Nitrate removal from water phase using Robinia pseudoacacia bark for solving eutrophication

The bio-absorbent of Robinia pseudoacacia (R. pseudoacacia) bark was modified with sulfuric acid and their nitrate removal efficiency in water phase was investigated. At 2.5 ppm, the nitrate removal efficiency of R. pseudoacacia bark modified with 2, 4, 6, 8 and 10 M H2SO4 was 54, 61, 69, 72 and 72%, respectively, and the maximum removal efficiency was increased by 100% as compared with the raw R. pseudoacacia bark. The XPS analysis results reveal that the acidic functional groups such as carboxylic, carbonyl and phenol groups were increased by 48% in the 8M H2SO4 modified R. pseudoacacia bark, and the specific surface area and the total pore volume increased by two-times to 4.94m2/g and 0.0113 cc/g, respectively. In addition, 0.1 M sodium hydroxide performed as the best desorption agent for desorption rates using hydrochloric acid, sodium hydroxide and ethylenediamine tetraacetic acid (EDTA), in order to recover the nitrate. Collectively, these results could be employed as economical and practical engineering data for the development of nitrate removal process.