Kinetic Study of Ammonia Removal using Activated Rice Husk

Abstract

Ammonia pollution causes eutrophication and algal bloom, which eventually disrupts the marine ecosystem’s equilibrium. Efforts have been made to either recover or remove ammoniacal nitrogen from water resources. Electrochemical, precipitation, adsorption, biological and membrane technology have been developed with varying degrees of complexity and arrangement to overcome this problem. To date, adsorption is widely used to remedy water resources as it is cost and energy effective while being simple to operate and maintain. Adsorption kinetic models are important in evaluating the performance of adsorbent and reveals the adsorption mass transfer mechanism. Nevertheless, the kinetic studies reported in the literature was not complete as only a few models were considered. Meanwhile, the statistical parameter to validate the model was commonly depended on R2 value alone. The objective of this study is to provide a comprehensive kinetic study of ammonia adsorption using activated rice husk, to the readers by investigating the validity of 9 kinetic models in fitting the experimental data. All the models are validated by using R2, R2, residual sum of square (SSE) and (mean square error) MSE. Result showed > 0.99 R2 values and low R2, SSE, MSE were found for Mixed order, Ritchie’s and Elovich models. This indicates that the ammonia adsorption process was governed by the adsorption at the active sites of the adsorbent and it was mainly driven by the chemisorption.