Faculty Publications
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Item Role of ZSM5 catalyst and char susceptor on the synthesis of chemicals and hydrocarbons from microwave-assisted in-situ catalytic co-pyrolysis of algae and plastic wastes(Elsevier Ltd, 2022) Suriapparao, D.V.; Tanneru, T.; Rajasekhar Reddy, B.R.; Yerrayya, A.; Bhasuru, B.A.; Pandian, P.; Prakash, S.R.; Sankar Rao, C.; Sridevi, V.; Desinghu, J.The synergetic effect between algae biomass in co-pyrolysis with synthetic plastics (polypropylene (PP), polyethylene (PE), and expanded polystyrene (EPS)) was investigated in this work. Individual feedstock pyrolysis and co-pyrolysis of algae with PP, PE, and EPS were conducted at a constant supply of microwave energy (420 J/s). Pyrolysis char was used as a susceptor in all the experiments. The average heating rate was varied in the range of ∼50–60 °C/min for achieving the final pyrolysis temperature of 600 °C. In catalytic co-pyrolysis, the ZSM-5 catalyst was used for upgrading the physicochemical properties of pyrolysis oil. The use of catalyst promoted the excessive cracking of biomass in co-pyrolysis, leading to higher gas and coke residue comparatively. The viscosity, density, and flash point of oil obtained in catalytic co-pyrolysis were significantly reduced. While the oil obtained from individual pyrolysis of algae is rich in phenolic derivatives, and that of PP, PE has aliphatic hydrocarbons, and EPS has monoaromatic hydrocarbons as major compounds. The synergistic role of plastic and biomass in co-pyrolysis was observed in the formation of products and oil composition. The bio-oil from catalytic co-pyrolysis is composed of aliphatic oxygenates, aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, and phenolics. The chemicals and hydrocarbons present in the oil have a carbon number in the range of C6 to C30. An increase in carbon and hydrogen elemental composition was observed in bio-oil obtained from co-pyrolysis. © 2021 Elsevier LtdItem Exploring the protection of spray-pyrolysed tungsten oxide hydrophobic coating on stainless steel in a marine environment(Springer, 2024) Gautam, V.; Praveen, L.L.; Vardhan, R.V.; Mandal, S.Tremendous potential in the field of anti-biofouling coatings to prevent stainless steel (SS)-based underwater pipelines, sea vessels and other marine structures have been recognized to protect from biofouling, which is often initiated by algae attachment over the surface. In this work, hydrophobicity in spray-pyrolysed tungsten oxide (TO) coating on SS-316 substrate has been reported for the first time, via post-processing treatment using octadecyltrimethoxysilane (ODTMS) to induce self-assembled monolayer (SAM). Initially, structural and vibrational characteristics of ODTMS and ODTMS-treated TO (OTO) coating on SS were analysed using X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopies. OTO-coating depicted a water contact angle (WCA) of 121°, revealing its hydrophobic nature, with further affirmation from X-ray photoelectron spectroscopy (XPS). Durability of the TO-coating was explored using the scratch hardness (Hs) test at different loading conditions (5, 10 and 15 N). Biofouling study was conducted by culturing blue-green algae (BGA, Phormidium sp.) in an in-house laboratory setup for 40 days, using seawater (collected from the Arabian Sea, Karnataka). The SS, TO- and OTO-coatings were immersed for 14 days in a controlled sea-water environment in the laboratory with the presence of BGA. A comparative study on the areal-algae attachment was keenly analysed over SS-, TO- and OTO-coatings. This work can be projected as a promising application providing multi-dimensional solutions in creating scratch-resistant and anti-biofouling coatings on SS in the shipbuilding industry. © Indian Academy of Sciences 2024.Item Electrochemical performance and structural evolution of spray pyrolyzed Mn3O4 thin films in different aqueous electrolytes: effect of anions and cations(Royal Society of Chemistry, 2024) Adoor, P.; Hegde, S.S.; Badekai Ramachandra, B.R.; George, S.D.; Raviprakash, R.This work presents the impact of cycling in different cationic and anionic aqueous electrolytes on the electrochemical storage performance of the Mn3O4 thin film electrode prepared using the chemical pyrolysis method. Studies on the as-deposited electrode confirmed the formation of Mn3O4 phase. Extensive electrochemical analysis was performed using Na2SO4, NaCl, Li2SO4, K2SO4, and MgSO4 electrolytes to examine the influence of cations and anions on charge storage behaviour. Considerable changes were observed in the specific capacitances owing to different ionic sizes as well