Faculty Publications
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Item Activated carbon-based dye-sensitized solar cell for development of highly sensitive temperature and current sensor(Institute of Physics Publishing helen.craven@iop.org, 2019) Dasari, K.K.; Gumtapure, V.Activated carbon was produced from coconut shells using steam activation method. The process followed by intermediate pyrolysis performed at 575° C. The production yields end products as carbon, biofuels and gases. The developed activated charcoal is implemented as counter electrode in demonstrating Dye Sensitised Solar Cell using naturally available sensitizer. In addition, Dye Sensitised Solar Cell based current and temperature sensors were developed for highly remote optoelectronics applications. Anthocyanin dye extracted from pomegranate juice generated maximum current of 10 mA cm-2. The characteristics of the cell was performed with different optic filters wavelength ranging 400-650 nm and the maximum efficiency was developed for wavelength of 445 nm. © 2019 IOP Publishing Ltd.Item Experimentation and Prediction Analysis on the Mechanical Performance of Fish Scale and Coconut Shell Powder-Based Composites(Taylor and Francis Ltd., 2022) Lokesh, L.; Shanmugam, B.K.; Mayya D, S.; B.p, P.; Naveen Kumar, N.; Hanumanthappa, H.In India, the utilization of natural fibers for developing new composites with desirable properties has been increasing from the last decade. Bio-waste such as fish scale and coconut shell (CS) powder was utilized to develop natural fiber-based composites in the present work. Three composite specimens, i.e., 30 wt% fish scale (FS), 30 wt% CS powder (CS), and 5 wt% fish scale (FS)+ 5 wt% CS powder specimen, were developed. The tensile, flexural, and impact strength testing was carried out on each specimen. A comparative study was drawn between the test results of the specimen. The experimental results showed that the CS powder-based composites yield improved mechanical properties compared to the fish scale-based composites. Furthermore, a quadratic and cubic mathematical model was developed on the experimental results of tensile and flexural testing for each specimen. The regression results show that the cubic regression model yields better prediction results than the quadratic regression model for all the composite specimens. The experimental results showed that the largely available fish scale and CS powder could be used to produce biowaste-based value-added material that provides a sustainable and eco-friendly approach. © 2021 Taylor & Francis.Item Role of coconut shell biochar and earthworm (Eudrilus euginea) in bioremediation and palak spinach (Spinacia oleracea L.) growth in cadmium-contaminated soil(Academic Press, 2022) Noronha, F.R.; Manikandan, S.K.; Nair, N.The contamination of soil with heavy metals is known to affect the yield the soil fertility, which in turn affects the growth of agricultural crops. This study investigates the role of coconut shell biochar (CSB) and earthworms (Eudrilus euginea) in the bioremediation and growth of Palak spinach (Spinacia oleracea L.) in cadmium (Cd) contaminated soil. The soils were amended with different combinations of CSB and earthworms and incubated for 35 days. Later, the soil samples were analyzed for the changes in the soil properties, soil enzyme activity, and heavy metal contents. It is observed that the treatments with both CSB and earthworms resulted in the improvement of soil properties and soil enzyme activity which was directly related to soil fertility. Meanwhile, the maximum removal of 94.38% of total Cd content in the soil was obtained for the soil sample contain both CSB and earthworms. The improved soil properties resulted in a higher germination percentage of Spinacia oleracea L. seeds in the Cd contaminated soil. © 2021 Elsevier LtdItem Model Footing Tests and Analytical Studies on Clayey Soil Bed Reinforced with Coconut Shell Mat(Springer Science and Business Media Deutschland GmbH, 2022) Kolathayar, S.; Gadekari, R.S.The cellular confinement systems are becoming popular in ground improvement because of their efficiency in improving the bearing capacity of soil due to the lateral confinement effect. The commercially available geocells are made from polymer materials and they are costly. This study presents the performance evaluation of coconut shell mat as a cellular confinement system in clayey soil. It is the first of its kind application of coconut shells for soil reinforcement through a lateral confinement mechanism. This soil reinforcement system using coconut shells is termed “Geococoshell” by the authors. A series of model plate load tests were conducted on unreinforced soil, soil reinforced with High-Density Polyethylene (HDPE) geocells, and soil reinforced with coconut shell mats to evaluate the performance of coconut shell mat reinforced soil bed. The results of the experiments showed that coconut shells reinforced clayey soil improved bearing capacity up to 1.5 times compared to HDPE geocell reinforced clayey bed. The effect of different patterns of placing coconut shell mat was also studied and discussed in the paper. The analytical studies have been conducted considering the reinforcement mechanisms of coconut shell mat embedded in the soil bed. