Pollution of waters by chlorinated organic pollutants is difficult to clean using actual remediation methods because these pollutants are highly stable. For instance, chloroform (CHCl₃) is poorly reactive with common oxidants such as iron-activated persulfate, ozone and Fenton’s reagents. Therefore, there is a need to develop new oxidants. Here, we designed a new dechlorination system, in which tannic acid and NaOH work synergistically to activate persulfate. We tested the effect of temperature and concentrations of persulfate, NaOH and tannic acid, on chloroform removal from water. Free radical-quenching experiments were performed to identify active species. Results show that chloroform removal increased from 42.5 to 97.6 wt.% after the addition of 300 mg/L tannic acid in 0.4 M NaOH. Superoxide radicals (O^·−₂) was primarily responsible for the degradation of chloroform in the persulfate/NaOH/tannic acid system, in which tannic acid reacts with persulfate to produce hydroperoxide. Hydroperoxide then reduces persulfate to generate sulfate radicals (SO₄^·−), and produces O^·−₂. NaOH-activated persulfate produces hydroxyl radicals (HO^·), which can oxidize chloroform. This dechlorination system showed excellent degradation efficiency for recalcitrant halogenated compounds, making it a very promising candidate for practical applications.

含氯有机污染物对水的污染很难使用实际的补救方法进行清洁，因为这些污染物是高度稳定的。例如，氯仿（CHCl ₃）与普通氧化剂，如铁活化的过硫酸盐，臭氧和Fenton试剂的反应性差。因此，需要开发新的氧化剂。在这里，我们设计了一种新的脱氯系统，其中单宁酸和NaOH协同作用以活化过硫酸盐。我们测试了温度和过硫酸盐，NaOH和单宁酸浓度对从水中去除氯仿的影响。进行自由基猝灭实验以鉴定活性物质。结果表明，在0.4 M NaOH中添加300 mg / L单宁酸后，氯仿的去除率从42.5％提高到97.6 wt。％。超氧自由基（O^· _-2）主要负责过硫酸盐/ NaOH /鞣酸体系中氯仿的降解，其中鞣酸与过硫酸盐反应生成氢过氧化物。然后，氢过氧化物还原过硫酸盐以生成硫酸根（SO ₄ ^·−），并生成O ^· ₋₂。NaOH活化的过硫酸盐产生羟基自由基（HO ^·），可氧化氯仿。该脱氯系统对难降解的卤代化合物显示出极好的降解效率，使其成为实际应用中非常有希望的候选者。