Faculty Publications
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Item Enhancing Strength Properties of Hydroxyapatite Composites with Bentonite Clay(Taylor and Francis Ltd., 2025) Satish, P.; Hadagalli, K.; Nowl, M.S.; Siddeswara, R.; Kalikeri, S.; Mandal, S.The main inorganic component of human hard tissues is hydroxyapatite (HA, Ca10(PO4)6(OH)2) and the mechanical and biological performance of HA can be improved by incorporating clay minerals to create HA-clay composite scaffolds. This study demonstrates a high-strength biocomposite of HA and bentonite with a significant reduction of open porosity, considering bentonite clay for its biocompatibility. Prawn shells (Fenneropenaeus indicus - marine resource) were utilized as a sustainable source of calcium to synthesize high-purity HA through a wet-chemical process, offering an innovative approach to valorize bio-waste. HA-bentonite clay composites were made by compacting 10-40 wt% of bentonite clay with HA using uniaxial pressing, followed by sintering at 1100°C for 2 h. Characterization techniques like X-ray diffraction, Raman, Fourier transform infrared spectroscopy and field emission scanning electron microscopy verified the phases, structures, vibrational bonds and morphology of the synthesized materials. Energy dispersive X-ray spectroscopy and inductively coupled plasma mass spectrometry analysis were performed for elemental composition and heavy metal detection, respectively. The HA-bentonite (30 wt%) composite achieved an exceptional compressive strength of 155 MPa and an open porosity of 7%, surpassing bare HA. Adding 30% bentonite increased compressive strength six fold and decreased open porosity by 51% compared to bare HA. This novel approach to HA-bentonite scaffolds promises enhanced wear resistance and cellular proliferation in bone tissue engineering. © 2025 Indian Ceramic Society.Item Comprehensive utilization of crustacean wastes by chemical-catalytic transformations using levulinic acid as a sustainable platform chemical(Springer Science and Business Media Deutschland GmbH, 2025) C, P.N.; Nowl, M.S.; Mandal, S.; Dutta, S.Shell residues from seafood processing and aquaculture industries encounter significant challenges in waste management. There are many traditional and emerging applications of shell waste, but their enormous scale of production outpaces the utilization. This work reports the comprehensive utilization of shell waste by sequentially converting their major components into value-added products by selective chemical transformations. The pigments were extracted using ?-valerolactone (GVL), a biorenewable solvent produced from carbohydrate-derived levulinic acid (LA). The protein component was separated from shells under hydrothermal conditions with or without using any inorganic base. The calcite component was then reacted with LA and formic acid to form calcium levulinate and calcium formate, promising dietary supplements and chemical feedstock. Finally, chitin was converted into LA (30 mol%) under optimized conditions (150 °C, 4 h). Separation and value-addition of the components of crustacean exoskeletons demonstrated in this work are scalable, the products are marketable, and the catalyst used is recyclable. LA produced from chitin is used as the reagent and for synthesizing GVL for a closed-loop biorefinery. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.