Study On Pb²⁺ Adsorption And Mechanical Properties Of Modified Fabric Composite Polyurethane Foam

Due to its porous structure and high specific surface area,soft polyurethane foam is easy to be separated from water in practical application,and is often used as an adsorbent or carrier for sewage treatment.However,pure polyurethane foam is not ideal for adsorption,so it needs to be treated.In this study,polyurethane foam was used as the matrix,and low-cost melamine and bentonite were added to adjust cell size and increase Pb²⁺adsorption sites.The interface structure was studied by combining the mechanical properties of nonwoven fabric,and the adsorption property of composite fabric was improved again by modifying the composite fabric.Finally,a composite material with low cost,high strength,no secondary pollution and good adsorption effect was obtained.First,by adding melamine and bentonite to the polyurethane foam,a porous composite material with heavy metal adsorption properties is obtained.The cell size of the polyurethane porous composite was affected by the addition of melamine and bentonite.The cell size of the polyurethane porous composite decreased with the increase of particles,and the compression performance increased by 54%.In the adsorption experiment,the effects of p H,contact time,initial concentration on the adsorption,as well as the effect of particle content on the mechanical properties were studied.The experimental results show that the porous composite foam has a good removal effect on Pb²⁺,and the maximum removal rate can reach 94.8%,which is 69%higher than that of Neat PU foam.And its maximum adsorption capacity is 29.45mg/g.The adsorption process fits well with the Langmuir isotherm model,and fits well with the pseudo-second-order kinetic model.Next,in order to improve the adsorption performance of the melamine-bentonite composite polyurethane foam,the fabric was added to the fabric composite polyurethane foam,and the influence of the nonwoven fabric and the fabric-foam interface on the adsorption and mechanical properties was studied.The results showed that after adding fabric,the maximum adsorption capacity of P200-PUMB was31.63mg/g,the maximum adsorption capacity of N200-PUMB was 30.81mg/g,which was higher than that of the composite foam without fabric.And the compression performance of the composite foam is significantly improved.Besides,the adsorption processes of P200-PUMB and N200-PUMB have a better fitting with the Langmuir isotherm model and a better fitting with the pseudo-second-order kinetic model.Finally,in order to further improve the adsorption performance of the material,modified fabric composite polyurethane foam was prepared by modifying the fabric,focusing on the adsorption effect of the modified fabric.The results showed that bentonite played a physical crosslinking role in the process of acrylamide crosslinking.As the content of bentonite increased,the removal rate of Pb²⁺increased.Under the condition of 40%compression,the compressive strength of PU-P-PU is 11.44%higher than that of P-PU.The maximum adsorption capacity of PU-P-PU to Pb²⁺is 39.05mg/g,which is 10%higher than that of P-PU.The adsorption process of PU-P-PU and P-PU is better fitting with the Langmuir isotherm model and the pseudo-second-order kinetic model.Moreover,the particle internal diffusion model of this material can be divided into two steps:surface adsorption and internal diffusion.