Synthesis Of Polymer-Supported Functional Ionic Liquids And Their Application For Efficient Removal Of Phenols And Antibiotics From Waters

Phenolic compounds,as an important industrial raw material and intermediate of valuable fine chemicals,are one of the highly toxic and refractory persistent organic pollutants.They can cause significant harm to aquatic organisms and public water even at very low concentrations,the WHO stipulates that the content of phenols in drinking water should not exceed 0.001 mg/L.Nowadays,antibiotics are becoming irreplaceable in treating various diseases for human and veterinary,but they could not be completely metabolized by organisms.Their continuous introduction into the environment can bring about the changes in microbial community structure and may induce the bacteria to generate drug resistance.A variety of antibiotics have been frequently detected in aquatic environment in many countries due to their increasing usage and consumption.Therefore,how to fastly,efficiently and simply remove these pollutants from waters is of great importance.Ionic liquid?ILs?composed solely of ions,which remain liquid at/close room temperature.Due to their unique physical and chemical properties such as undetectable vapor pressure,excellent solvation qualities and high chemical/thermal stability,they showed great advantage in extracting pollutants.However,ILs are expensive,relatively large amount usage of ILs in biphasic systems is costly and cannot be completely separated from water.To overcome this limitation,the supported ILs materials have been developed as a platform technology for a variety of applications since they combine the benefits of ILs with the supports and can greatly reduce the usage of ILs.Herein,three novel supported task-specific IL adsorbents with high adsorption capacity,quick removal process,strong anti-interference capability and excellent regeneration ability were prepared by chemical bonding,and characterized with the aid of FE-SEM,FT-IR,TGA,XPS and EDS techniques.Their adsorption performance were examined by using p-Nitrophenol?PNP?,ceftiofur sodium?CFS?and sulfadiazine sodium?SDS?as the model pollutants,respectively.The main research contents and conclusions are as follows:?1?A novel supported task-specific IL adsorbent?PS-CH₂-[C₂NH₂MIm][Br]?was prepared by chemically grafting 1-aminoethyl-3-methylimidazolium bromide?[C₂NH₂MIm][Br]?ionic liquid onto the surface of chloromethyl polystyrene resin?PS-CH₂Cl?and its performance to remove p-nitrophenol?PNP?from water was systematically investigated by both batch process and dynamic column elution method.It was shown that the adsorbent not only exhibited excellent adsorption performance towards high concentration PNP with an ultrahigh adsorption capacity of 1269.8 mg/g within 30 min,but also could effectively remove trace PNP from water at the concentration as low as 0.0025 mg/L.Common interfering ions and neutral molecules in water especially K⁺,Na⁺,Ca²⁺,Mg²⁺,NO₃^-,and Cl^-did not interfere with the removal of PNP even if their concentrations?1mol/L?were 1000000 times higher than that of PNP,which indicates its potential in removal of PNP from high salinity wastewater.The adsorbent could be easily regenerated and recycled at least 10 times with no loss in separation performance.The possible adsorption mechanism was investigated in various approaches.In addition,the adsorbent was applied to remove PNP in real water samples,and promising results were reported.?2?In this work,a superior hydroxyl-functionalized ionic liquid based polymer?PS-[Hemim][Cl]? was prepared for highly efficient removal of ceftiofur sodium?CFS?antibiotic from aqueous solutions,and the effect of various factors on the adsorption was investigated.It was found that the PS-[Hemim][Cl]exhibited a super-high adsorption capacity of 1260.5 mg/g for CFS within 60 min and kept high removal efficiency in a wide range of antibiotic concentrations from 5 ppb level to 1000 mg/L.Even the concentration of common inorganic ions was 1000 times higher than that of CFS,the adsorption efficiency remained above 93%.At the same time,the PS-[Hemim][Cl]showed excellent adsorption performance for the antibiotics with similar structure to CFS.Compared with commercially available adsorbents,the adsorption capacity of PS-[Hemim][Cl]for CFS was 4-468 times higher under the same experimental conditions.The application of PS-[Hemim][Cl]to real wastewater containing different concentrations of CFS was investigated and promising results were reported.Additionally,preliminary mechanism studies suggested that electrostatic attraction,hydrogen bond and ion exchange synergistically contributed to the highly efficient adsorption of CFS.In this work,a novel polystyrene supported ionic liquid?PS-CH₂-[TSiIm][Cl]?material was prepared by chemically functionalized chloromethyl polystyrene resin with 1-?Trimethylsilyl?imidazole,and the novel adsorbent was used for the removal of sulfadiazine sodium?SDS?from water.The effects of pH,temperature,contact time and initial SDS concentration on the adsorption were systematically investigated.On the basis of the above data,the as-prepared material was used as solid-phase extraction adsorbent,and column experiments were carried out to investigate the effect of sample volume and common coexisting ions on the removal of PNP and regeneration of the adsorbent.Results showed that SDS adsorbed onto the PS-CH₂-[TSiIm][Cl]could be well evaluated by Langmuir model and the maximum adsorption capacity could be reached as high as 438.2 mg/g.Simultaneously,the PS-CH₂-[TSiIm][Cl]exhibited excellent removal performance towards trace SDS at ppb level?0.005 mg/L?,the removal efficiecy was above 95.65%.Common inorganic ions such as K⁺,Na⁺,Ca²⁺,Cl^-had no effect of on the removal of SDS even if their concentrations were 20000 times higher than that of SDS.And the PS-CH₂-[TSiIm][Cl]was easy to regenerate without loss in adsorption performance.Additionally,the PS-CH₂-[TSiIm][Cl]was applied to remove the SDS from environmental water samples.The possible adsorption mechanism was also investigated and the results suggested that the adsorption of SDS was predominated by hydrogen bonding,?-?interaction and electrostatic attraction.Therefore,in consideration of its excellent adsorption performance,facile operation and easy regeneration,the PS-CH₂-[TSiIm][Cl]could be a highly efficient and economical adsorbent for the separation and pre-concentration of SDS from contaminated water.