Simultaneous optimizing removal of manganese and ammonia nitrogen from electrolytic metal manganese residue leachate using chemical equilibrium model

• Published in: Ecotoxicology and environmental safety 2019-05, Vol.172, p.273-280
• Main Authors: Shu, Jiancheng, Wu, Haiping, Chen, Mengjun, Wei, Liang, Wang, Bin, Li, Bing, Liu, Renlong, Liu, Zuohua
• Format: Article
• Language: English
• Subjects: Ammonia - chemistry; Ammonia nitrogen; Chemical equilibrium model; Chemical Precipitation; Electrolysis; Electrolytic metal manganese residue leachate; Industrial Waste; Manganese; Manganese - chemistry; Manganese Compounds - chemistry; Metallurgy; Models, Chemical; Nitrogen - chemistry; Struvite; Struvite - chemistry; Waste Management - methods; Water Pollutants, Chemical - chemistry
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2019.01.071

Electrolytic metal manganese residue leachate (EMMRL) was produced from long-term deposition of electrolytic metal manganese residue. EMMRL contains huge amount of manganese and ammonia nitrogen which could seriously damage the ecological environment. In this study, a chemical equilibrium model-Visual MINTEQ was used to simultaneously optimize removal of manganese and ammonia nitrogen from EMMRL with chemical precipitation methods. In the laboratory experiment, the effect of different N: P ratios and pH were investigated, and the characterization of the precipitates was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). The results showed that over 99.9% manganese and 96.2% ammonia nitrogen were simultaneously removed, respectively, when molar ratio of N:P was 1:1.15 at pH 9.5. Moreover, the experimental results corresponded well with the model outputs with respect to ammonia nitrogen and manganese removal. Manganese was mainly removed in the form of MnHPO4·3H2O and manganite, and ammonia nitrogen was mainly removed in the form of struvite. Economic evaluation indicated the chemical precipitation methods can be applied in the factory when the price of precipitation was higher than 0.295 $/kg. [Display omitted] •Chemical equilibrium model was used to optimizing removal of Mn2+ and NH4+.•The experimental results corresponded well with the model outputs.•Over 99.9% Mn2+ and 96.2% NH4+ removal efficiency was obtained simultaneously.•Mn2+ was mainly removed as MnHPO4 and manganite, and NH4+ was removed as struvite.