Removal of Cobalt and Strontium in Aqueous Solution by Adsorption using Brewer’s Spent Grain

One byproduct of brewing beer is Brewer’s spent grain (BSG), which is reused in animal feed. However, BSG has valuable potential for other products such as biochar because of its high protein and fiber content. Radioactive waste is one of the biggest concerns in Korea because of the permanent shutdown of the Gori nuclear power plant. In this study, we aimed to used BSG-850, a biochar originating from BSG after pyrolysis, for the adsorption of cobalt (Co) and strontium (Sr), which are two radionuclides that contribute to radioactive waste. At 298 K, BSG-850 exhibited adsorption capacities of 3.304 and 1.462 mg/g for Co and Sr, respectively. At 308 K, BSG-850 exhibited adsorption capacities of 4.659 and 2.54 mg/g for Co and Sr, respectively. At 318 K, BSG-850 exhibited adsorption capacities of 5.516 and 3.036 mg/g for Co and Sr, respectively. The reusability of BSG-850 capacity was 75.3, 47.8, 43.6, and 36.2% for Co after 1, 2, 3, and 4 cycles, respectively. For Sr adsorption, the capacity was 93.6, 84.2, 57.2, and 32.7% after 1, 2, 3, and 4 cycles, respectively. In the presence of other competitive ions, the adsorption capacity decreased. Through this research, the adsorption capacity and adsorption properties of BSG-origin biochar for Co and Sr were confirmed. Thus, BSG may be a desirable option for solving radioactive waste problems.