The Zn-TPP solution was prepared by dissolving 25.6 mg of Zn-TPP powder (Sigma Aldrich) in 3 mL of toluene. Then the mixture of Zn-TPP and toluene was stirred on a stirrer for 2 hours to allow Zn-TPP powder to be fully dissolved in toluene [25]. To encapsulate Zn-TPP into resin microbeads (sphere with diamater of 30-50 um), the prepared Zn-TPP solution was poured into 375 mg cation exchange resin microbeads (Sigma-Aldrich). 5 mL deionized water was added into the mixture of Zn-TPP solution and resin beads. The resulting mixture was again stirred on a stirrer for 5 hours at room temperature [23]. After that it was observed under microscope that the resin microbeads were filled with Zn-TPP dyes