Adsorption of Nitrogen and Phosphorus in Water by Eggshell Modified with FeCl3 Hongcui Li, Yurong Li, Feifei Yan and Xiangzheng Yin E3S Web Conf., 245 (2021) 03081 Published online: 24 March 2021 DOI: 10.1051/e3sconf/202124503081