CO2 evolution

Lawlor, D.W. Fock, H. (1975). Photosynthesis, photorespiratory CO2 evolution of water stressed sunflower leaves. Planta, 126, 247-58. 

Table III. Summary of Zero-order Rate Constants for the Isothermal Decomposition of MDI in terms of CO2 Evolution...

Bowker, 1993]. This is supported by the TAP reactor experiments since the maximum of the CO response curve occurs between 5.5-6.0 seconds, while the CO2 evolution occurs earlier between 4.5-5.0 seconds. It is also seen that both KOAc and Au enhance the formation of CO. This agrees with the earlier observations with the CO response curves, and supports the hypothesis that the secondary COj peak occurs from the conversion of CO to CO. ... 

Figure 3a. CO2 evolution from the reaction of a molecular beam of CO with oxygen predosed onto Rh(l 10) to a coverage of 0.7 monolayers at a crystal temperature of 540 K, showing low reactivity at high oxygen coverage.

III. SELECTIVE ION TRANSFER AT THE W/0 INTERFACE COUPLED WITH REDOX REACTIONS BETWEEN FLAVIN MONONUCLEOTIDE IN W AND A FERROCENE DERIVATIVE IN O AND CO2 EVOLUTION [19,21]... 

C. Estimation of Reaction Processes Involved in Electrolytic CO2 Evolution... 

After the reaction, freeze the solution and lyophilize to remove excess ammonium carbonate. Complete removal of volatile salt can be accomplished by re-dissolving the solid in warm methanol. After the completion of CO2 evolution, dry the saccharide by evaporation under vacuum. Removal of ammonium carbonate is essential, as the ammonium ion will interfere with any subsequent conjugations attempted with the glycosylamine derivative. 

Additionally, there is a growing use of off-gas analysis for measuring oxygen uptake, CO2 evolution and respiratory quotient measurement. 9, 641 However, this is not likely to find widespread use despite its usefulness unless the cost involved can be lowered. 

Studies by Saeger and Tucker, however, showed that CO2 evolution from degradation of dibutyl phthalate, DEHP and Santicizer 711 was 85-95% of the theoretical (9). Johnson and coworkers (10) later showed the evolution of from ring labeled DEHP. 

In DMFCs, methanol crossover and carbon dioxide gas management are critical issues that have be dealt with. Argyropoulos, Scott, and Taama [98] used a transparent fuel cell (fhe anode end plate was made out of acrylic) to visualize the CO2 evolution and management on the anode side. Both CFPs and CCs were used as anode DLs and it was observed that CFP (Toray carbon paper) was not a suitable material due to its poor gas removal properties. 

Figure 9. Temperature programmed oxidation (TPO) data showing CO2 evolution m/e = 44) of thermally deposited carbon from a Cu-Ce02-YSZ SOFC anode material after exposure to n-butane for 30 min (solid line) and a graphite powder sample (dashed line). (Reprinted with permission from ref 172. Copyright 2003 The Electrochemical Society, Inc.)...

Aerobic degradation of diethyl phthalate by acclimated soil and activated sewage sludge microbes was studied using an acclimated shake flask CO2 evolution test. After 28 d, loss of diethyl phthalate (primary degradation) was >99%, with a lag phase of 2.3 d, and ultimate biodegradation (CO2 evolution) was 95%. The half-life was 2.21 d (Sugatt et al., 1984). 

The ultimate biodegradability of a substrate, such as is depicted in Figure 4, may, in addition to oxygen uptake, be measured by disappearance of organic carbon, CO2 evolution and the formation of water. A radiotracer approach provides a more accurate determination and is the only feasible way of measuring the formation of water in the aqueous medium required for all metabolic processes. 

In a Gledhill-modified version (30) of the Sturm CO2 evolution shake flask test (31). the following nonionic ethoxylates were studied ... 

Another interesting feature of these CO2 evolution tests is that CO2 formation was still increasing for the linear alcohol ethoxylates but had reached a plateau for the branched nonionics. This suggests the formation of more bioresistant intermediates in the case of the branched surfactants. 

Figure 7. Ultimate biodegradation of nonionic surfactants by CO2 evolution.

