Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
40 results
Search Results
Item Biodegradable and Biocompatible Polymeric Materials for Dentistry Applications(wiley, 2022) Pallavi, K.C.; Isloor, A.M.; Rao, L.N.The ongoing review assembles particulars regarding the diverse biodegradable polymeric materials, also which are specified by sole criteria of biocompatibility that are utilized for diagnosis and treatment needed in dentistry. Natural polymeric substrates are conjunct with various other bioactive molecules or polymers, which strikes off limitations of the former yielding an emerging composite modeled to attain the form of encapsulated microspheres, hydrogels, membranes, nanofibers, and scaffolds. The sustainability of particular polymeric material in the biomedical stream such as dentistry is decided by evaluating aspects, such as the extent of immunogenicity on employing, degradability time versus functionality time, noncytotoxicity, and performance on respective treatment. Enormous materials have been modeled, which have proven their viability in treating dental conditions, like chronic periodontitis, microbial attacks like bacterial and fungal infections, and bone deterioration, also in the controlled discharge of oral drugs. © 2022 Scrivener Publishing LLC.Item Biopolymeric Nanofibrous Materials for Environmental Remediation(wiley, 2022) Pallavi, K.C.; Isloor, A.M.The present content gathers information regarding the use of nanofibrous materials fabricated out of biopolymers in environmental problems. Biopolymers are environment-friendly and nonhazardous in character. Various conventional methods have been employed so far to solve problems, such as water pollution, air contamination, and soil infertility. Membranes of different types, filtration systems, and various sorbents have been found useful in the removal of contaminants. Apart from all those, nanofibrous materials attain great importance due to their noncomparable high surface area, minute pore size, diameter in the nanorange, and good adsorptive property. Nanofibers can be fabricated out of diverse polymers through various techniques, such as electrospinning. The surface modifications, such as chemical grafting and oxygen plasma treatment induced functional group insertion, can be done, which imparts high potential in respective applications. The present review chapter describes about nanofiber fabrication technique, properties of the resultant nanofiber mat, and their importance in environmental remediation, such as removal of airborne and waterborne contaminants. © 2022 Scrivener Publishing LLC.Item Nonporous polymeric membranes for biohydrogen purification(Elsevier, 2025) Mendonca, N.R.; Isloor, A.M.; A.F., A.F.Biohydrogen generated from biomass is a clean form of hydrogen. The dark fermentation process for the generation of biohydrogen gives a mixture of H2 and CO2 from which biohydrogen needs to be purified. From the available methods for biohydrogen purification, membrane technology is the most viable since it is less energy-intensive and can be combined easily with other processes. Both polymeric as well as inorganic membranes are employed in gas separation processes. Of these, nonporous polymeric membranes are economically viable and are hence used in large-scale gas separations. The use of nonporous polymeric membranes, composed of polymers like polybenzimidazole, polyimide, and polysulfone, for biohydrogen purification is an ongoing area of research which can help to generate hydrogen for use in hydrogen fuel cells, hence reducing the dependence on fossil fuels which pollute the environment. © 2026 Elsevier Inc. All rights reserved.Item Separation of dimethyl phenol using a spiral-wound RO membrane - Experimental and parameter estimation studies(2009) Srinivasan, G.; Sundaramoorthy, S.; Murthy, D.V.R.Reverse osmosis (RO) is increasingly used as a separation technique in chemical and environmental engineering for the removal of organics and organic pollutants present in waste water. Treatment of organics by RO is dependent on many factors and hence developing a viable RO system involves extensive pilot-plant studies. The removal of an organic compound, namely dimethyl phenol, using a polyamide membrane was investigated in this study. Experiments were conducted on a laboratory-scale spiral-wound RO module. The permeate concentrations and rejection coefficient values were measured for various transmembrane pressures and feed concentrations. A maximum rejection of 97% was observed. A mathematical model was developed for the RO module assuming a solution-diffusion mechanism for solute and solvent transport through the membrane and considering the concentration and pressure to be uniform on both permeate and retentate sides. The model has four parameters. A graphical method for estimating the model parameters was proposed. The model and the estimated parameter values were validated with the experimental data. The model was able to predict the permeate concentration within an error of 19% and rejection within 2% error. © 2009.Item Synthesis and desalination performance of Ar+-N+ irradiated polysulfone based new NF membrane(2011) Hegde, C.; Isloor, A.M.; Padaki, M.; Wanichapichart, P.; Liangdeng, Y.In the last few years, membrane technology has gained more attention from polymer chemists throughout the globe. Nowadays, surface modification of membrane is very useful in biotechnology and food science. In the present investigation, we have synthesized polysulfone based composite nanofiltration (NF) membranes, and characterized these membranes by FT-IR, SEM and membrane performance studies. Surface plasma treatment was carried out by irradiation with argon and nitrogen beams in suitable conditions. It was observed that nitrogen beam caused surface roughness that was more severe than the Ar beam. After irradiation, water contact angle was slightly increased. For pure water permeability, flux increased linearly with the operating pressure. However, for the salt solution, the flux was decreased marginally and salt rejection increased after irradiation due to surface modification. The modification effect was characterized in terms of contact angle, AFM employed roughness measurement and dielectric property. It revealed that irradiated NF membranes showed higher salt rejection and lower flux as compared to the nonmodified membranes. Accordingly, the roughness of the membrane surface intensively affected the performance of RO membrane. © 2010 Elsevier B.V.Item Conversion of microfiltration membrane into nanofiltration membrane by vapour phase deposition of aluminium for desalination application(2011) Padaki, M.; Isloor, A.M.; Nagaraja, K.K.; Nagaraja, H.S.; Pattabi, M.Preparation and modification of NF