The photoelectrocatalytic oxidation of an anionic surfactant (internal olefin sulfonate C20-C24, IOS) in synthetic oilfield wastewater was investigated by photocurrent measurements using a sulfur and nitrogen co-doped titanium dioxide electrode (S,N-TiO₂/Ti). For the electrode preparation, S,N-TiO₂ films were supported on Ti expanded meshes by sol–gel dip-coating, followed by thermal treatment at 400 °C. Photocurrent measurements were performed by linear sweep voltammetry (LSV) under UV–Vis irradiation using different IOS concentrations (20–200 ppm). The photocurrent values obtained at 0.5 V vs Ag/AgCl (i_ph) for each IOS concentration (C_IOS) were used to plot the 1/i_ph vs 1/C_IOS graph, in which two trends were identified. For high IOS concentrations (70–200 ppm), the values fitted well to the unimolecular Langmuir–Hinshelwood (LH1) kinetic model (R² = 0.973), which can be associated with the direct oxidation mechanism. For low IOS concentrations (20–70 ppm), the values fitted better to a linear combination of both unimolecular and bimolecular Langmuir–Hinshelwood (LH1 and LH2) kinetic models (R² = 0.854), which can be associated with direct and indirect oxidation mechanisms, respectively. These results suggest that at high IOS concentrations the IOS adsorption plays the main role on the photoelectrocatalytic oxidation, while at low IOS concentrations both IOS adsorption and H₂O adsorption (surface hydrophilicity) play important roles on the photoelectrocatalytic oxidation.

通过使用硫和氮共掺杂的二氧化钛电极（S，N-TiO ₂ / Ti）进行光电流测量，研究了合成油田废水中阴离子表面活性剂（内部烯烃磺酸盐C20-C24，IOS）的光电催化氧化。对于电极的制备，将S，N-TiO ₂薄膜通过溶胶-凝胶浸涂法支撑在Ti膨胀网片上，然后在400°C下进行热处理。通过使用不同IOS浓度（20–200 ppm）的UV–Vis照射，通过线性扫描伏安法（LSV）进行光电流测量。对于每个IOS浓度（C _IOS），在0.5 V vs Ag / AgCl（i _ph）下获得的光电流值用于绘制1 / i _ph与1 / C _IOS的关系图，其中确定了两个趋势。对于较高的IOS浓度（70-200 ppm），该值非常适合单分子Langmuir-Hinshelwood（LH1）动力学模型（R ²  = 0.973），这可能与直接氧化机理有关。对于较低的IOS浓度（20–70 ppm），该值更适合单分子和双分子Langmuir-Hinshelwood（LH1和LH2）动力学模型的线性组合（R ²  = 0.854），这可以与直接和间接氧化相关机制。这些结果表明，在高IOS浓度下，IOS吸附在光电催化氧化中起主要作用，而在低IOS浓度下，IOS吸附和H ₂O吸附（表面亲水性）在光电催化氧化中起重要作用。