Exploring The Potential Hazards And Control Methods Of Ionic Liquids To Water Quality Safety

The rapid development of the global economy has brought increasing environmental pollution problems,especially water pollution.Water pollution control is based on comprehensive and accurate analysis and identification of water safety.However,the current water quality assessments are limited to the national standard analysis for limited chemical pollutants,and it is impossible to accurately analyze a large number of emerging pollutants（such as ionic liquids）.Chemicals below emission limits can also have synergistic effects and lead to a higher ecotoxicity.Therefore,it is necessary to establish a water quality assessment based on biological health effects.Ionic liquids,owing to their low vapor pressure and excellent solvating ability,are being increasingly applied in organic synthesis,electrochemistry,biomedicine and catalysis to replace highly toxic organic solvents.This application almost eliminates the pollution of organic solvents to the atmosphere,but ionic liquids mainly pollute aquatic environment and soils,directly endangering eco-environment and human health.Therefore,we urgently need to reveal the key structure-activity relationship of ionic liquid toxicity to design novel low-toxicity ionic liquids and explore new methods for ionic liquid removal.（1）Considering human oral exposure is the major route,our investigations employed a human cell panel（modeling oral exposures）including human stomach（GES-1）,intestinal（FHC）,liver（Hep G2）and kidney（HEK293）cells to explore ionic liquids-induced cytotoxicity.We discovered that the cytotoxicity of ionic liquids was human cell line-dependent with cytotoxicity in an order of FHC>GES-1>Hep G2>HEK293.For this reason,a toxicity assay using a single cell line was highly inappropriate.（2）The molecular mechanisms and structure-activity relationships of ionic liquid-induced cytotoxicity were systematically studied by using ionic liquid combinatorial chemical compound library,cell biological effects,lipidomics big data analysis and molecular simulation methods.Compared to anions（Br^-,OTs^-and OTMBS^-）we tested,the cation of ionic liquids played a major role in causing cytotoxicity.Ionic liquids with cations having longer hydrophobic sidechains（IL09 vs.IL01）readily insert into cell membranes with enhanced membrane and lipidomic perturbations,induce cytotoxicity by triggering cell cycle arrest and apoptosis.Reducing sidechain length and incorporating three nitrogen atoms（triazolium）instead of two（imidazolium）in the cation core alleviated cytotoxicity by reducing cell membrane perturbations and cell function interference.The discovery of these structure-activity relationships provides important guiding principles for the design of the next-generation of“green”and safe ionic liquids.（3）For efficient control of ionic liquids,we screened novel engineered nanomaterials from low-toxicity engineered nanomaterials that can be used to remove emerging pollutants in the aqueous environment.We found that two-dimensional nanomaterials Mo S₂ and WS₂ exhibited good adsorption capacity for ionic liquids,dominated by chemical adsorption,the exposed sulfur atoms in the outer layer provide a large number of active sites and may effectively adsorb ionic liquid cations through electrostatic interactions.And the adsorption of ionic liquids by spherical nanoparticlesα-Fe₂O₃ and Zr O₂ is dominated by physical adsorption.In a specific solution system,the positive correlation between adsorbent dosage and ionic liquid removal efficiency is related to more adsorption sites brought by the increased surface area of nanoparticles.And the decrease or overlapping of the adsorption active sites will lead to a decrease of adsorption capacity.So,the dosing ratio of adsorbent should be appropriately selected according to the concentration of the adsorbate.Furthermore,the decrease in p H and increased ionic strength inhibited the adsorption of ionic liquids by nanomaterials,while the presence of natural organic matter brings a positive effect on the removal of ionic liquids.The human cell panel modeling oral exposure constructed in this subject used as a water health risk assessment directly assess water quality safety based on biological effects,which fundamentally overcomes the limitation that the current water quality assessment is limited to trace analysis of individual pollutants.Key structure-activity relationships were elucidated based on combinatorial chemical compound library,cellular biotoxicity,omics data analysis,and computer simulations;novel nanomaterials that can be used to remove ionic liquids were discovered through low-toxicity engineered nanomaterial screening.Our research has made great strides in ensuring the safety of water quality.