Experimental investigation on the oxidation of printing ink wastewater under hydrothermal flames. Issue 6 (December 2021)

• Record Type: Journal Article
• Authors: Zhang, Fengming; Li, Yufeng; Liang, Zhaojian; Wu, Tong; Huang, Yingfei
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 6(2021)
• Publication Date: 2021-12
• Subjects: Printing ink wastewater -- Hydrothermal flame -- Supercritical water oxidation -- Additive -- Reaction mechanism; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.106745
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: Printing ink wastewater has a strong color and contains high salinity and high concentrations of complex organic compounds, posting a severe threat to the ecological environment and human health. In this work, supercritical water oxidation of printing ink wastewater is performed within a transpiring wall reactor (TWR) to avoid corrosion and salt plugging issues. The high concentration of organic matter in printing ink wastewater is used to form hydrothermal flames for enhanced degradation. Flame temperatures, gaseous and aqueous products characteristics, as well as the anti-corrosion and salt plugging performance of the reactor, are obtained. A remarkable temperature fluctuation due to the multi-component systems indicates the instability of hydrothermal flame. The salt recovery rate of 94.56% and the integrity of the porous tube inner wall indicate that TWR has a good performance in terms of anti-corrosion and salt plugging. Under typical conditions, the removal rates for chemical oxygen demand, total nitrogen, and color are 99.52%, 70.07%, and 97.89%, respectively. Alkanes, nitrogenous compounds, benzodiazepines, and heterocyclic compounds in the aqueous products, and CO, H2, NH3, and CH4 in the gaseous products are the main intermediate products of printing ink wastewater under hydrothermal flames. Ammonia nitrogen, as the main intermediate product, inhibits the complete oxidation of nitrogenous organic compounds. Additionally, higher KNO3 concentrations promote the complete oxidation of nitrogenous organic compounds, while higher NaOH concentrations can increase the pH value and slightly facilitate degradation. In addition, higher feed flow rates prevent deposition and adhesion of additives that occur at high concentrations. Graphical abstract: ga1 Highlights: SCWO of printing ink wastewater is conducted via a transpiring wall reactor. High concentration of organic matter is used to form hydrothermal flames. Ammonia nitrogen inhibits the complete oxidation of nitrogenous organic matter. KNO3 promotes degradation of ammonia nitrogen and nitrogenous organic matter. Higher feed flows prevent the agglomeration of additives at high concentrations.