2. Materials and methods

2.1 Materials

The extractant TMPD (97%) and the diluent CCl4 (97%) were purchased from TCI Co. Ltd.. Boric acid (99.5%), purchased from Tianjin Kemi’ou Chemical Reagent Co., was used as the boron source. Ultrapure water was used in all experiments. The simulated brine was prepared by dissolving H3BO3 in saturated magnesium chloride solution or ultrapure water, while the pH value of experimental solutions was adjusted using HCl or NaOH. All reagents were of analytical grade and were used without further purification.
The SL brine used in this study was collected from the Xitaijiner SL (located in the central part of the Qaidam Basin in China) and provided by Qinghai Citic Guoan Co.. The main characteristics of the brine are presented in Table 1.
Table 1. Main characteristics of the brine.