Brief Discussion on the Research and Application of a Lithium Content Monitoring Scheme to the Comprehensive Utilization of Gas Field Produced Water

Currently, the most common method of detecting lithium ions in salt lake water and oilfield production water is instrumental analysis, such as atomic emission spectroscopy, atomic absorption spectroscopy, ion chromatography, ultraviolet spectrophotometry, and complexometric titration. However, for instrumental analysis, the equipment is expensive, the operation is complicated, and the samples require complex pre-processing, which makes it difficult to detect lithium on-site. For complexometric titration, the operation steps are cumbersome during the production process, which limits its suitability for on-site inspection. As lithium’s position in industrial production gradually increases, the demand becomes increasingly large, and fluorescent probe detection technology, with simple operation and high selectivity, is gradually entering the field of view. Studies have shown that crown ether compounds have a complexing effect on alkaline earth metals. Among them, crown ether compounds such as 12-crown-4, 14-crown-4, and dibenzo-14-crown-4 show excellent selectivity in lithium ion recognition experiments because their internal pore size matches the size of lithium ions. Other cations are difficult to form complexes with them. Therefore, crown ether compounds can be used as recognition groups for lithium ion fluorescent probes. This article will introduce the existing instrumental analysis and titration methods for detecting Li+, explain the current research progress of fluorescent probes based on crown ether compounds, and put forward goals and prospects regarding their poor solubility.