Faculty Publications
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Item Kinetic and thermodynamic studies on the adsorption of heavy metals from aqueous solution by melanin nanopigment obtained from marine source: Pseudomonas stutzeri(Academic Press, 2018) Manirethan, V.; Raval, K.; Rajan, R.; Thaira, H.; Mohan Balakrishnan, R.M.The difficulty in removal of heavy metals at concentrations below 10 mg/L has led to the exploration of efficient adsorbents for removal of heavy metals. The adsorption capacity of biosynthesized melanin for Mercury (Hg(II)), Chromium (Cr(VI)), Lead (Pb(II)) and Copper (Cu(II)) was investigated at different operating conditions like pH, time, initial concentration and temperature. The heavy metals adsorption process was well illustrated by the Lagergren's pseudo-second-order kinetic model and the equilibrium data fitted excellently to Langmuir isotherm. Maximum adsorption capacity obtained from Langmuir isotherm for Hg(II) was 82.4 mg/g, Cr(VI) was 126.9 mg/g, Pb(II) was 147.5 mg/g and Cu(II) was 167.8 mg/g. The thermodynamic parameters revealed that the adsorption of heavy metals on melanin is favorable, spontaneous and endothermic in nature. Binding of heavy metals on melanin surface was proved by Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Photoelectron Spectroscopy (XPS). Contemplating the results, biosynthesized melanin can be a potential adsorbent for efficient removal of Hg(II), Cr(VI), Pb(II) and Cu(II) ions from aqueous solution. © 2018 Elsevier LtdItem Source apportionment studies on particulate matter (PM10 and PM2.5) in ambient air of urban Mangalore, India(Academic Press, 2018) Kalaiarasan, G.; Mohan Balakrishnan, R.M.; Sethunath, N.A.; Manoharan, S.Particulate matter (PM10 and PM2.5) samples were collected from six sites in urban Mangalore and the mass concentrations for PM10 and PM2.5 were measured using gravimetric technique. The measurements were found to exceed the national ambient air quality standards (NAAQS) limits, with the highest concentration of 231.5 ?g/m3 for PM10 particles at Town hall and 120.3 ?g/m3 for PM2.5 particles at KMC Attavar. The elemental analysis using inductively coupled plasma optical emission spectrophotometer (ICPOES) revealed twelve different elements (As, Ba, Cd, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sr and Zn) for PM10 particles and nine different elements (Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sr and Zn) for PM2.5 particles. Similarly, ionic composition of these samples measured by ion chromatography (IC) divulged nine different ions (F?, Cl?, NO3 ?, PO4 3?, SO4 2?, Na+, K+, Mg2+ and Ca2+) for PM10 particles and ten different ions (F?, Cl?, NO3 ?, PO4 3?, SO4 2?, Na+, NH4 +, K+, Mg2+ and Ca2+) for PM2.5 particles. The source apportionment study of PM10 and PM2.5 for urban Mangalore in accordance with these six sample sites using chemical mass balance model (CMBv8.2) revealed nine and twelve predominant contributors for both PM10 and PM2.5, respectively. The highest contributor of PM10 was found to be paved road dust followed by diesel and gasoline vehicle emissions. Correspondingly, PM2.5 was found to be contributed mainly from two-wheeler vehicle emissions followed by four-wheeler and heavy vehicle emissions (diesel vehicles). The current study depicts that the PM10 and PM2.5 in ambient air of Mangalore region has 70% of its contribution from vehicular emissions (both exhaust and non-exhaust). © 2018 Elsevier LtdItem Biosynthesis of cobalt oxide nanoparticles using endophytic fungus Aspergillus nidulans(Academic Press, 2018) Vijayanandan, A.S.; Mohan Balakrishnan, R.M.Metallic oxide nanoparticles have profound applications in electrochemical devices, supercapacitors, biosensors and batteries. Though four fungi were isolated from Nothapodytes foetida, Aspergillus nidulans was found to be suitable for synthesis of cobalt oxide nanoparticles, as it has proficient tolerance towards metal under study. The broth containing precursor solution and organism Aspergillus nidulans had changed from pink to orange indicating the formation of nanoparticles. Characterization by x-ray diffraction analysis (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and energy dispersive x-ray analysis (EDX) confirmed the formation of spinel cobalt oxide nanoparticles at an average size of 20.29 nm in spherical shape with sulfur-bearing proteins acting as a capping agent for the synthesized nanoparticles. The nanoparticles could be applied in energy storage, as a specific capacitance of 389 F/g showed competence. The study was a greener attempt to synthesize cobalt oxide nanoparticles using endophytic fungus. © 2018 Elsevier LtdItem Ultrasonication-assisted green synthesis and characterization of gold nanoparticles from Nothapodytes foetida: An assessment of their antioxidant, antibacterial, anticancer and wound healing potential(Editions de Sante, 2023) Susanna, D.; Mohan Balakrishnan, R.M.; JagadeeshBabu, J.Nanotechnology and biogenic synthesis of metal nanoparticles using plants have attracted immense attention recently owing to their beneficial applications. Ultrasonication technique was employed for the rapid one-step phytochemical synthesis of AuNPs from the extracts of Nothapodytes foetida leaves. The N. foetida AuNPs exhibited the characteristic UV absorption peak at 524 nm. Several analytical techniques, including FESEM, TEM, XRD, FTIR, TGA, ICP and zeta potential analysis, were performed for their effective characterization. These analyses revealed highly stable (– 60.7 mV) crystalline AuNPs, majorly spherical, ranging between 5 and 30 nm. Furthermore, CCD-RSM was incorporated to determine the influence of the temperature, N. foetida leaf extract and HAuCl4 concentration on the synthesis of AuNPs. LC-MS revealed the phytocompounds that contributed to AuNP synthesis which was subsequently confirmed by TPC and TFC reduction. Potent radical scavenging ability accompanied by the antibacterial activity of the AuNPs was also evaluated. Importantly, AuNPs also reduced the cell viability of MG63 and A549 cell lines, exhibiting significant anticancer activity along with appreciable wound-healing properties. These findings suggest that these AuNPs possess tremendous biological potentialities and can be bio-prospected further for various multidisciplinary applications. © 2023 Elsevier B.V.Item Functionalization of β-cyclodextrin onto NiFe2O4 nanoparticles for the removal of ketoprofen and diclofenac from the aqueous solutions(Institute for Ionics, 2024) Ilango, I.; Mohan Balakrishnan, R.M.; Visvanathan, C.; Bui, X.-T.; Velusamy, P.A new β-CD functionalized nickel ferrite nanocomposite was synthesized and used to remove pharmaceutical drugs, such as ketoprofen (KF) and diclofenac (DCF). The co-precipitation approach was utilised to synthesize nickel ferrite (NFO) nanoparticles, which were then functionalized with TEOS to form NFO@SiO2; β-cyclodextrin was then functionalized using GPTMS as an interface to form NFO@SiO2@β-CD. FTIR, ZD, FE-SEM, EDX, TGA/DTG, VSM, BET, zeta potential and particle size analysis were then used to characterise the nanocomposites. The NFO@SiO2@β-CD has an average diameter of 109.1 nm, superparamagnetic behaviour, a mesoporous surface and a specific surface of 20.78 m2/g. The functionalized NFO@SiO2@ β-CD nanocomposite removed 94% of diclofenac in 5 min and 80% of ketoprofen in 360 min with the adsorption capacities of 8.46 and 0.54 mg/g, respectively. The obtained experimental datum for both the pollutants was fitted in kinetic and isotherm models, with the pseudo-second-order kinetic model and Freundlich adsorption isotherm showing the best fit with the highest regression of R 2 = 0.99. The nanocomposite was regenerated using 0.1 M NaOH and recycled for about four consecutive cycles in which the reduction in the removal efficiency of ketoprofen and diclofenac was observed to be 51.36% and 64%, respectively. These results suggested that the NFO@SiO2@β-CD nanocomposite could be used specifically to target the low-concentrated pharmaceutical pollutants. Graphical Abstract: Schematic representation of Functionalization of β-Cyclodextrin onto NiFe2O4 nanoparticles for the removal of ketoprofen and diclofenac from the aqueous solutions. [Figure not available: see fulltext.] © 2023, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.