Selective and efficient adsorption of H3BO3 from Salt Lake brine solution by ZIF-67-derived hollow cobalt sulfide

The design of adsorbents with high recognition activity, high site density and high mass transfer efficiency is the significant to the removal of specific non-metallic ions from Salt Lake brines. Here we report the fabrication of ZIF-67-derived hollow Co 3 S 4 nanoadsorbent for the adsorption and separation of boron (B) in complex water from concentrated salt solutions. The adsorption experiments displayed that the B adsorption capacity of the hollow Co 3 S 4 material exhibited substantial B adsorption capacity, reaching 283.3 mg·g −1 , which represents an impressive 7.3-fold improvement over ZIF-67. On these grounds, a series of kinetic and thermodynamic studies were conducted, and the results revealed that the adsorption process is more consistent with the spontaneous exothermic reaction of the Langmuir adsorption isothermal model (R 2  = 0.999). The results of the charge density and density of states depicted that Co atoms strongly interact before and after adsorption, and that Co atoms are tend to react spontaneously with H 3 BO 3 , which serves as the primary adsorption site. The interaction including electrostatic and hydrogen bonds jointly realizes in B adsorption performance with high selectivity and excellent cycle stability. This study highlighted the high adsorption performance of the hollow Co 3 S 4 for boron in real water of the Salt Lake brine and provided a new idea for the design of other ZIFs derived hollow nanoadsorbent for practical applications.