Materials Chemistry, Electrochemistry, Catalysis and Environmental Chemsitry.
9
Scopus Publications
Scopus Publications
Catalytic Conversion of 2- Methyl Phenol to Salicylaldehyde Using Manganese-Oxide Doped Cellulose-Derived Carbon Spheres Divya T, James Arulraj, Sreeja P. Balakrishnan Chemistryselect, 2025 In this study, we report on the hydrothermal synthesis of MnOx‐anchored carbon spheres as an effective catalyst. A new method is employed to prepare carbon spheres from cellulose. Using a solvent‐free process, the prepared catalyst is used to convert o‐cresol to salicylaldehyde. Methods including XRD, Raman spectroscopy, FE‐SEM, EDS mapping, and HR‐TEM are used to examine the structural and morphological characteristics of the catalyst. It is confirmed from the BET analysis that doping with MnOx increases the surface area of the carbon spheres. At standard atmospheric pressure, the conversion of o‐cresol to salicylaldehyde is highly selective due to the enhanced surface area and active sites of MnOx‐doped carbon spheres. Under atmospheric pressure, the MnOx/CS catalysts show excellent efficiency, yielding 96% salicylaldehyde in under 1 h. This study underscores the feasibility of using MnOx‐doped carbon spheres as a robust catalyst for the controlled oxidation of o‐cresol. The results show that the catalyst has a great deal of activity and effectiveness, as well as being cheap and reusable, which greatly increases its potential for real‐world catalytic applications.
Exploring the efficiency of green synthesized silver nanoparticles as photocatalysts for organic dye degradation: unveiling key insights Aman Sharma, Sachin Sunny, James Arulraj, Gurumurthy Hegde Nano Express, 2024 Silver nanoparticles (AgNPs) have received a lot of interest for their several applications, including their remarkable potential as photocatalysts for organic dye degradation. This research thoroughly investigates the efficacy of ecologically friendly, green-synthesized AgNPs in the treatment of synthetic dye-contaminated wastewater. The synthesis of AgNPs from various biological substrates is investigated, emphasizing their economic viability, significant conductivity, and considerable biocompatibility. The improper disposal of synthetic dyes in wastewater poses severe environmental and health risks due to their non-biodegradable nature and persistent chemical features. In response to this challenge, this review paper investigates the capability of AgNPs to serve as effective photocatalysts for degrading a range of organic dyes commonly found in industrial effluents. Specific dyes, including methyl orange, congo red, nitrophenol, methylene blue, and malachite green, are studied in the context of wastewater treatment, providing insights into the efficacy of AgNPs synthesized from diverse biological sources. The review sheds light on the photocatalytic degradation methods used by green-synthesized AgNPs, shedding light on the transition of these synthetic dyes into less hazardous compounds. It also delves into the toxicity aspect of the AgNPs and its possible remediation from the environment. The ecologically friendly synthesis procedures investigated in this work provide an alternative to traditional methods, highlighting the importance of sustainable technologies in solving modern environmental concerns. Furthermore, a comparative examination of various biological substrates for AgNPs synthesis is presented, evaluating their respective dye degradation efficiencies. This not only helps researchers understand the environmental impact of synthetic dyes, but it also directs them in choosing the best substrates for the production of AgNPs with enhanced photocatalytic activities.
