• P-ISSN 0974-6846 E-ISSN 0974-5645

Indian Journal of Science and Technology


Indian Journal of Science and Technology

Year: 2013, Volume: 6, Issue: 1, Pages: 1-7

Original Article

Freeze-Drying Kinetics in Synthesis of Biological Hydroxyapatite-Supported Catalyst


Kinetics of freeze-drying for the preparation of high performance bone-derived-hydroxyapatite (BDHAp) supported iron catalyst has been experimentally evaluated and modeled using standard drying models. The BDHAp was economically derived from Rohu fish (Labeo rohita) bone, which is considered as a municipal solid waste (MSW). After wet-impregnation of Fe2 (SO4 )3 .H2 O on BDHAp, the precipitated mass was freeze-dried using three types of radiation viz. grey body radiation (GBR), infrared radiation (IRR) and tungsten halogen lamp radiation (THLR).Freeze-drying kinetics for all the different heating systems were evaluated and compared with standard drying models. THLR-assisted-freeze-drying (THLRAFD) rate was found maximum among all the thermal radiation. Midilli model was found to corroborate the experimental freeze-drying kinetics of THLRAFD operation. The acidity of the catalysts prepared through THLRAFD (10.27, 10.36 and 11.21 mmol KOH/g catalyst) was found higher than their air-dried counter parts (8.14, 9.01 and 9.60 mmol KOH/g catalyst) corresponding to 65, 75 and 85°C drying temperatures at 1.75 Fe2 (SO4 )3 .H2 O to BDHAp weight ratio. The prepared Fe-BDHAp catalyst developed through THLRAFD possessed appreciable acidity making it suitable for application as an efficient heterogeneous acidic catalyst.
Keywords: Freeze-drying kinetics, tungsten halogen lamp radiation, biological hydroxyapatite-supported iron catalyst


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