Browsing by Author "Vegi, Maheswara Rao"

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    Attenuation of nitrate from Aqueous Solution using Raw and Surface Modified Biosorbents from Adansonia Digitata Fruit Pericarp
    (Elsevier, 2022-07-14) Mihayo , David; Vegi, Maheswara Rao; Vuai, Said Ali Hamad
    The prevalence of nitrate in potable water is a serious environmental concern. Several methods for eliminating nitrate from water have been made and implemented. During the course of this research, raw (RADFP) and surface-modified fruit pericarp (SMADFP) biosorbents derived from the Adansonia digitata plant were applied in order to remove nitrate from an aqueous solution. The external features of the biosorbents were studied with the aids of SEM and BET. The FT-IR spectrometer was utilized for identification of the functional groups of the ad sorbents. A UV-Vis device was used to quantify the nitrate concentration. The adsorbents under investigation exhibit a heterogeneous pore structure with a considerable number of mesopores, with surface areas of 361.527 and 379.877 m2 per gram for RADFP and SMADFP, respectively. FT-IR spectra revealed the presence of carboxyl, hydroxyl, carbonyl, and halogen groups on the adsorbent. The maximum nitrate removal efficiencies of RADFP and SMADFP were 64.55 and 88.95%, respectively. The maximum adsorption efficiencies are achieved when the pHis 2, the starting concentration is 27.50 mg/L, the contact period is 75.00 min, and the amount of biosorbent is 5.50 g. RADFP and SMADFP have a removal capacity of 12.45 as well as 25.18 mg per gram and adsorption intensity of 3.2300 and 5.4500, respectively. The investigational values for the elimination of nitrate ions concurred well to both Freundlich and Langmuir models with R2 values of 0.99917 and 0.99763 for RADFP and SMADFP, respectively, and pseudo-second-order kinetic model with R2 values of 0.99817 and 0.99947, respec tively for RADFP and SMADFP. It can be concluded that SMADFP is a relatively better biosorbent than RADFP, which will be utilizable for the remediation of nitrate from an aqueous solution.
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    Water Hyacinth Derived Activated Carbon Electrode Materials for Water Defluoridation Using Capacitive Deionization Technology
    (ELSEVIER, 2025) Kalilo, Hassan Johnson; Elisadiki, Joyce; Vegi, Maheswara Rao; Vuai, Said Ali Hamad
    Safe water is a vital component of human life that requires purification to reduce the concentration of ionic pollutants using appropriate water treatment techniques, such as capacitive deionization (CDI) water treatment technology. The porous activated carbon electrode materials have prepared via the carbonization of water hy- acinth plants followed by chemical activation using KOH at different temperatures (400-700◦C with an incre- ment of 100◦C) labeled as CWH-400, WHAC-500, WHAC-600 and WHAC-700 all being activated for 1 h where CWH represents carbonized water hyacinths and WHAC represents water hyacinths activated carbon. The activation temperature has a significant effect on the specific surface area of the porous carbon prepared, as it increases from 464.67 m²/g for CWH-400 to 1020.01 m²/g for WHAC-700. The defluoridation experiments were done using water samples with initial fluoride concentrations of 4.21, 4.61 and 3.51 mg/L for water samples from Arusha (A), Manyara (B) and Shinyanga (C) respectively when the 2 V was supplied to the cell with 10 mL/ min flow rate at 3 hours charging time. The defluoridation results were 1.28, 1.37, and 1.15 mg/L for water samples A, B, and C, respectively. The WHAC-700 electrode was found to possess a capacitance of 501.89 F/g, exhibiting removal efficiencies of 69.60%, 70.28%, and 67.24% for water samples from Arusha (A), Manyara (B), and Shinyanga (C), respectively, at a potential of 2 V with a charging time of 3 hours. Therefore, the water hyacinth plants are suitable precursors for preparing porous activated carbon electrodes to be used in a CDI cell for the defluoridation of any water sample