2.3. Analysis
Color measurement of RB181 was recorded using a UV/vis
spectrophotometer (T80+ Pg Ins. Ltd.). The wavelength of 635 nm
(the maximum absorbance lmax) was used for color measure-
ments. The pH, temperature of the solution was measured by a
digital ion analyzer with various electrodes whose brand is Orion
pH meter (SM 4500-H+ B). And temperature is also measured
sensor (resistance). The total organic carbon (TOC) analysis was
measured by TOC-V ASI-V, Shimadzu (EN 1484). The chemical
oxygen demand (COD) analyses were done using a closed reflux
colorimetric method (SM 5220C).