This study investigates the sustained oxidation performance of sulfate-based electrooxidation at a boron-doped diamond anode; more specifically, the continued oxidation of a model compound, diatrizoate, in the absence of applied current (i.e., off-grid oxidation). Two approaches were taken: delayed sample quenching with methanol, and application of intermittent current supply. For samples electrooxidized in Na₂SO₄ anolyte for 10–15 min, a delay of 60 min in sample quenching yielded an additional diatrizoate removal of 53%. This impact of sample quenching delay was observed at both pH 2 and pH 7, indicating that the source of sulfate and hydroxyl radicals was present at both pH values. Intermittent current supply (cycles of 5 min ON/15 min OFF) enabled a saving in electrical energy consumption by ~35% compared to constant current, due to continued removal of diatrizoate during the OFF periods. Electrooxidation in NaNO₃ anolyte did not show any off-grid oxidation of diatrizoate, confirming the crucial role of electrochemically activated sulfate. Given that the sulfate concentration was only 150 mg L⁻¹, the results presented herein may have significant implications in the electrochemical treatment of various types of contaminated water, from groundwater to sulfate-rich wastewater.

这项研究调查了在掺硼金刚石阳极上硫酸盐基电氧化的持续氧化性能。更具体地说，在没有施加电流的情况下，模型化合物泛影酸盐的继续氧化（即离网氧化）。采取了两种方法：用甲醇延迟样品淬灭，以及施加间歇性电流供应。用于在Na ₂ SO _4中电氧化的样品阳极液处理10–15分钟，样品淬灭延迟60分钟，可以再去除53％的次氮酸盐。在pH 2和pH 7均观察到样品淬灭延迟的影响，表明在两个pH值下均存在硫酸根和羟基自由基。间歇电流供应（5分钟ON / 15分钟OFF的周期）与恒定电流相比，由于在OFF期间持续去除了次氮酸盐，因此可节省约35％的电能消耗。NaNO ₃阳极电解液中的电氧化未显示泛影酸盐的离网氧化，证实了电化学活化的硫酸盐的关键作用。考虑到硫酸盐浓度仅为150 mg L ^-1，本文介绍的结果可能对从地下水到富含硫酸盐的废水等各种类型的污水的电化学处理产生重大影响。