Design of Linear Model for Water Hardness Removal by Activated Coconut Shell Carbon using Design of Experiment Method

The present study reports the water softening by adsorption of hardness ions onto
Activated Coconut Shell Carbons. In the previous study, it was found that 500°C Activated
Coconut Shell Carbon removed more hardness ions compared to coconut shell carbons (400,
500°C) and the other activated carbon (400°C). Therefore, 500°C ACSC was selected and
used as the adsorbent for batch experiments. Characterization of Activated Coconut Shell
Carbon was identified by Fourier Transform Infrared Spectroscopy and Scanning
Electron Microscopy techniques. Batch experiments were carried out to determine the
effect of various adsorbent factors such as adsorbent dose, pH, and contact time, on the
adsorption process using synthetic water samples. Full Factorial Design with
centerpoints (0,0) was used to determine the optimal values of parameters that provide
the highest removal efficiency. The number of experiments carried out were based on
the levels of each parameter, number of replicates and number of centerpoints. The total
number of experiments was 28.