Heavy metal removal with pure and biochar rice husks: modelling and optimisation using Box-Behnken design

Abstract

In this work, the most common heavy metals such as Cu (II), Zn (II), and Pb (II) removal from aqueous leachate of industrial waste were investigated using pure and biochar rice husks. The influence of such parameters as pH, adsorbent dose (g L-1), and contact time (min) on the biosorption of rice and biochar rice was examined by using response surface methodology (RSM) based upon Box-Behnken surface statistical design at a leaching solution, Ci = 32.69 g L-1 as a fixed input parameter. The results show that both linear and squared terms of process variables are found significant on the response variable. The optimum conditions depending on both combinations and individual of all responses for the removal of Zn (II), Cu (II), and Pb (II) ions were determined using the optimising algorithm. To sum up, the use of biochar rice husk is found better than the use of pure rice husk according to statistical analysis. This study strongly indicated that pure and biochar rice husks are an influential alternative adsorbent for the removal of heavy metal ions by sorption.