Effect of (a-c) pH and (d-f) sulfite concentration over ibuprofen pseudo first-order degradation rate constant (k) by the Fe(II)/sulfite, electro-sulfite, and electro-Fe(II)/sulfite processes. Conditions: Fe(II)/sulfite process – 10 μM ibuprofen, 0.1 mM Fe(II), 1 mM sulfite, 10 mM Na2SO4, initial pH 7; electro/sulfite process – 10 μM ibuprofen, 1 mM sulfite, 10 mM Na2SO4, 200 mA, initial pH 7; electro/Fe(II)/sulfite process – 10 μM ibuprofen, 0.1 mM Fe(II), 1 mM sulfite, 10 mM Na2SO4, 200 mA, initial pH 7. Solution pH and sulfite concentration varied as indicated.