Browsing by Author "Uma, U."

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A Review on Heavy Metal Adsorption Using Nanocomposites for Wastewater Treatment
(Springer, 2025) Uma, U.; Gopi Kumar, S.
An introduction of heavy metals through anthropogenic activity into water streams polluting the environment. The effective requirement for removal of heavy metal from wastewater and utilize the treated water for managing the water scarcity among population over the world. The studies on carbon-based nano-materials and its utility in heavy metal removal are improving incredible attraction over the past decades. Carbonaceous nanomaterials exhibit the distinctive properties of hybridized carbon bonds with extraordinary physical–chemical properties at a nano-scale. The special attention focused on different nanomaterials such as graphene-oxide and, carbon nano-tubes. This present study reviews the utilization of nanomaterial composites in the adsorption of heavy metals in the wastewater purification. Further the innovation, forthcoming development, challenges of cost-effective and environmentally acceptable nanomaterials and its interaction between adsorbents for water purification are discussed and reviewed in this article. This review concluded that nanomaterials have many unique morphological and structural properties that qualify to be as effective absorbents to solve several application environmental purifications. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.
Enhanced photoresponse and efficient charge transfer in porous graphene-BaTiO3 nanocomposite for high performance photocatalysis
(Elsevier Ltd, 2023) Bhat, D.K.; Bantawal, H.; Uma, U.; Shenoy, U.S.
Porous graphene-BaTiO3 (PGBT) nanocomposite was synthesized by a simple one pot solvothermal method and its photocatalytic activity was evaluated by studying its efficiency in degrading methylene blue (MB) dye under visible light. The combination of experimental and theoretical analysis revealed enhanced photocatalytic activity of the PGBT composite, which could be attributed to (i) the interaction of BaTiO3 nanoparticles with PG sheets via Ba–C bond, (ii) reduced band gap due to the introduction of hybridized states leading to increased absorption in visible range and (iii) large surface area which provides more active sites for the efficient adsorption of MB dye. The formation of Ba–C bond proved to be highly advantageous for the efficient transport of photogenerated charge carriers, thereby suppressing the recombination of charge carriers. The synthesized nanocomposite showed three times higher photodegradation efficiency compared to BaTiO3. In addition to this, the composite also showed an excellent cyclic stability indicating its suitability as an effective photocatalyst for the environmental remediation. © 2023 Elsevier B.V.
Insights into the dopant engineering in copper-doped SrTiO3 nanocubes
(Elsevier B.V., 2023) Bhat, D.K.; Uma, U.; Shenoy, U.S.
In recent years, semiconductors have captivated the scientific community due to their potential to harness the abundant and sustainable energy from the sun to effectively treat water pollutants. Herein, we present combined theoretical and experimental insights into the enhanced activity of photocatalytic degradation of cationic and anionic dye viz methylene blue (100% in 90 min) and rose bengal (99.6% in 30 min) in presence of copper doped SrTiO3 catalyst. First principles density functional theory study reveals the introduction of additional states due to copper doping resulting in the decrease in the band gap making it visible light active. Experimental analysis reveals a change in the morphology from broccoli type assorted spherical particles to cubic shaped structures resulting in three times increase in the surface area as a consequence of doping copper. The adopted one pot solvothermal approach not only resulted in materials with high cyclic stability but also resulted in a versatile material, which can be applied for degradation of other dyes. © 2023
Nanocubic Copper-Doped SrTiO3 for Photoreduction of Cr(VI) and Photodegradation of Methyl Violet
(American Chemical Society, 2023) Uma, U.; Shenoy, U.S.; Bhat, D.K.
Visible light photocatalysis using nanomaterials is a pragmatic approach for efficiently eliminating pollutants as environmental pollution is a major stumbling block. The wide band gap of SrTiO3 is permuted to an appropriate value by adding a suitable dopant to make it function as a visible light photocatalyst. Nanocubic copper-doped strontium titanate was prepared through a single-pot solvothermal route and tested for its photocatalytic activity. An exceptional 99% photoreduction of Cr(VI) ions to Cr(III) within 15 min and 100% in 25 min and 99% photodegradation of the methyl violet dye within 120 min was observed for the 0.5 CuST sample. First principles density functional theory calculation reveals the reduced band gap of the doped samples due to the introduction of additional energy levels above the valence band edge to be the reason behind the increased photocatalytic efficiency. In addition to this, the three-fold increase in surface area and low recombination rate of charge carriers in the doped nanocubes also favor in enhancing the activity. © 2023 American Chemical Society.