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ThesisItem Embargo Synthesis of boron and phosphorous doped graphene fabricated with magnesium ferrite – bentonite nanocomposite for the remediation of pollutants(Punjab Agricultural University, 2022) Manpreet Kaur; Manpreet KaurGraphene oxide (GO) doped with heteroatoms are gaining interest in depollution of water because of their large surface area. The boron-doped GO (B-GO), phosphorous-doped GO (P-GO) and boron and phosphorous co-doped GO (BPGO) in different w:w ratios were synthesized and fully characterized using analytical techniques viz. FT-IR, XRD, SEM-EDS, TEM, BET, Mössbauer and XPS. In order to impart magnetic features to doped GO materials, magnesium ferrite-bentonite (MGF-B) was used to fabricate nanocomposite of MGF-B and BPGO having hierarchical nanoflowers like morphology (HNFs). TEM of co-doped GO showed more wrinkled surface than doped GO, whereas in case of HNFs, chiffon-like BPGO nanosheets were wrapped on the MGF-B surface, resulting in a porous flower-like morphology. The synthesized materials were explored as adsorbents for the removal of Pb(II) and As(III) ions and as photocatalysts for the degradation of martius yellow, p-nitrophenol and malathion from synthetic waste water. The trend for the percentage removal of heavy metals by adsorption and degradation of organic pollutants by photocatalysis in the descending order was found to be: HNFs > BPGO-1:1 > BPGO-1:5 > BPGO-1:0.2 > MGF-B > P-GO > B-GO > GO. The adsorptive and photocatalytic potential of HNFs was greater as compared to pristine, doped and codoped GO due to high surface area, remarkable charge transfer ability and layered structure of codoped GO sheets. The HNFs possessed appreciable saturation magnetization than doped and co-doped GO layers, which led to its easy separation and reusability. Box-Behnken design was utilized for exploring the simultaneous effects of the independent variables on removal of metal ions and degradation of organic pollutants (as dependent variable) using HNFs. The adsorption and photocatalytic mechanism was proposed on the basis of adsorption isotherm, thermodynamic, kinetic and quenching studies. Enhanced activity of HNFs with adsorption of heavy metal could be defined by the electronic structural properties of elements. The best adsorbent and photocatalyst were also tested for spiked solution containing different metal ions and real life industrial water matrices.ThesisItem Embargo Synthesis of xylan and lignin based hydrogels and their use as growth media for rice (Oryza sativa)(Punjab Agricultural University, 2023) Japanpreet Kaur; Ramandeep KaurLignocellulosic biomass is the most economical and highly renewable crop residue in the world. It is nonedible plant material composed of cellulose, hemicellulose, and lignin and is present in environment as agriculture wastes which includes crop residues like paddy straw, wheat straw, etc. Lignin and xylan were extracted from paddy straw by pre-acid treatment which was followed by alkaline hydrolysis. Structural characterization of lignin and xylan was done by FT-IR and 1H-NMR spectra respectively. Different hydrogels were synthesized using lignin and xylan as the raw material, PVA as the matrix template, citric acid, and succinic acid as crosslinkers and were structurally characterized by FT-IR and SEM analysis. Hydrogels that were synthesized using citric acid as crosslinker were observed to cause loose bonding between polymers and resulted in formation of large pores in hydrogels whereas, hydrogels synthesized using succinic acid as crosslinker were observed to have less porosity and tight bonding network. The swelling ratio and reswelling capacity of hydrogels revealed that lignin hydrogels outperformed all other hydrogels. All the synthesized hydrogels were tested for their role as soil culture media ingredient for the germination of rice seedlings. Germination percentage was calculated on seventh day after sowing of rice seeds and it came out to be maximum in case of xylan/lignin hybrid citric acid crosslinked (LXC) hydrogels in both normal and stress conditions. Seedling length, total fresh weight, total dry weight, and leaf area were calculated after 30 days. All the hydrogels performed well in stress conditions as compared to normal conditions. Xylan/lignin hydrogel and lignin hydrogel synthesized using citric acid performed best and showed highest growth under stress conditions. It was concluded that the synthesized hydrogels could be used effectively