| With the occurrence of crude oil leakage and industrial discharge,the ecological environment has been seriously polluted,among which adsorption method has been widely used in oil-water treatment because of its low cost and simple operation.Among the numerous oil absorption materials,the solid foam based on cellulose has attracted much attention because of its unique porous network structure,excellent liquid-holding property and biodegradability.However,due to poor selective adsorption and recycling,greatly limit its application field.So the cellulose-based solid foam with―on-off‖wetting property effectively solves the above disadvantages,and it can realize intelligent desorption while adsorbing oil,greatly improving its circulation performance,thus becoming a hot spot in the research field.Therefore,in this paper,Bagasse Fiber(BF)was used as raw material to prepare cellulose-based stable wet foam by foam forming method.On this basis,light,porous and strong cellulose-based solid foam with a three-dimensional network structure was prepared by freeze-drying method.By impregnating and loading the block polymer with functional segments on its surface,cellulose-based solid foam with controllable wettability was prepared with the p H value of the medium as―switch‖.The research results are as follows:(1)Cellulose-based stable wet foam was prepared by foam forming method.Firstly,the optimum technological conditions for preparing cellulose-based wet foam were obtained by single factor and response surface optimization.The results showed that when tetradecanol(TDA)and Arabic gum(GAC)concentrations were 0.015 g/m L and 0.010 g/m L,sodium dodecyl sulfate(SDS)concentration was 0.015 g/m L,BF concentration was 1.8 wt%and stirring speed was 2000 rpm,the foam had the best stability,with air content and drainage rate of 56%and 3.5%,respectively.Then,the network refinement and skeleton reinforcement were carried out on the cellulose wet foam.Using the―patch-bridging‖mechanism refined the fiber network,and the influence of patch number on foam stability and bubble size was studied.The results showed that when the weight(dry weight)ratio of nanofibrillated cellulose(NFC)to BF was 20%the bubble had the best stability and the smallest diameter(113μm).The fiber skeleton was reinforced by capillary foam technology,and the effect of gelatin concentration on the surface morphology and rheological behavior of cellulose foam was studied.The results showed that when the volume fraction of gelatin reached more than 1.6%,the cellulose wet foam has high yield stress and could maintain its three-dimensional morphology in natural environment.(2)The cellulose-based solid foam was prepared by freeze-drying.The results showed that the cellulose-based solid foam had a three-dimensional structure with a minimum pore size of 47μm,the porosity was over 98%,the density was 0.096-0.018 g/cm~3,and the stress was 55.746 k Pa under 60%strain.It was an excellent carrier of functional materials with the characteristics of ultra-light weight and firmness.(3)The cellulose-based solid foam with controllable wettability was prepared by impregnation method.The synthesized p H-responsive block copolymer was loaded on the surface of solid foam by simple impregnation,which not only improved the mechanical strength(106.652 k Pa)of the foam,but also realized the wettability conversion between underwater super-oleophilic(0°)and super-oleophobic(156°)foam in different p H media,and the adsorption capacity was as high as 48.773 g/g.Cycling experiments showed that the modified cellulose-based solid foam had excellent cycling performance,and its adsorption capacity could reach 80%after five cycles. |
PDF Full Text Request