Study on the Adsorption of Nickel (II) in Water by Modified Dried Duckweed Yanping Qu, Xinjun Li, Lin Lin, Shouge Wang, Min Guo and Wenchan Dong E3S Web Conf., 245 (2021) 03083 Published online: 24 March 2021 DOI: 10.1051/e3sconf/202124503083