http://dspace.dtu.ac.in:8080/jspui/handle/123456789/22 2026-07-03T14:59:00Z http://dspace.dtu.ac.in:8080/jspui/handle/repository/22761 Title: DEVELOPMENT OF C-F BOND IN ORGANIC MOLECULES AND THEIR APPLICATIONS Authors: PRAKASH, CHANDRA; SINGH, RAM (SUPERVISOR) Abstract: The present work has been carried out to design the methodology and synthesis of aliphatic and aromatic fluoroorganic compounds containing the C-F bond and overcome some of the limitations reported in the literature. Chapter 1 provides a general description of fluoro-organic chemistry, the effect of fluorination on organic compounds, and their applications in various fields. The literature discussed in this chapter covers various fluorination mechanisms, including direct fluorination, electrochemical fluorination, nucleophilic fluorination, electrophilic fluorination, and radical fluorination, used for the synthesis of fluoroorganic compounds. This chapter also covers the different reagents used for the generation of the C-F bond in aliphatic and aromatic organic molecules. Chapter 2 covers the materials and methods, which describe different materials and instruments used in experimentation. The section explains the procedures for the synthesis of fluoroacetophenone derivatives and the synthesis of 3,7-difluorinatedoxindole derivatives. The methods for the -fluorination of acetophenone derivatives in a Fe(NO3)3·9H2O/KBr/TBAF mediated reaction and synthesis of 3,7-difluorinated oxindole derivatives, from indoles via Selectfluor mediated fluorination have been given in this chapter. This chapter also mentions the procedure for the synthesis of 3-indoleacetic acids, used as raw material. The characterisation data of the synthesized fluorinated compounds, as well as the synthesized starting materials, with different spectroscopic techniques, the determined melting points, and physical states of the synthesized compounds are also mentioned in this chapter. The general Method for the evaluation of flame retardancy of the selected synthesized compounds as per UL 94 has also been covered in this chapter. Chapter 3 is the results and discussion, which covers a detailed explanation about the design of the methodology for fluorination, optimization of reaction conditions, and synthesis and characterization of different fluorinated molecules. It also covers the detailed procedure for the preparation of polyurethane films, their testing, and results. To synthesize the 3,7-difluorinated oxindole derivatives, the ester of indoleacetic acid was synthesized by reaction with various alcohols. Chapter 4 summarized the work done, discussed the prospects and societal impact of the work. This chapter is followed by the references used in the thesis. 2025-10-01T00:00:00Z http://dspace.dtu.ac.in:8080/jspui/handle/repository/22747 Title: ELECTROCHEMICAL SENSOR FOR ANTIBIOTIC DETECTION Authors: HUDDA, DIVYA; KUMAR, D. (SUPERVISOR) Abstract: The research work presented in this thesis discusses the fabrication of an electrochemical sensor utilizing a molecularly imprinted polymer approach, which provides quantitative information for detecting antibiotic residues in various fields. Antibiotics are a class of chemical compounds that are extensively used to cure and prevent infectious diseases in humans, animals, and aquaculture due to their bacteriostatic and bactericidal actions. However, most of these antibiotics are non-biodegradable and can be excreted in the form of metabolites in the environment through human or animal excreta, wastewater discharge, and agricultural land runoff. Additionally, the misuse of veterinary medicine can lead to residues in animal-derived foods, including milk, eggs, meat, and fish. These residual antibiotics or their metabolites can lead to several problems, including bacterial resistance, allergic reactions, liver damage, and cancer, thus posing a huge threat to human and animal health. Therefore, developing a sensitive and effective detection technique is crucial and necessary to accurately monitor trace amounts of antibiotic contamination, thereby protecting living beings from its injurious effects. The analytical methods commonly used for antibiotic detection are based on spectroscopic and chromatographic techniques, which have certain limitations, including long analysis times, complexity, and high expenses associated with operating highly specialized equipment, as well as low sensitivity. To overcome these limitations, we require a new method that is simple, costeffective, has a low detection limit, and is easy to use. Recently, electrochemical sensors have emerged as an attractive alternative to these conventional techniques due to their fast response, high sensitivity, the possibility of real-time analysis, and cost-effectiveness. However, natural receptors, such as antibodies, enzymes, and hormones, are utilized by these electrochemical sensors as their recognition components. Despite their high selectivity and sensitivity, they remain costly and sensitive to environmental factors. In this context, a molecularly imprinted polymer (MIP) is a suitable alternative due to x its ease of preparation, high selectivity and low cost. MIPs are synthetic materials with high recognition binding cavities that target the analyte. MIP films are fabricated via the electropolymerization of functional monomers in presence of template molecules (analyte) on the surface of electrode. Following electropolymerization, the embedded template molecules are extracted from the polymer matrix, leaving behind the cavities that resemble the template molecules’ size, shape, and functional groups. Although MIPs have garnered considerable attention due to their unique recognition ability and high selectivity efficiency, they have several drawbacks, including low sensitivity, poor adhesion to the electrode surface, and high diffusion barriers. In this regard, incorporating 2D materials with the MIP electrochemical sensor can enhance the imprinted cavities and facilitate electron transfer. Further, a novel two-dimensional material, MXene, an emerging transition metal carbide or carbonitrides, has been recognized for its electrochemical