| With the rapid development of our economy and industrialization degree unceasing enhancement,heavy metals in water body pollution problem is increasingly outstanding.Due to their toxicity and tendency towards bioaccumulation and unbiodegradability,heavy metals can enter into the plants and animals through food chain cycle and can cause great harm to the ecological environment and human health.Therefore,prevention and treatment of heavy metal pollution has been the key of the environmental protection work.As a new "green solvent" in the 21 st century,ionic liquids have been widely applied in organic synthesis,analytical chemistry,electrochemical,catalytic reaction and extraction separation fields,owing to their unique features such as low volatile,good solubility and extraction ability.Ionic liquids have been used for extraction separation of heavy metal ions,which not only decrease the use of volatile traditional organic solvents,but also reduce the harm to the environment waters.However,due to its high costs,directly usage of ionic liquid is big and need tedious procedures for separation,which limited its industrial application.In recent years,supported ionic liquid,a new type of solid adsorbent,solved the above problems and exploit the advantages of the carrier to the full,which is easy to seperate and recycle.In this work,ionic liquid structured adsorbents were prepared via chemically and applied to the separation and removal of heavy metal ions.The main contents were as follows.1.An ionic liquid structured adsorbent was prepared via chemically functionalized chloromethylated cross-linked polystyrene with N-methylimidazolium;the anionic functional immobilized ionic liquid as synthesised further activation treatment of the above material with sodium hydroxide,by adsorption experiments to optimize the synthetic parameters.The surface morphology and structure were characterized by scanning electron microscopy,infrared spectra,thermogravimetric analysis and X-ray photoelectron spectroscopy analysis,which proved N-methylimidazolium joined successfully.Accordingly to Boehm methodology,a series of bases of different strengths were applied for deterimination the points of zero charge.2.In order to study the supported ionic liquid for selective removal of Hg(Ⅱ),the adsorption experiments investigated the influence of the pH of the solution,adsorption time,solution temperature oscillation,dosing quantity of the material and the initial concentration of Hg(Ⅱ).The result showed that the adsorbent can effectively remove Hg(Ⅱ)with low concentration to 0.97 μg·L-1,which suggested it high sensitivity.The equilibrium time was short,the adsorption quantity was up to 633.63 mg · g-1,and in the presence of 12 kinds of metal ions the adsorbent can be preferential adsorption of Hg(Ⅱ).It was determined that adsorption data followed both the Langmuir model and pseudo-second-order kinetics with good correlation,which obtained satisfactory results.3.The anionic functional immobilized ionic liquid was examined the removal efficiency of different heavy metal ions in a series of acidity conditions.With Pb(Ⅱ)as target adsorbate,the effect of various parameters such as contact time,solution temperature,the amount of adsorbent and initial concentration of Pb(Ⅱ)were carried out to arrive at optimum conditions.Results showed that under the best conditions,in 45 minutes the adsorption reach equilibrium and adsorption amount was up to 151.6 mg · g-1.99.1% of Pb(Ⅱ)was removed effectively,when the concentration is low to 4.20 μg·L-1.The adsorption were described well by the Langmuir model and pseudo-second-order kinetics.At the best conditions,it was used for separation and removal of Pb(Ⅱ)from real water samples such as well water,water,industrial waste water,which obtained good agreements. |
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