This invention discloses a method for removing and stabilizing liquid chromate ion and other oxy-metal ions with barium compounds. ;Barium compounds with very low water solubility, such as barium silicate, barium carbonate, barium fluorosilicate, ect. can be used as powerful adsorbents for adsorbing chromate ion (CrO42) and other oxy-metal ions from liquid solutions at a wide pH range with very high adsorption capacity. For instance, one gram of barium silicate can adsorb chromate up to 200 mg. The adsorption capacity is higher than that of all the chromate adsorbents currently available. The chromate waste solution treated by barium silicate leaves as low as 0.01 ppm chromate in the solution. Also disclosed in this invention is a de-sorption process of chromate. Adder de-sorption, the chromate is recovered as a resource and the adsorbents are regenerated for reuse with the same adsorption power. ;Barium compounds with high water solubility, such as barium chloride and barium hydroxide etc. are used to prepare solutions, and then mixed with liquid wastes containing chromate ion and other oxy-metal ions to form very poorly soluble precipitates of barium compounds. The ions from liquid waste are thus removes by filtration, or the ions are immobilized in the solidification of the wastes, thereby promoting the efficiency of solidification and upgrading the quality of the solidified wastes.
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