Chemical oxo-precipitation (COP) has become a promising method to treat boron wastewater at room temperature by using hydrogen peroxide to convert boric acid to perborate species which were precipitated with alkaline earth metals. This work develops a model that explicitly predicts the solubility of barium perborates at given pH, ionic strength and concentrations of barium ions and peroxide species at 25 °C. The solubility product constants (pKsp) of two major barium perborate - amorphous Ba(B(OH)3OOH)2 (A-BaPB) and crystalline BaB(OH)2(OO)2B(OH)2 (C-BaPB) - were experimentally estimated to be 8.335 ± 0.109 and 9.190 ± 0.057, respectively. The solubility curves of BaPBs were established to confirm that C-BaPB is much more stable and less soluble than A-BaPB. The model developed herein can properly predict the effluent levels of boron after chemical oxo-precipitation of the boron-containing wastewaters.

Solubility products of barium perborates in aqueous solution at 25°C for predicting residual boron levels in effluents of chemical oxo-precipitation

254th National Meeting (2017)

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