The preparation conditions of electro-modification (current density) and pyrolysis (pyrolysis temperature and heating rate) processes were simultaneously optimized using response surface methodology with the quadratic regression model associated with Box-Behnken design. By numerical optimization, the phosphate adsorption capacity of 245.06 mg/g was achieved, corresponding to 99.9% of the predicted values under statistically optimized conditions (current density: 38.78 mA/cm2, pyrolysis temperature: 584.1 °C, heating rate: 6.91 °C/min). By considering R2 and three error functions values, the experimental results of adsorption kinetics, and the equilibrium isotherms at different temperatures (10-30 °C) showed that predictive pseudo-second-order and Sips isotherm models could adequately interpret the phosphate adsorption process for 'statistically optimized electrically modified'-biochar (SOEM-biochar). The maximum phosphate adsorption capacities of SOEM-biochar were found to be 273.9, 345.1, and 460.3 mg/g at 10, 20, and 30 °C, respectively, which are higher than that of other adsorbents reported in the literature.
Bibliographical noteFunding Information:
This work was supported by grants from the National Research Council of Science and Technology (Project No. Asia-02-002). Appendix A
© 2016 Elsevier Ltd.
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Renewable Energy, Sustainability and the Environment
- Waste Management and Disposal