A novel chemical oxo-precipitation (COP) process for efficient remediation of boron wastewater at room temperature

Chemical oxo-precipitation (COP), which combines treatment with an oxidant and precipitation using metal salts, was developed for treating boron-containing water under milder conditions (room temperature, pH 10) than those of conventional coagulation processes. The concentration of boron compounds was 1000mg-BL^-1. They included boric acid (H₃BO₃) and perborate (NaBO₃). Precipitation using calcium chloride eliminated 80% of the boron from the perborate solution, but was unable to treat boric acid. COP uses hydrogen peroxide (H₂O₂) to pretreat boric acid, substantially increasing the removal of boron from boric acid solution by chemical precipitation from less than 5% to 80%. Furthermore, of alkaline earth metals, barium ions are the most efficient precipitant, and can increase the 80% boron removal to 98.5% at [H₂O₂]/[B] and [Ba]/[B] molar ratios of 2 and 1, respectively. The residual boron in the end water of COP contained 15ppm-B: this value cannot be achieved using conventional coagulation processes.