Recovery phosphate and ammonium from aqueous solution by the process of electrochemically decomposing dolomite

• Published in: Chemosphere (Oxford) 2021-01, Vol.262, p.128357, Article 128357
• Main Authors: Li, Xuewei, Zhou, Xiaowen, Yang, Bo, Wen, Zhen
• Format: Article
• Language: English
• Subjects: Ammonium Compounds - chemistry; Ammonium Compounds - isolation & purification; Calcium - chemistry; Calcium Carbonate - chemistry; Dolomite; Electrochemical Techniques - methods; Electrochemistry; Electrodes; Fertilizers; Hydrogen-Ion Concentration; Magnesium - chemistry; Natural minerals; Phosphates - chemistry; Phosphates - isolation & purification; Phosphorus - chemistry; PO4–P and NH4–N recovery; Silicon Dioxide; Solutions; Waste Disposal, Fluid - methods; Waste Water - chemistry; Water Pollutants, Chemical - chemistry
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2020.128357

The cost-effective recovery of phosphate is of great significance to the mitigation of phosphorus resource depletion crisis. The electrochemical-decomposition of dolomite was developed to recover phosphate and ammonium from aqueous solution. The dolomite ore is mainly composed of CaMg(CO3)2 (53.73%), CaCO3 (28.93%) and SiO2 (16.59%). The continuous release of Mg2+ and Ca2+ were achieved by electrochemically decomposing dolomite ore, accompanied by the generation of base solution (9.0–10.5). The main factors affecting the recovery performance of phosphate (PO4–P) and ammonium (NH4–N) are current, initial concentration of PO4–P and NH4–N, initial pH of feed solution and feed rate. For a 30-d operation, the recovery rate of PO4–P was maintained at 90–97% and that of NH4–N at 50–60% under optimized operating conditions. The recovered product had low water solubility but high citric-acid-soluble, and was proposed as a slow-release fertilizer for crops. The proposed process as a simple, effective and green route may serve as a new strategy for recovering PO4–P and NH4–N from wastewaters. [Display omitted] •Mg2+ and Ca2+ can be released from dolomite ore by electrochemical decomposition.•A high alkaline solution can be created by the electrochemical process.•Phosphate can be efficiently recovered as well as ammonium.•The precipitates did not give any environmental burden, which can be as a fertilizer.