Phytotoxicity of ionic liquids with different structures on wheat seedlings and evaluation of their toxicity attenuation at the presence of modified biochar by adsorption effect.

The toxic effects of eight common ionic liquids (ILs) on wheat seedlings was evaluated with specific emphasis on the influence of concentration range, anion species and cation chain length of ILs. The growth of wheat seeds was significantly inhibited by ILs, especially under higher concentration, presence of the fluoride anion and the longer alkyl chain length of the cation. The modified biochar (PB-K-N) efficiently removed the ILs from aqueous solutions, the order of the adsorption capacities was as follows: [Bmim]OAc [Bmim]CHO [Bmim]BF [Bmim]Br, [Domim]Br [BPy]Br [Omim]Br [Bmim]Br [Emim]Br. Furthermore, the wheat growth of all ILs groups except [Bmim]BF group in the presence of PB-K-N was also similar to that of the control groups, which clearly demonstrated that PB-K-N could decrease or alleviate toxicity of ILs toward wheat by adsorption effect. Therefore, the biochar application was effective in improving plant resistance to ILs stress by adsorption, to reduce the phytotoxicity of ILs and provide an alternative approach for the utilization of PB-K-N in ILs contaminated water and soils.