The TG-FTIR analysis is thus consistent with the FT-IR analysis. The lower carboxyl group concentration brought about by preliquefaction at 350 C with a catalyst and solvent is accompanied by a decrease in CO2 evolution. The lower aliphatic concentration is accompanied by lower methane and lower tar at 350 C. 

Warning-. CO2 evolution. The sodium chloride-sodium carbonate solution was prepared from 185 g of sodium chloride and 110 g sodium carbonate dissolved in water to give a total volume of 1 L. 

Healy and Young (58) observed that the conversion of vanillic and ferulic acids under anaerobic conditions to methane and CO2 was nearly stoichiometric. More than half of the organic carbon could potentially be converted to methane. This could have great importance in studies where the degradation of phenolic compounds are studied by trapping the evolved CO2. Under anaerobic conditions, part of the normal CO2 evolution may be shifted to methane production with a subsequent low reporting of CO2 evolved, and an underestimation of microbial activity in the soil (51). 

ASTM D 6400-04 (homopolymers) >60% of theoretical CO2 evolution after 180 days ASTM D 6400-04 (heteropolymers) >90% of theoretical CO2 evolution after 180 days <10% of the weight of the specimen shall fail to pass through a >2-mm fraction sieve Density, dry solids, volatile solids, salt content, pH, content of elemental N, P, Mg, Ca Rate of germination and biomass >90% of blind value of compost without polymer... 

CO2, a blank compost inoculum without an additional carbon source (polymer sample) is simultaneously tested under the same conditions. The CO2 content of the exhaust air of both vessels is compared. After subtracting the CO2 evolution of the blank inoculum, the CO2 evolution related to the test polymer is monitored and plotted as a biodegradation curve (see Fig. 1). Finally, the activity of the compost inoculum in the controlled composting test is validated using a cellulose reference instead of the polymer. In Fig. 1, the biodegradation curve of Ecoflex is depicted. After 80 days, 90% of the theoretical CO2 evolution is reached. Thus, Ecoflex is ultimately biodegradable according to the ISO standard for compostable polymers (ISO 17088), which requires 90% of the theoretical CO2 evolution within 180 days. 

As shown in Table III, there is no significant difference in glucose uptake by cotton leaf discs immediately after exposure, but after 24 hr the uptake has nearly doubled. The percentage distribution of radioactivity in various extraction fractions is approximately the same in control and ozone-treated tissues. CO2 evolution from the added glucose is virtually identical in control and treated tissues. Isotope incorporation into the water soluble fraction, which would include amino acids, organic acids, and soluble carbohydrate, is also quite similar. Some distributional differences in the insoluble fraction are noted between... 

Soils amended with arsenic-contaminated plant tissues were not measurably affected in CO2 evolution and nitrification, suggesting that the effects of adding arsenic to soils does not influence the decomposition rate of plant tissues by soil microorganisms (Wang et al. 1984). The half-life of cacodylic acid is about 20 days in untreated soils and 31 days in arsenic-amended soils (Hood 1985). Estimates of the half-time of inorganic arsenicals in soils are much longer, ranging from 6.5 years for arsenic trioxide to 16 years for lead arsenate (NRCC 1978). 

Mendez-Roman and Cardona-Martinez [55] examined titanium dioxide catalysts with FTIR spectroscopy during the photocatalytic oxidation of toluene. Reaction intermediates, believed to be benzaldehyde and benzoic acid, were reported to accumulate on catalyst samples. This accumulation of intermediates was found to be reduced in the presence of gas-phase water. Mendez-Roman and Cardona-Martinez concluded that toluene appeared to be converted to benzaldehyde, which was then oxidized further to form benzoic acid. They suggested that the accumulation of benzoic acid led to the observed apparent catalyst deactivation. Other researchers, however, have argued that benzoic acid is unlikely to be the compound responsible for apparent deactivation in the photocatalytic oxidation of aromatics. For example, Larson and Falconer [43] concluded, based on higher CO2 evolution rates for benzoic acid relative to toluene during photooxidation, that benzoic acid was not sufficiently recalcitrant to be responsible for the deactivation seen with aromatic contaminants. 

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