Directional amine-based solvent extraction for simultaneous enhanced water recovery,salt separation and effective descaling from hypersaline brines  

作　　者：Yuyao Zhang Litao Jia Jin Zhao Xuming Liu Shuyu Dong Chuanyang Liu Yuanyuan Cui 

机构地区：[1]Shougang Research Institute of Technology,Beijing 100043,China [2]Research Center of Environmental Technology in Water Pollution Source Identification and Precise Supervision,School of Environment,Tsinghua University,Beijing 100084,China

出　　处：《Frontiers of Environmental Science & Engineering》2024年第3期83-92,共10页环境科学与工程前沿（英文）

基　　金：supported financially by a grant from Shougang Group Co.,Ltd.,China(No.K202200134Y).

摘　　要：The feasibility of simultaneous water recovery,salt separation and effective descaling of hypersaline brine was investigated by diisopropylamine(DIPA)-based directional solvent extraction(DSE),using diluted/concentrated seawater with initial saline concentration range of 12–237 g/L at extraction temperatures of 5 and 15℃,respectively.The water recovery shows an obvious boundary at saline concentration of 115 g/L under dual effect of specific water extraction efficiency and extraction cycles.High Cl^(–) ion concentration in product water is in sharp contrast to the nearly complete removal of SO_(4)^(2–)and hardness ions,indicating that DIPA-based DSE process indeed achieved efficient separation and purification of Cl^(–) ion from hypersaline brines.Especially,the radical precipitation of Mg^(2+)and Ca^(2+)ions in form of Mg(OH)_(2)and CaCO_(3)demonstrates effective descaling potential,although it leads to more DIPA residues in dewatered raffinate than product water.Moreover,an exponential correlation between the Cl^(–) removal efficiency and specific water extraction efficiency further reveals the intrinsic relationship of water extraction process and transfer of Cl^(–) ion to the product water.Overall,the study provides a novel approach for integrating the water recovery and separation of Cl^(–) ion from ultra-high-salinity brines with radical precipitation of Mg^(2+)and Ca^(2+) ions in one step.

关 键 词：Hypersaline brines Directional solvent extraction Salt separation Ca^(2+)and Mg^(2+)descaling 

分 类 号：X52[环境科学与工程—环境工程]