Preparation Of Biomaterials Derived Solid Acids By Deep Eutectic Solvent Systems

According to the National Bureau of Statistics,as of 2021,the output of shrimp and crab products in my country has reached 8 million tons.In the process of shrimp and crab processing,a large amount of crustacean biomass waste such as shrimp and crab shells will inevitably be produced.The ecological high-value processing of crustacean biomass raw materials can not only realize the reuse of waste resources,protect the environment and benefit people’s livelihood,but also effectively promote agricultural efficiency,increase farmers’ income,and it has become a new economic growth point that promotes the comprehensive utilization of by-products of aquaculture and aquatic product processing industry.However,the traditional treatment process for crustacean biomass resources requires a sufficient amount of acid-base solutions and organic solvents,and consumes large amounts of water,has a long process flow,and causes serious pollution to the environment.Therefore the industry has rarely used this traditional method.Eutectic mixtures represented by choline salts are ionic liquids that have received widespread attention in recent years,and their English name is Deep Eutectic Solvents(Abbreviated as DES).DES has many properties of traditional ionic liquids,such as low melting point,wide range of liquid range,and wide electrochemical window.It also has its own characteristics.Including:(1)The preparation process is simple and easy and the atom utilization is high,without purification and separation;(2)Excellent biodegradability and biocompatibility;(3)The properties of DES can be adjusted by the composition ratio;The high-value utilization of crustacean biomass resources provides a new option.Based on the above research background,with shrimp shell powder as the raw material and metal salt-containing eutectic solvent as the medium,the development of functional materials based on shrimp shell/MOFs composite catalyst and shrimp shell/metal(hydrogen)oxide composite solid acid catalyst Basic research provides new ideas for the direct transformation of discarded shrimp shells.The main research contents and innovative research results are as follows:(1)Preparation and application of shrimp shell/metal-organic framework polymer-based biomass composite catalyst.In this system,the metal salt and ethylene glycol are mixed in proportion to form a eutectic solvent,and shrimp shell powder is added to the nylon tank and placed in a mechanical ball mill;the organic ligand is mixed with the ball mill mixture to further prepare the shrimp by solvothermal method Shell/metal organic framework polymerized biomass composite catalyst.The product has abundant pores and shows high reactivity in the condensation reaction of acetal and Knoevenagel.This method has the advantages of environmental protection and energy saving,short reaction time,high efficiency,simple operation,and low cost of reaction conditions.Compared with traditional water and DMF(N,Ndimethylformamide)and other common impregnation solvents,the eutectic solvent system has the advantages of Higher metal replacement efficiency,lower solvent vapor pressure and operational safety provide new ideas for the functional application of waste shrimp shells under mild conditions,and expand the research approach for high-value utilization of waste biomass.(2)Preparation and application of zirconium-based shrimp shell biomass composite catalysts.This system uses edible freshwater crayfish meal waste as raw material,zirconium salt-containing deep eutectic solvent as medium,through ball milling and high temperature calcination to prepare biomass composite solid acid.A series of characterizations show that the catalyst has suitable acid strength and high catalytic activity,and can make a variety of aldehyde/ketone substrates and ethylene glycol complete the Knoevenagel condensation reaction in a short time.Moreover,the catalyst can be easily and quickly regenerated by washing,drying,and then calcining,and has stability.Turning waste into treasure,simple and convenient operation,and abundant acid sites are the most important advantages of this solid acid catalyst prepared from waste shrimp shells.It is of great significance for the efficient conversion and recycling of the whole component of waste biomass and the construction of sustainable development economic system.(3)Preparation and application of iron-based shrimp shell biomass composite catalyst.In this system,the iron salt eutectic solvent that can form infiltration with shrimp shells,has affinity and designability is used as the medium,and the food waste of edible crayfish is used as the raw material.The iron ion component in the eutectic solvent is exchanged with the calcium carbonate in the shrimp shell powder,and the protein component in the shrimp shell is removed at the same time to prepare an iron-based shrimp shell biomass composite catalyst with chitin as the main skeleton.Based on the principle of turning waste into treasure and harm into benefit,using shrimp shells and other wastes as raw materials,a green,efficient,and milder application condition heterogeneous Fenton catalyst is prepared for the degradation process of antibiotic simulated wastewater,reducing Energy consumption creates more direct economic benefits.