Browsing by Author "Adiyo, Nancy"

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    Adsorption and kinetics of chlorpyrifos from wastewater using activated carbon from orange peels.
    (Busitema University, 2026) Adiyo, Nancy
    Widespread agricultural use of Chlorpyrifos leads to severe surface runoff and aquatic contamination. Traditional wastewater treatments fail to eliminate this persistent, lipophilic pollutant, posing human health risks like neurotoxicity. Commercial activated carbon effectively captures such organic pollutants but remains prohibitively expensive. Utilizing abundant agricultural waste like orange peels offers a dual solution for cost-effective environmental remediation and sustainable waste management. The study aimed to synthesize and characterize orange peel-derived activated carbon (OPAC), evaluate optimal operating parameters (pH, dosage, contact time), and examine adsorption kinetics and isotherms. Prepared orange peels were chemically activated with phosphoric acid (H3PO4) at a 1:2 w/w ratio and carbonized. Characterization included Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and iodine number determination. Batch experiments were monitored using UV-Vis spectrophotometry at a maximum wavelength of 290 nm to trace Chlorpyrifos concentrations. Characterization confirmed a highly active material with a prominent iodine number of 435.0. pH optimization revealed that Chlorpyrifos removal is significantly higher in acidic media, peaking at an 87.5% removal efficiency at pH 3.0 and decreasing sharply past the point of zero charge (pHzpc=7.0). Kinetic data aligned closely with the pseudo-second-order model (R2=0.9954), showing a calculated equilibrium capacity (qe) of 7.07 mg/g and establishing that chemisorption is the rate-limiting step. Equilibrium profiling demonstrated an excellent fit with the Langmuir isotherm model (R2 = 0.9944), yielding a maximum monolayer capacity (Qm) of 10.57 mg/g and a favorable dimensionless separation factor (RL) of 0.3339. Conversely, the Freundlich model was unfavorable (n = 1.8202). In conclusion, orange peel-derived activated carbon serves as a highly efficient, ecologically sustainable, and low-cost bio-adsorbent for remediating pesticide-polluted water systems.