Nitrate Removal from Aqueous Solution by Adsorption Using Municipal Solid Waste-Derived Activated Biochar

Author : Revilla, Patricia Nadine Decena
Major Adviser : Detras, Monet Concepcion M.
Committee Members : Alfafara, Catalino G.; Migo, Veronica P.
Year : 2019
Month : June
Type : Thesis
Degree: BS
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Nitrate is considered as a major groundwater pollutant causing serious health and environmental effects. In this study, the removal of nitrate from aqueous solutions using municipal solid waste-derived activated biochar (MSWAB) via adsorption was explored. Initially, municipal solid waste (MSW), another prominent source of environmental pollution, was used as feedstock to produce biochar, which was chemically activated using potassium hydroxide, producing MSWAB. Activation of MSWAB resulted to an increase in surface area from 2.5 to 6.5 m2/g. The effect of initial nitrate concentration (A), pH (B), and adsorbent dosage (C) on nitrate removal were then evaluated using a 2k factorial experiment. Results show that initial nitrate concentration, pH, and two-way interactions AB and AC have significant effects on % nitrate removal. Nitrate removal was found to increase as the initial nitrate concentration and pH decreases. Using Response Surface Methodology (RSM), the local optimum conditions for maximum nitrate removal of 66.97% were determined to be at 30 mg/L initial nitrate concentration and pH 2 at 10 mg/mL adsorbent dosage. The appropriate isotherm for nitrate adsorption onto MSWAB was the Freundlich isotherm. Comparison with commercial activated carbon (CAC) in terms of nitrate removal efficiency at local optimum conditions showed that MSWAB is inferior to CAC. However, it is still notable that MSWAB was able to reduce the nitrate concentration from 30 mg/L to 11.27 mg/L which satisfies the 14 mg/L DENR effluent standard for Class C water bodies, showing its potential as an alternative adsorbent for treatment of nitrate-laden wastewaters.

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