Facile Synthesis Of Novel Hybrid Nanomaterials And Their Catalytic And Biological Applications

Water pollution by organic contaminant is a severe environmental concern for mankind and ecosystem.Several industries such as cosmetics,textile,plastics,paper,food processing,etc.use large scale amount of dyes.The discharge of dyes into hydrosphere?rivers,lake,ocean,etc.?has posed many challenges to human society because of the non-biodegradability of their nature.In addition,very low concentration of dyes?<1 mg/L?is visible and aesthetically undesirable which affects significantly the water body.Similarly,healthcare-associated infections in hospitals cause significant economic consequences on healthcare systems.Most of nosocomial infections are produced by drug-resistant or multi-drug resistant bacteria.The design of new antibacterial materials has been one of the most important challenges in the development of new strategies for the control of healthcare-associated infections.Besides,a strong interest in natural substances with high antioxidant activity has been particularly observed.Indeed,oxidative stress induced by multiple factors is the main cause of many pathological conditions such as inflammation,cancer,coronary heart disease and even skin aging.To overcome all these problems,the quest for designing novel materials has become a great challenge for researchers aiming to address the urgent real-world demands.To meet this target,significant attention has been paid to develop new routes toward designing and synthesizing of materials owning desirable properties.Hence,in this direction,efforts have been undertaken to introduce superior functionality materials based on combination of multiple components with minimum production cost.This work is devoted to do research and construct novel hybrid materials and to apply on different applications with enhanced efficiency,excellent stability and profound reusability.These are the main themes that have been studied in this thesis:1.Herein,we reported an effectual method for designing a novel form of nanozyme laccase mimic namely Cu/H3BTC,using copper ions and 1,3,5-benzene tricarboxylic acid?1,3,5-H3BTC?.This Cu-based metal-organic framework?MOF?was synthesized through a simple procedure of mixing of two usual reagents at room temperature.Amido Black 10B?AB-10B?was chosen as a model dye for degradation consequences.Results showed that Cu/H3BTC MOF revealed significantly higher catalytic efficacy under certain conditions like high pH,extreme temperature,and high salt condition and have long-term storage stability,which can lead significant decline in catalytic activity of laccase.In addition,the degradation of AB-10B was up to 60%after ten cycles,showing good recyclability of Cu/H3BTC MOF.The UV/visible spectral changes clearly showed that Cu/H3BTC MOF was an effective laccase mimic for the degradation of azo dye AB-10B,which was degraded more easily within the time duration of 60 mins.The Cu/H3BTC MOF also possessed fundamental activities like laccase with regard to oxidation of the phenolic compounds.Moreover,a technique for the quantitative detection of epinephrine by Cu/H3BTC MOF was established.These findings help to understand the laccase-like reactivity and provide a basis for future design and application of metal-based catalysts.2.The objective of this paper was to design a more effective antibacterial agent to overcome the problem of fast-growing bacterial resistance.The results showed that Cu/H3BTC MOF exhibited notable antibacterial activity towards Staphylococcus aureus?S.aureus?and Escherichia coli?E.coli?and could significantly disrupt the cell membrane,resulting in discharge of cell constituents.In addition,morphological changes were elucidated by using scanning electron microscope?SEM?.SEM photographs demonstrated noticeable and apparent changes in the morphology of bacterial cells,signifying cell damage which was further confirmed by confocal laser scanning microscopy?CLSM?test.Furthermore,a result of agarose gel electrophoresis?AGE?has shown that Cu/H3BTC MOF could enter to the bacterial cells by impairing cell membranes and inhibiting the synthesis of DNA.These findings indicated that Cu/H3BTC MOF would be a potent antimicrobial material to hinder the growth of pathogenic microbes.3.The development of eco-benign experimental procedures for the synthesis of nanomaterials is a fundamental developing branch of green nanotechnology.In this paper,green synthetic route was used to synthesize novel Au@Fe₂O₃ nanocomposite using citrus sinensis fruit extract as a reducing and stabilizing agent.The as synthesized Au@Fe₂O₃ nanocomposite was successfully characterized by UV-visible spectroscopy?UV?,X-ray diffraction?XRD?,Scanning electron microscope?SEM?,EDX,Fourier transform infrared?FT1R?spectrophotometry and Zeta potential.The results from UV-vis spectroscopy showed two SPR peaks of Fe₂O₃ and Au coated at 290 and 520 nm respectively.XRD result confirmed the crystallinity of Au@Fe₂O₃ Au@Fe₂O₃ nanocomposite showed better antioxidant activity to effectively scavenge DPPH.The Au@Fe₂O₃ has also been tested for antibacterial activity which showed an effective antibacterial activity against multi drug resistant E.coli and Bacillus subtilis.Furthermore,Au@Fe₂O₃ also demonstrated better photo catalytic activity for methylene blue?MB?degradation.We proposed that the existence of organic acids?citric acids?also played a significant role in the stabilization of Au@Fe₂O₃,and plants?Citrus sinensus?containing such component might be more effective for the green synthesis of Au@Fe₂O₃ nanocomposite.The findings of this study proved the overwhelming therapeutic and photocatalytic potential of bio-inspired Au@Fe₂O₃ nanocomposite which could be a novel candidate for the effective remediation of microbes and toxic organic pollutants.