Coconut coir biochar for the sorption of ammonium, nitrite, nitrate: Impacts of its chemical properties and pH-dependent

Abstract

The objective of this study is to determine the physico-chemical properties and the influence of pH on the ammonium, nitrite, and nitrate adsorption capacity of coconut coir biochar, to be used as a filtration material in water treatment. The study used conventional methods to determine the biochar yields, total ash, bulk density, pH, and EC. The material structure was analyzed by SEM, BET, FTIR, and XRD. At the same time, the impact of pH on the adsorption capacity of nitrogen compounds in coconut fiber biochar was determined through adsorption efficiency. As a result, the water holding capacity and the specific surface area are about 503.87 ± 36.44% and 378.41 m²/g respectively. The average adsorption and desorption pore sizes are 0.118nm and 0.121nm. There are functional groups O-H, C = O, -CH, C = C that helped enhance chemical adsorption. The coconut coir biochar has a pHPZC of 5.2 and an amorphous carbon structure. The pH value for good adsorption of ammonium, nitrite, and nitrate are 8, 2 with the adsorption efficiency of about 40%, 99.78%, and 99.11%, respectively, thereby aiming to optimize the removal of nitrogen compounds in the environment.