Browsing by Author "Kitemangu, Aisha"

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Assessment of hydrochemistry, fluoride distribution, and non-carcinogenic health risks in groundwater of the Manyara region, Tanzania
(Springer Nature, 2026-02-03) Kitemangu, Aisha; Banyikwa, Andrew; Rwiza, Mwemezi; Malima, Nyemaga; Machunda, Revocatus; Mataba, Gordian; Vegi, Maheswar
Fluoride (F−) contamination in groundwater is a major global public health concern. Prolonged intake of F⁻ above 1.5 mg/L and 10 mg/L may lead to skeletal fluorosis and crippling fluorosis, respectively. The Manyara region, located within Tanzania’s fluoride belt in the Eastern African Rift Valley, is one of the areas most affected by elevated F− levels in groundwater. The extent of F⁻ pollution and associated health risks in this region remains poorly documented. This study assessed the hydrochemistry, spatial distribution of F−, non-carcinogenic health risks, and the suitability of groundwater for drinking and irrigation using 225 borehole water samples collected from all six districts of the region. Parameters analyzed included pH, EC, TH, Ca2+, Mg2+, Na+, K+, HCO3−, Cl−, SO42−, NO3−, and F−. Irrigation suitability of water was evaluated using EC, %Na, RSC, SAR, Kelley's Ratio, and MAR. Results show that F− levels ranged from 0.01 to 23.44 mg/L. Overall, 48.00% of samples contained F− above 1.5 mg/L, and 3.56% of samples exceeded 10.0 mg/L. The Hazard Quotient (HQ) values ranged from 1.00 to.06 (infants), 0.91–6.35 (children), and 0.35–2.42 (adults), indicating elevated health risks, particularly for infants and children. EC values ranged from 63.18 to 8,911.50 µS/cm, with 19.11% of samples exceeding the recommended limit of 2,500 µS/cm. The order of ions was found to be Ca2+ > Na+ > Mg2+ > K+ and HCO3⁻ > Cl− > SO42− > NO3− > F−. Most samples were suitable for irrigation, but high salinity poses localized challenges.
Enhanced fixed-bed column adsorption using a ternary MgO-impregnated eggshell–kaolin composite: Toward an efficient and sustainable fluoride removal technology
(Sage, 2026-01-26) Kitemangu, Aisha; Machunda, Revocatus; Rwiza, Mwemezi; Malima, Nyemaga; Banyikwa, Andrew; Mataba, Gordian
In this study, a ternary MgO-impregnated eggshell–kaolin (EKM) composite was synthesized and evaluated for fluoride removal from water under fixed-bed column adsorption. The composite, prepared by co-precipitation and wet impregnation, was characterized using XRD, FTIR, SEM EDX, and Brunauer–Emmet–Teller analyses. Results confirmed successful integration of the three components, yielding a mesoporous structure with a surface area of 158.5 m2 g−1. The composite exhibited good defluoridation performance under varying operational conditions. Higher bed depth and lower flow rate enhanced adsorption capacity, achieving up to 6.35 mg g−1 at 10 mg L−1 influent fluoride concentration. Breakthrough data were well described by the Thomas, Clark, and Yoon–Nelson models (R2 ≥ 0.94) at lower influent concentration, moderate f low rate, and greater bed depth, while the bed depth service time model confirmed a linear increase in service time with bed depth. The adsorbent maintained good regeneration ability across four cycles. Co-existing anions showed interference with the uptake of F−, with inhibitory effects following the order: PO3− 4 >SO2− 4 >NO− 3 > Cl−. The study estimated that 11.11 g of EKM composite yields 2 L of safe water for less than USD1. These results highlight the EKM com posite as an efficient and sustainable adsorbent for practical defluoridation applications.
Enhanced fixed-bed column adsorption using a ternary MgO-impregnated eggshell–kaolin composite: Toward an efficient and sustainable fluoride removal technology
(2026-01-26) Kitemangu, Aisha; Machunda, Revocatus; Rwiza, Mwemezi; Malima, Nyemaga; Banyikwa, Andrew; Mataba, Gordian
In this study, a ternary MgO-impregnated eggshell–kaolin (EKM) composite was synthesized and evaluated for fluoride removal from water under fixed-bed column adsorption. The composite, prepared by co-precipitation and wet impregnation, was characterized using XRD, FTIR, SEM EDX, and Brunauer–Emmet–Teller analyses. Results confirmed successful integration of the three components, yielding a mesoporous structure with a surface area of 158.5 m2 g−1. The composite exhibited good defluoridation performance under varying operational conditions. Higher bed depth and lower flow rate enhanced adsorption capacity, achieving up to 6.35 mg g−1 at 10 mg L−1 influent fluoride concentration. Breakthrough data were well described by the Thomas, Clark, and Yoon–Nelson models (R2 ≥ 0.94) at lower influent concentration, moderate flow rate, and greater bed depth, while the bed depth service time model confirmed a linear increase in service time with bed depth. The adsorbent maintained good regeneration ability across four cycles. Co-existing anions showed interference with the uptake of F−, with inhibitory effects following the order: PO3−4>SO2−4>NO−3 > Cl−. The study estimated that 11.11 g of EKM composite yields 2 L of safe water for less than USD1. These results highlight the EKM com posite as an efficient and sustainable adsorbent for practical defluoridation applications.