BPB Reports

Paper Details

BPB Reports
Vol. 2 No. 6 p.119-124 2019
Regular Article
Application of Activated Clay for Improvement of Water Quality in Wire Electric Discharge Machining
  • Naohito Kawasaki (Faculty of Pharmacy, Kindai University / Antiaging Center, Kindai University / kawasaki@phar.kindai.ac.jp)
Eri Nagahashi 1) , Fumihiko Ogata 1) , Takehiro Nakamura 1) , Naohito Kawasaki 1) 2)
1) Faculty of Pharmacy, Kindai University , 2) Antiaging Center, Kindai University
Received: November 25, 2019;   Accepted: December 13, 2019;   Released: December 23, 2019
Keywords: activated clay, electrical conductivity, wire cut, zinc ion, adsorption

In this study, the availability of activated clay treatment for decreasing the electrical conductivity in the real wire cut water was demonstrated. Activated clay (AC) was prepared, and its characteristics were investigated. The ability to adsorb Zn2+ and the removal ability through electrical conductivity were evaluated. It was found that the AC had a montmorillonite-like structure. Its specific surface area, micropore volume, mesopore volume, and macropore volume were 125.0 m2/g, 0.7 μL/g, 172.6 μL/g, and 13.7 μL/g, respectively. The cation exchange capacities at pH 5 and pH 10 were 56.2 and 67.2 cmol/kg, respectively. The effects of temperature, contact time, and pH of the solution on the adsorption of Zn2+ were measured. The amount of Zn2+ adsorbed by the AC increased with an increase in the adsorption temperature or in the pH. Adsorption isotherms data were fitted to the Freundlich equation compared to the Langmuir equation. Adsorption equilibrium was reached within 30 min, and kinetic data were fitted to the pseudo-second-order model compared to the pseudo-first-order model. Additionally, the AC was proven to effectively suppress the electrical conductivity. The suppression achieved by using washed AC was higher than that obtained by virgin AC. Washing AC with distilled water is useful for removing released ions (SO42-). Therefore, the column treatment packed with washed AC was evaluated in this paper. Finally, washed AC could remove Zn2+, resulting in the reduction of electrical conductivity (removal percentage is 47%). These findings provide significant information that can be useful for the removal of Zn2+ and reducing the electrical conductivity from wire cut water.