Bromelain enhances digestibility of Spirulina-based fish feed Samskrathi A. Sharma, Siddharthan Surveswaran, James Arulraj, Krishnakumar Velayudhannair Journal of Applied Phycology, 2021 Microalgae like Spirulina ( Arthrospira platensis ) are protein rich and can be alternative protein sources to fishmeal and soybean meal in fish feed formulation. The present study aims to improve the protein bioavailability of Spirulina by cost-effective protein extraction followed by protease supplementation in fish feed, using in vitro studies. Different extraction procedures such as microwave-assisted, high pressure, and temperature-mediated extraction, boiling and an isoelectric precipitation were employed to study the protein yield from Spirulina powder, and this was compared with the conventional soybean meal and fishmeal conditioning during feed manufacture. Bromelain is a potent protease that has not been widely used as a feed additive with Spirulina. To study the comparative efficiency of bromelain and other proteases like papain and trypsin on Spirulina and conventional feed substrates, a protease assay was performed at different temperatures and enzyme concentrations. The digestibility of these substrates was also studied in vitro, using gut extracts from the fingerlings of Mozambique tilapia ( Oreochromis mossambicus ). Unlike an in vivo feeding trial, a novel method was used to study the effect of protease supplementation on the inherent digestibility of the gut with an in vitro method. Bromelain showed the highest activity on all the substrates at both the temperatures. Bromelain supplementation improved the in vitro digestibility of the Spirulina that were subjected to protein extraction, more than the un-extracted one. The results of the present in vitro study suggest that Spirulina could serve as an alternative protein source, and bromelain-based supplementation could improve the digestibility of Spirulina-based fish diets.
Sunova spirulina Powder as an Effective Environmentally Friendly Corrosion Inhibitor for Mild Steel in Acid Medium S. J. Hepziba Magie Jessima, S. Subhashini, James Arulraj Journal of Bio and Tribo Corrosion, 2020 Spirulina, blue green algae is a rich source of proteins and vitamins with excellent antioxidant properties. Sunova spirulina powder an effective, green corrosion inhibitor was used to evaluate its inhibition efficiency towards mild steel in 1 M HCl medium. Weight loss studies of mild steel showed an inhibition efficiency of 96% for 600 ppm concentration of inhibitor solution and 12 h of immersion period at 303 K. The percentage of inhibition efficiency increased with a step up of 10 K raise in temperature from 303 to 333 K and thereafter decreased. The results obtained were further validated by inductively coupled plasma optical emission spectrometric (ICP-OES) measurements and electrochemical techniques that included Tafel polarisation, linear polarisation and AC impedance studies. Potentiodynamic polarisation study marked the inhibitor to be a mixed type inhibiting both cathodic and anodic reactions. The adsorption studies proved that the adsorption process was spontaneous and followed Langmuir adsorption isotherm. The thermodynamic activation and adsorption parameters calculated showed that the mechanism of inhibition involved a physisorption process initially and then it slightly shifted towards chemisorption process at higher temperature. The protective layer formed on the metal surface was studied using FTIR and SEM. The complex formation between the Fe2+ and the active constituents of the spirulina extract was verified using UV visible spectra and fluorescence spectra. The effect of inhibitor concentration and temperature on corrosion rate was tested statistically using two-way analysis of variance (ANOVA) technique.
Solvent-Mediated and Mechanochemical Methods for Anion Exchange of Carbonate from Layered Double Hydroxides Using Ammonium Salts Bhojaraj, James Arulraj, Mikhail R. Kolinjavadi, Michael Rajamathi ACS Omega, 2019 Deintercalation of carbonate from layered double hydroxides (LDH) followed by intercalation of another anion (decarbonative intercalation) is a good method for the synthesis of crystalline LDH with different intercalated anions. We have carried out decarbonative intercalation of halides, nitrate, acetate, and sulfate by refluxing the carbonate-LDH with the corresponding ammonium salt in 1-butanol to obtain ordered LDH incorporating the desired anion. The crystallinity of the precursor LDH is retained in the anion-exchanged products, making this reaction a useful tool to prepare ordered LDH containing various anions. In addition, the morphology of the LDH is also retained after the exchange, making the reaction morphotactic. As the reaction is facilitated by the weak acidity of the ammonium salt, just grinding the carbonate-LDH with the ammonium salt of the desired anion also results in anion exchange. However, while the crystallinity of the LDH is retained, the morphology changes possibly due to breaking up of the crystals during the reaction.
