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20182
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Subject: Chemistry × Author: Navneet Kaur × Start date: 1975 × Type: Thesis ×
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    ThesisItemOpen Access
    Physico-chemical studies on synthesized graphene oxidemagnesium ferrite based nanocomposites and their adsorption potential for Ni (II) ion
    (Punjab Agricultural University, Ludhiana, 2018) Navneet Kaur; Manpreet Kaur
    Role of magnetic nanocomposites for the remediation of waste-water is a thrust area of research. In the present study, hybrid graphene oxide (GO) based inverse spinel magnesium ferrite (MgFe2O4) nanocomposites (NCs) with bentonite/charcoal/chitosan were synthesized using facile sonication method. p-XRD patterns confirmed the presence of spinel ferrite phase in the NCs with the crystalline size 8-32 nm. FT-IR spectra displayed absorption bands corresponding to GO, MgFe2O4 NPs and bentonite/charcoal/chitosan in the NCs along with red shift of bands corresponding to C=O, C=C and O-H stretching. TGA confirmed higher stability of NCs over pristine GO. MgFe2O4 NPs imparted appreciable saturation magnetization to the NCs (4.03-11.10 emug-1). SEM and TEM revealed high porosity and immobilization of clusters of MgFe2O4 NPs onto GO sheets in the NCs. BET surface area of the NCs ranged from 58.34 to 165.29 m2g-1 and was markedly higher than pristine MgFe2O4 NPs. Removal of Ni (II) ions was studied by batch adsorption method. Langmuir, Temkin and Freundlich models were followed in perfect way. Maximum adsorption capacity from Langmuir model ranged between71.43-111.11 mgg-1 for NCs. Kinetic data fitted pseudo-second-order equation. Thermodynamic parameters revealed spontaneous and endothermic removal using NCs; whereas using GO the removal was exothermic. Percentage removal of Ni (II) was maximum for MgFe2O4 NPs and their binary NCs with GO. Effect of co-existing ions on Ni (II) adsorption was studied in Pb-Cd-Ni-Zn system. NCs possessed higher removal potential for Pb (II) as compared to Ni (II) due to the lower hydration energy of the former. For electroplating waste-water the optimum adsorbent dose required for complete metal ion removal was higher than that for spiked water because of presence of other interfering ions.
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    ThesisItemOpen Access
    Chemistry and antioxidant potential of dill (Anethum graveolens L) seed essential oil
    (Punjab Agricultural University, Ludhiana, 2018) Navneet Kaur; Chahal, K.K.
    The present investigation deals with chemistry and antioxidant potential of dill (Anethum graveolens L.) seed essential oil. The dill seed essential oil was analysed using GC–MS which showed the presence of 31 compounds. Carvone (41.15 %) was identified as major compound; other compounds identified were limonene (23%), camphor (9.25%), dihydrocarvone (3.75%), butyl acetate (2.65%), dill apiole (1.65%) and dill ether (1.02%) etc. The essential oil was fractionated into its non-polar and polar fractions by column chromatography. Carvone, limonene and camphor were isolated from dill seed oil using column chromatography. Carvone, limonene and camphor were chemically transformed into different derivatives viz. carveol, carvone semicarbazone, carvone oxime, camphor oxime and perillyl alcohol. Isolated and transformed compounds were identified using FT-IR, 1HNMR and 13CNMR spectroscopy. Methanol, dichloromethane and hexane extracts were prepared by Soxhlet extraction method. Presence of phytochemicals such phenols, flavonoids, anthraquinone, reducing sugar, tannins, cardiac glycosides and saponin were tested in hexane, dichloromethane and methanol extract. Quantitative estimation of phenolic, flavonoid, sugars, peroxide value and saponification value was calculated. Dill seed essential oil, its fractions, isolated and derivatized compounds were tested for their antioxidant potential at different concentration levels viz. 1.0, 0.5, 0.25, 0.1 and 0.05 mg ml-1. The antioxidant potential of tested components were evaluated using 2, 2 diphenyl-1-picrylhydrazyl (DPPH•), hydroxyl (OH•), nitric oxide (NO•), superoxide (O2•­) radical scavenging methods and ferric reducing antioxidant power (FRAP) assay. Methanol extract was found most active among extracts and fractions whereas carveol showed maximum potency for radical savenging activity amongst isolated and derivatised compounds.