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Item Upgrading of coconut shell-derived pyrolytic bio-oil by thermal and catalytic deoxygenation(Taylor and Francis Ltd., 2024) Dasari, K.K.; Gumtapure, V.; Dutta, S.The objective of this study is to upgrade the pyrolysis oil obtained from coconut shells via thermal deoxygenation and catalytic hydrodeoxygenation (HDO) and compare the elemental properties of the upgraded bio-oil samples. The crude coconut shell pyrolysis oil (cr-CSPO) was obtained in 33% yield by intermediate pyrolysis (575°C) of pre-dried coconut shells. The higher heating value (HHV) of cr-CSPO was found to be 16.46 MJ/Kg. The thermal and catalytic upgrading was done at 250°C, 30 bar of hydrogen pressure, a reaction time of 3 h, and a stirring speed of 350 rpm. In the case of catalytic upgrading, 10% Pd/C (10 wt% of cr-CSPO) was used as the catalyst. Thermally heating the cr-CSPO under identical conditions without the catalyst provided oil of HHV 25.94 MJ/kg. Catalytic HDO of the cr-PCSO showed a noticeable increase in the HHV value to 30.57 MJ/kg. The results indicate significant improvement in the combustion properties of cr-CSPO by thermal treatment and more so by the catalytic HDO chemistry. © 2020 Taylor & Francis Group, LLC.Item Experimental investigation on sludge conditioning and dewatering using an agricultural biomass coupled with resource recovery(Academic Press, 2024) Chopade, G.; Devatha, C.P.In this study, the effect of modified areca husk fibre biochar (MAFB-AlCl3) on dairy sludge conditioning and dewatering along with raw and modified coconut shell biochar (MCSB-FeCl3) was investigated. Further, MgO impregnated biochars of areca husk fibre and coconut shells was carried out to evaluate the performance on phosphate recovery from the diary sludge. The enhancement in sludge dewatering with MAFB-AlCl3 were evaluated experimentally and significant reduction of capillary suction time (CST) (51.6 %), moisture content (18%), zeta potential (1.3 mV) and increased settleability (32.7%) were observed. The sludge conditioning parameters namely dosage (% of dry solids (DS)), rapid mixing time (RMT), slow mixing time (SMT) were optimized by response surface methodology for the modified biochars. Optimum CST (31.51 s) was obtained at dosage (50 % of DS), RMT (9.89 min) and SMT (17.23 min). Results of batch study for phosphate recovery by MgO impregnated biochars (MgB) was found to be 96.6 % and 100 % by MgB of areca husk fibre (MgAFB) and coconut shells (MgCSB) respectively. The morphological characteristics and elemental distribution using field emission scanning electron microscopy (FE-SEM) & energy dispersive X-ray spectroscopy (EDS) reveals the structural change in the sludge particles for the modified biochars as well as for sludge. Hence MAFB-AlCl3, MgAFB and MgCSB is proved to be suitable and an effective candidate for sludge conditioning and dewatering coupled with phosphate recovery in handling the diary sludge. © 2024 Elsevier LtdItem Long-lasting Bacillus safensis CG1 and Bacillus cereus DKBovi-5 based coconut shell biochar spore composites as self-healing additives for bio-mortar production(Elsevier B.V., 2024) Anoop, P.P.; Palanisamy, T.; Gupta, A.; Gopal, M.The major challenge in the production of bio-mortar lies in the effective storage of immobilised bacterial carriers. This study explores the effective storage and use of coconut shell biochar as a carrier for bacterial spores. Bacillus safensis CG1 and Bacillus cereus DKBovi-5 were immobilised in biochar and stored at 4 °C and 25 °C for 120 days. The storage at 4 °C showed enhanced viability, and Field Emission Gun Scanning Electron Microscopy studies revealed the firm adherence of bacterial spores within the biochar pores, attributed to the secretion of extracellular polymeric substances. Biochar-based spore composites stored at 4 °C were subsequently added as self-healing additives in mortar. Mechanical, self-healing, and microstructural evaluations demonstrated that the biochar with Bacillus cereus DKBovi-5 exhibited superior results. Cracks up to 0.888 mm were healed within 56 days, indicating enhanced healing efficiency, as supported by higher ultrasonic pulse velocity and a lower resistivity ratio. Brunauer-Emmett-Teller 20-point adsorption-desorption analysis showed that biochar with Bacillus cereus DKBovi-5 mix possessed the smallest pore width of 3.086 nm. Additionally, Field Emission Gun Scanning Electron Microscopy- Energy Dispersive X-ray Spectroscopy, X-ray Diffraction, and Fourier Transform Infrared Spectroscopy analyses confirmed the formation of biogenic calcium carbonate in the healed regions. Overall, the biochar composite with Bacillus cereus DKBovi-5 showed significantly improved performance compared to Bacillus safensis CG1 and is recommended as a long-lasting self-healing additive for large-scale construction applications. © 2024 Elsevier B.V.Item Non-reactive biochar and Bacillus pumilus RSB17-based healing powder: A sustainable solution for enhanced bacterial viability in self-healing mortar(Elsevier B.V., 2025) Anoop, P.P.; Palanisamy, T.Existing mortar uses self-healing powders that are based on mineral admixtures, whose reactive nature negatively impacts bacterial viability and diminishes their