Phosphate adsorption from synthetic aqueous solutions by waste mussel shell: kinetics and isotherms studies

Abstract

The amount of phosphorus released to the wastewater from industry is alarming. One of the phosphorus effects to the environment is eutrophication that will cause algal blooms. Algal blooms will cover the water surface and cause the aquatic plants to not getting enough sun. Insufficient sunlight caused the plants to die thus limiting the oxygen supply to other aquatic life because photosynthesis cannot occur. This research focuses on reducing the amount of phosphorus in a synthetic aqueous solution by using waste mussel shell as absorbent and evaluate the data experiment using kinetic and isotherm models. A batch study was carried out using different adsorbent mass of waste mussel shell and different concentrations of synthetic solution. The absorption efficiency increased with the increasing mass of waste mussel shell but reached constant when the waste mussel shell reached the adsorption limit as equilibrium state. The adsorption was successfully achieved following the pseudo-second order, giving the R2 as 0.9991. Isotherms model analysis showed that the Freundlich isotherms model was insufficient to explain the adsorption of phosphate onto waste mussel shell compared to Langmuir isotherm model (R2=0.8505). The study advanced the understanding of the kinetic adsorption and isotherm study of waste mussel shell and proved that the waste mussel shell has the potential to reduce the amount of phosphorus released into the wastewater. The contribution of this study is alternative adsorbent from waste mussel shell to treat the wastewater in a prospective wastewater treatment facility setting.