National Institute of Technology Calicut

About: National Institute of Technology Calicut is a education organization based out in Kozhikode, Kerala, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 3627 authors who have published 4638 publications receiving 50830 citations. The organization is also known as: Calicut Regional Engineering College & NIT Calicut.

Tailored design of polyurethane based fouling-tolerant nanofibrous membrane for water treatment

Abstract: Polyurethane (PU) nanofibers have gained attention due to their good mechanical properties and water resistance. However, the applicability in water filtration is limited due to their hydrophobic nature. A new class of high performance fouling tolerant hydrophilic PU based nanofibrous membranes have been fabricated by an electrospinning technique. The electrospun parameters of the PU systems were thoroughly optimized for ideal fiber diameter and fiber morphology suitable for water filtration. The effects of polyvinylpyrrolidone (PVP) concentration in membrane morphology, as well as physical and chemical properties of the developed membranes, were studied. PU/PVP exhibited improved hydrophilicity, which was confirmed from the contact angle and protein adsorption results. Under low pressure, all PVP modified membranes showed a water flux higher than that of 1000 lm−2 h−1. Furthermore, the PU/PVP membranes exhibited good rejection performance, higher than 80% for olive oil and 99% for gingelly oil. The results showed that the incorporation of PVP into the PU membrane caused a significant improvement in the antifouling property and membrane performance. Antifouling properties of the developed membrane were investigated using the Hermia model and the fouling mechanism is fitted with a cake filtration model. All these results showed that electrospun PU/PVP nanofibrous membrane could be a promising candidate for cost effective water treatment.

Molecular Sorption by Heterogeneous Natural Rubber/Poly(ethylene-co-vinyl acetate) Blend Systems

Abstract: The sorption of n-alkanes, viz. hexane, heptane and octane by cross-linked natural rubber/poly(ethylene-co-vinyl acetate) (NR/EVA) blends has been studied at 28, 38, 48 and 58°C, with special reference to the effects of EVA content, cross-linking systems, penetrant nature and temperature. The solvent transport was found to decrease with increase in EVA content in the blends. The effects of blend ratio on the transport characteristics have been correlated with the phase morphology of the blends, using scanning electron micrographs and optical micrographs. Among the three vulcanising systems, viz. sulphur (S), dicumyl peroxide (DCP) and a mixed system (S + DCP) employed for the matrix, the DCP cross-linked blends exhibited the lowest solvent uptake. Octane has been found to show higher interaction with the blends than hexane and heptane, probably owing to the closer solubility parameter values. The computed transport coefficients, viz. diffusion coefficient and permeability coefficient, were found to decrease with increase in EVA content in the blends. At room temperature, the mechanism of diffusion was found to deviate slightly from the regular Fickian trend for all blend systems. The blend–solvent interaction parameter and the activation energy for transport were also determined from the sorption data.