Preparation And Adsorption Performance Of Novel Porous Composite

Porous material has attracted great interest in analytical chemistry due to its high specific surface area and tunable pore size. In this paper, the porous composites based polymeric ionic liquid and 26-membered hexaazamacrocycle were prepared and characterized, and employed as adsorbent in solid-phase extraction（SPE） and magnetic solid-phase extraction（MSPE） for extraction and separation of organic pollutants.Polymeric ionic liquid based porous composite was prepared by the reation of poly-（1-vinyl-3-butylimidazolium bromide）（P[VBim]Br）and polyacrylic acid（PAA） in alkaline solvents. The obtained P[VBim]Br-PAAcomposite was characterized by SEM, FTIR, thermogravimetric analysis and nitrogen adsorption-desorption. The adsorption performance of P[VBim]Br-PAA as new adsorbent was evaluated by using some organic pollutants as target analytes, such as organophosphorus pesticides, polycyclic aromatic hydrocarbons（PAHs）, phthalates, phenols and anilines, as well as inorganic anions. The results demonstrated that P[VBim]Br-PAA displayed highest adsorption efficiency for PAHs. In order to further explore the adsorption mechanism of P[VBim]Br-PAA as adsorbent, using four PAH（phenanthrene, fluoranthene, acenaphthene and pyrene） as target analytes, the isotherms and kinetics parameters of the adsorbents were evaluated. The results showed that the adsorbent indicated different adsorption behaviors. Phenanthrene, fluoranthene and acenaphthene were fitted to Freundlich isotherm model and followed pseudo-second order kinetics model, while pyrene was fitted to Langmuir isotherm model and pseudo-first order kinetics model.Polymeric ionic liquid withbis（trifluoromethansulfonyl）imide anion was synthesized through the anion-exchange reaction of P[VBim]Br and lithium bis（trifluoromethansulfonyl）imide（LiTf2N）. P[VBim]Tf2N based porous composite was prepared by reacting P[VBim]Tf2N and PAA in alkaline solvents. The resulting material was characterized by SEM, FTIR, and nitrogen adsorption-desorption. The P[VBim]Tf2N-PAA composite was for the first time used as adsorbent in SPE for extraction and determination of four of PAHs in environmental water sample using HPLC. The extraction parameters influencing the extraction efficiency, including adsorbent amount, sample flow rate, eluent solvent and its volume, were optimized. Under the optimized conditions, good linearity of the proposed method was obtained with correlation coefficients（r2） of 0.9879-0.9991. The limit of derection（LOD） defined as signal-to-noise of 3, was 0.01 μg L-1 for naphthalene, acenaphthene and phenanthrene, and 0.1 μg L-1forfluoranthene. The repeatability, expressed as relative standards deviations（RSD） of 5 replicates, was 4.3-1.8%. The proposed method has been successfully used to determine PAHs from lake water samples with satisfactory relative recovery（81.4-108.4%） and RSD（3.2-0.6%）. In addition, the reusability of the new adsorbent was investigated, and the results showed that no obvious decrease in extraction efficiency was observed after 8 times of recycling.The perhydro 26-membered hexaazamacrocycle（Ph[26]-HAM） was immobilized onto magnetic silica surface by reacting of the amino of Ph[26]-HAM with ethylene oxidof γ-glycidoxypropyl trimethoxysilane ethane, completing layer-layer assemble of Ph[26]-HAM. The Ph[26]-HAM-based porous magnetic material was prepared through layer-by-layer assembly technique and characterized by TEM, FTIR, vibrating sample magnetometer and elemental analysis. Fe₃O₄@SiO2@（EPPS-Ph[26]-HAM）2 was used as adsorbent in MSPE for extraction and determination of phenolic compounds in environmental water sample. The extraction parameters influencing the extraction efficiency, including assembling layers, amount of adsorbent, adsorption time, desorbent solvent and its volume, were optimized. Under the optimized conditions, good linearity of the proposed metheod was obtained with correlation coefficients（r2） of 0.9967-0.9996. The repeatability, expressed as relative standards deviations（RSD） of 5 replicates, was 1.8-11.1%. The proposed method has been successfully used to determine real environment water sample with relative recovery（30.3-90.0%） and RSD less than 7.6%. The results indicated that Fe₃O₄@SiO2@（EPPS-Ph[26]-HAM）2-MSPE-HPLC was suitable for the determination of phenolic compounds in environmental water samples.