Module 1 · after Hemmi et al., 2021 and 2025

Photodegradation kinetics

Simulate tetracycline removal with the published constants, fit your own measurements to the pseudo-first and pseudo-second order models, or check the consistency of a results table.

Catalyst Initial concentration C₀: mg/L Limited to the range measured in the paper (no extrapolation). Irradiation time: min Overlay the other catalyst (same C₀ if measured)

The k₁ and k₂ constants are interpolated between the rows of the published tables (k₂ on a log scale). The second-order model is the one retained by the authors.

Your measurements (time in min, then value) Paste two columns from Excel or a text file: tab, semicolon or spaces; decimal comma accepted. The second column is C₀ (mg/L) Also fit C₀ (otherwise fixed)

The example is simulated from the published parameters (ZnAl₂O₄, C₀ = 12.7 mg/L, k₂ = 3.70×10⁻³) with slight noise: the papers’ raw measurements are not published.

Model	k	C₀ (mg/L)	R²	SSE	ARED (%)	t½ (min)	V₀ (mg/L/min)
Paste your measurements then click “Fit”.

SSE = Σ(C_cal − C_exp)² ; ARED = (100/N)·Σ|C_cal − C_exp| / C_cal ; t½ = ln2/k₁ or 1/(k₂·C₀) ; V₀ = k₁·C₀ or k₂·C₀². The best model (lowest SSE) is highlighted.

Recomputes the half-life and initial rate of each row from k₂ and C₀, then shows which assumption explains the published values: measured or nominal C₀, V₀ = k₂·C₀² or k₂·C₀.

Table