applications due to its high surfaceto-volume ratio, superior hydrophilicity, good electrical conductivity, large specific area, and superior electron transport ability. Integrating MXene with other components or functionalizing its surface can impart additional advantageous properties to the resulting composites through synergistic effects, thus enhancing the overall biosensing capabilities. This work mainly focuses on the synthesis, characterization and application of MXene (Ti3C2Tx) and its composites with TiO2, CuS, and Ag for the fabrication of a highly sensitive and selective MIP-based electrochemical sensor for the detection of antibiotic, i.e., levofloxacin. The synthesized material was electrophoretically deposited on the ITO-glass surface and then the modified electrode was coupled with the MIP film through electropolymerization. Furthermore, electrochemical response studies were performed using DPV and EIS techniques. Finally, the applicability of the fabricated platforms was validated with spiked real samples which prove their efficiency. 2026-03-01T00:00:00Z http://dspace.dtu.ac.in:8080/jspui/handle/repository/22674 Title: APPLICATIONS OF MEMBRANE-BASED OPERATIONS IN SEPARATION OF NATURAL PHENOLIC COMPOUNDS Authors: TIWARI, ASHWANI KUMAR Abstract: With the growing global population, there is an increasing need to develop sustainable and green separation processes for high-value bioactive compounds. Naturally occurring phenolic compounds such as betanin and rutin have gained considerable importance in the food and pharmaceutical industries; however, existing separation methods often rely on solvent-intensive, energy-demanding, or non-scalable techniques that compromise product purity and biological activity. Although membrane-based processes have been explored for polyphenol recovery, there remains a lack of systematic, model-integrated, and scale-up-oriented studies that bridge laboratory experimentation with industrial feasibility, particularly for real feed streams. In this context, the present thesis makes a distinct contribution by establishing nanofiltration (NF) as a quantitatively optimised and industrially translatable platform for the selective concentration of two structurally different phenolic compounds, namely betanin and rutin. A self-assembled NF setup using HFT-NF 150 membranes is employed to generate a comprehensive experimental dataset, wherein the individual and interactive effects of pressure, feed concentration, and feed flow rate on permeate flux and solute rejection are rigorously evaluated. Unlike prior studies that report only empirical trends, this work integrates a three-parameter Spiegler-Kedem transport model to extract membrane reflection coefficients, solute permeability, and hydraulic permeability, thereby providing mechanistic insight into solute-membrane interactions and enabling predictive validation of experimental performance. A further aspect of this research is the application of variance-based global sensitivity analysis to membrane separations, allowing the quantitative ranking of operating and transport parameters by their influence on flux and rejection for phenolic solutes. This approach moves beyond conventional one-factor-at-a-time analyses and establishes a robust framework for rational process optimisation. Crucially, the thesis extends beyond model solute systems to address the separation of betanin from its natural matrix, beetroot juice, an area scarcely examined in existing literature. Comprehensive fouling studies using multiple theoretical fouling models are performed to elucidate viii dominant fouling mechanisms, quantify flux decline behaviour, and assess long-term operational stability under realistic feed conditions. These results provide actionable design insights to mitigate fouling and extend membrane longevity. Finally, scale-up simulations grounded in experimentally derived transport and sensitivity parameters demonstrate the technical feasibility of translating laboratory findings into an industrial-scale NF unit. Collectively, this thesis offers a unified experimental-modelling-scaling framework for phenolic compound recovery, delivering original contributions in mechanistic understanding, optimisation strategy, real-feed validation, and process design that advance the state of the art in sustainable membrane-based separations. 2026-01-01T00:00:00Z http://dspace.dtu.ac.in:8080/jspui/handle/repository/22536 Title: SYNTHESIS OF TERNARY LAYERED DOUBLE HYDROXIDES AND THEIR COMPOSITES FOR ENVIRONMENTAL APPLICATIONS Authors: PATHAK, JIGYASA Abstract: The thesis focuses on the synthesis of layered double hydroxides (LDH) and their composite materials under ambient conditions, with emphasis on environmental applications. The structure, morphology, thermal stability, optical and catalytic behaviour of the synthesized LDHs were studied using various instrumentation techniques. Further, the synthesized lattice was utilized for the elimination of toxic effluents i.e. nitroarene compounds (NACs) and anionic azo dyes from wastewater. In addition, ZnCuNi-LDO and ZnCuCe-LDO were used as photocatalysts for the degradation of Ciprofloxacin (CIF) drug and cationic/anionic azo dyes. Afterwards, a smartphone-based approach was opted for the determination of dye concentration. The results obtained were in agreement with those obtained from UV-Vis spectrophotometer. Upon the successful formation of layered structure, the structure regaining capability i.e. memory effect and anion exchange properties were investigated. The PXRD and FTIR results confirmed the structure regaining ability of the lattice i.e. memory effect as well as the exchange of anion in the interlayer region. Moreover, the synthesis of carbon nitride-based composite materials was also carried out with synthesized LDHs, and were later used for the degradation of p- NP and Congo Red (CR). Subsequently, the magnetically separable Fe3O4/SiO2/ZnCuNi- LDH composite was synthesized using electrostatic self-assembly method. The composite was utilized for the catalytic hydrogenation of p-NP and reduction of cationic dye Rhodamine B (RhB). 2025-12-01T00:00:00Z