Ceria doped titania nano particles: Synthesis and photocatalytic activity Radhika R. Nair, James Arulraj, K.R. Sunaja Devi Materials Today Proceedings, 2016 Ceria (0.5, 1 and 2 mol%) doped titania nano catalysts were prepared by combustion synthesis method, using titanium isopropoxide as the starting material. The prepared catalysts were characterized by X-ray diffraction (XRD), Energy dispersive X-ray analysis (EDX), Scanning electron microscopy (SEM) and Infra red spectroscopy (FTIR). Total acidity of the prepared catalysts were determined by temperature programmed desorption of ammonia (TPD – NH 3 ). XRD pattern of 1% ceria doped titania obtained by calcinations at 873 K indicated that the samples were crystalline with a mixture of anatase and rutile phase. No peaks corresponding to cerium oxide were observed XRD patterns indicating that the amount of cerium is negligible on the surface of titania catalyst. The photo catalytic activity was evaluated for the degradation of methylene blue (MB) under visible light irradiation. The degradation rates of MB on cerium doped TiO 2 samples were higher than that of pure TiO 2 . The introduction of structural defects (cationic ceria dopant) into the titania crystal lattice leads to the change of band gap energy. As a result, the excitation energy is expanded from UV light of anatase TiO 2 to visible light for ceria doped titania.
Preparation of anionic clay-birnessite manganese oxide composites by interlayer oxidation of oxalate ions by permanganate James Arulraj, Michael Rajamathi Journal of Solid State Chemistry, 2013 Oxalate intercalated anionic clay-like nickel zinc hydroxysalt was obtained starting from nickel zinc hydroxyacetate, Ni3Zn2(OH)8(OAc)2·2H2O, by anion exchange. The intercalated oxalate species was reacted with potassium permanganate in such a way that the layered manganese oxide formed was within the interlayer region of the anionic clay resulting in a layered composite in which the negative charges on the birnessite type manganese oxide layers compensate the positive charges on the anionic clay layers. Birnessite to anionic clay ratio could be varied by varying the reaction time or the amount of potassium permanganate used.
Delamination of surfactant-intercalated brucite-like hydroxy salts of cobalt and copper and solvothermal decomposition of the resultant colloidal dispersions Jacqueline. T. Rajamathi, Anthony Arulraj, N. Ravishankar, James Arulraj, Michael Rajamathi Langmuir, 2008 Surfactant anion intercalated hydroxy salts of copper and cobalt of the formula M(OH)2- x (surf)x.mH2O [M = Cu, Co; surf = dodecyl sulfate, dodecyl benzene sulfonate, and x = 0.5 for Cu and 0.67 for Co] delaminate readily in 1-butanol to give translucent colloidal dispersions that are stable for months. The extent of delamination and the colloidal dispersion observed in these solids is higher than what had been observed for layered double hydroxides. The dispersions yield the corresponding nanoparticulate oxides on solvothermal decomposition. While the copper hydroxy salt forms approximately 300 nm dendrimer-like CuO nanostructures comprising nanorods of approximately 10 nm diameter, the cobalt analogue forms approximately 20 nm superparamagnetic particles of Co3O4.
Anionic clays as hosts for anchored synthesis: Interlayer bromination of maleate and fumarate ions in nickel-zinc layered hydroxy double salt James Arulraj, Jacqueline T. Rajamathi, Kandikere R. Prabhu, Michael Rajamathi Solid State Sciences, 2007 Anionic clay-like nickel zinc hydroxyacetate, $Ni_3Zn_2(OH)_8(OAc)_2.2H_2O$ was ion exchanged with maleate and fumarate ions. While the maleate enters as monoanion, fumarate enters as dianion. Also these anions take up different orientations in the interlayer region. The intercalated organic species could be reacted with bromine water in such a way that the brominated product remains intercalated making the reaction a true intracrystalline reaction. The stereochemistry of the reaction of the intercalated fumarate was identical to that of the free fumarate ion – both yielding only the anti addition product. While free maleate ion yielded only the anti addition product, the intercalated maleate ion yielded a small percentage of the syn addition product along with the anti addition product. The organic products could be quantitatively recovered by anion exchange with oxalate ions.
