Adsorption Of Phosphorus From Wastewater Onto Biochar : Batch And Fixed-bed Column Studies

Abstract

Eutrophication has become a global environmental issue due to heavy agricultural activities. Phosphorus is one of the limiting nutrients governing the growth of algae and excessive release of phosphorus into aquatic environments has contributed significantly to the eutrophication process. Biochar, a low-cost adsorbent, has been proven to possess adsorption capacity, which can be utilized to remove pollutants from wastewater. This study was set out to investigate its ability to remove phosphorus in two different methods.

Biochar loaded with Fe3+ was prepared for batch experiments, in which an experimental design matrix had been created using factorial design methodology. The precursor of the biochar was wood biomass. Regression analysis was performed to create a model and study the individual effects and interaction effects of three independent variables, pH, initial concentration, and biochar dosage. The results showed that all variables had significant effect on the removal efficiency. Additionally, strong interaction effects were observed in two pairs, pH-Initial phosphorus concentration and pH-biochar dosage.

Natural biochar was used in fixed-bed column study to determine the impact of different flow rates on the removal efficiency, hydraulic loading rate, empty bed contact time, and saturation point. It was found that a higher flow rate led to a decrease of the removal efficiency. Moreover, the breakthrough point and saturation point occurred much faster.