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Uniform carbon spheres with hollow core and porous shell structures were controllably fabricated through carbonizing fine core/shell particles of polystyrene/cross-linked poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol), obtained by a simple template approach. [ABSTRACT FROM AUTHOR]

[Display omitted] • Negatively charged hollow crosslinked polymer fiber membranes were fabricated. • The membrane exhibited high adsorption capacity and rate for cationic dyes. • The membrane indicated high flux of 530 L·m−2·h−1 without external driven pressure. • The rejection ratio of 100% and 20 L pure water per gram of membrane were achieved. • The membrane showed absolute superiority to the reported carboxylated cellulose fabrics membrane. The complete, high-efficiency removal of cationic dyes in industrial wastewater before discharge becomes particularly urgent due to their biological toxicity. The membranes have emerged for removal of dyes benefiting from free separation, cheap component and easy operation, and thus aroused increasing research interest. Herein, the negatively charged hollow crosslinked aromatic polystyrene (PS) fiber (HPF-C) membrane has been successfully synthesized by a rapid room-temperature crosslinking of linear PS in HPF membrane, followed by deep sulfonation. The sulfonated HPF-C (HPF-C-S) membrane showed high experimental equilibrium adsorption capacity of 443.6 mg·g−1 for basic red 46 (BR46) with initial concentration of 50 mg·L-1. Its maximum adsorption capacity (346.0 mg·g−1) of methylene blue (MB) calculated by Langmuir model was about 5 times that of carboxylated cellulose fabrics (CCFs) membrane and higher than that of the most reported or commercially available nanofiber/nanoparticle adsorbents. Without external driven pressure, a flow rate of cationic dye solution through HPF-C-S membrane was up to 530 L·m−2·h−1 which was about 90 times that (6 L·m−2·h−1) of the CCFs membrane. The solution concentration through the HPF-C-S membrane always remained 0 mg L-1 (lower than the LODs of UV) before the permeation volume reached 4000 mL for 2 mg L-1 BR46 solution (In other words, 20 L of clean water could be obtained through per gram of membrane) and 1500 mL for 2 mg L-1 MB solution, respectively. The rejection ratio of 100% fully met the environmental criterion for wastewater disposal, indicating absolute superiority to the reported CCFs membrane that could not completely purify dyes. Moreover, the HPF-C-S membranes indicated excellent sustainability and stability. Besides, the kinetics, thermodynamics and mechanism behind these phenomena were studied. [ABSTRACT FROM AUTHOR]

Abstract: Using “two-stage” dispersion polymerization method polystyrene (PS) microspheres with “hard shell and soft core” are synthesized. Through treating these cross-link particles with supercritical carbon dioxide (SC CO2), these microspheres were welded together. After ultrasonic treatment, these welded microspheres were successfully separated and the submicron-sized pits were engraved on the surfaces of these particles, which finally realized the transformation of these particles from isotropy to anisotropy. The transformation degree of these microspheres (size and the depth of the pits on the microspheres) could be adjusted by changing the temperature and pressure of SC CO2. The SEM results illustrated that the anisotropic degree of the microspheres enhanced with increasing the pressure of SC CO2 in certain range and then decreased. Elevating the temperature at the same pressure could greatly enhance the anisotropic degree of these microspheres. Slight changing the cross-link density of the shell could also have obvious effect on the transformation degree of the PS particles. [Copyright &y& Elsevier]

Abstract: Using the excellent transport properties of supercritical carbon dioxide, tetraethyl orthosilicate (TEOS) could be easily carried into the template of the cross-linked polystyrene (PS) microspheres. Through the sol–gel procedure, the TEOS penetrated into the PS microspheres was transferred into silica. After sintering these composite particles, hollow silica microspheres were obtained. Through the above method, the hollow titanium dioxide microspheres also could be synthesized. The formation mechanism of the hollow particles was discussed and the morphology of the hollow microspheres was characterized by transmission electron microscopy (TEM) and scanning electronic microscope (SEM). [Copyright &y& Elsevier]

Abstract: Uniform porous carbon nanofibers with an average diameter of 90nm were fabricated by forming polyphosphazene nanofibers and carbonizing them, without the need for any activation step. The structure and morphology of the carbon nanofibers were characterized by SEM, TEM, EDX, XRD, Raman spectrum and N2 adsorption. Results showed that the carbon nanofibers have a BET surface area of about 540m2 g−1, a total pore volume of about 0.37m3 g−1, and a narrow pore size distribution in the micropore range. [Copyright &y& Elsevier]