Optimization of preparation conditions of highly efficient activated carbon for use in water treatment - experimental design approach

The objective of this study was the utilisation of Cucumis melo biomass as a new precursor to produce highly efficient activated carbons by chemical activation method using phosphoric acid (H3PO4) as the activating agent and their evaluation with high removal efficiency (%) values of SN, BPA and Cr (VI). The effects of four factors controlling the activation process, such as time of activation (1-3 h), the temperature of activation (300-500 degrees C), the concentration of H3PO4 (1.5-2.5 mol/L) and contact time (60-90 min) were used. In order to reduce the number of experiments, full factorial experimental design at two levels (2(4)) were carried out in order to achieve simultaneously optimal preparation conditions and high removal of SN, BPA and Cr (VI). The experimental results showed that the removal efficiency of SN and BPA onto activated carbons was more influenced by the temperature of activation and time of activation with a positive effect. Further, and in same as, the interaction between time of activation and temperature of activation had a negative effect on the SN and BPA removal. While the factors influenced the chromium removal are the H3PO4 concentration and the temperature of activation with a positive effect. Moreover, the interaction between the temperature of activation and H3PO4 concentration had a negative impact for chromium ions removal. Based on the statistical data, the best conditions for the removal of SN, BPA and Cr (VI) by the prepared activated carbon samples were investigated. The maximum removal efficiency of SN, BPA and Cr (VI) obtained under these experimental conditions were 94.20%, 94.14% and 96.80% respectively. Thus, the characterisation results showed that the surface of cucumis melo activated carbon has acidic nature and have a large amount of acidic functional groups with a BET surface area of 407.94 m(2)/g.