Preparation And Properties Characterization Of Cellulose-Based Separation Composites

With the development of technology and industry,a mass of sanitary sewage and industrial wastewater was let out into the aquatic environment.Urban sewage treatment plants and factories need to treat wastewater produced in the process of life and production,soluble and insoluble organic contaminants in wastewater threatened the aquatic environment,typically,organic oils and organic dyes are notorious examples of these contaminants.Faced with the increasingly serious problem of water pollution,many researchers have devoted themselves to the study of wastewater treatment containing these pollutants.From point of the chemical properties and structural characteristics of the material itself,researchers changed or utilized the wettability of the material to the liquid,and then improved the separation ability and degradation efficiency of the oil-water separation material and the dye degradation material,respectively.Based on this research background,we are committed to fabricating superhydrophilic cellulose-based separation materials with degradable and reproducible biomass materials.The final purpose was to achieve water purification and high-value utilization of waste.In this paper,the performances of these separation materials in oil-water separation or dye degradation are explored and their basic and potential scientific problems are analyzed to further evaluate the application potential and development prospects of these separation materials.The experiments are mainly carried out in oil-water separation ability or dye degradation ability,and application range of materials.The research is as follow:(1)Considering the wettability and environmental protection of the material itself,the waste corn straw was chosen as the raw material.Fabricating corn straw powder mingled nylon composite materials(CSPNM)by mixing blending,scraping coating,and phase inversion processes.The CSPNM applied for high efficiency(>99.6%),high speed(831.73±26.62 L·m-2·h-1)separation of oil-in-water emulsion with superhydrophilic and underwater superoleophobic property,and maintained excellent separation ability(>99.0%)after 20 cycles,which suggests the CSPNM has stable structure and superior oil antifouling ability.In addition,corn straw powder is a skeleton of CSPNM to protect the structure in the water coagulation bath of the phase inversion process.Obtaining a stable structure in a mild environment,which exhibits excellent performance on emulsion separation and improves the mechanical properties of CSPNM.A preliminary attempt was made on the application of corn straw in oil-water separation materials,and the utilization of corn straw waste with high additive value was developed.(2)Considering that the wastewater often contains two kinds of pollutants,namely oil and dye,the bacterial cellulose material(BCM)loaded with palladium nanoparticle(BCMPd)to solve the problem of removing complex pollutants.BCM was obtained by mechanical stirring and percolating bacterial cellulose with super-long fiber on a basal membrane,and BCM served as a support and reducing agent in the subsequent reduction of PdNPs.Bi-functional BCMPd was successfully obtained and used for continuously removing emulsions and dye degradation in wastewater by physical sieving and chemical reduction.Meanwhile,the enhancement factors for the water transfer ability and demulsification capacity correlated directly with the wettability and surface structure of BCMPd.Furthermore,the dosage of bacterial cellulose was adjusted to reveal the mechanism for the enhanced water transferability and demulsification capacity.Together,the information obtained in this work can be useful for boosting the solution of issues of high cost and single-function which in the fabrication of separation materials,providing an alternative approach for better treatment of complex wastewater.(3)Organic oils and organic dye removals are primarily hindered by material resource renewability.Wood is very suitable for preparing separation materials due to its long parallel channel structure,certain thickness,active surface chemistry,and hydrophilicity.However,balsa wood has limited hydrophilicity and specific surface area which limited flux and load capacity.Partially removed lignin and hemicellulose in two steps by the traditional chlorate-alkali hydrolysis method could solve this problem.Then,loaded PdNPs via hydrothermal reaction could efficiently degrade dye.In conclusion,the information obtained in this work is helping to promote the application of wood in separation materials,solve problems of low chemical activity of polymer membrane separation material and reduce PdNPs need an extra reducing agent.Wood is biodegradable and environmentally friendly.(4)Deep eutectic solvent(DES)removes lignin and hemicellulose partially via one step to achieve the goal of increasing specificity surface area,porosity,chemical reactivity,and save reaction time.Subsequently,loading PdNPs via hydrothermal reaction to efficaciously separate the oil-water mixture and degrade dye.Moreover,the enhancement factors for the oil-water separation and excellent catalytic performances are directly correlated with the high porosity and large PdNPs content compared with numerous separation materials.Adjusting DES treatment time to control porosity and PdNPs content,which solves the problems of a sudden drop in flux caused by oil fouling and low catalytic activity attribute to low PdNPs content and reaction space.A further in-depth study exploring the mechanism which enhances water permeability,oil antifouling properties,and catalytic activity.The environmental-friendly,high flux,and excellent degradation efficiency of loaded PdNPs of DES treated wood are suitably facilitating wood-based practical application of separation materials.(5)The cellulose-based material is in a wet environment for a long time in the process of wastewater treatment.To avoid the influence of microorganisms on the cellulose-based material,antibacterial loaded AgNPs wood composite material(NWSAg)is fabricated and studied.The NWSAg was prepared using the mechanism of silver mirror reaction via vacuum impregnation and hydrothermal reaction to achieve AgNPs loaded without an extra reducing agent.The hydrophilicity and dye degradation properties of NWSAg were controlled by adjusting the hydrothermal reaction time.After adding NWSAg for cultivating 36 h,the concentration of S.aureus and E.coli were decreased from 4×104 CFU/mL to 8.8×103 CFU/mL and from 2×104 CFU/mL to 2.3 CFU/mL,respectively,showing good antibacterial performance and certain bactericidal effect.To sum up,this work is simple to operate,decreases the influence of microorganisms on cellulose-based separation materials in the application,and provides a guarantee for the durability of materials.