In this work, porous carbon materials produced from poly(furfuryl alcohol) (PFA)/polyvinylpyrrolidone/silica composite electrospun fibers have been prepared by sol–gel, carbonization and etching processes. PFA acts as carbon source, tetraethyl orthosilicate (TEOS) serves as a template and poly(propylene oxide)-block-poly(ethylene oxide)-block-poly(propylene oxide) triblock copolymer Pluronic F127 works as a structure-directing agent. Three samples (C-1, C-2 and C-3) with different pore structures have been prepared. The structures of the pores are demonstrated to be dependent on the amount of TEOS and the presence or absence of F127 by means of various characterization methods. After the carbonization process, carbon material yields of 35.5%, 38.6% and 40.3% are obtained, corresponding to the samples of electrospun nanofibers M-1, M-2 and M-3, respectively. When further treated by the hydrofluoric acid (HF) etching, the regular morphology of the electrospun nanofibers disappears gradually by prolonging the etching time, and the as-obtained typical product C-3 has a high specific surface area (SSA) of 897 m2 g−1 and a specific capacitance of 205.5 F g−1 at the scan rate of 20 mV s−1 in KOH electrolyte solution. It is revealed that the structure of the pores and the high SSA are responsible for the excellent electrochemical performance of the porous carbon materials. According to the results, the typical product C-3 is a promising electrode material for electrical double-layer capacitors.

Mesoporous polyvinylpyrrolidone (PVP)/SiO2 composite nanofiber membranes functionalized with thioether groups have been fabricated by a combination method of sol–gel process and electrospinning. The precursor sol was synthesized by one-step co-condensation of tetraethyl orthosilicate (TEOS) and 1,4-bis(triethoxysilyl)propane tetrasulfide (BTESPTS, (CH3CH2O)3Si(CH2)3S–S–S–S(CH2)3Si–(OCH2CH3)3), with the triblock copolymer poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (P123, EO20PO70EO20) as template. After the addition of PVP, nanofiber membranes were prepared by electrospinning. The membranes were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) images, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), N2 adsorption–desorption isotherms, and an Elementar Vario EL analyzer. The composites were used as highly selective adsorbents for Hg2+ due to the modification with thioether groups (–S–), and were conveniently separated from the waste water. The composite could be regenerated through acidification.Graphical abstractMesoporous PVP/SiO2 composite nanofiber membranes functionalized with thioether groups have been fabricated. The membranes exhibited excellent performance in removing Hg2+ ions in aqueous solutions..Research highlights► Thioether-functionalized fiber membranes were fabricated, which have large surface area due to the mesostructure. ► The nanofibrous membranes exhibited highly selective and capacious adsorption of Hg2+ attributed to the presence of thioether groups. ► The membranes showed good recycling properties.

Colloidal silica (SiO2) scale is considered to be the most undesirable inorganic deposit formed in industrial water. It is formed either in bulk or on surfaces such as membrane, heat exchangers and pipelines. Conventional mineral scale inhibitors do not inhibit its formation. Chemical cleaning is difficult and not free from hazards. Ongoing research on silica scale prevention has led to experiments using various chemical approaches, such as ion exchange, coagulation, and softening. This paper focuses on a scale inhibition approach using a novel chemical additive, adipic acid/amine-terminated polyether D230/diethylenetriamine copolymer (AA/AT/DE). The influence of various concentrations of AA/AT/DE on colloid silica formation are tested and compared to traditional mineral inhibitors, such as phosphonates and anionic polymers. Phosphonates include ATMP, HEDP, EDTMP, DTPMP, HTDMP, and PBTCA, while anionic polymers include PAA, PMA, PESA, PASP, and AA/AM. Among these, only AA/AT/DE showed significant inhibitory activity in contrast to mineral inhibitors, which showed virtually no inhibition. Based on the zeta potential of colloid silica aqueous solutions in the presence of AA/AT/DE, an attractive interaction between AA/AT/DE and silica particles may be present. AFM images of silica also confirm that AA/AT/DE can interfere with the silica polymerization reaction.Graphical abstractAA/AT/DE is an efficient inhibitor to prevent colloidal silica from scaling, it shows significant effect under the dosage of 10 mg L−1 or more. The following figure shows that soluble silica concentration in solution in which 10 mg L−1 AA/AT/DE was added can be maintained at 295 mg L−1 after 96 h, which is comparatively higher than the control test. And in a certain range, the inhibitory effect rises as the dosage increases.Highlights► AA/AT/DE is an efficient inhibitor towards the prevention of colloidal silica scale formation while traditional scale inhibitors such as phosphonates or anionic polymers show no inhibition effects at all. ► AA/AT/DE is more environmental friendly compared to traditional scale inhibitors. ► Adding effective scale inhibitors such as AA/AT/DE is more economical and broadly applicable in industrial water processing systems.

A mesoporous polyvinyl alcohol (PVA)/SiO2 composite nanofiber membrane functionalized with cyclodextrin groups was prepared by sol–gel/electrospinning process. The spinnable sol was synthesized by one-step co-condensation of tetraethyl orthosilicate (TEOS) and silylated monochlorotriazinyl-β-Cyclodextrin (APTES-β-CD), with cetyltrimethyl ammonium bromide (CTAB) as template. After the addition of PVA, nanofiber membranes were prepared by electrospinning. The membranes were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) images, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption–desorption measurement and an Elementar Vario EL analyzer. The composites were used as highly efficient adsorbents for indigo carmine dye due to the presence of cyclodextrin groups and were conveniently separated from the waste water. Furthermore, the composite could be regenerated through acidification.Graphical abstractMesoporous nanofiber membranes functionalized with cyclodextrin groups have been fabricated by electrospinning. The membranes showed excellent performance to remove indigo carmine dye in aqueous solutions.Highlights► A cyclodextrin-functionalized fiber membrane was prepared by sol–gel process and electrospinning technique. ► The functionalized membrane exhibited large surface area attributed to the mesostructure. ► The nanofibrous membranes showed good performance in adsorption of indigo carmine dye due to the presence of cyclodextrin groups.

•A excellent heavy metal chelating agent (TEPA-SM) was synthesized.•TEPA-SM can efficiently stabilize Pb from fly ash with less dosage compared with traditional agent.•TEPA-SM can largely chelate heavy metal Pb under strong acid or alkaline environment.•Heavy metals stabilized with TEPA-SM cannot be easily leached out under nature conditions.This work compares the performance of stabilizing Pb by Sodium sulfide (Na2S), Sodium phosphate (Na3PO4), thiourea (H2NCSNH2), and mercapto functionalized dendrimer (TEPA-SNa) in MSWI fly ash, including leaching toxicity analysis and leaching behavior analysis, as a function of pH. The leaching toxicity in fly ash indicated that leaching value of Pb stabilized by Na2S, Na3PO4, and H2NCSNH2 has remained higher than the limit value (0.25 mg/L) with a dosage of 10%. However, the leaching value associated with TEPA-SNa approaches zero at a dosage of 3%. The effective leaching test results showed the leaching amount of Pb stabilized by TEPA-SNa with a dosage of 3% to be 3.58 mg/kg less than the maximum allowable amount of leaching (5 mg/kg), but the amount of Pb leached by Na2S, Na3PO4, and H2NCSNH2 was much higher than 5 mg/kg. The leaching behavior of Pb as a function of pH showed that the leaching concentration of Pb stabilized by TEPA-SNa can approach zero at a dosage of 5% no matter how the pH changes. In summary, TEPA-SNa can interact with Pb2+ in the acid–base environment and effectively immobilize Pb2+ in fly ash in the long term.