Electrospinning organic solvent resistant preoxidized poly(acrylonitrile)nanofiber membrane and its properties

A high performance preoxidized poly(acrylonitrile)(O-PAN)nanofiber membrane with excellent solvent resistance,thermal stability and flexibility was fabricated by the preoxidation of electrospun PAN nanofiber membrane.The performance of resultant O-PAN nanofiber membrane was optimized by altering the PAN concentration and preoxidation temperature.The results showed that the O-PAN nanofiber membrane which made from PAN concentration of 14%(mass)and preoxidation temperature of 250.0
℃ have a more optimal comprehensive performance.In the long-term separation test of SiO2 particle(1 μm)in DMAc suspension,the permeate flux of O-PAN nanofiber membrane stabilized at 227.91 L·m^(-2)·h^(-1)(25
℃,0.05 MPa)while the SiO2 rejection above 99.6%,which showed excellent solvent resistance and separation performance.In order to further explore the application of the O-PAN nanofiber membrane,the OPAN nanofiber membrane was treated with fluoride and used in oil/water separation process.The O-PAN nanofiber membrane after hydrophobic treatment showed excellent hydrophobicity and good oil/water separation performance with the permeate flux about 969.59 L·m^(-2)·h^(-1)while the separation efficiency above 96.1%.The O-PAN nanofiber membrane exhibited a potential application prospect in harsh environment separation.

Colored Nano-Silica and Its Adsorption on Cellulosic Materials

Deep understanding has been achieved for nanotechnology,which has greatly advanced the development of technology.The adsorption property,as one of conventional properties of nanomaterials,is well known but has not been fully applied.In this paper,nanomaterials were used as adsorbents,and further their adsorption properties on substrates were studied.Spherical nano-silica was selected as a representative,which was labeled with a dye.The chemical bonding between the dye and nano-silica was confirmed by Fourier transform infrared(FTIR)spectroscopy.It was proved that the adsorption was a spontaneous,endothermic and entropy increase process.The adsorption model conformed to the Langmuir-type adsorption model.Reaction kinetic studies showed that the number of reaction stages in the adsorption process was about 1.45.The adsorption state was studied to verify the existence of nanomaterials as an adsorbent on the surface of the polymer,and then provided a demonstration for feasibility of the general polymer surface modification method.

Application Research on K/S Value in Determination of Reactive Dyes Fixation Rate

Reactive dyes are the main dyes in printing and dyeing of cellulosic fibers.Reactive dyes fixation rate is a vital indicator to measure the degree of the covalent bond between cellulose and reactive dyes.However,the determination of the fixation rate is tedious and time-consumptive.Based on the theory of reactive dyes dyeing and application of modern computer color matching technology,the relationship between K/S value and the fixation rate with the reactive dyes on cotton fabric was studied.The feasibility of K/S value instead of the traditional washing method for the determination of reactive dyes fixation rate was proved.In this study,the K/S value of the fabric has an excellent linear relationship to the reactive dyes fixation rate obtained by the washing method.The reactive dyes fixation rate can be obtained through the K/S correction value.

Natural keratin-based Fe-S_(1)N_(3) single atom catalyst for insights into the coordination regulation effect of Fenton-like catalysis with high efficiency

Single atom catalysts(SACs)have attracted great attention,yet the quest for highly-efficient catalysts is driven by the current obstacles of ambiguous structure-performance relationship.Here,we report a nature keratin-based Fe-S_(1)N_(3)SACs with ultrathin two-dimensional(2D)porous carbon nanosheets structure,by controlling the active center through the precise coordination of sulfur and nitrogen.Compared with natural silk-based Fe-N_(4) catalyst,the Fe-S_(1)N_(3)SACs exhibit excellent Fenton-like oxidation degradation ability.X-ray absorption fine structure(XAFS)and electron paramagnetic resonance(EPR)results confirm that S doping is conducive to electron transfer,to accurately generate·OH with high oxidative degradation capacity at the active site.Therefore,the optimized Fe-S_(1)N_(3)catalyst showed higher oxidation degradation activity for organic pollutant substrates(methylene blue(MB),Rhodamine B(RhB)and phenol),significantly superior to Fe-N_(4) samples.This work is devoted to the treatment and application of natural fibers,which provides a novel method for the synthesis of SACs and the regulation of atomic coordination environment.