effectiveness over time. This study aims to develop non-reactive, sustainable biochar-based healing powders with extended bacterial viability to serve as self-healing admixture in bio-mortar. Biochar from coconut husk, coconut shell, and coconut leaf petiole was evaluated for compatibility with Bacillus pumilus RSB17, emphasizing bacterial growth and calcium carbonate precipitation. Coconut shell biochar demonstrated superior performance and was used to formulate a microbial biochar healing powder. Another healing powder was prepared by lyophilizing the bacterial spore solution without protectants. The shelf life was evaluated for 180 days at 4 °C and 25 °C, demonstrating that microbial biochar healing powder at 4 °C maintained bacterial viability above the 4.5 log CFU/g threshold necessary for effective calcium carbonate precipitation, while lyophilized spore powder stored at 25 °C dropped below the threshold at 90 days. Microbial biochar healing powder stored at 4 °C for 180 days was integrated into the mortar, which healed crack width up to 0.80 mm at 56 days under submerged rainwater maintained at 27 °C ± 2 °C and 85 % ± 5 % relative humidity. Electrical resistivity decreased from 28.16 ?·m to 21.35 ?·m, the permeability coefficient dropped from 153.90 mm/s to 0 mm/s, and compressive strength regained 90.53 %, which collectively indicated enhanced self-healing. Microstructural analysis confirmed the stable cuboid calcite crystals with a crystallite size of 86.62 nm. Thus, Microbial biochar healing powder produced from coconut shell biochar and Bacillus pumilus RSB17 and stored at 4 °C is an effective self-healing admixture for bio-mortar applications with a minimum storage period of 180 days. © 2025 Elsevier B.V.Item Experimental Evaluation of Geocoir Cell-Reinforced Sand Beds with Different Infill Materials(Springer Science and Business Media Deutschland GmbH, 2025) Namburu, S.K.; Venkateswarlu, H.; Kolathayar, S.Exploring sustainable alternatives to polymeric materials for reinforcement applications has gained considerable momentum in recent years. This research explores the use of locally sourced, bio-based materials, specifically geocoir cell mattresses and coconut shell infills, to offer eco-friendly and cost-effective reinforcement solutions. The methodology involves conducting model plate load tests on sand beds, both unreinforced and reinforced with geocoir cell mattresses filled with either coconut shell pieces or sand. The primary objective is to evaluate the load-settlement behaviour and load-bearing capacity of these reinforced beds. The study demonstrates that geocoir cell-reinforced sand beds, when filled with coconut shell pieces, exhibit significantly enhanced load-settlement behaviour compared to traditional sand infill. The results indicate that coconut shell infill increases load-bearing capacity by up to 4.98 times and reduces settlement by 88%. These findings demonstrate the potential of geocoir cells and coconut shells as eco-friendly, cost-effective alternatives for soil reinforcement in construction. The benefit of this study is understanding performance benefits of geocoir cell with coconut shell infill and utilizing such material in for reinforcement applications reduce the reliance on synthetic polymers and enhance the geotechnical performance in terms of extending the service life and minimizing the maintenance costs. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.Item Dual-role of coconut shell biochar as a soil enhancer and catalyst support in bioremediation(Springer Science and Business Media Deutschland GmbH, 2025) Manikandan, S.K.; Nair, V.The application of soil amendments has been proposed to influence soil properties, thereby improving agricultural productivity. They are known to increase the organic matter content, water holding capacity, and soil porosity, which play a significant role in the growth and development of plants. In work, experiments were carried out to evaluate the impact of coconut shell biochar as a soil amendment and microbial cell support to remediate cadmium-contaminated soil. To investigate the roles of biochar size and concentration on soil water holding capacity, the laterite loam soil is mixed with the biochar having different particle sizes of less than 1 mm, 1–2 mm, and 2–5 mm and concentrations of 1%, 5%, and 10% (w/w). The effects of combining biochar with different concentrations of 1%, 5%, and 10% (w/w) of farmyard manure on plant growth of Solanum lycopersicum L, soil nutrient changes, and enzyme activity are also investigated. The biochar particle size of <1 mm and concentration of 10% showed the highest (41.5%) water holding capacity and 90.47% germination, and 464.25 seed vigour index for Solanum lycopersicum L. Further 21 days soil incubation experiments were conducted to explain the effect of the biochar, and P. stutzeri immobilized on biochar on cadmium adsorption and bioavailability in soil. Cadmium removal of about 73.84% was obtained from contaminated soil compared to the control. It is suggested that coconut shell biochar generation from coconut shells could be a sustainable crop residue management option to enhance the soil physico chemical properties and also to remediate soil. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2023.