ABSTRACT

Electro-Fenton (EF) oxidation has high oxidation abilities and is widely used in the treatment of biorefractory and chemically refractory organic wastewater. However, it generates a large amount of iron sludge, which limits large-scale application. In this work, the comparative study of EF oxidation and anodic oxidation (AO) of the secondary effluent of petrochemical wastewater using boron doped diamond anode is carried out. In EF oxidation, the effects of Fe²⁺ concentration, pH value, and current density are investigated. The optimal conditions consist of the following: Fe²⁺ concentration of 1.5 mmol·L⁻¹, pH of 4, and current density of 10 mA·cm⁻². In AO process, the effect of adding $\mathrm{S}{\mathrm{O}}_4^{2-}$, Cl⁻, $\mathrm{N}{\mathrm{O}}_3^{-}$, $\mathrm{P}{\mathrm{O}}_4^{3-}$, and $\mathrm{C}{\mathrm{O}}_3^{2-}$ is investigated; the optimal conditions can be obtained by adding a Na₂SO₄ solution (0.075 mol·L⁻¹). When compared with AO, although EF oxidation has a higher treatment efficiency, its energy consumption is higher, and the generated effluent (with 155 g of iron sludge·m⁻³) dramatically increases the post-treatment cost, thereby limiting its large-scale application. For AO with Na₂SO₄ solution (0.075 mol·L⁻¹) and a COD removal efficiency of 70%, the corresponding treatment time is 1.34 h and the energy consumption is 2.44 kWh·m⁻³.

摘要

电芬顿（EF）氧化具有很强的氧化能力，广泛用于处理难处理的生物和难处理的有机废水。但产生大量铁泥，限制了大规模应用。在这项工作中，使用硼掺杂金刚石阳极对石油化工废水二次出水进行EF氧化和阳极氧化（AO）的比较研究。在EF氧化中，研究了Fe ²⁺浓度、pH值和电流密度的影响。最佳条件包括：Fe ²⁺浓度为1.5 mmol·L ^-1，pH值为4，电流密度为10 mA·cm ^-2。在AO过程中，添加的效果$\mathrm{小号}{\mathrm{○}}_4^{2-}$, 氯^- ,$\mathrm{ñ}{\mathrm{○}}_3^{-}$, $\mathrm{磷}{\mathrm{○}}_4^{3-}$， 和 $\mathrm{C}{\mathrm{○}}_3^{2-}$被调查；_{添加Na 2} SO ₄溶液(0.075 mol·L ^-1 )可获得最佳条件。与AO相比，EF氧化虽然处理效率更高，但能耗更高，产生的出水（含铁泥·m ^{-3 155g}）大幅增加后处理成本，限制了其规模化应用。对于含Na ₂ SO ₄溶液（0.075 mol·L ^-1）的AO，COD去除率为70%，相应的处理时间为1.34 h，能耗为2.44 kWh·m ^-3。