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| Hydrothermal technology is a core environmental protection technique, which can be used in the waste water treatments and biomass conversion. In this paper, a novel idea is proposed to produce formic and acetic acids from wastewater containing phenolic compounds by alkali hydrothermal oxidations. The effects of major parameters on the yields of formic acid and acetic acid, including reaction temperature, reaction time, oxygen supply and types of alkali catalysts, were investigated. The results indicated that the optimum conditions for the production of formic and acetic acids were as follows: reaction temperature of 300 C, reaction time of 90 s, H2O2 supply of 60% and NaOH concentration of 1.5 mmoL. In the optimum condition the yields of formic acid and acetic acid reached 4.8% and 23.5%, respectively. In addition, the effect of different alkalis on the yields of formic and acetic acids was also investigated. The results showed that compared with the addition of NaOH, the addition of KOH showed a more pronounced effect on improving the yield of acetic acid. This research indicated that high value-added formic and acetic acids can be recovered as resources through hydrothermal oxidation of phenolic wastewater, and thus hydrothermal oxidation has a high potential for converting phenolic compounds in wastewater into value-added products. |
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| Keywords:Organic waste; Phenol; Hydrothermal oxidation; Acetic acid; Formic acid |
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