• Hysteresis in sorption - XII. Influence of the temperature of activation of silica gel on the hysteresis effect

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      https://www.ias.ac.in/article/fulltext/seca/025/02/0174-0180

    • Keywords

       

      Hysteresis Loop; Activation Temperature; Residual Water; Saturation Pressure; Cavity Volume

    • Abstract

       

      The effect of the activation temperature of silica gel on the hysteresis effect has been studied. Sorption and desorption of water vapour at 30°C. have been conducted on gels activated at 35° C., 70° C., 140° C., 300° C., 500° C. and 1000° C.

      All the gels gave permanent and reproducible hysteresis loops. A marked variation however, was noticed in the total sorptive capacity and the area of the loop.

      The results indicate that from 35° C. to 140° C., there is a decrease in the capillary space in the gel but from 140° C. to 500° C., the capillary space remains practically unaltered. Whereas, above 500° C., the gel suffers structural change, the capillaries collapse and there is a marked decrease in the total capillary volume.

    • Author Affiliations

       

      T Krishnappa1 2 K Subba Rao1 B Sanjiva Rao1

      1. Department of Chemistry, Central College, Bangalore, S. India
      2. University of Sheffield, Sheffield
    • Dates

       
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