Fully Automated Measuring Equipment for Aqueous Boron and Its Application to Online Monitoring of Industrial Process Effluents

Abstract

Fully automated measuring equipment for aqueous boron (referred to as the online boron monitor) was developed on the basis of a rapid potentiometric determination method using a commercial BF4(-) ion-selective electrode (ISE). The equipment can measure boron compounds with concentration ranging from a few to several hundred mg/L, and the measurement is completed in less than 20 min without any pretreatment of the sample. In the monitor, a series of operations for the measurement, i.e., sampling and dispensing of the sample, addition of the chemicals, acquisition and processing of potentiometric data, rinsing of the measurement cell, and calibration of the BF4(-) ISE, is automated. To demonstrate the performance, we installed the monitor in full-scale coal-fired power plants and measured the effluent from a flue gas desulfurization unit. The boron concentration in the wastewater varied significantly depending on the type of coal and the load of power generation. An excellent correlation (R2 = 0.987) was obtained in the measurements between the online boron monitor and inductively coupled plasma atomic emission spectrometry, which proved that the developed monitor can serve as a useful tool for managing boron emission in industrial process effluent.