环丙沙星分子印迹聚合物的制备及其吸附特性的研究

以环丙沙星(CIP)为模板分子,α-甲基丙烯酸(MAA)为功能单体,三甲基丙烯酸三羟甲基丙烷酯(TRIM)为交联剂,进行热聚合.通过对于功能单体和交联剂的用量对分子印迹聚合物吸附性能的影响的研究,得到最佳的聚合配比为n(CIP):n(MMA):n(TRJM)=1:6:16,并以此配比制得了对环丙沙星具有特异选择性吸附的分子印迹聚合物.通过静态平衡结合法研究了模板聚合物的结合动力学以及该聚合物的结合能力和选择特性,通过Scatchard分析法研究了印迹聚合物对模板分子的结合特性.结果表明,该印迹聚合物具有良好的吸附能力和吸附选择性,静态吸附分配系数KD为41.64,分离因子α为1.62;该印迹聚合物中形成了2类不同的结合位点,经计算它们的离解常数分别为Kd1=5.249×10-5mol·L-1,Kd2=2.237×10-3mol·L-1.     

Cross-Linked Ionic Liquid Polymer for the Effective Removal of Ionic Dyes from Aqueous Systems: Investigation of Kinetics and Adsorption Isotherms

In the current study, we have synthesized an imidazolium based cross-linked polymer, namely, 1-vinyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)imide (poly[veim][Tf₂N]-TRIM) using trimethylolpropane trimethacrylate as cross linker, and demonstrated its efficiency for the removal of two extensively used ionic dyes—methylene blue and orange-II—from aqueous systems. The detailed characterization of the synthesized poly[veim][Tf₂N]-TRIM was performed with the help of ¹H NMR, TGA, FT-IR and FE-SEM analysis. The concentration of dyes in aqueous samples before and after the adsorption process was measured using an UV-vis spectrophotometer. The process parameters were optimised, and highest adsorption was obtained at a solution pH of 7.0, adsorbent dosage of 0.75 g/L, contact time of 7 h and dye concentrations of 100 mg/L and 5.0 mg/L for methylene blue and orange-II, respectively. The adsorption kinetics for orange-II and methylene blue were well described by pseudo-first-order and pseudo–second-order models, respectively. Meanwhile, the process of adsorption was best depicted by Langmuir isotherms for both the dyes. The highest monolayer adsorption capacities for methylene blue and orange-II were found to be 1212 mg/g and 126 mg/g, respectively. Overall, the synthesized cross-linked poly[veim][Tf₂N]-TRIM effectively removed the selected ionic dyes from aqueous samples and provided >90% of adsorption efficiency after four cycles of adsorption. A possible adsorption mechanism between the synthesised polymeric adsorbent and proposed dyes is presented. It is further suggested that the proposed ionic liquid polymer adsorbent could effectively remove other ionic dyes and pollutants from contaminated aqueous systems.     

Integrated Adsorption–Photodegradation of Organic Pollutants by Carbon Xerogel/Titania Composites

Recent studies on the removal of pollutants via adsorption include the use of carbon-based adsorbents, due to their high porosity and large surface area; however, such materials lack photoactive properties. This study evaluates the synergistic effect of integrated mesoporous carbon xerogel (derived from resorcinol formaldehyde) and titanium dioxide (TiO₂) for combined adsorption and photodegradation application. The complex formed between carbon xerogel and TiO₂ phase was investigated through FTIR, proving the presence of a Ti-O–C chemical linkage. The physicochemical properties of the synthesised adsorbent–photocatalyst were probed using FESEM, BET analysis and UV–Vis analysis. The kinetics, equilibrium adsorption, effect of pH, and effect of adsorbent dosage were investigated. The expansion of the absorbance range to the visible range was verified, and the corresponding band gap evaluated. These properties enabled a visible light response when the system was exposed to visible light post adsorption. Hence, an assistive adsorption–photodegradation phenomenon was successfully executed. The adsorption performance exhibited 85% dye degradation which improved to 99% following photodegradation. Further experiments showed the reduction of microorganisms under visible light, where no microbial colonies were observed after treatment, indicating the potential application of these composite materials.     

