Measurement specificity, nitrogen

The specific surface area of the fresh and used catalysts was measured by nitrogen adsorption method (Sorptometer 1900, Carlo Erba Instruments). The catalysts were outgassed at 473 K prior to the measurements and the Dubinin equation was used to calculate the specific surface area. The acidity of investigated samples was measured by infrared spectroscopy (ATI Mattson FTIR) by using pyridine (>99.5%, a.r.) as a probe molecule for qualitative and quantitative determination of both Bronstcd and Lewis acid sites (further denoted as BAS and LAS). The amounts of BAS and LAS were calculated from the intensities of corresponding spectral bands by using the molar extinction coefficients reported by Emeis (23). Full details of the acidity measurements are provided elsewhere (22). 

The surface area of the catalysts was measured by nitrogen physisorption (Sorptometer 1900, Carlo Erba). The fresh and regenerated samples were outgassed at 150°C and the spent samples at 100°C for 3 hours. The specific surface area was calculated with the Dubinin equation. 

Likewise, the Haul and Dtimbgen method of measuring specific surface areas through nitrogen adsorption has developed into an industrial standard [8]. 

The specific surface area was measured by nitrogen adsorption at -195 C. The cumene cracking reaction was conducted by pulse technique under the following conditions O.IO g catalyst, H, flow rate 75 ml/nin, pulse volume 1 ul. 

Similarly as for carbon materials, the maximum hydrogen uptake in different zeolites shows a good correlation with the BET specific surface area measured by nitrogen adsorption [73]. Beyond the specific surface area the interaction of hydrogen molecules with zeolites is strongly influenced by the type and the concentration of cations present in the framework channels. This is well reflected by, for example, the increase in the isosteric heat of adsorption in zeolites with increasing aluminum... 

A number of studies have measured DOC production from macroalgae and an estimated 30—45% of macroalgal production is released as DOM (e.g., Mann, 1982 Sieburth, 1969). Relatively httle is known, however, about release of N containing compounds specifically. Nitrogen release can take several forms including NH4, urea, DCAA, and a suite of different free amino acids (Tyler et ai, 2003). The high recovery of added, as either (96% recovery)... 

Specific surface areas of various carbonized materials were measured by nitrogen gas adsorption with BET methods using an automated surface area analyzer (micro-track type 4200, Nikkiso, Japan). For mesopores whose diameter were less than SO nm, the surface areas and pore volumes were measured by carbon dioxide adsorption. The carbon dioxide adsorption at 298 K was measured with Bellsorp 28 (BEL Japan). The pore volume was determined using Dubinin-Radushkevich equation [4], and the surface area was determined by Medek s method [S]. 

Specific surface area and pore volume distribution were measured by nitrogen adsorption in an Accusorb 2100E Micromeritics adsorption analyzer. The data were interpreted using the BET equation, assuming a cross-sectional area of 16.2 for Nj. 

Elemental analysis was carried out by inductively coupled plasma using a TJA IRIS-HR spectrometer after dissolving the compounds in a minimum amount of hydrochloric acid. X-ray diffraction spectra (XRD) were recorded on a Siemens D-500 diffractometer with a graphite-filtered CuKa radiation (1,5405 A). ESR spectra were recorded at 77 K using an ER 200 tt Brucker spectrometer. An ASAP 2000 Micrometries apparatus measured specific surface areas by nitrogen adsorption at 77K after degassing the samples in situ at 353 K for 4h. 

Specific surface areas, mesopore volumes and pore distributions were determined from nitrogen adsorption data at 77 K using a BELSORP 28SA (Nippon BEL. Co.). All the samples were outgassed at 413 K for 3 h before measuring the nitrogen adsorption. The X-ray powder diffraction patterns were obtained on a MAC Science MXP-18 instrument using Cu-Ka radiation with a Ni filter. 

The specific surface area of vanadium pentoxide coated membrane was 1.1 m /g, and the average pore diameter of it, measured by nitrogen adsorption, was 30A. Macro pores identified by mercury intrusion did not exist, and the porosity was approximately 9%. From results of isotherm adsortion-desorption curve,as shown in Fig.2, V2O5-coated membrane has slit-shaped pore structure. Hence the pores mostly exist between the V2O5 layers, and the surface of those are nearly non-porous. 

Total Nitrogen, The fuel samples were pyrolyzed/combusted at 1000°C in a flow of argon/oxygen and the chemiluminescence for the reaction of NO with ozone measured (4. Types of specific nitrogen compounds found are discussed elsewhere in this book (5). 

Specific surface area measurements and nitrogen isotherm adsorptions were determined on a Micromeritics ASAP 2405, with a pretreatment of 3 h at 150°C under secondary vacuum, to avoid thermal degradatation of grafted ligands. Castaing microprobe analyses were recorded on a JEOL JXA 8800 in order to confirm homogeneous distribution of ligands and active species. 

Four commercial samples of activated charcoals were used in most of the work, the specific surface areas ranging from 3.5 X 10 to 1.3 X 10 cm.Vg., as measured by nitrogen adsorption. It must, however, be made clear that the data on surface coverage quoted in the paper are based on effective areas determined by the use of the adsorbate used in the experiment. These effective areas were always less than the areas determined by nitrogen ad-... 

The total concentration of protein may be measured by nitrogen, or by specific gravity or refractive index. The method is generally applicable to sera and to serum protein solutions. Care should be taken to check the possibility of absorption by nonprotein constituents of serum which in some diseases such as cirrhosis of the liver may be considerable. The presence of such substances is shown by a marked fall in absorption of the serum after dialysis. 

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