http://nopr.niscpr.res.in/handle/123456789/44350 Sun, 11 Oct 2026 06:08:46 GMT 2026-10-11T06:08:46Z http://nopr.niscpr.res.in/handle/123456789/44360 Title: John Isotherm for the characterisation of microporous carbons: A comparative evaluation of adsorption phenomena Authors: Achari, V Sivanandan; Thomas, Mercy; Jayasree, S; Rajalakshmi, A S; Lopez, Raichel Mary; Ravindran, Bindia Abstract: John <em>(J)</em> isotherm model stated as log log P = C + n logV , for solid-gas equilibrium, is a unique contribution from India for the study of porous materials. These isotherms are generally characterised by different phases of adsorption marked by a sudden change in slope and sharp kinks in isotherm plots of loglog P versus log V. John isotherm is otherwise known as the phase change method. The isotherm model envisages the degree of porosity, by which the categorisation of porous materials could be done. The volume adsorbed, <em>V(J)</em> corresponding to saturation pressure P_s is  taken as the limiting micropore volume (LMV) or John adsorption capacity. The adsorption behaviour of some known microporous carbons has been analysed using John isotherm.  John isotherm along with five other isotherm models, Freundlich, Langmuir, D-R, BET and I plot methods are studied, constants and parameters are compared. There are three carbons, namely GC, its hydrogen treated form H2TGC and the nitric acid treated prodigy NITGC, whose isotherm data available is used to plot John isotherms to report the merits of the isotherm method. The results reveal that John isotherm model give excellent fit to the reported experimental data and provide precise information about the funcional mechanism of adsorption. The study aims to establish the application of John isotherm as a simple empirical isotherm model for characterising the microporosity of carbon materials over a wide range of concentration and relative pressure. The main purpose of this research paper is to reaffirm the application of John isotherm for its universal acceptance to study materials of microporous nature. Page(s): 123-139 Thu, 01 Mar 2018 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/44360 2018-03-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/44359 Title: Porous activated carbon material derived from sustainable bio-resource of peanut shell for H₂ and CO₂ storage applications Authors: Ariharan, Arjunan; Viswanathan, Balasubramanian Abstract: Porous activated carbon materials have numerous properties for use in energy storage applications as in adsorbent materials for solid state H₂ and CO₂ storage. In this work, the synthesis of activated porous carbon material derived from the sustainable source of peanut shell (Arachis hypogaea) is described by carbonization and activation processes using KOH as activating agent. The peanut shell derived porous activated carbon material denoted as (PDPAC), shows spherical and sheet like morphology with specific surface area of 1726 m²/g. Interestingly, this peanut derived porous activated carbon material exhibit hydrogen storage capacity of ~1.2 wt% at 298 K and 100 bar pressure. However, the CO₂ storage capacity of 3.5 mmol CO₂ g^-1 at 298 K and 1.0 bar pressure is achieved. Furthermore, this paper presents the state-of-the-art on the synthesis of activated porous carbon materials with maximization of porosity, the use of cheap biomass waste derived precursors and tailoring of their textural properties. Page(s): 140-149 Thu, 01 Mar 2018 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/44359 2018-03-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/44358 Title: Phase transfer catalysis: Effect of cationic surfactants on the free radical polymerization of methylmethacrylate Authors: Murugan, E; Geethalakshmi, D Abstract: The effect of cationic surfactants, decyltrimethylammonium bromide (DTAB), dodecyltrimethylammonium bromide (DDTAB) and tetradecyltrimethylammonium bromide (TDTAB), has been studied as phase transfer catalysts (PTCs) on the free radical polymerization of methylmethacrylate (MMA) using potassium peroxydisulfate (PDS, K₂S₂O₈) in toluene-water biphase system. Of the three PTCs in their respective critical micellar concentration (CMC) and in common concentration, the TDTAB show comparatively high rate of polymerization (Rp), 7.76 × 10^-5mol.L^-1.S^-1, at the lowest reaction time of 30 min in its concentration of 2 × 10^-2mol.L^-1. Detailed kinetic study of polymerization of MMA has been carried out using TDTAB at a fixed time of 30 min by varying [MMA], [K₂S₂O₈], [TDTAB] and temperature. Based on the kinetic results, the free energy of activation has been calculated, and a suitable mechanism and rate law has been proposed. Page(s): 150-157 Thu, 01 Mar 2018 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/44358 2018-03-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/44357 Title: Adsorption of <em>p</em>-nitrophenol from aqueous solutions by Zr⁴⁺ activated carbon: Adsorption isotherm studies Authors: Achari, V Sivanandan; Rajalakshmi, A S; Jayasree, S; Lopez, Raichel Mary Abstract: The dynamic adsorptive separation of <em>p</em>-nitrophenol from aqueous solution by newly modified coconut shell based granular activated carbon impregnated with Zr⁴⁺ has been studied. The adsorption behaviour is described by isotherm models of Langmuir, Freundlich and Dubinin-Radushkevich equations. The isotherm parameter shows loading of activated carbon with zirconium ions during stages of activation significantly improve the adsorption potential of activated carbon towards <em>p</em>-nitrophenol. Pore structure characteristics of the newly prepared granular activated carbon GACZR 1273 and GACOZR 1273 have been determined by nitrogen (N₂) gas adsorption isotherms data at 77K. Study shows each carbon has its own specific characteristics such as porosity, pore structure and surface area compared to their respective starting carbon GAC and GACO. The surface characteristics of carbon are directly related to the adsorptive removal of <em>p</em>-nitrophenol from aqueous solution under dynamic and equilibrium condition. Page(s): 158-169 Thu, 01 Mar 2018 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/44357 2018-03-01T00:00:00Z