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An electrochemical sensor (Cu[Formula: see text]-IIPs/GCE) was developed for detection of Cu[Formula: see text] in water. Cu[Formula: see text]-IIPs/GCE was prepared by dispersing Cu[Formula: see text] imprinted polymers (Cu[Formula: see text]-IIPs) on a preprocessed glassy carbon electrode. Cu[Formula: see text]-IIPs were synthesized on the surface of modified carbon spheres by ion imprinting technology. The electrochemical performance of Cu[Formula: see text]-IIPs/GCE was evaluated by differential pulse voltammetry method. The response of Cu[Formula: see text]-IIPs/GCE to Cu[Formula: see text] was linear in [Formula: see text][Formula: see text]mol/L to [Formula: see text][Formula: see text]mol/L. The detection limit was [Formula: see text][Formula: see text]mol/L ([Formula: see text]). The current response value of Cu[Formula: see text]-IIPs/GCE was 2.14 times that of the nonimprinted electrode. These results suggest that Cu[Formula: see text]-IIPs/GCE can detect the concentration of Cu[Formula: see text] in water, providing a new way for heavy metal ions adsorption and testing.

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Environmental contextBecause of the multiple industrial applications of metals, contamination by metal ions is widespread and can at times endanger the environment and the health of human beings. We prepared ion-imprinted adsorbents to achieve selective recognition and smart separation of low-concentrations of copper ions from water. These smart imprinted materials have high potential for selective adsorption and removal of contaminant copper ions, particularly at very low concentrations. AbstractA temperature-responsive magnetic adsorbent (poly(N-propyl acrylamide) grafted magnetic carbon microspheres, Cu2+-IIP) was synthesised by ion imprinting technology for low concentration Cu2+ removal. Cu2+-IIP was prepared by using N-propyl acrylamide as a thermo-sensitive functional monomer, N,N-methylene-bis-acrylamide as a cross-linker and ammonium persulfate as an initiator. The morphologies and microstructures of samples were characterised by transmission electron microscopy, Fourier transform infrared spectrometry, thermogravimetry and vibrating sample magnetometry. Adsorption experiments were conducted in terms of kinetics, isotherms and selective recognition adsorption at low feed concentrations. Results indicate that Cu2+-IIP possesses good recognition selectivity and affinity for Cu2+, and can be separated from the treated solution quickly by applying an external magnetic field. The adsorption capacity towards Cu2+ depends on temperature and reaches a maximum value of 45.46 mg g−1 at 35 °C, higher than that of the non-imprinted polymer. The adsorption behaviour of Cu2+ on Cu2+-IIP can be well defined with both the pseudo-second-order kinetic model and Langmuir isotherm model. Cu2+-IIP performs good adsorption selectivity towards Cu2+ because the relative selectivity factors of Cu2+ with respect to Ni2+, Zn2+ and Cd2+ are 7.14, 7.60 and 6.77, respectively. The adsorption capacity of Cu2+-IIP remained 88.41 % after five cycles.

Different cultural groups establish different usage habits while using public spaces and there are contradictions between them. For instance, the issue of whether Beijing’s public waters can be used as winter swimming spaces is controversial. Based on Edward William Soja’s Trialectics of Spatiality, we analysed the literature analysis, semi-structured interviews and participatory observations to conduct the survey, and the following conclusions were drawn. First, the contradictions between winter swimmers and public water administrators in Beijing are divided into three stages, and the turning points of these stages are based on the changes in Secondspace. Second, after three rounds of gradual progress in the Trialectics of Spatiality, Firstspace not only preserves the winter swimming areas for Beijingers but also avoids the current contradictions due to different usages of public waters between different subjects. Third, winter swimmers and urban managers may not be aware of the potential contradictions of public waters in the future without using Soja’s concept of Thirdspace (or Lefebvre’s concept of “representation of space”).