Browsing by Author "Mkelemi, Magdalena"

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    Assessment of Mpanda groundwater contamination and the effectiveness of the baobab seeds-derived biochar for iron removal from groundwater
    (NM-AIST, 2024-08) Mkelemi, Magdalena
    Groundwater in Mpanda District, Tanzania, faces excessive iron content, causing a reddish brown colouration due to oxidized iron species. The present study evaluated Mpanda groundwater contamination and the effectiveness of baobab seeds-derived biochar for iron removal from groundwater. First, the physicochemical quality of groundwater was investigated. Nineteen boreholes were randomly selected for assessment, with samples collected in rainy and dry seasons. The study revealed significant variations in groundwater quality both between seasons and among boreholes. Temperature, total dissolved solids, electrical conductivity, lead, iron and manganese exceeding World Health Organization and Tanzania Bureau of Standards limits in some boreholes; necessitating water treatment for human use. Second, the effectiveness of baobab seeds-derived biochar for iron removal from groundwater was assessed. Baobab seeds, were sun-dried, oven dried at 105 ºC, carbonized at 700 ºC, and ground into fine powder. The influence of pH, time, temperature and dose of biochar on the iron removal from groundwater was assessed. Six 1000 mL beakers were filled with groundwater and adsorbent doses of 0.6 g/L, 1.2 g/L, 1.8 g/L, 2.4 g/L, and 3.0 g/L were added into five beakers with the sixth serving as a control. The highest removal efficiency of iron was observed within 5.0-8.0 pH range. Over time, the removal efficiency increased to 87% at 120 minutes and 3.0 g dose, with an initial iron concentration of 5.88 mg/L and residual concentration of 0.76 mg/L. Baobab seeds-derived biochar showed promising efficiency in removing iron ions and is recommended for sustainable iron removal from groundwater.
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    “Tree of life”: how baobab seed-derived biochar could lead to water safety for underprivileged communities through heavy metal (Fe) removal – SDG 6
    (Royal science of chemistry, 2024-09-24) Mkelemi, Magdalena; Mwaijengo, Grite; Rwiza, Mwemezi
    The abnormally gigantic baobab tree (Adansonia digitata) is often referred to as the “Tree of Life” due to its ability to provide food, water, shelter, and traditional medicine for both humans and animals in arid regions. This special tree is a landmark of Africa's savanna and has attracted the attention of the global research community. This study investigated the potential of biochar derived from baobab seeds for the removal of metallic ions from groundwater. The biochar, prepared at 700 °C, exhibited a unique surface morphology with deep voids and varied structures, suggesting increased surface area and favorable conditions for adsorption. SEM-EDX analyses confirmed the elemental composition, with carbon being the predominant element. Furthermore, XRD analysis indicated an amorphous structure, enhancing adsorption capacity for heavy metal ions. Additionally, BET analysis revealed a significant surface area (1386.704 m2 g−1 ) and well-defined pores, emphasizing the material's potential for metallic ion removal. The metallic ion of choice for this research was Fe because of its abundance in the study area and the community's need for affordable technology for discoloration of reddish-brown groundwater caused by Fe ion presence. In the batch mode equilibrium studies, the effect of pH, contact time, adsorbent particle size, adsorbent dose, solution temperature, and initial metal ion concentration was investigated. Optimal pH metallic ion removal occurred under neutral pH conditions, with higher removal efficiency observed at increased contact time (up to 120 min) and adsorbent doses. Adsorption isotherm modeling using Langmuir and Freundlich models indicated favorable adsorption, with the Freundlich model providing a slightly better fit. In conclusion, baobab seed-derived biochar demonstrated promising potential as an efficient and sustainable adsorbent for metal ion removal from groundwater. Further exploration, including the development of activated carbon and field applications, is recommended for a comprehensive understanding and practical optimization of this material's capabilities for metal ion removal.