as an ingredient of soil culture media owing to their tendency to absorb and retain water properly.ThesisItem Open Access Nanocomposite of magnesium ferrite and manganese oxide as polyphenol oxidase mimic and photocatalyst(Punjab Agricultural University, Ludhiana, 2022) Harmilan Kaur; Manpreet KaurArtificial enzymes have received immense interest due to their exceptional properties such as high stability and low-cost. Polyphenol oxidase enzyme mimic is well known for its contribution in the field of food industry, biosensors, medicine and water remediation. In the present study, Mn3O4 and MgFe2O4 nanoparticles and nanocomposites were synthesized by sol-gel and ultra-sonication methods. Their polyphenol oxidase (PPO) mimic activity was comparatively analyzed. The synthesized nanoparticles and nanocomposites were characterized by FT- IR, XRD, SEM-EDS, BET, and VSM. The results revealed that MgFe2O4@Mn3O4 possess unique catalytical features. XRD analysis of synthesized materials depicted crystalline nature. The PPO-like activity of synthesized NPs and NCs were analyzed using catechol and resorcinol as substrates. MgFe2O4@Mn3O4(1:2) were observed to be the best PPO mimic. Kinetic analysis under optimized conditions indicated higher binding affinity of nanocomposite as compared to pristine manganese oxide. MgFe2O4@Mn3O4 (2:1) showed to be best photocatalytic potential for catechol and resorcinol degradation in aqueous solution. The efficiency of degradation was put to the test in relation to the variation of several experimental parameters including: pH; nanoparticles dose and contact time These aforementioned parameters were optimized and examined for the influence that they exerted on the efficiency of degradation which involved the usage of the Box-Behnken design methodology. According to the ANOVA results that yielded a confidence level of 95 %, a high regression along with fitting values were obtained between the results of the experimental degradation of catechol and resorcinol and the predicted quadratic model. Thus, the present study indicated that a catalyst of MgFe2O4@Mn3O4 nanocomposite in different ratios have promising performance as photocatalyst and PPO-mimic for degradation of polyphenols.ThesisItem Restricted Evaluation of doped strontium ferrite nanoparticles functionalized with silica, carbon quantum dots and Cl-doped graphene for the removal of contaminants(Punjab Agricultural University, 2022) Grewal, Jaspreet Kaur; Manpreet KaurDoped spinel ferrites and their functionalized nanocomposites with silica (SiO2), carbon quantum dots (CQDs) and chlorine doped graphene oxide (Cl-GO) have attracted immense interest as adsorbents and photocatalysts for water remediation. This work reports the facile strategy for the synthesis and evaluation of Sr1-xTixFe2O4+δ, SiO2, CQDs, Cl-GO and their functionalized nanocomposites for the removal of Cd(II), As(III), p-nitrophenol, pendimethalin and martius yellow from contaminated water. The structural, magnetic, adsorptive and photocatalytic properties were comprehensively studied using different analytical techniques viz. XRD, XPS, FTIR, BET, VSM, TEM, SEM-EDS and 57Mӧssbauer spectroscopy. TEM micrographs revealed the decreased extent of agglomeration in Sr0.4Ti0.6Fe2O4.6 and Sr0.7Ti0.3Fe2O4.3 due to the introduction of non-magnetic Ti4+ ions. TEM image of Sr0.4Ti0.6Fe2O4.6-Cl-GO NC displayed wrinkled nanosheets of Cl-GO containing ferrite NPs with particle size of 25-30 nm distributed over their surface. The fabrication of core-shell nanostructures with SiO2 was clearly visible from their TEM micrographs. The trend for the percentage removal of heavy metals by adsorption and degradation of organic contaminants by photocatalysis in the descending order was found to be: Sr0.4Ti0.6Fe2O4.6-Cl-GO > Sr0.4Ti0.6Fe2O4.6-CQDs > Sr0.4Ti0.6Fe2O4.6@SiO2 > SiO2@Sr0.4Ti0.6Fe2O4.6 > Sr0.4Ti0.6Fe2O4.6. The increased adsorption potential of functionalized nanocomposites as compared to pristine NPs was attributed to the increased surface area, functional moieties, and decreased particle size. The higher photocatalytic efficiency of Sr0.4Ti0.6Fe2O4.6-Cl-GO nanocomposite could be ascribed to the fast charge transfer, stabilization and hindered recombination of electron-hole pairs at the interface of Cl-GO and Sr0.4Ti0.6Fe2O4.6 NPs. Box-Behnken Design (BBD) of response surface methodology was utilized for exploring the simultaneous effects of independent variables on the removal of heavy metal ions and organic pollutants using Sr0.4Ti0.6Fe2O4.6-Cl-GO