http://dspace.dtu.ac.in:8080/jspui/handle/123456789/22 2026-04-28T04:02:35Z 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 http://dspace.dtu.ac.in:8080/jspui/handle/repository/22532 Title: PHYTOCHEMICAL INVESTIGATION OF SOME UNDERUTILIZED CEREALS IN INDIA Authors: SHARMA, RITU Abstract: The thesis titled “Phytochemical investigation of some underutilized cereals in India” focuses on the comprehensive exploration of the bioactive compounds, nutritional analysis, and biological profiling of the selected underutilized cereals of India. The present thesis aimed to investigate the phytochemical and biological profiling of selected underutilized cereal samples of India - adzuki beans (Vigna angularis), mung beans (Vigna radiata), horse gram/kulthi beans (Macrotyloma uniflorum), little millet (Panicum sumatrense), and rice beans (Vigna umbellata), followed by proper identification, authentication, and sequential Soxhlet extraction using different polarity solvents and to further evaluate their potential for functional food applications. All five selected cereal samples were subjected to a detailed proximate analysis, fatty acid methyl ester analysis, elemental analysis, amino acid profiling, and phytochemical analyses using GC-MS and UHPLC-QTOF-MS to establish a comprehensive profile of their nutritional and metabolite content. The phytochemical screening focused on both qualitative and quantitative estimation of major as well as minor phytoconstituents such as phenolics, flavonoids, tannins, saponins, alkaloids, and phytosterols, using GC-MS and UHPLC-QTOF-MS. Based on the distinct phytochemical profile and literature evidence, adzuki bean and mung bean were selected for the evaluation of anti-obesity activities through in-vitro pancreatic lipase and HMG-CoA reductase inhibition assays. The nutritional assessment highlights that these underutilized cereals are a valuable source of essential macronutrients - namely carbohydrates, protein, and dietary fiber - in addition to a wide array of amino acids (essential, non-essential, and non-proteinogenic amino acids). The phytochemical profiling of these underutilized cereals revealed that the different solvent extracts contained flavonoids, terpenoids, and phenols. Various secondary metabolites were identified using a non-targeted approach, which belong to several natural product classes, including flavonoids, sugars, amino acids, fatty acids, fatty acid derivatives, and other organic acids. Through a targeted approach, vi metabolites including catechin-7-O-glucoside, catechin, epicatechin, quercetin, gallo-catechin, gallic acid, caffeic acid, para-coumaric acid, and glycitein were identified using UHPLC-QTOF-MS. In-vitro anti-obesity activity revealed the effectiveness of adzuki and mung beans as potent HMG-CoA reductase and pancreatic lipase inhibitors. The findings of anti-obesity activities indicate that adzuki beans and mung beans can be utilized to prevent obesity and related disorders. This research not only emphasizes the nutritional and biological value of these lesser-known cereals but also explores the formulation and evaluation of novel breakfast cereals/flakes and nutritional cookies developed from underutilized legumes - Vigna radiata (mung bean) and Vigna angularis (adzuki bean)- as sustainable, plant- based interventions to combat obesity and related disorders. Incorporating these legumes enhances the formulations' protein, fiber, and micronutrient content and introduces bioactive compounds with significant health benefits like weight loss and cholesterol lowering benefits. An important milestone of this work was the commercial interest, leading to collaboration with Kalsubai Purest Company, a local food enterprise based in Maharashtra. Based on my research formulations, their R&D team created a trial batch and is currently working toward market launch as a nutritious and functional food. The significance of this research was further recognized through an appreciation letter from Kalsubai Purest Company, acknowledging its practical value and real-world applicability. In addition to product development application of these underutilized cereals, we also investigated the potential of underutilized cereals’ mucilage and further explored their application by synthesizing mucilage-based hydrogels. For this purpose, we have explored four new sources of mucilage, namely adzuki beans, amaranth, proso millet, and little millet. The underutilized cereals’ mucilage application has been examined by developing hydrogels through the free radical copolymerization technique. This study demonstrated that the mucilage isolated from underutilized cereals might be a good feedstock for a hydrogel-forming agent, which can be explored in the food, cosmetics, and pharmaceutical industries. vii Overall, this work provides a comprehensive evaluation of the selected underutilized Indian cereals, identifying key bioactive metabolites and demonstrating their potential in the development of anti-obesity and cholesterol-lowering novel functional foods. The study not only contributes to scientific understanding of these neglected cereals but also supports their integration into sustainable food systems, promoting both nutrition security and agricultural biodiversity. 