In this article, morphology, structure and size controllable chitosan microspheres with high mechanical strength were synthesized by microfluidic technology combining chemical crosslinking and used as an adsorbent for...In this article, morphology, structure and size controllable chitosan microspheres with high mechanical strength were synthesized by microfluidic technology combining chemical crosslinking and used as an adsorbent for methyl orange. The synthesized adsorbents were characterized using scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR), and an Energy Dispersive Spectrometer(EDS). The effect of pH revealed that the adsorption process depended on pH and the pH variation of methyl orange solution after adsorption indicated that adsorption capacity was affected through the associated role of chitosan nature and pH variation. Experimental results suggested that the as-prepared chitosan microspheres were controlled within a narrow size distribution(coefficients of variation is 1.81%), whose adsorption capacity reached to 207 mg·g^(-1) and mechanical strength was suitable to resist forces. In addition, the adsorption isotherm was well fitted with the Langmuir model, and the adsorption kinetic was best described by the pseudo-second-order kinetic model.The high performance microfluidic-synthesized chitosan microspheres have promising potentials in the applications of removing dyes from wastewater.展开更多
A microsphere biosorbent with uniform size （CV = 1.52%）, controllable morphology and component, and high mechanical strength was synthesized from chitosan by microfluidic technology combining with chemical crosslink...A microsphere biosorbent with uniform size （CV = 1.52%）, controllable morphology and component, and high mechanical strength was synthesized from chitosan by microfluidic technology combining with chemical crosslinking and solvent extraction. This chitosan microsphere （CS-MS） was prepared with a two-step solidification process, which was acquired by drying for the enhancement of mechanical property in final. The adsorption behavior of CS-MS towards copper （II） and main influencing factors on adsorption performance were investigated by batch experiments. Kinetic data high-lighted dominant chemical bonding along with electrons transferring in adsorption process. Isothermal analysis indicated that adsorption capacity was relevant to the number of active site. All these explorations provided a new direction for preparing highly comprehensive performance sorbent used in heavy metal treatment via microfluidic technology.展开更多
In this work, the authors considered the periodic optimal control problem of Fitzhugh-Nagumo equation. They firstly prove the existence of time-periodic solution to Fitzhugh-Nagumo equation. Then they show the existen...In this work, the authors considered the periodic optimal control problem of Fitzhugh-Nagumo equation. They firstly prove the existence of time-periodic solution to Fitzhugh-Nagumo equation. Then they show the existence of optimal solution to the optimal control problem, and finally the first order necessary condition is obtained by constructing an appropriate penalty function.展开更多
基金Supported by the National Basic Research Program of China(2014CB748500)the National Natural Science Foundation of China(51578239,51322805)
文摘In this article, morphology, structure and size controllable chitosan microspheres with high mechanical strength were synthesized by microfluidic technology combining chemical crosslinking and used as an adsorbent for methyl orange. The synthesized adsorbents were characterized using scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR), and an Energy Dispersive Spectrometer(EDS). The effect of pH revealed that the adsorption process depended on pH and the pH variation of methyl orange solution after adsorption indicated that adsorption capacity was affected through the associated role of chitosan nature and pH variation. Experimental results suggested that the as-prepared chitosan microspheres were controlled within a narrow size distribution(coefficients of variation is 1.81%), whose adsorption capacity reached to 207 mg·g^(-1) and mechanical strength was suitable to resist forces. In addition, the adsorption isotherm was well fitted with the Langmuir model, and the adsorption kinetic was best described by the pseudo-second-order kinetic model.The high performance microfluidic-synthesized chitosan microspheres have promising potentials in the applications of removing dyes from wastewater.
基金We acknowledge the support by the National Basic Research Program of China （2014CB748500） and the National Natural Science Foundation of China （Grant Nos. 51578239 and 51322805）.
文摘A microsphere biosorbent with uniform size （CV = 1.52%）, controllable morphology and component, and high mechanical strength was synthesized from chitosan by microfluidic technology combining with chemical crosslinking and solvent extraction. This chitosan microsphere （CS-MS） was prepared with a two-step solidification process, which was acquired by drying for the enhancement of mechanical property in final. The adsorption behavior of CS-MS towards copper （II） and main influencing factors on adsorption performance were investigated by batch experiments. Kinetic data high-lighted dominant chemical bonding along with electrons transferring in adsorption process. Isothermal analysis indicated that adsorption capacity was relevant to the number of active site. All these explorations provided a new direction for preparing highly comprehensive performance sorbent used in heavy metal treatment via microfluidic technology.
基金supported by the Fundamental Research Funds for the Central Universities,ChinaUniversity of Geosciences(Wuhan)(CUGSX01).
文摘In this work, the authors considered the periodic optimal control problem of Fitzhugh-Nagumo equation. They firstly prove the existence of time-periodic solution to Fitzhugh-Nagumo equation. Then they show the existence of optimal solution to the optimal control problem, and finally the first order necessary condition is obtained by constructing an appropriate penalty function.