as hydrated ionic radius of the electrolyte ions. Accordingly, the electrode unveiled a good performance showing a specific capacitance of around 187 F g−1 at 0.5 A g−1 in K2SO4 electrolyte. Further, the electrode properties are examined after 500 CV cycles to trace the changes in the structural and morphological properties. X-ray diffraction (XRD) and Raman spectroscopic studies illustrate a partial phase transformation of electrodes from Mn3O4 to MnO2 irrespective of the electrolytes. These results are further corroborated with X-ray photoelectron spectroscopic (XPS) analysis where there was an increment in the oxidation state of manganese. It has been observed that the surface properties were significantly changed with cycling, as manifested by the wettability studies of the electrodes. The obtained results brings out the significance of electrolyte ions on the charge storage characteristics of Mn3O4 thin film electrodes in light of their possible application in electrochemical capacitors. © 2024 The Royal Society of Chemistry.Item Effect of Ni doping on the acetone vapor sensing performance of ZnO nanofibers(Elsevier Ltd, 2025) Prabhu, N.N.; Shivamurty, B.; Anandhan, S.; Rajendra, B.V.; Kulkarni, S.D.Nickel-doped zinc oxide (NiZ) nanofibres (NFs) were fabricated using sol-gel electrospinning (ES) technique followed by pyrolysis from an aqueous solution of polyvinyl alcohol/zinc acetate/nickel acetate tetrahydrate. The morphology of the NiZ NFs was analyzed using Scanning Electron Microscopy (SEM), which revealed a uniform and well-defined fibrous structure. X-ray diffraction (XRD) results indicated complete removal of the organic phase from NiZ NFs during pyrolysis. The structural analysis confirmed the incorporation of Nickel (Ni) into the Zinc oxide (ZnO) lattice without altering its wurtzite crystal structure. The optical properties and bandgap variations were evaluated using UV–visible spectroscopy, which indicated a bandgap narrowing with increasing Nickel doping. The Photoluminescence (PL) spectroscopy confirmed the presence of defect states and recombination processes in the NFs. The gas sensing performance was investigated by measuring the response to various analytes at a concentration of 50 ppm with varying operating temperatures. The results indicated that the highest response was observed for 5 w% NiZ NFs towards acetone vapors. The response and recovery time were recorded at 80 s and 60 s. The enhanced sensitivity is attributed to the optimal doping concentration, which significantly improves the surface reaction and charge carrier mobility. © 2024 The AuthorsItem Novel adsorption-based upgradation of end-of-life polypropylene pyrolysis oil using carbonised rice husk(Elsevier Ltd, 2025) Kailas, T.G.; A R, A.; Dutta, S.; Madav, V.Plastic waste management is a global issue, with end-of-life polypropylene (EoL PP) having significant contribution. Polypropylene degradation forms undesirable compounds in pyrolysis oil, reducing its quality and limiting its fuel usability. Pyrolysis offers a promising solution for converting plastic waste into valuable fuels; however, the presence of degraded materials necessitates an effective upgrading process to enhance the fuel quality. This study introduces an innovative ex-situ adsorption-based upgradation technique using carbonised rice husk (CRH), an abundantly available, sustainable and cost-effective biomass residue, to significantly improve the quality of pyrolysis oil derived from EoL PP. The upgradation process reduced sulphur content in polypropylene pyrolysis oil from 0.19 % to 0.02 %. The cetane index, a key fuel quality metric, rose from 43.83 to 55.25, enhancing combustion properties. Proton nuclear magnetic resonance showed an increase in paraffin content from 53.15 vol% to 60.81 vol%, improving energy content and combustion efficiency. Olefins and aromatics decreased, improving fuel stability and reducing emissions. GCxGC TOF-MS analysis revealed a decrease in oxygenates and an increase in diesel-range hydrocarbons, improving fuel quality and stability. This comprehensive study highlights the dual benefits of CRH in enhancing fuel quality and supporting circular economy practices, making a significant contribution to the development of sustainable fuel alternatives in the waste-to-energy conversion sector. © 2024Item Development of machine learning model for the prediction of selectivity to light olefins from catalytic cracking of hydrocarbons(Elsevier Ltd, 2025) Mafat, I.H.; Sharma, S.K.; Surya, D.V.; Sankar Rao, C.S.; Maity, U.; Barupal, A.; Jasra, R.Light olefins are the primary building block for the production of petrochemicals and