Browsing by Author "Muwanguzi, Joshua"

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    Adsorption And Kinetics Of Thiamethoxam From Wastewater Using Activated Carbon From Rice Straws Biomass
    (2026-08-28) Muwanguzi, Joshua
    Thiamethoxam (TMX) is a highly toxic neonicotinoid pesticide, and its entry into water sources endangers both human and aquatic life, necessitating the development of a low-cost, eco-friendly adsorbent for its removal. In this study, we examined the adsorption of Thiamethoxam from Aqueous solutions using Rice straw Activated Carbon (RSAC) as a low-cost and environmental friendly adsorbent. The main objective of this study was to evaluate the effectiveness of Rice Straw Activated Carbon in removing Thiamethoxam under varying operational conditions including contact time, adsorbent dosage, initial concentration and solution pH. Batch adsorption experiments were carried out and residual concentrations were determined using a UV-Vis spectrometry based on a calibration curve. The results showed that adsorption efficiency increased with contact time reaching equilibrium at approximately 120 minutes. Adsorption was enhanced by increasing adsorbent dosage, while higher initial Thiamethoxam concentrations resulted in reduced percentage removal due to saturation of active sites. The optimum adsorption occurred at pH 6, a contact time of 120 minutes, and a dosage of 0.5 g adsorbent, with a maximum removal efficiency of 84.6%. Characterisation of the Rice Straw Activated Carbon using the Scanning Electron Microscope revealed a highly porous and heterogeneous surface structure. At the same time, Fourier Transform Infrared Spectroscopy (FTIR) confirmed the presence of functional groups such as OH and C-O, which facilitated adsorption interactions. Equilibrium data were best described by the Langmuir Adsorption Isotherm, suggesting monolayer adsorption. Kinetic studies showed that Pseudo Second Order model provided the best fit, indicating that chemisorption was the dominant rate controlling mechanism. The findings demonstrated that Rice Straw Activated Carbon is an effective, low cost, and sustainable adsorbent for removal of Thiamethoxam from contaminated Water.