http://nopr.niscpr.res.in/handle/123456789/66913 Sat, 10 Oct 2026 06:57:55 GMT 2026-10-10T06:57:55Z http://nopr.niscpr.res.in/handle/123456789/66928 Title: Utilizing tea waste for methylene blue removal: Insights from batch and fixed-bed adsorption studies Authors: Meshram, Saurabh; Rahul Dhongde, Nikhil; Suryavanshi, Shivani; Chaudhary, Amit; Rajbongshi, Dhanjit Abstract: This study explores the potential of tea waste as a cost-effective and eco-friendly biosorbent for the removal of hazardous methylene blue (MB) dye from aqueous solutions. The tea waste-based adsorbent has been synthesised and characterised using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy to examine its functional groups, crystallinity, and surface morphology. Batch adsorption experiments evaluated the impact of initial dye concentration, contact time, and adsorbent dosage. Isotherm analysis revealed Langmuir model compatibility with a high monolayer capacity (qₘₐₓ = 454.54 mg/g), indicating effective surface interaction. Kinetic modeling showed excellent fit with the pseudo-second-order model (R² = 1.000), suggesting chemisorption as the primary mechanism. A fixed-bed column study assessed the effects of flow rate, bed height, and column diameter on breakthrough behaviour. Optimal conditions 4 mL/min flow rate, 2 cm bed height, and 1.5 cm column diameter achieved a 105 min. breakthrough time. Process optimization via Box–Behnken response surface methodology confirmed the model's predictive strength. The results demonstrate that tea waste is a promising low-cost biosorbent for the efficient removal of MB dye, with potential application in wastewater treatment systems Page(s): 697-709 Sat, 01 Nov 2025 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/66928 2025-11-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/66927 Title: Enhanced photocatalytic and antibacterial performance of ZnO and ZnS synthesized using natural fuel: Influence of green synthesis, particle size, and morphology Authors: Karthick, J.; Sreenivasan, V. S. Abstract: This study reveals the eco-friendly synthesis of zinc oxide (ZnO) and zinc sulfide (ZnS) nanoparticles using aqueous neem flower (Azadirachta indica) extract as a green reducing and stabilizing agent. The nanoparticles have been characterized by XRD, FTIR, UV-visible spectroscopy, FESEM, EDX, and DLS techniques. Structural and morphological characterization confirmed the efficacious development of hexagonal ZnO and cubic ZnS phases, with crystallite sizes of 40.42 nm and 16.24 nm, respectively. FTIR analysis revealed the existence of phytochemical capping groups, indicating the role of neem extract in nanoparticle stabilization. DLS analysis further supported these results, which showed a broader size distribution for ZnO (85.69 nm) and a narrower, polydisperse distribution for ZnS (24.93 nm). The photocatalytic performance has been examined under sunlight for degradation of acrylic orange and alizarin red S dyes. ZnO exhibited superior photocatalytic performance, degrading 95.72% of acrylic orange and 92.37% of alizarin red S, with higher rate constants than ZnS, and maintaining over 88% stability after five reuse cycles. Additionally, both nanoparticles demonstrated effective antibacterial activity, with ZnO showing larger inhibition zones against S. aureus and E. coli, likely due to its higher reactive oxygen species generation and more favourable morphology. Page(s): 710-722 Sat, 01 Nov 2025 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/66927 2025-11-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/66926 Title: Design and evaluation of eco-engineered B4C/Fly ash composites: A green material for gamma and neutron shielding applications Authors: Cansu Şahin, Meryem; Manisa, Kaan Abstract: In this study, eco-engineered composite pellets made of fly ash and boron carbide (B₄C) are designed and evaluated for gamma-ray and neutron shielding applications. Composite samples with different B₄C ratios (0–75 wt%) have been prepared and examined using both theoretical and experimental methods. XRD and SEM are used for structural and morphological characterizations. A NaI(Tl) detector is used to measure gamma-ray attenuation parameters such as LAC, MAC, HVL, TVL, MFP, Zeff, and buildup factors. These values are further evaluated using Phy-X/PSD and GAMOS simulations. Values for the fast neutron removal cross-section (FNRCS) are also calculated. The composite with the most balanced performance is BCFA25, which has a compact microstructure and improved attenuation efficiency. Increasing the content of boron and carbon with lower atomic numbers increased neutron shielding but decreased Zeff and electron density. Strong agreement is found between theoretical models and experimental outcomes. The results indicate that B₄C/fly ash composites, especially BCFA25, offer a lead-free and sustainable option for radiation shielding in industrial, nuclear, and medical applications Page(s): 723-733 Sat, 01 Nov 2025 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/66926 2025-11-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/66925 Title: Surfactant-assisted synthesis of Cu-Doped Co3O4@carbon nano flake nanocomposites for effective photocatalytic breakdown of brilliant green dye under UV irradiation Authors: Vinayagasundaram, Chandrakala; Samson Nesaraj, Arputharaj Abstract: This study explores the fabrication, characterization, and photodegradation efficiency of Cu-doped Co3O4 (0–50 mol%) incorporated into a carbon nano flake (CNF) composite for the removal of brilliant green dye. The synthesized materials have been analyzed using XRD, SEM-EDAX, TEM, UV-DRS, and XPS, confirming an FCC crystalline structure with irregular spherical grains. Under UV light irradiation, Cu-doped Co3O4and Cu-doped Co3O4@CNF achieved 91.8% and 98.4% dye removal within 40 min. The improved efficiency is attributed to the effective role of Co3O4 nanoparticles in reducing electron-hole recombination, enhancing photocatalytic activity and promoting the degradation of organic pollutants in wastewater treatment applications. Page(s): 734-748 Sat, 01 Nov 2025 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/66925 2025-11-01T00:00:00Z