Study on Advanced Pretreatment of Seawater by Electrolysis and Neutralization of Acidic Waste Water with By-Product Magnesium Hydroxide

Abstract:

The advanced pretreatment by electrolysis of Bohai seawater in Tianjin used a diaphragm electrolyzer in the experiment. Removal efficiency and influence factors of the method were analyzed. Results show that turbidity, organic compounds, SDI and chroma of seawater were effectively decreased by electrolysis. Removal efficiency was significantly increased by current density, operation time and inter-electrode distance, and the optimum electrolytic conditions was determined as inter-electrode distance of 2 cm, current density of 15.87 mA·cm^-2, operation time of 10 minutes. It was investigated that when the water quality after electrolysis was of pH 8.6, the chroma and turbidity decreasing trend slowed down, with chroma of 0.052 A, removal rate reached 88.4%; the residual turbidity reduced to 2.52 NTU, removal rate reached 90.71%. A PH of about 8.5, COD_Cr decreasing trend slowed down, and when COD_Cr < 750 mg/L, it conformed to the requirements of the reverse osmosis water. With the study on neutralization of steel pickling waste liquor by the by-product of magnesium hydroxide, it is found that the quality of treated water reached 3^rd level national emissions standards (300-1000 mg/L). Magnesium hydroxide slurry of Cr (VI) removal rate reached 100%, conforming to the 1^st level national industrial wastewater discharge standards (< 0.5 mg/L).

• Periodical: Advanced Materials Research (Volumes 821-822)
• Pages: 1071-1080
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.821-822.1071
• Online since: September 2013
• Authors: Jing Nie, Shou Zhi Yi, Di Miao
• Keywords: Diaphragm, Magnesium Hydroxide, Pretreatment, Seawater Electrolysis

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