PVA粘结剂对夹炭布结构与性能的影响OA

The composite structured carbon cloth can filter and adsorb particulate matter and volatile organic compounds in the air,and the binder,as a key component in the preparation of the composite structured carbon cloth,plays an important role in regulating the structure and performance of the material.To further explore the mechanism and regulation strategies of the binder,this study used melt-blown nonwoven fabric and coconut shell activated carbon(CSAC)particles as raw materials,with polyvinyl alcohol(PVA)as the binder,to construct multilayer melt-blown carbon composite structured materials.By controlling key process parameters such as the basis weight of the melt-blown fabric(77 g/m2,81 g/m2 and 85 g/m2),the mass fraction of the PVA binder(2%～6%),and the CSAC loading,the influence of each factor on the material's filtration performance and formaldehyde adsorption performance was systematically investigated.Techniques including scanning electron microscopy(SEM),N2 adsorption-desorption,surface electrostatic potential testing,and adsorption kinetic models were used to reveal the intrinsic structure-performance relationships and mechanisms of action. The research results indicate that increasing the surface density of meltblown nonwoven fabric can improve filtration efficiency,but the increase in filtration resistance is even more significant,resulting in the base fabric with a surface density of 77 g/m2 having the best overall filtration performance(highest quality factor).The introduction of the PVA binder has a significant regulatory effect on the loading behavior of CSAC particles:the CSAC loading amount increases exponentially with the PVA mass fraction and gradually approaches saturation.The binder also affects the material's pore structure:when the PVA mass fraction is 5%,the composite structured carbon cloth achieves the maximum specific surface area(246.507 m2/g)and pore volume(0.138 cm3/g),with a CSAC loading of 141.76 g/m2.This sample exhibits the optimal overall filtration performance,with a quality factor(Qf)of(0.03526±0.00091)Pa-1.The changes in filtration performance are attributed to the multiple effects of PVA on the material's pore structure and surface electrostatic properties:an appropriate amount of PVA helps to fix CSAC particles and form suitable pores,whereas excessive PVA blocks channels and forms a continuous film on the fiber surface,leading to a decrease in specific surface area,attenuation of surface electrostatic potential,and increased airflow resistance,thereby reducing filtration efficiency and the quality factor.In terms of formaldehyde adsorption performance,the sample with the largest specific surface area and pore volume(5%PVA by mass fraction)exhibited the highest equilibrium adsorption capacity((3.664±0.023)mg/g)and removal rate((57.20±0.36)%).The adsorption performance is closely related to the CSAC loading and the material's pore structure parameters,and excessive PVA causing pore blockage leads to a decline in adsorption performance.Adsorption kinetic analysis shows that the pseudo-second-order kinetic model(R2=0.99977)fits the adsorption process better than the pseudo-first-order model(R2=0.95387),indicating that chemisorption predominates,along with physical adsorption characteristics.The intraparticle diffusion model further reveals that the adsorption process is controlled by multi-step diffusion:initially dominated by boundary layer diffusion,followed by intraparticle diffusion control,ultimately reaching adsorption equilibrium. In summary,this study clarifies the key role of PVA binder in the preparation of composite structured carbon cloth and establishes a cascade regulation relationship among binder mass fraction-CSAC particle loading-pore structure-filtration and adsorption performance.It provides a theoretical basis and technical support for the structural design and performance regulation of multifunctional air purification materials.