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The sequential nitration and magnetization of waste styrofoam to form a novel adsorbent has been investigated. The novelty of this study assigned approach lies in the introduction of an anionic surface on the styrofoam, enabling it to adsorb cationic Pb2+ ion, combined with its magnetic property that facilitates rapid and practical recovery. The nitration was conducted using concentrated nitric acid in the presence of sulfuric acid, and the magnetization was performed by coprecipitation of Fe2+ and Fe3+ at high pH to form Fe3O4. The prepared adsorbents were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), and Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX) instruments. The characterization data clearly showed the evidence that nitrated-magnetic-styrofoam was successfully produced. The adsorption process of Pb2+ ion from aqueous media was evaluated via batch experiment. The contact time of the adsorption, adsorbent weight, solution pH, and initial concentration of Pb2+ were optimized to get the best adsorption condition. The adsorbent with 33.3 wt% of Fe3O4 fraction revealed a compromise of high adsorption effectivity around 90.0% and efficient separability with the optimum condition of 30 mg adsorbent dose at solution pH 6 within 60 minutes of adsorption time and initial concentration at 50 mg L-1 Pb2+. The parameters isotherm and kinetic of adsorptions were also determined. According to three simulated isotherm models of Langmuir, Freundlich, and Sips, Langmuir isotherm is well-fitted with an adsorption capacity of 9.81 mg g-1. The adsorption kinetic matches to a pseudo-second order giving an adsorption rate constant of 0.131 g mg-1 min-1 and is expected to give chemisorption mechanism.

Since concrete is a fundamental component of all types of construction, many researchers are concentrating on developing High Performance Concrete (HPC) using efficient manufacturing processes. Nano silica is a quartz and silica dust this can be replaced instead of cement to achieve great strength and to produce sustainable concrete. Sustainable concrete is eco-friendly concrete produced by industrial waste materials and other materials, nano silica when substituted instead of concrete produce less carbon emission in environment compare to cement concrete. High performance concrete is one that is strong, durable, and easy to work in. With correct material selection, mix design, and concrete handling from the fresh stage through the hardening stage, HPC can be achieved. This study aims to produce a High Performance Concrete (HPC) using sisal fibres, nano silica and delonixregia pods. M70 mix design was followed to produce a HPC and it is compared with conventional concrete with 0.36 w/c ratio. The pods of delonixregia ash is replaced from 1% to 7% to produce HPC, the delonixregia ash is added in HPC as a corrosion inhibitor. The nano silica is used from 0.5 % - 3.5% and the sisal fibre was replaced from 0.5 -1% and super plasticizer of 2% instead of cement content by volume replacement. The mechanical characteristics are analyzed in this investigation. The test results shows satisfactory results in the performance of HPC with the pods of delonixregia with 5%, nano silica with 2.5% and sisal fibres with 1% of replacement in ternary blended cement concrete with 2% replacement of super plasticizers (M13 mix).