Browsing by Author "ALISHBA AYUB"

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    Synthesis and optimization of covalent−organic frameworks for photocatalytic degradation of methylene blue in water using box−behnken design
    (UMT, Lhr, 2024) ALISHBA AYUB
    The biosphere is heavily impacted by environmental contamination caused by human activities, industrial output, nuclear power generation, and organic processes. These activities cause the discharge of a variety of hazardous compounds into the environment, notably heavy metal ions, organic dyes, and new pollutants such as food biotoxins and additives. Even in relatively small amounts, these contaminants pose severe health concerns to people. Organic contaminants in water are extremely harmful to both the environment and human health because of their mutagenic, poisonous, and carcinogenic properties. Various methods for the removal of water pollutants have been developed, including membrane processes, absorption, and photocatalytic degradation. Photocatalytic degradation is a highly effective and energy-efficient process that converts contaminants into tiny molecules that dissolve spontaneously. The semiconductor photocatalyst is an important part of the photocatalytic decomposition process. A variety of photocatalysts have been studied, including polymer-based materials, inorganic metal oxides/sulfides, metal-organic frameworks, graphitic carbon nitride and covalent organic frameworks. Covalent organic frameworks (COFs) are crystalline porous organic materials made up of organic building blocks held together by strong covalent bonds. Diverse COFs have been designed and deployed in areas such as sensing, gas storage, optoelectronics and catalysis. COFs have a large surface area, extended π-conjugate framework, and excellent stability, making them ideal for photocatalysis. COFs have attracted a lot of attention as photocatalysts because of their ability to degrade dyes with minimal energy consumption. In this presented work, melamine and 2,5-diydroxyterephthalic acid (DHTA) were used to synthesize a covalent organic framework (COFDHTA-MEL). The synthesized substance was fully characterised using fourier transform infrared spectroscopy. COFDHTA-MEL was employed as a photocatalyst for the breakdown of cationic methylene blue (MB) dye in aqueous solution under sunlight. This study is focused on three key factors including catalyst dosage (A), radiation time (B), and pH of solution (C), to evaluate their impact on MB removal. For the optimization of dye degradation process, a Box-Behnken Design (BBD) statistical research was carried out in combination with Response Surface Methodology (RSM). Parameters were chosen within suitable ranges through experiments involving varying catalyst amounts, pH and assessing radiation times. In this methodology, total 17 experiments were designed out of which the optimal dye degradation conditions were found to be 0.075 g L-1 of catalyst, 90 minutes of radiation, and a pH of 6. Moreover, the projected coefficient of regression (R2) value according to these optimal circumstances was 98%, indicating a strong correlation between prediction and experimental observation. These findings show that the COF has tremendous potential as a photocatalyst for removing organic dyes from water. Covalent Organic Frameworks offer promising future prospects as photocatalysts due to their large surface area, tunable porosity, and structural versatility. Research focusing on improving light absorption, stability, and broad-spectrum activity can significantly improve their efficiency. COFs can be tailored for environmental remediation, such as water purification as well as energy conversion processes like hydrogen production. Their incorporation with other materials can further enhance their photocatalytic performance, making them invaluable for sustainable solutions.