nanocomposite. The best adsorbent and photocatalyst were also tested for spiked solution containing different metal ions and real life water matrices.ThesisItem Embargo Synthesis of pyrimidinone derivatives and their antimicrobial activity(Punjab Agricultural University, 2023) Baljinder Kaur; Utreja, DivyaAn efficient protocol has been used for the synthesis of pyrimidinone derivatives via a onepot three-component condensation reaction of aryl aldehydes, malononitrile and barbituric acid in aqueous conditions using tetrabutylammonium hydrogen sulfate. A simple procedure, short reaction time, high yields (78–93 %), broader substrate scope, easy handling of the catalyst and simple work-up, i.e., non-column chromatographic separation of the desired products were attractive features of this process. The structures of synthesized derivatives (4aj) were confirmed by spectral analysis. The in vitro antimicrobial activity of the compounds was determined by the agar well diffusion method against Dickeya sp. (Gram-negative bacteria) and Streptomyces scabiei (Gram-positive bacteria). The synthesized compounds exhibited zone of inhibition at 10.67 ± 0.33, 9.50 ± 0.29 and 10.75 ± 0.14 mm in diameter for (4f), (4g) and (4j) respectively against Dickeya sp., compared to Gentamicin as standard (zone of inhibition at 19.17 ± 0.22 mm). The compounds were found to be potent towards the antioxidant activity. Using H2O2 scavenging assay, the derivatives (4g), (4j), (4i) and (4f) emerged to display promising antioxidant activities with inhibition percentages at 82.01 ± 0.28, 81.57 ± 0.34, 80.97 ± 0.19 and 76.97 ± 0.29 respectively, similar to the ascorbic acid and gallic acid (percent inhibition of 80.46 ± 0.32 and 79.51 ± 0.10, respectively) used as reference standards.ThesisItem Embargo Chemical composition and antifungal potential of kalonji (Nigella sativa L.) seeds and clove (Syzygium aromaticum) essential oils and their major constituents(Punjab Agricultural University, Ludhiana, 2022) Akansha; Kaushal, SoniaThe present study investigates the chemical composition and antifungal potential of kalonji (Nigella sativa L.) seeds and clove (Syzygium aromaticum) buds essential oils and their major constituents. The kalonji seeds and clove buds essential oils were extracted by hydrodistillation and characterized by Gas Chromatography-Mass Spectrometry. Thymoquinone (18.07%) and eugenol (68.64%) were major compounds in kalonji seeds and clove buds essential oils respectively and were isolated by column chromatography. Both the essential oils and their major compounds were tested for their antifungal activity against Colletorichum gloeosporoides and Penicillium digitatum using poison food technique. Among the essential oils, clove buds essential oil was more effective having MIC values of 18 and 35 ppm against P. digitatum and C. gloeosporoides respectively. Among the major compounds, thymoquinone was more effective having MIC values of 7.0 and 8.5 ppm against P. digitatum and C. gloeosporoides respectively. The synergistic interaction of kalonji seeds / clove buds essential oils and thymoquinone /eugenol against above said fungi was tested by checkerboard method. The combination of eugenol and thymoquinone showed a synergistic interaction against P. digitatum (FICI: 0.48). Molecular docking studies of major compounds present in kalonji seeds and clove buds essential oil suggested that thymoquinone bound effectively with targeted fungal protein i.e., α-β-tubulin with the maximum binding energy of -5.15 kcal mol-1 . Hence, thymoquinone and combination of thymoquinone and eugenol present as major compounds in kalonji seeds and clove buds essential oils can be used as natural and ecofriendly antifungal agents against C. gloeosporoides and P. digitatum respectively.ThesisItem Embargo Chemical modifications of paddy straw xylan for the preparation of sustainable bio films(Punjab Agricultural University, Ludhiana, 2022) Kapil, Sristhi; Mankoo, Ramandeep KaurThe present study involved valorization of paddy straw by conversion of its constituent polymer xylan and chemically modified xylans into biofilms. Paddy straw was found to contain 44% cellulose, 22% hemicellulose, 8% lignin, 21% extractives, and 5% silica. Hemicellulosic xylan (19.94%) extracted with 10% NaOH (85°C, 2.6 h) was chemically modified to acetylated (AX) and carboxymethylated xylan (CMX) followed by their structural characterization by FT-IR and NMR spectra. Xylan was found to show maximum antioxidant potential (Ascorbic acid equivalents value 7.6 at 10 mg/ml) and CMX showed highest antibacterial potential (Inhibition zone diameter of 31.80 and 29.75 mm against Bacillus and Pseudomonas, respectively). Biofilms were prepared by reaction of xylan/modified xylan (1 and 2%) with polyvinyl alcohol using eco-friendly and cheap crosslinker citric acid and glycerol as plasticizer. FT-IR and SEM analysis were performed for biofilms characterizations. 