Formaldehyde is a recalcitrant pollutant, which is difficult to remove from wastewater using conventional and advanced treatments. The objective of this research was to remove the organic matter from formaldehyde from an industrial wastewater, achieving its total mineralization and allowing the reuse of the water. The treatment was based on the reaction of formaldehyde with nitric acid, which was first studied and modelled with synthetic waters. Results show that it was possible to almost completely mineralize the formaldehyde (>95% TOC removal) at the best conditions studied (1.72 M of nitric acid and 85 °C of temperature). The addition of NaNO2 accelerated this reaction; however, after 2 h of reaction time, its effect was negligible at the maximum concentration of HNO3 studied. The results obtained with industrial wastewater fit well with the model. It is concluded that formaldehyde in actual wastewaters can be successfully removed through direct mineralization with nitric acid, under selected conditions.

中文翻译：

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模拟用硝酸处理甲醛的矿化

甲醛是一种顽固的污染物，使用常规和先进的处理方法很难从废水中去除。这项研究的目的是从工业废水中去除甲醛中的有机物，实现其完全矿化并允许水再利用。该处理基于甲醛与硝酸的反应，该反应首先用合成水进行研究和建模。结果表明，在研究的最佳条件（1.72 M 硝酸和 85 °C 温度）下，甲醛几乎完全矿化（> 95% TOC 去除）是可能的。NaNO2 的加入加速了这个反应；然而，在 2 小时的反应时间后，在所研究的最大 HNO3 浓度下，其影响可以忽略不计。用工业废水获得的结果与模型非常吻合。结论是，在选定的条件下，通过用硝酸直接矿化可以成功去除实际废水中的甲醛。