, each island is approximately nm high and about 140 nm in diameter, ... low-coordination surface atoms of unique local geometry and bonding, which may also lead to substantial surface relaxation, reconstruction, or faceting In TiO2 single crystals, these low-coordination...

Ngày tải lên: 11/08/2014, 12:21

... that is less strain on the rod bearings and main bearings, resulting in longer engine life VII LOOKING AHEAD Table lists the main findings and benefits reported for S.I and diesel engines There are ... reduced cylinder liner wear and less oil use Gives improved ring sealing: preventing blowby Leads to less pitting of valve and seats: maintaining performance longer Keeps engine cooling efficiency: ... eliminated, having been converted to useful energy in the engine To achieve this would be a significant contribution to environmental engineering, and the way to so involves the application of interfaces...

Ngày tải lên: 11/08/2014, 12:21

... are two main alternatives in treating municipal and industrial plastic wastes: energy recycling, in which plastics are incinerated, with some energy recovery, and mechanical recycling, in which ... studies using solid catalysts involve pure zeolites, a crystalline, porous aluminosilicate made up of a linked framework of [SiO4]4Ϫ and [AlO4]5 edge-sharing tetrahedra, or amorphous silica alumina ... and interconnecting sinusoidal channels that increase shape selectivity in ˚ petrochemical reactions Zeolite Y has larger pore openings of 7.4-A diameter ˚ with three-dimensional connecting cavities...

Ngày tải lên: 11/08/2014, 12:21

... chlorine by coprocessing catalysts or absorbent during the pyrolysis [20–22] All of these efforts succeed to some extent in removing chlorine content in PVC-containing plastics before or during ... was also obtained by plotting the content of Cl-containing compounds in the MX/ PVC oil against the carbon number of each normal paraffin (equivalent to boiling points) [33] The chlorine compounds ... effective in the destruction or reduction of dioxins from municipal solid-waste incineration products [27] In ABS degradation, iron oxides showed a catalytic effect in decomposition of N-containing...

Ngày tải lên: 11/08/2014, 12:21

... However, degeneracy in primers can lead to preferential binding of targets (Isenbarger et al., 2008) Although inosine modifications not result in degeneracy, the stability of inosine pairing was found ... aid in subsequent identification of the fecal contamination sources in unknown samples The method is then applied to blind samples and environmental waters, and the findings are validated against ... of fecal contamination in water bodies This chapter demonstrates the use of HOPE to identify the origins of contamination in feces, contaminated aqueous samples, blind samples and environmental...

Ngày tải lên: 14/09/2015, 08:47