membrane are challenging aspects in research. In the present work, we have synthesised Polysulfone (PSf) microfiltration membrane and reduced the pore size to nano level by physical vapour deposition (PVD) of aluminium metal. Membrane pore size was reduced from micro pore to nano pore, which rejected 42.22% of NaCl from the solution with 164L/m2h. And also water permeation decreases from 1.10324-10-10 to the 9.141-10-12. The SEM and AFM pictures showed the surface modification and metal deposition in the pores. The performance of the membrane was studied by dead end flow cell using 3.5% of NaCl solution, in which PVD membrane showed 42.22% of rejection with 16.4L/m2h flux. Thermal analysis from DSC showed Tg of 265°C. Contact angle measurement, and water uptake were also reported. © 2011 Elsevier B.V.Item An analytical model for spiral wound reverse osmosis membrane modules: Part II - Experimental validation(2011) Sundaramoorthy, S.; Srinivasan, G.; Murthy, D.V.R.This paper presents the experimental studies carried out for validation of a new mathematical model [1] developed for predicting the performance of spiral wound RO modules. Experiments were conducted on a laboratory scale spiral wound RO module taking chlorophenol as a model solute. Experiments were carried out by varying feed flow rate, feed concentration and feed pressure and recording the readings of permeate concentration, retentate flow rate, retentate concentration and retentate pressure. A total of 73 experimental readings were recorded. The membrane transport parameters Aw (solvent transport coefficient) and Bs (solute transport coefficient) and the feed channel friction parameter b were estimated by a graphical technique developed in this work. The mass transfer coefficient k, estimated using the experimental data, was found to be strongly influenced by solvent flux and solute concentration apart from the fluid velocity. Taking the effects of solvent flux, solute concentration and fluid velocity, a new mass transfer correlation for Sherwood number is proposed in this work for the estimation of mass transfer coefficient. Comparison of model predictions with experimental observations demonstrated that the model was capable of predicting permeate concentration within 10% error, retentate rate flow within 4% error and rejection coefficient within 5% error. © 2011 Elsevier B.V.Item Polysulfone/N-phthaloylchitosan novel composite membranes for salt rejection application(2011) Padaki, M.; Isloor, A.M.; Wanichapichart, P.N-phthaloylchitosan (CS) was synthesized by the reaction of chitosan with phthalic anhydride in dimethyl formamide. Different compositions of polysulfone (PSf) and N-phthaloylchitosan were used to prepare novel polysulfone/N-phthaloylchitosan (PSf/CS) composite membranes by phase inversion method. The composition ratios between the former and the latter were 80:20, 85:15, 90:10, and 95:5. Water flux results revealed that, PSf:CS 80:20 membrane is found to have greatest effective pore area while PSf:CS 95:05 membrane has the smallest value. The pore area is found to be larger with the increase in CS composition. In addition, its water swelling property increases with the increase of CS composition. Water flux results are in consistent with dielectric constant value. Use of known molecular weight of polyethylene glycol rejection study, revealed that, PSf:CS 95:05 membrane possessed the smallest pore size among these membranes. In conclusion, change of ratio between PSf and CS, considerably affects membrane pore size and hydrophilicity. For salt filtration, membrane PSf:CS 95:05 showed 93%, 76.11% and 70.12% rejection of MgSO4, Na2SO4, and NaCl, respectively. © 2011 Elsevier B.V.Item Validation of an analytical model for spiral wound reverse osmosis membrane module using experimental data on the removal of dimethylphenol(2011) Srinivasan, G.; Sundaramoorthy, S.; Murthy, D.V.R.A new analytical model for spiral wound RO module has been recently proposed by Sundaramoorthy et al. [1] and the same has been validated [2] with experimental data obtained on a laboratory scale RO unit used for the removal of chlorophenol. In this paper, the need to check the validity of this model with solutes other than chlorophenol is addressed by conducting suitable experiments with dimethylphenol as solute and validating this experimental data with the model. The four model parameters namely solvent transport coefficient Aw, solute transport coefficient Bs, feed channel friction parameter b and the mass transfer coefficient k were estimated. The results show that the mass transfer coefficient is influenced not only by fluid velocity but also by the solvent flux and solute concentration. A new correlation for mass transfer coefficient k, proposed by Sundaramoorthy et al. [2] for experimental data taken with chlorophenol as solute is also shown to be consistent with the experimental readings recorded in this study taking dimethylphenol as solute. Comparison of model predictions with the experimental observations demonstrated the capability of the model in predicting permeate concentration within 12% error, retentate flow within 5% error and rejection coefficient within 2% error. © 2011 Elsevier B.V.Item An analytical model for spiral wound Reverse Osmosis membrane modules: Part I - Model development and parameter estimation(2011) Sundaramoorthy, S.; Srinivasan, G.; Murthy, D.V.R.A mathematical model for spiral wound Reverse Osmosis membrane module is presented in this work. The model incorporates spatial variations of pressure, flow and solute concentration in the feed channel and uniform conditions of pressure in the permeate channel. Assuming solution-diffusion model to be valid, explicit analytical equations were derived for spatial variations of pressure, flow, solvent flux and solute concentration on the feed channel side of the module. Analytical procedures for estimation of model parameters were presented. Graphical linear fit methods were developed for estimation of parameters Aw (solvent transport coefficient), Bs (solute transport coefficient) and b (feed channel friction parameter). The mass transfer coefficient k was assumed to vary along the length of the feed channel with varying conditions of flow, solute concentration and pressure. Explicit analytical equations for estimation of mass transfer coefficient were presented. In this paper (Part I), theoretical studies on development of mathematical model and methods for estimation of model parameters are presented. In Part II of this paper series [1], Studies on validation of this model with experimental data are presented. The studies cover experimental work on a spiral wound RO module with an organic compound namely chlorophenol as a solute. © 2011 Elsevier B.V.