Monitor application of multi-electrochemical sensor in extracting bromine from seawater

In this paper, a set of online measurement devices of multi-electrochemical sensor was investigated. Combined with industrial distributed control system, it was first applied in extracting bromine from seawater to realize the real-time adjustment of production process parameters. In the process of extracting bromine from seawater, the pH value of acidified raw brine, the addition amount of Cl₂ in the oxidation stage and the addition amount of SO₂ in the absorption stage are key parameters to control the whole production process. The multi-electrochemical sensor realized a rapid and high-throughput detection of the above parameters by integrating an all-solid-stage bromide ion selective electrode (Br-ISE), Eh electrode and pH electrode. The Br-ISE and the pH electrode were self-developed electrodes and the Pt electrode was Eh electrode. The pH electrode was used to control the addition amount of H₂SO₄ during the acidification of the brine. The Eh electrode was used to control the addition amount of Cl₂ during the oxidation stage and the addition amount of SO₂ during the absorption stage. The Br-ISE was used to monitor the Br^- concentration change in the raw brine. Results showed the optimum range of Eh in the oxidation stage and absorption stage of brine were 950-1000 mV and 580-610 mV, respectively. The application of multi-electrochemical sensor in industrial bromine production can realize real-time control of material addition and save the cost of production.