Dear Chandrasekhar

                                    N719 dye adsorption  can  be  quantitatively determined from the UV-Visible spectroscopic measurements  by monitoring the absorbance at or near

510 nm (probable abs. max.) . First prepare 10ml  N719 dye solution in 0.1 M NaOH and note its absorbance max. Determine the absorbance of  adsorbed dye from the desorbed dye solution obtained by dipping dye coated TiO2 film in 10 mL 0.1 M NaOH solution for 10 minutes. Then subtract the concentration to find the quantity of dye adsorbed. Use formula A= ECX...

Dear Chandrasekhar you can take uv visible absorption spectra to see the absorption of dye.  but still it will not give exact amount of dye.

Dear Chandrasekhar

                                    N719 dye adsorption  can  be  quantitatively determined from the UV-Visible spectroscopic measurements  by monitoring the absorbance at or near

510 nm (probable abs. max.) . First prepare 10ml  N719 dye solution in 0.1 M NaOH and note its absorbance max. Determine the absorbance of  adsorbed dye from the desorbed dye solution obtained by dipping dye coated TiO2 film in 10 mL 0.1 M NaOH solution for 10 minutes. Then subtract the concentration to find the quantity of dye adsorbed. Use formula A= ECX...

 Dear Sayyed Saheb

                                         The dye adsorption in this case is negligible. So can't be monitored by calibration curve and absorbance measurements...

kind regards

KKN

Agree with KKN.

Generally, the concentration of adsorbed dyes can be calculated using standard linear graph. For ex., taking 20, 40, 80, 160 and 320 ppm concentration of dyes and analyzing its OD using UV-visible spectroscopy (at constant wavelength). The linear plot should be drawn between concentration (x axis) and OD (y axis). Now, the unknown sample (the material will be put into the particular concentration of dye, after time t, only the liquid sample will be taken from that) will be analyzed for its OD value at the same wavelength. Now, the OD will be matched with the concentration in the standard graph or else, y = mx formula can be used. This is the concentration of remaining dye in the solution (consider it as 'b'). If the initial concentration of dye was 'a' ppm, then, 'the amount of dye adsorbed by the material = a - b.

From your UV absorption, you can determine surface coverage with this formula: Γ = (A(λ)/ε(λ))/1000, where Γ is the surface coverage in mol cm-2, A(λ) is the absorbance of the film at λ (530 nm in this case), and ε (λ) is the extinction coefficient for N719 at λ max (530 nm). You will need to look into literature to determine the extinction coefficient value for N719 at 530nm