2% xylan biofilms showed maximum inhibition (94.25%) of DPPH radical at 4 mg/ml. 2% CMX biofilms exhibited maximum antibacterial effectiveness with diameter of zone of inhibition 33.5 and 30.5 mm against Bacillus and Pseudomonas, respectively. This may be due to large number of undissociated COO- ions (citric acid) in CMX biofilms which was evident from lesser cross-linking observed in their SEM images. 2% CMX biofilms also showed highest biodegradation (86.5%) which may be attributed to formation of ether bonds along with ester bonds which leads to their fast degradation. Owing to good bioactive properties of prepared biofilms, it was concluded that these can be appropriate material for food packaging by replacing synthetic plastics.ThesisItem Embargo Preparation and Evaluation of Citronella and Lemon Grass Essential Oil Formulations Against Phomopsis Blight of Brinjal(Punjab Agricultural University, Ludhiana, 2022) Pooja; UrvashiThe present investigation deals with the extraction and chemical investigation of lemon and citronella grass essentiall oil and their emulsifiable concentrates (EC) formulation as fungicide against Phomopsis vexans. GC-MS analysis of the lemongrass EO revealed citral B (37.75%), citral A (21.93%) and farnesene (8.80%) as the major compounds whereas citronella grass EO showed citronellal (24.80%), geraniol (21.88%) and citronellol (14.58%) as major compound. EC formulations comprising of EO were prepared using castor oil as solvent and emulsifier blends (10%) with hydrophilic-lipophilic balance (HLB) value (12.86) suitable for the EO formulation. Among six EC formulations prepared from each EO, CF6 and LF6 type performed well in terms of emulsion stability, cold test, accelerated storage and foam test indicating feasibility for their commercial production. EC50 value of citronella, lemon grass EO and EC formulations CF6 and LF6 were 0.0087, 0.0098, 0.009 and 0.0126, respectively which were tested by Poisoned Food Technique and were compareable with Zineb 75 WP. CF6 and LF6 formulation at 0.1% inhibits the growth of P. vexans under field condition. Among all the tested components, CF6 formulation was better as compared to LF6 formulation. EC formulations are the better way for the effective application of EO under in vitro and in vivo condition as they are easy to prepare and can be used ecofriendly.ThesisItem Embargo Evaluation of trace elements and heavy metal analysis in commercial tea(Punjab Agricultural University, Ludhiana, 2022) Manbeer Singh; Tandon, RituTea is one of the world's most popular non-alcoholic beverage owing to its nutritional value and antioxidant potential due to catechins and flavonoids. Recently, the consumption rate of various teas has increased rapidly. Stringent guidelines laid by food regulations by FSSAI, EU, USFDA etc. for tea have made the analysis of inorganic metal contaminants as a mandatory requirement for its sa consumption as well as export. ICP-MS (inductively coupled plasma mass spectrometry) is among the most sensitive equipment for analysis of the same at trace and ultra-trace levels but with the use of validated method. The study was therefore planned to validate ICP-MS method for analysis of heavy metals and trace elements in three types of tea viz. green, black and herbal along with their nutritional status. High sensitivity was observed with low LOD and LOQ values for both heavy metals (Chromium, Arsenic, Cadmium, Nickel, Mercury, Lead) and trace metals (Copper, Zinc, Selenium, Cobalt) in various teas in the range of 0.003 to 0.620 µg/kg and 0.010 to 2.048 µg/kg respectively. The linearity for all metals was obtained with R≥ 0.995 and accuracy of the method was established by spiked experiments where recoveries were achieved in the range of 75 to 125%. Precision data indicated very small %RSD ranging 0.46% to 13.44% For nutritional analysis, total polyphenol content (TPC) and antioxidant capacity of three tea, was carried out in relation to steep time where 15 min steep time was optimized for maximum extraction of the both. The study indicated good correlation among the both parameters.
