Nickel (Ni2+) plays a crucial role in the battery industry, but its high concentration in industrial wastewater poses significant health risks, necessitating an efficient removal process. Selective adsorption presents a promising technology for metal recycling from wastewater; however, there is currently no adsorbent that exhibits sufficient selectivity for Ni2+ over other divalent metals. In this study, we synthesized highly Ni2+ selective alginate beads modified with dimethylglyoxime (D-Ca-alg) and evaluated their Ni2+ separation and enrichment behavior. D-Ca-alg exhibited superior Ni2+ adsorption capacity (74.9 mg/g) compared to pristine alginate beads (Ca-alg) (50.6 mg/g). By increasing the solution pH, the Ni2+ uptake of D-Ca-alg proportionally increased and reached a maximum (61.6 mg/g at pH > 5). The physicochemical analysis revealed that both ion exchange and chelate formation are the main mechanisms of Ni2+ adsorption onto D-Ca-alg. Also, the selective Ni2+ separation ability of D-Ca-alg from other metal ions was evaluated in lithium-ion battery (LIB) recycling industry waste effluents. At pH 3, D-Ca-alg selectively separates Ni2+ from the solution without co-adsorption of Li+ and Co2+. In the continuous Ni2+ adsorption test, D-Ca-alg packed column treated more than 85 bed volumes (BV) of 20 mg/L Ni2+ solution with a flow rate of 1.0 mL/min. Finally, with 4 consecutive elutions of Ni2+ saturated D-Ca-alg packed columns, around 4000 ppm of Ni2+ enriched solution was obtained. Overall, our findings underscore the potential of D-Ca-alg as an effective adsorbent for Ni2+ recovery from LIB waste effluents, addressing environmental concerns and promoting sustainability in the battery industry.