Adsorption of Potassium Nitrate onto spent mushroom compost for agricultural applications

Abstract

The excessive use of nitrogenous fertilizers in agricultural activities had increased the concentrations of nitrate in surface and ground waters. Therefore, the presence of nitrate in water gives problems to human, aquatic life and environment. In order to overcome this problem, adsorbents such as agricultural wastes can be used to adsorb nitrate from fertilizer. In this study, Spent Mushroom Compost (SMC) was used as adsorbent in the adsorption process. This study was conducted to evaluate the process parameters such as effect of nitrate concentration ( 0.2, 0.4, 0.6, 0.8 and 1 g/L), effect of SMC dosage (1g, 2g, 3g, 5g, and 10g) and effect of particle sizes ( 250μm, 500μm, 1 mm and 2 mm), in terms of adsorption isotherm and kinetic study. It was observed from this study that pretreated SMC was better than untreated SMC at temperature 25oC and pH 7. The results show that the adsorption of nitrate onto SMC fitted with Freundlich model compared to Langmuir model. The kinetics of adsorption fitted with pseudo secondorder model with linear regression coefficients of 0.9866.