Faculty Publications
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Item Antifouling and performance enhancement of polysulfone ultrafiltration membranes using CaCO3 nanoparticles(2013) Nair, A.K.; Isloor, A.M.; Kumar, R.; A.F., A.F.Calcium carbonate nanoparticles were synthesized from calcium nitrate via chemical precipitation method. The nanoparticles were characterized using scanning electron microscope (SEM), Attenuated total reflectance infra red (ATR-IR) spectrum and by X-ray diffraction (XRD). These nanoparticles were used as additive for polysulfone (PSf) ultrafiltration membrane along with polyethylene glycol (PEG) as pore forming agent. The PSf hybrid membranes were characterized by ATR-IR, XRD, and SEM studies. ATR-IR and XRD results indicated the successful incorporation of the nanoparticles in the membranes. Cross sectional images of the membranes along with the elemental mapping of calcium on the membrane surface were assessed using SEM. Hydrophilicity of the membranes was evaluated in terms of contact angle measurements. The permeability of the membranes was determined by measuring the pure water flux (PWF). Membranes were also subjected to antifouling studies using bovine serum albumin (BSA) as the standard protein for rejection. The membranes showed better permeability and antifouling property with the increased addition of CaCO3 nanoparticles. © 2013 Elsevier B.V.Item 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 Oxalic acid optimization for iron-based solid waste conversion into a carbon-sequestering composite building material(Elsevier B.V., 2025) M, N.; Palanisamy, T.The cement industry significantly contributes to global CO2 emissions, accounting for approximately 164 million metric tonnes annually, while total emissions from all sources reach 37 billion metric tonnes. Concurrently, the iron and steel sector generates substantial waste, producing about 500 kg of waste per tonne of steel. Addressing these environmental challenges is crucial for sustainable development. This study presents a sustainable alternative to traditional cement by developing a novel binder material composed primarily of waste iron. The alternative binder not only avoids CO2 emissions but also absorbs CO2 during carbonation curing, effectively contributing to carbon sequestration. Key parameters, including particle size, oxalic acid dosage, and water-to-binder ratio, were individually tested and analyzed for their impact on compressive strength, leading to the finalization of a 75?m particle size and a 0.2 water-to-binder ratio, which yielded compressive strengths of up to 45 MPa. The wet mix method for oxalic acid incorporation demonstrated superior performance compared to the dry mix approach. Comprehensive analyses, including XRD, FTIR, TGA/DTG, and FESEM, confirmed the enhanced reactivity and performance of the material with finer particles and optimized oxalic acid dosage. By utilizing 80% of waste materials, this alternative binder addresses both waste management and carbon capture, aligning with global sustainability objectives and advancing the development of eco-friendly building materials. © 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 Coconut shell biochar–Bacillus cereus DKBovi-5 based biocomposite as a sustainable additive for cement mortar: Effect of pyrolysis temperature on characterization, strength, hydration, and healing(Elsevier B.V., 2025) Anoop, P.P.; Palanisamy, T.Although biochar–bacteria composites have been explored for self-healing in cementitious materials, the influence of pyrolysis temperature on microbial compatibility and healing performance has been insufficiently investigated. This study addresses this gap by examining how pyrolysis temperature affects the physicochemical properties of coconut shell biochar and its effectiveness as a microbial carrier in mortar. Biochar produced at 300 °C, 400 °C, and 500 °C was characterized, and Bacillus cereus DKBovi-5 was immobilized onto it to form biocomposites. The biocomposites were incorporated into mortar to evaluate mechanical, microstructural, and crack healing performances. Characterization of biochar showed enhanced crystallinity at 500 °C as indicated by XRD, development of primary and secondary pores confirmed by FESEM, and increased micronutrient concentrations due to thermal enrichment observed through ICP-MS. Compressive strength restoration increased from 80.21 % to 91.23 % between 300 °C and 500 °C temperatures. TGA analysis, interpreted using Bhatty's method, indicated an increase in the degree of hydration from 61.65 % to 65.33 %. Rietveld refinement of XRD data revealed a rise in calcite content from 24 % to 51 %. FESEM imaging confirmed the deposition of hydration products within the biochar pores. Healing evaluation showed closure of cracks up to 0.762 mm and 0.920 mm in mortars with 300 °C and 500 °C biocomposites, respectively, corresponding to healed areas of 92.49 % and 100 %. The healed products in all biocomposites were confirmed as calcite through FESEM-EDS and XRD analyses. Optimized pyrolysis at 500 °C yielded a biocomposite with superior microbial healing performance, establishing its suitability as a self-healing admixture in bio-mortar applications. © 2025 Elsevier B.V.Item A comprehensive study on quantification and characterization of microplastics in compost, landfill-soil and leachate(SAGE Publications Ltd, 2025) Dubey, A.P.; Thalla, A.K.Microplastics (MPs), a category of synthetic emerging pollutants, have been detected in various environmental matrices. This study assesses the abundance of MPs in the soil, wet compost (WC), Black soldier compost (BSC) and landfill leachate (LL) of the municipal solid waste management plant. Samples were pretreated with a Fenton reagent, followed by density separation and analysed using a digital portable microscope. They were then categorized based on their shape, colour and size to provide information on their distribution. The work reveals an average MP count of 7590?±?1004.092 MP kg?1in soil. MPs were 5900?±?565.69 MP kg?1for BSC, 11,350?±?353.55 MP kg?1for WC and LL samples 98.83?±?6.83 MP L?1. Notably, a significant proportion of MPs, 85% in soil, 86% in compost and 72.6% in LL, measured size less than 300?µm. Samples showed different proportions of fragments, microbeads and fibres, with white/transparent and black being the predominant colours of MPs. Additionally, the study identifies the physicochemical properties of the samples, and the polymer types are identified using attenuated total reflectance-Fourier transform infrared spectroscopy. The study revealed that polypropylene and polyethylene are the most abundant polymers in the samples, indicating that landfills serve as significant sources of MPs. The adopted MP extraction method was tested for its recovery efficiency, and the recovery rates for leachate, compost and soil were found to be 94.3%, 80% and 77.9%, respectively. This research offers insight into the types and abundance of MPs in southern India’s landfills, prompting further studies on detection methods. © The Author(s) 2025