Enhanced degradation of tetracycline by gas-liquid discharge plasma coupled with g-C_(3)N_(4)/TiO_(2)

Plasma-catalysis is considered as one of the most promising technologies for antibiotic degradation in water.In the plasma-catalytic system,one of the factors affecting the degradation effect is the performance of the photocatalyst,which is usually restricted by the rapid recombination of electrons and holes as well as narrow light absorption range.In this research,a photocatalyst g-C_(3)N_(4)/TiO_(2) was prepared and coupled with gas-liquid discharge(GLD)to degrade tetracycline(TC).The performance was examined,and the degradation pathways and mechanisms were studied.Results show that a 90%degradation rate is achieved in the GLD with g-C_(3)N_(4)/TiO_(2) over a 10 min treatment.Increasing the pulse voltage is conducive to increasing the degradation rate,whereas the addition of excessive g-C_(3)N_(4)/TiO_(2) tends to precipitate agglomerates,resulting in a poor degradation efficiency.The redox properties of the g-C_(3)N_(4)/TiO_(2) surface promote the generation of oxidizing active species(H2O2,O3)in solution.Radical quenching experiments showed that·OH,hole(h^(+)),play important roles in the TC degradation by the discharge with g-C_(3)N_(4)/TiO_(2).Two potential degradation pathways were proposed based on the intermediates.The toxicity of tetracycline was reduced by treatment in the system.Furthermore,the g-C_(3)N_(4)/TiO_(2) composites exhibited excellent recoverability and stability.

Effect of hygrothermal aging on moisture diffusion and tensile behavior of CFRP composite laminates

Carbon Fiber Reinforced Polymer(CFRP)composites are widely used in aircraft structures,because of their superior mechanical and lightweight properties.CFRP composites are often exposed to hygrothermal environments in service.Temperature and moisture can affect the material properties of composites.In order to make clear the moisture diffusion behavior and the properties degradation of composites,the TG800/E207 composite laminates with four stacking sequences[0]16,[90]16,[±45]4s,and[(+45/0/0/-45)s]sare designed and manufactured.Moisture absorption tests are carried out at 80℃,90%RH.It is shown that the moisture absorption curves of composite laminates present a three-stage.A modified Fickian model was proposed to capture the diffusion behavior of TG800/E207 composite laminates.The relationships among the non-Fickian parameters,the environmental parameters and the stacking sequences of CFRP were correlated and compared.Results showed that the modified Fickian curve is sensitive to the diffusivity of Stage Ⅰ and Stage Ⅱ.Compared with unaged specimens,the maximum tensile stress for[0]16,[90]16,[±45]4s,and[(+45/0/0/-45)s]sdecreased by 14.94%,28.15%,11.96%,and 26.36%,respectively.The strains at failure for[0]16,[90]16,[±45]4s,and[(+45/0/0/-45)s]sdecreased by 55.38%,62.65%,46.41%,and31.71%,respectively.The elastic modulus for[0]16,[90]16,[±45]4s,and[(+45/0/0/-45)s]sincreased by 90.93%,94.57%,49.22%,and 8.22%,respectively.[90]16sample has the minimum saturated moisture content and the maximum strength degeneration.