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Porous carboxymethyl chitosan (PCMC) beads were synthesized via ionic coacervation/chemical crosslinking, using polyethylene glycol (PEG) as a porogen and calcium chloride and glutaraldehyde as physical and chemical cross-linkers. The as-synthesized PCMC beads were characterized using SEM, EDS, BET, TGA, FTIR and XPS analysis and then tested for the removal of Co(II) from aqueous solution. The effects of the initial pH, Co(II) concentration and temperature were investigated. It was found that the adsorption equilibrium is reached within 6 h and the maximum adsorption capacity is 46.25 mg g À1 .In addition, the kinetics and equilibrium data are well described by pseudo-second-order kinetics and the Langmuir isotherm model. Moreover, the desorption and re-adsorption performance was also studied, and the results revealed that the prepared new adsorbent still showed good adsorption performance after five cycles of regeneration. Finally, the adsorption mechanism, including chemical and physical adsorption, was proposed on the basis of the microstructure analysis, adsorption kinetics and isotherm results, and chemical adsorption was found to be the main adsorption mechanism during the process of the removal of Co(II).

BACKGROUND Heavy metal pollution has become one of the most serious environmental problems. Novel approaches are needed for removal of heavy metal from water. Copper, a familiar heavy metal, has attracted much attention for its remarkable toxic domino offect at elevated concentrations. RESULTS A novel ion imprinted approach combined with microfluidic technology was explored. Cu2+ was taken as ionic template and chitosan was used as carrier material. Chemical crosslinking was applied in the formation of imprinted sign. A selective biosorbent of ion‐imprinted microspheres (IIMS) with uniform size, regular shape and high performance for Cu2+ had been prepared. The SEM, FTIR, EDS, XPS were employed to detect their distinct features. IIMS showed much higher adsorption capacity (qm=81.97 mg g−1) than those non‐imprinted chitosan microspheres (CSMS). The adsorption isotherm fitted the Langmuir equation while thermodynamic adsorption results were considered strong proof of an adsorption exothermal process. IIMS exhibited excellent selectivity for Cu2+ when competitive metal ions and Cu2+ co‐existed together, which profited from the specific spaces of Cu2+ template left after crosslinking and desorption. Results confirmed that chemical adsorption was dominant and amino played an important role in adsorption process. CONCLUSION IIMS showed high adsorption capacity and excellent selectivity for Cu2+. Combining microfluidic technology with an ion‐imprinted method proved to be a promising process for preparing selective materials. © 2017 Society of Chemical Industry

In this paper, a memristor with structure of Cu/ PEDOT:PSS/ Ta was fabricated at room temperature. The conductance could be modulated incrementally by pulse sequences. The amplitude, width, frequency and quantity of the pulse sequence play important roles in conductance variation, which is similar to the weight of synapses. Several important synaptic learning behaviors such as short-term potentiation (STP), long-term potentiation (LTP) and spike-timing dependent plasticity (STDP) were emulated by this memristor, respectively. It is found that the movement of Cu ions is critical for this device.