The Functionalization For Loopah Fiber And Its Performance Study On Adsorption And Catalytic Degradation

Textile printing and dyeing is an industry to meet people’s need to beautify life.The pollution caused by wastewater from this industry has become a major environmental problem all over the world.At the technical level,adsorption and catalytic degradation are viewed as effective means to remove dye residues in wastewater at present.Adsorbents and catalysts are the key of adsorption and catalytic techniques.As adsorbent and catalyst matrix,biomass materials have the characteristics of easy separation,wide source of raw materials,cheap and easy to obtain,degradable,renewable and environmentally friendly in practical applications.however,too few adsorption sites and low catalytic activity on the surface of biomass materials make it difficult to apply directly.Therefore,it is of great significance to study and develop new adsorbents and catalysts in wastewater treatment technology by surface modification for biomass materials.As an abandoned biomass material,the loofah fiber（LF）has a three-dimensional reticular spatial structure and a multi-level microscopic pore channel.Its polar inner and outer surface hydroxyl groups make it water body affinity,which is beneficial to the mass transfer of guest with water as medium.As adsorbent matrix and catalyst support,it has high mechanical strength,easy solid-liquid separation and recovery,so it can be reused,which is a kind of available substrate.but the adsorption and catalytic degradation performance of untreated natural LF is still unsatisfactory.Therefore,it is necessary to strengthen the adsorption and catalytic performance by surface modification technology.In this paper,the adsorption and catalytic degradation properties of LF were enhanced by surface modification.Specific studies are as follows:（1）The highly efficient modified loofah-based adsorbent（LF-arg）was prepared by grafting functional small molecule arginine on the surface of LF by simple and green process（normal temperature,water phase,no pollution）.By means of catalysis of Lewis acid,the normal temperature esterification reaction between hydroxyl groups and arginine carboxyl groups on the surface of LS was realized,so that the abundant guanidine group was enriched on the LF matrix surface and made it a cationic adsorbent.the adsorption type is illustrated by the investigation of the adsorption performance,the adsorption performance was evaluated,and the corresponding adsorption mechanism was analyzed,which indicated that it is an efficient,easy solid-liquid separation and reusable practical adsorbent.and the structure-activity relationship of this modified adsorption material was elucidated by a series of characterizations.（2）To avoid the self-polymerization of monomers in Fe²⁺/H₂O₂ initiation system,a new method of preloading Fe²⁺on the LF matrix complexation reaction was proposed and designed to construct LF-loaded Fe²⁺/H₂O₂ heterogeneous initiation system at solid-liquid interface.A LF grafted macromolecular polyacrylic acid（LF-g-PAA）adsorbent was successfully prepared in a solid-liquid reaction system with hydroxyl groups as active sites and acrylic acid as reaction monomers.The process was completed at room temperature.The preparation process was simple and mild.The corresponding characterization,performance verification and mechanism analysis were also carried out.（3）Based on the structural characteristics of the LF,a strategy of using the whole LF material（monolithic LF）as the matrix was proposed to load n ZVI on the surface of the LF by simple liquid phase reduction precipitation method.The results show that the monolithic LF can promote the dispersion of active components,thus improving the utilization rate of active components and enhancing the catalytic degradation performance of the materials.Compared with the granular LF matrrix,the monolithic LF improved the catalytic degradation efficiency of the system by 31%.（4）The catalytic degradation efficiency of layered bimetallic hydroxides（Ni Co-LDH）loaded on the surface of the monolithic LF Ni Co a one-step solvothermal reaction based on the monolithic LF also increased by 75%,further enriching the derivation of the material preparation route supported by the whole loofah complex.The catalytic material is constructed by the active component construction with controllable loading ratio.the conditions under the best catalytic performance were discussed.The innovative points of this paper are as follows:（1）The covalent bonding reaction between carbohydrates on the surface of biomass and reactants in the water phase at room temperature and heterogeneous conditions was realized,that is,the heterogeneous esterification between the surface hydroxyl of the solid loofah fiber and the carboxyl group on the arginine molecule in the liquid phase;the addition reaction between the free radicals produced on the surface of the loofah fiber and the carboxyl group on the acrylic acid molecule.（2）A LF-loaded Fe²⁺/H₂O₂ heterophase initiation system at the solid-liquid interface was constructed for the production of free radicals on the surface of lignocellulose materials.（3）The preparation of catalyst supported by biomass was designed and implemented,and the selection range of catalyst support was expanded.