Desiccant Properties Comparison of Natural Bio-polymers

Alfred Antony Christy, Thilini Nisansala Rathnaweera and Kalana Dasunpriya Halanayake

Background and Objective: Desiccants are substances used in the dehumidification process which is vital in order to avoid the degradation of materials. Silica gel is the most prominent type of desiccant used and today the world has developed an interest in bio-polymers due to certain demerits of silica. Hence this study was conducted to investigate the desiccant properties of the four commercial flours wheat, corn, potato and gram and to compare them with the common silica gel desiccant. Materials and Methods: The bio-polymers were dried under vacuum at 120°C and were studied over time using Near-Infrared spectroscopy for their-OH combination peak which appears at around 5200 cm^–1 and the derivative spectra were analyzed to recognize the specific-OH groups involved in the hydrogen bonding process. Further, the gravimetric analysis was used to study the rate of adsorption and their long term efficacies were detected using data loggers. Results: The results clearly indicated that adsorption of water occurs at C1, C2+C3, C4 and C6-OH groups for wheat and corn flour while potato and gram flour showed only three peaks attributing to C1, C2+C3 and C6-OH. Further, it was observed that C1 and C2+C3-OH groups have a similar and the highest rate. Conclusion: The rates of adsorption of all flours were greater than both analytical grade and commercial silica while corn flour was found to be an outstanding desiccant compared to conventional silica desiccant.

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