Activation heat treatment effects

Study of the temperature dependence of the salt and water permeabilities through heat treated PVA membranes indicates that the heat treatment effect is expressed mainly in changes in permeability activation energies. The activation parameters for water and salt permeability of PVA membranes following various treatments are presented in Table IV. It is evident that the salt permeability activation energy is increasing about 2-3 times as... 

Bezerra C, Zhang L, Liu H, Lee K, Marques A, Marques E, Wang H, Zhang J, (2007). A review of heat-treatment effects on activity and stability of PEM fuel cell catalysts for oxygen reduction reaction Journal of Power Sources 173 891-908 Blesl M, Fahl U, Ohl M, (2004). HochtemperaturbrennstofFzellen und deren Kostenentwicklung. BWK, 56 72-56... 

Bezerra CWB, et al. A review of heat-treatment effects on activity and stability of PEM fuel cell catalysts for oxygen reduction reaction.) Power Sources 2007 173(2) 89f-908. 

The catalytic activity and stability of the M-N4 macrocycle modified CNTs, especially in acid electrolyte, can also be enhanced by heat treatment processing [138, 141, 145]. Most heat treatment studies reported an continuous enhancement effect on the catalytic performance of the M-N4 macrocycle modified CNTs with the increase of annealing temperature up to 800 °C [138, 141, 144]. Kruusenberg et al. compared heat treatment effects on CoPc, FePc, CoP, and FeP modified multi-walled carbon nanotubes [141]. It was shown that the MP modified CNTs heat- treated at 800 °C exhibited higher ORR activity than the MPc modified CNTs [141]. 

The combination of chemical activation (heat treatment by sulfuric acid) and physical activation (by steam) has been investigated [64]. The impregnation coefficient of 28% was found to be particularly important. An increase in the activatimi temperature enhanced the surface area and pore volume in addition to increasing bum-off. With a yield of 15%, a maximum BET surface area of approximately 1,000 m /g was obtained. The adsorption of methylene blue and iodine were also examined. The effects of soaking the PET precursors with chemicals (in particular sulfuric acid) have also been investigated elsewhere [65,66]. 

Sorbate combined with mild heat has a synergistic effect with regard to microbial destmction thus, in the presence of 0.025—0.06 wt % sorbate, products such as apple juice, peach and banana sHces, fmit salads, and strawberries can be treated with less severe heat treatments to extend shelf life (119,120). Sorbates increase the heat sensitivity of various spoilage fungi under varying conditions of pH and water activity (121—124). A similar synergistic effect has been reported for the combination of sorbate with irradiation (125). 

Pet Foods and Commercial Animal Feeds. Eor many years, it has been known that stable, long-shelf-life, intermediate-moisture pet foods can be prepared through the use of 0.1—0.3 wt % sorbates. In these products, the antimicrobial effectiveness of sorbates is enhanced by a combination of moderate heat treatment, pH adjustment, and reduced water activity via humectants such as propylene glycol, or by adjusting sugar and salt content. These techniques have been reviewed extensively (138,139). 

The important (3-stabilizing alloying elements are the bcc elements vanadium, molybdenum, tantalum, and niobium of the P-isomorphous type and manganese, iron, chromium, cobalt, nickel, copper, and siUcon of the P-eutectoid type. The P eutectoid elements, arranged in order of increasing tendency to form compounds, are shown in Table 7. The elements copper, siUcon, nickel, and cobalt are termed active eutectoid formers because of a rapid decomposition of P to a and a compound. The other elements in Table 7 are sluggish in their eutectoid reactions and thus it is possible to avoid compound formation by careful control of heat treatment and composition. The relative P-stabilizing effects of these elements can be expressed in the form of a molybdenum equivalency. Mo (29) ... 

Shin, S,. Jang, J., Yoon, S. H. and Mochida, I., A study on the effect of heat treatment on functional groups of pitch-based activated carbon fiber using FTIR, Carbon, 1997,35(12), 1739 1743. 

Modification techniques for activated carhon were used to increase the removal capacity by surface adsorption and to improve the selectivity to volatile organic compounds (VOCs). Modified activated carbons (MACs) were prepared by modifying the purified activated carbon with various acids or bases. The effects of adsorption capacity and modified contents on the textural properties of the MACs were investigated. Furthermore, VOC adsorption and desorption experiments were carried out to determine the relationship between the adsorption capacity and the chemical properties of the adsorbents. High adsorption capacity for the selected VOCs was obtained over lwt%-H3P04/AC (lwt%-PA/AC). As a result, MAC was found to be very effective for VOC removal by adsorption with the potential for repeated use through desorption by simple heat treatment. 

Effect of heat treatment on PG inhibitor activity Suitable aliquots of D. maculata stem inhibitor were kept in a boiling water bath for various periods of time, cooled quickly and assayed for residual PG inhibitory activities. 

Zhang L, Lee K, Zhang JJ. 2007. The effect of heat treatment on nanoparticle size and ORR activity for carbon-supported Pd-Co alloy electrocatalysts. Electrochim Acta 52 3088-3094. 

Szanyi et al., using again in situ IR-TPD coupled skills, studied the effect of acid sites on the catalytic activities of a series of H+-modified Na-Y zeolites in the non-thermal plasma assisted NO reduction reaction using a simulated diesel engine exhaust gas mixture. The acid sites were formed by NH ion exchange and subsequent heat treatment of a NaY zeolite. The catalytic activities of these H+- modified NaY zeolites... 

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