Applied Chemistry

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Applied Chemistry

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Browsing Applied Chemistry by Author "Chiririwa, H."

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    Adsorption of Lead and Copper by Carbon Black and Sodium Bentonite Composite Material.
    (Chemic Publishing Company, 2017-10-30) Chiririwa, H.; Matthews, T.; Nyoni, B; Majoni, Stephen; Naidoo, E.B
    The efficiency of using a composite of carbon black and sodium bentonite in treating drinking water contaminated with lead and copper ions was analyzed. The effects of pH, contact time, concentration and adsorbent dosage using an adsorbent composite of 20 % sodium bentonite and 80 % carbon black were studied. The adsorption data was analyzed with respect to Langmuir, Freundlich and Temkin isotherms. The data fits well with the Langmuir isotherm model with high coefficients of determination for both metal ions adsorption. The adsorption kinetics follows a pseudo second-order model for both metal ions. The maximum metal ion uptake (qmax) of composite adsorbent is 7.69 and 0.80 mg/g for lead and copper, respectively.
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    Application of Unmodifed Brachystegia spiciformis Leaf Biomass in the Adsorption of Nitrate Ions
    (Springer, 2021-09-18) Ruwaya, K.; Mokone, J.G.; Chiririwa, H.; Majoni, S
    The application of Brachystegia spiciformis leaf powder in the adsorption of nitrate ions was conducted on both synthetic and real water samples. Optimum adsorption conditions for nitrate adsorption were pH of 4, equilibration time of 45 min, and biosorbent dose of 1.5 g. Batch adsorption was used in this study and nitrate ions were analyzed using the salicylic acid method. Non-linear adsorption isotherm fitting indicated that the experimental data was described well by the Langmuir model with a monolayer adsorption capacity of 5.97 mg/g. The Langmuir`s separation factor, , values were in the range, 0 <  < 1, indicating favorable interactions between nitrate ions and Brachystegia spiciformis leaf powder adsorbent. The pseudo first order model provided the best fit to the experimental kinetics data with an R2 value of 0.9880 and a rate constant of min−1. The Brachystegia spiciformis leaf powder adsorbent achieved 100% and 78% nitrate ions removal from dam water and industrial effluent water respectively. We have shown that a cheap biomass adsorbent that has high activity towards nitrate ions adsorption can be produced and applied in the adsorption of nitrates from water.