Zn(Ⅱ)/γ-MnOOH体系化学吸附的密度泛函理论研究

采用密度泛函B3LYP方法对Zn(Ⅱ)在水锰矿(MnOOH)2(H2O)6簇模型表面的水合、一级和二级水解三类共11种吸附构型进行了理论研究. 计算结果表明, 水合吸附构型的稳定性顺序为DC(双角)>SE-B(单边-B)>SE-A(单边-A)>DE(双边), 水解吸附构型的稳定性顺序为DC>SE-A>SE-B>DE, 均符合鲍林第三规则; 热化学分析结果说明, 其吸附和水解是相互制约的两个过程, 这一结论通过前线轨道理论分析得到了证明; 自然布居分析结果表明, 吸附过程中电子由簇模型向吸附质迁移; 结合电子供体-受体相互作用和前线轨道组成分析了吸附产物的稳定性.     

Controlled Activity Polymers. IV. Copolymers of 2-(1-Naphthylacetyl)Ethyl Acrylate With Hydrophilic Comonomers: Synthesis and Characterization

2-(1-Naphthylacetyl)ethyl acrylate (NAEA) was synthesized by esterification of 1-naphthylacetic acid (NAA) and 2-hydroxyethyl acrylate (HEA) and then polymerized to obtain the polymer-bound auxin NAA. The resulting polymer is potentially useful as a plant growth regulator through hydrolytic release of NAA. Copolymers of NAEA with hydrophilic comonomers were prepared by solution polymerization. The copolymer compositions were determined from elemental analysis, ¹³C-NMR, and UV spectroscopy. The copolymer microstructure was predicted from the reactivity ratios in order to investigate the influence on the behavior of controlled release. These model structures will be utilized for assessment of structure/hydrolysis relationships in a subsequent paper.     

A cation trap for anodic stripping voltammetry: NH3–plasma treated carbon nanotubes for adsorption and detection of metal ions

NH₃–plasma treated multi-walled carbon nanotubes (pn-MWCNTs) with cation traps for the detection of ultratrace quantities of Zn(II), Cd(II), Cu(II), and Hg(II) using square wave anodic stripping voltammetry (SWASV) is described. The pn-MWCNTs use their adsorption performance to enhance the sensitivity. It is found that under optimized conditions Zn(II), Cd(II), Cu(II) and Hg(II) were individually detected at potentials of −1.16, −0.78, −0.268 and 0.108 V, respectively. The detection limit (3σ method) of 0.314, 0.0272, 0.2263, and 0.1439 nM toward Zn(II), Cd(II), Cu(II), and Hg(II) is achievable, respectively. No interference could be seen during the simultaneous detection of Zn(II), Cd(II), Cu(II), and Hg(II). The pn-MWCNTs exhibit excellent selectivity owing to the different ability of adsorption. A study of the ability of pn-MWCNTs in practical application is carried out using a sample of water collected from Dongpu Reservoir in Hefei City, Anhui, China. It is found that the results were favorable when compared against inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis.     

Removal of permethrin pesticide from water by chitosan–zinc oxide nanoparticles composite as an adsorbent

Synthesis of chitosan–ZnO nanoparticles (CS–ZnONPs) composite beads was performed by a polymer-based method. The resulting bionanocomposite was characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) spectroscopy and infrared spectroscopy (FT-IR). Adsorption applications for removal of pesticide pollutants were conducted. The optimum conditions, including adsorbent dose, agitating time, initial concentration of pesticide and pH on the adsorption of pesticide by chitosan loaded with zinc oxide nanoparticles beads were investigated. Results showed that 0.5 g of the bionanocomposite, in room temperature and pH 7, could remove 99% of the pesticide from permethrin solution (25 ml, 0.1 mg L⁻¹), using UV spectrophotometer at 272 nm. Then, the application of the adsorbent for pesticide removal was studied in the on-line column. The column was regenerated with NaOH solution (0.1 M) completely, and then reused for adsorption application. The CS–ZnONPs composite beads appear to be the new promising material in water treatment application with 56% regeneration after 3 cycles.