Preparation Of Three-dimensional Porous Materials Based On Biomass And Its Application In Oil/water Separation

The upgrade of industrial activities and the acceleration of human production and life have brought about rapid economic development,while they have also caused irreversible destructive effects on the environment.Especially,the pollution of water resources is the most serious.Various soluble and hydrophobic pollutants all exist in the water environment,causing the death of aquatic livings and endangering the health of human.How to deal with these pollutants efficiently and quickly has become an urgent issue.The development of superwetting materials and their preparation technologies provide a theoretical and practical basis for the purification and treatment of water resources.This paper combines the physical and chemical characteristics of three-dimensional porous materials,and uses technologies such as freeze-drying and high-temperature carbonization to endow them different wettability and selectivity,which can achieve the goal of efficient and fast removal of multiple pollutants in oil and water.Also,it clarifies the mechanism and rules of three-dimensional porous materials to remove oil/water-soluble pollutants,which expands the recyclability and repeatability of three-dimensional porous materials in the field of water treatment.The main research results of this paper around these innovations are as follows:(1)For the environmental problems of soluble water/oil emulsion and oil-soluble dye,the typha orientalis are used as raw materials and a highly elastic three-dimensional porous material is directly obtained after degreasing treatment,filtration shaping and high-temperature carbonization.Since the carbonized fibers are interwoven to form a three-dimensional network structure,this porous material can completely restore to the original shape when the strain is 80%.This porous material has a rough structure and low oxygen content,of which,the contact angles of surface with water and oil are 153° and 0°,respectively.Due to its high porosity and double fiber tube effects,it can adsorb crude oil up to 160 times of its own weight.The porous material exhibits superhydrophobic and superlipophilic properties as a whole and it can effectively separate various types of water-in-oil emulsions by simple filtration.Meanwhile,Oil-soluble dyes(Sudan I,III,etc.)can be combined with the positively charged area of this material to be directly adsorbed by electrostatic action,with an efficiency of up to 99.99%.Finally,it also realizes the simultaneous removal of various water/oil emulsions and various oil-soluble dyes.(2)The platanus orientalis fibers are used as raw materials and after degreasing treatment,filtration shaping and high-temperature carbonization,a highly elastic biomass-based three-dimensional porous material that is capable of separating water/oil emulsion with high viscosity is directly fabricated.After carbonization,the platanus orientalis fibers form a three-dimensional network structure and it can recover to initial shape after compression of 100 cycles.This porous material also exhibits superhydrophobicity and superoleophilicity.With its structural sieving and coalescence effect,it not only efficiently and quickly removes the tiny water droplets in the water/oil(water/kerosene,water/PAO02,etc.)emulsions with lower viscosity,but also it can achieve complete separation of water/oil(water/PAO10,water/PAO40,etc.)emulsion with high viscosity.The separation process only relies on the gravity drive of the emulsion and the efficiency is as high as 99.90%,which provides a good foundation for the purification of industrial oily wastewater with high viscosity.(3)The soluble dyes can be easily adsorbed by biomass-based aerogels,causing its self-pollution,poor durability,and inability to be recycled for long term.Wood,used as supporting material,is subjected to alkaline and acidic oxidation to remove lignin and partial hemicellulose to obtain cellulose fiber.The compressible three-dimensional porous material can be obtained by in-situ growth of BiOBr and AgBr,combined with freeze-drying.The porous material exhibits superamphiphilic and underwater superoleophobicity as a whole.Based on its sieving and coalescence effects,it can separate oil/water(kerosene/water)emulsions with an efficiency of 99.91%.At the same time,a large number of hydroxyl groups on its surface can combine with water-soluble dyes(rhodamine B,methyl orange)molecules through hydrogen bonding to directly adsorb dyes.In addition,wood fiber introduces BiOBr and AgBr by in-situ method to endow it better photocatalytic degradation performance,which can realize the recycling of three-dimensional porous materials,and the initial function of removing tiny oil droplets and adsorbing water-soluble dyes are fully utilized.