Continuous manganese(II) ions removal from aqueous solutions using rice husk ash-packed column reactor

Abstract

This study was conducted to analyse the biosorption of manganese(II) from aqueous solutions by rice husk ash (RHA) in a continuous packed column reactor. Different column parameters were used, such as influent Mn(II) concentration, bed height and flow rate. The results showed that the equilibrium adsorption (mg g−1) has increased after increasing the influent Mn(II) concentration but decreased when increasing the flow rate and the bed height. When the influent Mn(II) concentration was expanded from 5 to 20 mg l−1 at a fixed bed height and flow rate, then Mn(II) uptake also expanded from 2.73 to 4.76 mg g−1. Similarly, by increasing the bed height from 7.5 to 22.5 cm and flow rate from 5 to 15 ml min−1, the adsorption capacity of Mn(II) decreased from 7.57 to 2.97 mg g−1 and 3.61 to 1.90 mg g−1, respectively. In addition, several empirical models such as Adams–Bohart, Wolborska, Thomas and Yoon–Nelson models were used in this study to investigate the breakthrough curves in a simple way. The best fitting was obtained with Adams–Bohart and Wolborska models which showed high degree of fitting (r2 ≥ 0.82). So Bohart–Adams and Wolborska models were the most suitable to estimate breakthrough curves obtained under varying experimental conditions.