Aqueous mixtures of methyl, ethyl and propyl paraben (MeP, EtP and PrP) prepared in real urban wastewater with low conductivity were treated by solar photoelectro-Fenton (SPEF) process at low input current (j = 10 mA cm⁻²) using a pre-pilot plant with an electrochemical reactor equipped with an air-diffusion cathode to electrogenerate H₂O₂ and a boron-doped diamond (BDD) or RuO₂-based anode. Comparative trials in simulated water matrices with or without Cl⁻ in the absence of natural organic matter (NOM) always led to a slower decay of parabens concentration and total organic carbon (TOC). This was mainly due to the superior regeneration of Fe²⁺ from photoreduction of Fe(III) complexes formed with NOM in real wastewater compared to that from Fe(OH)²⁺. In all matrices, a catalyst concentration as low as 0.20 mM Fe²⁺ was enough to ensure the production of OH in the bulk from Fenton’s reaction. SPEF with BDD yielded a complete removal of parabens in 180 min and 66% mineralization at 240 min. This gave rise to the greatest mineralization current efficiencies reported so far, up to 1000%, with a low energy consumption of 84 kWh (kg TOC)⁻¹. The synergy between homogeneous and heterogeneous catalysis, which allowed the efficient dosage of OH and M(OH) at low j, with simultaneous action of high UV power from sunlight justified such a good performance. Analogous apparent rate constants were determined for MeP, EtP and PrP. Slower decays were found with RuO₂-based anode due to its lower oxidation power. As a result, the MCE was 425% as maximum, but a lower energy consumption of 52 kWh (kg TOC)⁻¹ was needed. Since the role of active chlorine was of minor importance, the formation of toxic, refractory chloroderivatives was minimized. All by-products were transformed into malic, formic and oxalic acids prior to total mineralization.

在太阳能电池中制备的低电导率的对羟基苯甲酸甲酯，对羟基苯甲酸乙酯，对羟基苯甲酸丙酯和对羟基苯甲酸丙酯（MeP，EtP和PrP）的水混合物通过太阳能光电芬顿（SPEF）工艺在低输入电流（j  = 10 mA cm ^-2）下使用带有电化学反应器的预试设备，该电化学反应器配有空气扩散阴极以产生H ₂ O ₂和硼掺杂金刚石（BDD）或RuO ₂基阳极。在模拟水基质有或没有氯比较试验^-在没有天然有机物质（NOM）总是导致对羟基苯甲酸酯的浓度和总的有机碳（TOC）的一个较慢的衰减。这主要归因于Fe ²⁺的优异再生选自Fe的光还原在实际废水形成有NOM（III）配合物相比，选自Fe（OH）²⁺。在所有基质中，低至0.20 mM Fe ²⁺的催化剂浓度足以确保Fenton反应在本体中产生OH。含BDD的SPEF在180分钟内完全去除了对羟基苯甲酸酯，在240分钟时产生了66％的矿化。这带来了迄今为止报道的最大的矿化电流效率，高达1000％，能耗低至84 kWh（kg TOC）^-1。均相和非均相催化之间的协同作用，使得在低j浓度下可以有效地添加OH和M（OH），同时具有来自太阳光的高紫外线功率，证明了这种良好的性能。确定了MeP，EtP和PrP的相似表观速率常数。基于RuO ₂的阳极由于其较低的氧化能力而发现了较慢的衰变。结果，MCE的最大值为425％，但是需要更低的能耗52 kWh（kg TOC）^-1。由于活性氯的作用不太重要，因此将有毒难熔氯衍生物的形成减至最少。在全部矿化之前，所有副产物都转化为苹果酸，甲酸和草酸。