An adsorbent consisting of polyethyleneimine (PEI) immobilized in calcium alginate gel beads was synthesized and evaluated for Cr6+ removal. An evaluation of the synthesis process showed the importance of the PEI molecular weight on the immobilization efficiency. Polyethyleneimine of 70,000 Da molecular weight displayed the highest immobilization percentage at 52%. Batch kinetics and equilibrium tests showed that alginate-PEI (APEI) resin displayed considerable affinity for negatively charged Cr6+ complexes at low pH conditions ranging from pH 1.5-pH 3. The results also indicated the reduction of Cr6+ to less toxic Cr3+ species by the APEI adsorbent. The column adsorption experiments showed the ability of APEI resin to treat a 10mg/L Cr6+ solution with pH influent adjustment from pH 1.5 to pH 3 to concentrations that satisfy effluent standards for Cr6+ (< 0.1mg/L) and total Cr (< 0.5mg/L). Finally, comparisons with a highly aminated commercial resin Chitopearl CS-03 highlighted the unique ability of the hybrid APEI beads with its amine and carboxylic groups for the adsorption of Cr6+ as well as the retention of generated Cr3+ ions.