Optimization and modeling of Tramadol hydrochloride degradation by the homogenous photo-Fenton-like system assisted by in situ H2O2 formation

Abstract

This study examines the removal efficiency of Tramadol hydrochloride (TR) and mineralization (chemical oxygen demand, COD) by the effective photoinduced Fenton-simulated system under artificial light (UVA). The Box-Behnken design was used to optimize the value of each parameter. The model yielded the following optimal parameters: [TR]₀ = 10 mg, ratio ([Oxalate ]₀/[Fe³⁺]₀) = 100, initial pH = 2.83, and [Fe^{3 +}]₀ = 1.298 mg with effective TR removal (100%) and COD removal efficiency (72.82%). The presence of oxygen has a positive effect by increasing hydrogen peroxide production from 4.36 to 8.12 mg L^-1 and by maximizing a change in Fe³⁺ speciation. The degradation kinetics of ΤR in the oxygen-saturated medium is four times faster than that in the normal aerated medium. The K_app rate constants increased quickly from 5.72 × 10^-2 to 20 × 10^-2min^-1. The percent COD removal increased to 87.46%, and the final pH increased from 5.31 to 6.23.