polymers. Light olefins are largely produced from steam/catalytic cracking of naphtha or ethane/propane. Selectivity to light olefins is significantly dependent on the reaction conditions. In this article, several machine learning models are developed and tested to predict the selectivity of ethylene and propylene using seven input features. For this study, a total of eight ML models consisting of adaptive boost, extreme gradient boost, categorical boost, light gradient boost, decision tree with bagging, random forest, k-nearest neighbour, and artificial neural models are developed. The extreme gradient boost model gave the highest prediction accuracy for the ethylene selectivity, while the light gradient boost gave the highest R2 for the propylene selectivity. The SHAP analysis showed the input parameter's importance ranking for ethylene predictions as temperature > number of carbon atoms > Si/Al ratio > acidity > weight hourly space velocity > effect of diluent > number of hydrogen atoms. The importance ranking of input parameters for propylene selectivity was observed as weight hourly space velocity > acidity > temperature > Si/Al ratio > effect of diluent > number of carbon atoms > number of hydrogen atoms. © 2024 Elsevier LtdItem Comprehensive Characterization of Novel Jute Fabrics with Musa Paradisiaca Leaf Agro-Waste Based Micro Cellulosic Fillers Reinforced Epoxy Composites For Lightweight Applications(Korean Fiber Society, 2025) Indra Reddy, M.I.; Sethuramalingam, P.; Sahu, R.K.For lightweight, sustainable, high-strength products, hybrid bio-epoxy composites materials were the most excellent choice for the production industry. The investigation proceeds in developing a four-stacked sequence jute-woven mats reinforced with epoxy composite and added with micro-cellulose fillers. The extraction of micro cellulose from Musa paradisiaca plant leaf (MPPL) was carried out through a series of processes, including alkali treatment, acid hydrolysis, bleaching, and slow pyrolysis. The composite was fabricated using the conventional hand lay-up method and compression molding. The microcellulose was added to the stacked composite at varying weight percentages (0, 2.5, 5, 7.5, and 10%). Thermo-mechanical and water intake characterization were investigated using ASTM. The findings revealed that incorporating 5% MPPL cellulose into the jute-stacked layer sequence resulted in improved hardness (95 HRRW), tensile modulus (3407.69 MPa), tensile strength (79.74 MPa), flexural modulus (2195.752 MPa), flexural strength (56.87 MPa), and crystallinity index (72.7%). However, a reduction in impact strength (23.27 kJ/m2) was noted compared to the unfilled composite. The higher thermal degradation (480 °C) behavior of the filler-reinforced composite makes them a suitable material for applications in high-temperature environments. Fractographical morphology was also investigated to reveal the bonding behavior, voids formations, agglomeration of fillers, and fracture behavior. Thus, this distinguishable composite characterization will aid the manufacturing industries in producing high-strength biodegradable materials. © The Author(s), under exclusive licence to the Korean Fiber Society 2025.Item Mathematical Modeling of Fluidized Bed Magnetizing Roasting of Iron Ore Fines(John Wiley and Sons Inc, 2025) Sahoo, L.K.; Mantripragada, V.T.; Sarkar, S.The fluidized bed magnetizing roasting of low-grade iron ore fines is employed as a beneficiation technique in iron-making and steel-making industries. In the present work, the unreacted shrinking core reaction kinetic model is coupled with the two-fluid and kinetic theory of granular flow gas–solid flow model to simulate magnetizing roasting of hematite to magnetite in iron ore fines using a fluidized bed reactor. The model is validated with published experimental findings. Thereafter, the influence of different process parameters such as gas temperature, composition, velocity, and particle size on the reduction fraction and rate along with (Formula presented.) mass fraction and emission is studied. The reduction rate increases with gas temperature and (Formula presented.) mass fraction while it decreases with particle size. The (Formula presented.) emission increases with gas temperature, particle size, and (Formula presented.) mass fraction. However, the influence of gas velocity on these parameters is not significant. The reduction rate and time vary from 0.0010 to 0.0067 s?1 and 65 to 553 s, respectively, at a reduction fraction of 0.5. The (Formula presented.) mass fraction and emission range from 0.80 to 0.92 and from 0.63 to 4.14 g kg?1 ore, respectively. © 2024 Wiley-VCH GmbH.