Full factorial experimental design of Ni(II) removal from industrial wastewater by adsorption

The removal of Ni(II) from industrial wastewater was investigated using adsorption process by gyttja. Full factorial experimental design containing two levels and four factors (2(4)) was performed to improve Ni(II) removal by reducing the number of experiments and to optimise the experimental conditions for Ni(II) adsorption process. Ni(II) adsorption performance of gyttja was examined as a function of pH, contact time, temperature, and adsorbent concentration. The maximum Ni(II) removal was found as 36% at pH 3, with 25 g L-1 adsorbent concentration, for 60 min contact time at 50 degrees C with initial Ni(II) concentration of 3,404 mg L-1. The maximum adsorption capacity of gyttja was found as 6.80 mg g(-1) at pH 6, adsorbent concentration of 25 g L-1, contact time of 60 min and temperature of 20 degrees C. The predicted values of the model were found to be in agreement with experimental data. The present study may provide a theoretical basis for further research to treat wastewater with novel adsorbents.