2025-10-01T00:00:00Z http://dspace.dtu.ac.in:8080/jspui/handle/repository/22514 Title: SYNTHESIS AND APPLICATION OF NATURAL POLYMER BASED HYDROGELS Authors: MANU Abstract: The depletion of fossil-based resources and increasing environmental concerns have intensified the search for sustainable, biodegradable, and eco-friendly materials. Natural polymer-based hydrogels derived from humic acid (HA), lignin, and lignite have emerged as promising candidates due to their multifunctional properties, including their ability to enhance soil moisture retention, control agrochemical release, adsorb pollutants, and contribute to energy storage applications. This research focuses on the synthesis, characterization, and application of these bio-based hydrogels, systematically investigating their structural, thermal, rheological, and morphological properties to optimize their performance for various applications. The study begins with a comprehensive literature review exploring the significance of humic acid, lignin, and lignite in hydrogel synthesis and their applications in agriculture, and environmental remediation and energy storage. Key research gaps were identified, highlighting the need for more extensive studies on the multifunctionality of these natural polymers in hydrogel systems. The first experimental phase involved the synthesis and application of a lignosulfonate-grafted sodium acrylate hydrogel (LS-g- SAH) for controlled urea release. This hydrogel demonstrated 60% release of urea from LS-g-SAH in 24 h, significantly reducing nutrient leaching and improving soil fertility. The soil's water-holding capacity remarkably raised from 21.27 to 77.3 g using synthesized hydrogel. Also, the water evaporation rate reduced from 99 to 76.69% of the total added water. Enhanced water retention further contributed to increase in plant growth efficiency, making it a potential alternative to conventional fertilizers. vi Following this, a humic acid-grafted sodium acrylate hydrogel (HA-g-SH) hydrogel was developed for controlled pesticide release, taking dinotefuran as model pesticide. The hydrogel enabled sustained pesticide release over 49 h 78.45%, improving bioavailability and increasing pest control efficiency of dinotefuran. This approach minimized environmental toxicity by reducing pesticide leaching in soil and water. To further enhance the stability of pesticides, a lignite- sodium acrylate hydrogel (Lt-g- SAH) was synthesized for UV protection of dinotefuran. The study revealed that after 30 days of UV irradiation, Lt-g-SAH group exhibited remarkable stability, with only a marginal decrease of 1.58% in Dinotefuran release, resulting in a final concentration of 41.73 mg. In stark contrast, the Ctrl group experienced a substantial reduction of 28.11% in Dinotefuran release, with the final concentration diminishing to 25.42 mg. This marked disparity in pesticide release profiles can be attributed to the differential susceptibility of the formulations to UV-induced degradation over time. Based on the controlled-release capabilities, HA-g-SAH, LS-g-SAH, and Lt-g-SAH hydrogels were explored for comparative delivery of thiamethoxam. These hydrogels facilitated a controlled pesticide release for 49 h, reducing pesticide’s application frequency, and minimizing environmental contamination. The release pattern followed the Fickian release mechanism as stated by the Korsmeyer-Peppas model and the Weibull model. The swelling index revealed a distinct order, with HA-g-SAH exhibiting the highest absorbency, followed by LS-g-SAH, Lt-g-SAH, and the control group. Moreover, the synthesized hydrogels demonstrated a significant impact on reducing soil water evaporation rates from 99 to 72.85% (HA-g-SAH), 74.79% (LS-g- SAH), 78.23% (Lt-g-SAH), and 85.23% (Ctrl) of the total added water on the 54th day. vii Beyond their agricultural applications, these hydrogels were investigated for their potential in textile wastewater treatment. The comparative study demonstrated that HA- g-SAH, LS-g-SAH, and Lt-g-SAH hydrogels exhibited high adsorption capacities for methylene blue (MB), a common industrial dye, Under optimized conditions, HA-g- SAH achieved a maximum removal efficiency of 93.7 ±1.1% at 323.15 K, significantly outperforming LS-g-SAH (92.4 ±1.3%), Lt-g-SAH (82.4 ±1.4%), and the control (Ctrl) hydrogel (67.9 ±0.9%). The presence of functional groups in humic acid and lignin enhanced their binding affinity, making these hydrogels promising candidates for large- scale wastewater treatment applications. This thesis provides a comprehensive analysis of natural polymer-based hydrogels and their potential to address critical challenges in agriculture, and environmental management. The findings suggest that humic acid, lignin and lignite based hydrogels can significantly reduce environmental pollution, enhance soil fertility, improve plant growth, and remove contaminants from water. Further research should focus on optimizing the scalability, durability, and biodegradability of these hydrogels to maximize their practical benefits and commercial viability. 2025-11-01T00:00:00Z