http://nopr.niscpr.res.in/handle/123456789/66591 2026-10-10T23:55:59Z http://nopr.niscpr.res.in/handle/123456789/66603 Title: Advances in biochar-based absorbents: Sustainable solutions for heavy metal removal from contaminated water Authors: Khamkar, Maithili; Mehta, Nita Abstract: Heavy metal contamination in water poses serious environmental and health risks, necessitating cost-effective and sustainable remediation methods. Biochar, a carbon-rich material produced through the pyrolysis of organic waste such as agricultural residues, sewage sludge, and marine algae, has emerged as an efficient adsorbent for removing heavy metals. This review examines recent advancements in biochar-based adsorption, focusing on key factors influencing its efficiency, including feedstock type, pyrolysis conditions, surface functionality, and porosity. The study explores the role of modified biochars, such as magnetic biochar, in enhancing metal recovery while maintaining high adsorption capacity. The adsorption mechanisms like cation exchange, electrostatic interactions, complexation, and precipitation are analysed to explain the effectiveness of biochar in capturing heavy metals such as Pb(II), Cd(II), Cu(II), and Zn(II). Additionally, the impact of parameters such as pH, contact time, and initial metal concentration on adsorption performance is discussed. While biochar presents a scalable and eco-friendly wastewater treatment solution, challenges such as competitive adsorption in multi-metal systems, regeneration efficiency, and production costs remain there. Future research should focus on optimising biochar modifications, integrating it with existing treatment technologies, and enhancing its selectivity for specific contaminants Page(s): 553-571 2025-09-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/66602 Title: Efficacy of hazardous congo red removal from aqueous solutions via adsorption with carbon black: Batch and column study insights Authors: Meshram, Saurabh; Rahul Dhongde, Nikhil; Pandey, Lucky; P Dewangan, Gautam; N Joshi, Anuradha Abstract: This study investigates the potential of commercial carbon black, sourced from a local waste tyre recycling plant, as an adsorbent in both batch and continuous column adsorption processes for the removal of Congo red (CR). The carbon black has been characterized using Fourier transform infrared spectroscopy and scanning electron microscopy to assess its surface properties. Additionally, the study aims to analyze the physicochemical interactions between carbon black and CR. Key experimental variables, including adsorbent dosage, pH, and contact time, are optimized through batch adsorption experiments to determine their impact on the removal efficiency of CR dye. Batch adsorption experiments confirmed that carbon black (adsorbent) attains maximum adsorption capacities of 76.92 mg/g for CR dye. Among the tested kinetic models, the pseudo-second-order model (R2 = 0.998) best described CR adsorption onto carbon black, outperforming the pseudo-first-order model (R2 = 0.986). A continuous adsorption study has been done to determine the effect of the flow rate of water, adsorbent bed diameter and bed height on the breakthrough time. About 90% removal of CR occurs when the bed height is larger than 5 cm and the bed diameter is larger than 2.7 cm. Page(s): 572-583 2025-09-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/66601 Title: Pyrolysis-derived algal oil: A sustainable and high-performance green bio-lubricant Authors: Kumar Kataria, Ajay; Kumar Dubey, Ashok; Mohanty, Kaustubha; Sasmal, Soumya Abstract: Lubricating oils are essential in the mechanical industry, but their petroleum-based origin raises increasing environmental concerns. Bio-based lubricants offer a potential solution, provided they can achieve comparable performance and cost-competitiveness with conventional mineral-based and synthetic lubricants. Therefore, this study investigated the performance, biodegradability, and toxicity of pyrolysis-derived algal oil as a sustainable and environmentally friendly alternative to traditional lubricating oils. The pyrolytic algal-based lubricating oil exhibited a flash point of 273°C, indicating a reduced fire hazard, and a pour point of -15°C, suggesting suitability for low-temperature applications. The key advantages of this algal lubricating oil are its high biodegradability and low toxicity. It also demonstrated 85% degradation within 28 days. Toxicity levels have been assessed using both aquatic organisms and soil microbes. This algal lubricating oil is found to have low toxicity, with LC50 values of 125 mg/L for Daphnia magna and 150 mg/L for Danio rerio. Furthermore, the results showed that this algal lubricating oil enhanced soil microbial activity by 10%. The impact on plant life was assessed by monitoring germination and growth. A 90% germination rate is recorded, and subsequent plant growth is positive, with an observed biomass increase of up to 85%. Spill recovery tests demonstrated high recovery efficiencies of 85% in water and 80% in soil. The findings of this study support the use of pyrolysis-derived algal oil as a sustainable alternative to traditional lubricants. Page(s): 584-592 2025-09-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/66600 Title: Cattaneo-Christov heat flow analysis of hydromagnetic micropolar nanofluid over a chemically activated permeable stretching sheet Authors: Vinodkumar Reddy, M.; Ajithkumar, M.; Sucharitha, G.; Lakshminarayana, P/ Abstract: Several engineering and technological processes, such as air conditioning, machinery power collectors, food processing, refrigeration, and heat exchangers, need deep investigation of energy and mass transfer in various conditions. As a result, in this paper, we analyze the radiative flow of a hydromagnetic micropolar nanofluid with activation energy and chemical reaction using the Cattaneo-Christov energy flux model over an expanding porous sheet. Further, the consequences of suction, energy generation, and convective boundary conditions were also examined. Boundary layer approximation is utilized to obtain the primary partial differential equations of the model and reduced to nonlinear ordinary differential equations, using the appropriate transformations, the model equations are formulated for numerical simulation and further analysis. Using the inbuilt BVP5C function available in MATLAB, the numerical solutions for the coupled system of the nonlinear ordinary differential equations are obtained. Further, graphical and tabular representations are used to analyze the impacts of several physical parameters on the concentration, velocity, temperature, and microrotation fields. The outcomes reveal that the velocity and microrotation of the micropolar liquid movement are improved by increasing the magnetic and material parameters. An increase in the concentration Grashof number, thermal relaxation parameter, and temperature Grashof number leads to a reduction in the temperature distribution within the thermal boundary layer. Furthermore, the mass transfer rate is directly proportional to the thermophoresis and chemical reaction parameters Page(s): 593-604 2025-09-01T00:00:00Z