The widespread contamination of water resources by organic and inorganic pollutants, primarily from industrial effluents, presents significant environmental and health challenges. With its thorough exploration of the effectiveness of various methods for eliminating contaminants from aqueous solutions, this thesis offers key insights. It specifically delves into the potential of photocatalysis and adsorption, two promising water purification methods, thereby underlining this thesis's relevance and importance. A bioinorganic hybrid membrane consisting of cellulose fiber to grow the Bi₄O₅Br₂/BiOBr semiconductor nanosheet. CM/Bi₄O₅Br₂/BiOBr was synthesized at a low temperature directly on the cellulose membrane (CM) to preserve the carboxylic and hydroxyl functional groups on the surface that are responsible for the adsorption of metal ions. The bioinorganic membrane was tested for the photodegradation of RhB and MB dye and the adsorption of Co(II) and Ni(II). A photoactive catalyst, lignin/Bi₄O₅Br₂/BiOBr bioinorganic composite consisting of lignin substrate to grow the Bi₄O₅Br₂/BiOBr semiconductor nanosheet. The functional groups on the lignin substrate's surface responsible for the adsorption of metal ions were preserved. The composite was tested for the photodegradation of RhB and MB dye and adsorption of Co(II), Ni(II) and Pb(II). BiOBr nanosheets were synthesized via the solvothermal method. The growth of the BiOBr was controlled using an organic capping agent. The catalyst was tested for the photodegradation of RhB dye. The Ni and Co metal-organic frameworks (MOFs), MIL-100(Ti, Ni)/BiOBr, and MIL-100(Ti, Co)/BiOBr were fabricated via the solvothermal method to form a heterojunction. The catalyst was tested for the photodegradation of RhB dye. Numerous analytical techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM, EDX) mapping, X-ray photoelectron spectroscopy (XPS), and others, were used to confirm the catalysts' fabrication.  This thesis, with its emphasis on advancements, practical applications, and future directions in the field of organic dye degradation and heavy metal adsorption, aims to provide a robust framework for developing sustainable and scalable solutions for water purification.