Robert Mbedzi^1,*,, Hilary Rutto^1,, Tumisang Seodigeng^1, and Linda Sibali^2,

¹Clean Technology and Applied Materials Research Group, Department of Chemical and Metallurgical Engineering, Vaal University of Technology, Private Bag X021, South Africa

²Department of Environmental Sciences, College of Agriculture and Environmental Sciences, UNISA, Florida, 1709, South Africa

*Corresponding author: E-mail: robertm@vut.ac.za

In present study, the removal of Ca²⁺ from cooling tower water using Amberlite IR120 and Amberjet 1200 was optimized using the response surface methodology (RSM). The effect of operational parameters such as contact time (min), pH, dosage (mL), concentration (mg/L) and temperature (K) were investigated using a central composite design. The regeneration of the Amberlite IR120 and Amberjet were also studied. The study aimed to apply RSM to investigate and optimize the ion exchange operating parameters. Furthermore, the second-order empirical model was developed and correlated sufficiently to the ion exchange experimental data. The optimal ion exchange operating conditions for Amberlite IR120 and Amberjet 1200 were found to be: contact time was 120 min, dosage of 150 mL, the initial pH level of 2, a concentration of 4,00 mg/L and temperature of 343 K. Regeneration of Amberlite IR120 and Amberjet 1200 using 0.5 M NaCl stripping solution initially showed an increase in % Ca²⁺ and Mg²⁺ removal, then a decrease in subsequent cycles.

Amberlite IR120, Amberjet 1200, Cooling tower water, Response surface methodology, Ca²⁺, Mg²⁺, Regeneration.