Study On The Preparation Of Functional Biomass Composite Material And The Adsorption For Arsenic Removal From Water

Agroforestry biomass has been widely used in water remediation due to its advantages such as wide sources,convenient materials,rich functional groups,easy modification and environmental friendliness.Arsenic is one of the harmful substances that cause water pollution,and it can pose a great threat to human health.Therefore,it is of great practical significance to develop an economical,environmental friendly and efficient arsenic removal adsorbent using agroforestry biomass.This paper used three kinds of agricultural and forestry biomass as raw materials and FeOOH as precursor to synthesize three different biomass composite materials,and explored the adsorption effect of these three materials on arsenic in aqueous solution under the influence of different factors.1.In this paper,cellulose（WBC）was extracted from waste water bamboo shell by alkali treatment and decolorization method.The cellulose was used as the substrate,and the iron oxyhydroxide and copper oxide were grown on its surface by simple hydrothermal method to increase the adsorption possibility.The material was characterized by SEM,XRD,FTIR and XPS,and the results showed that FeOOH/CuO@WBC was successfully prepared and the iron oxyhydroxide exhibited an array rod-like structure on the water bamboo fiber.In addition,the effects of p H,interfering ions,temperature,time and other factors on the adsorption capacity were also studied.The results showed that the adsorption effect was better under acidic conditions,the disturbance degree of phosphate was relatively large,and the maximum adsorption capacity reached 49.4mg/g at 30°C.According to XPS,FTIR and the correlation coefficient（R²）after fitting the kinetic model,the possible mechanism of adsorption process is physical and chemical synergistic adsorption.The FeOOH/CuO@WBC synthesized in this work is based on the concept of"waste treatment with waste",which can effectively remove arsenic from aqueous solution and provide a beneficial idea for subsequent arsenic removal studies using agricultural and forestry biomass.2.In order to enhance the reactivity of metal nanoparticles and further improve the adsorption capacity,a novel NZVI@SiO₂@cotton fiber（FSC）composite material was synthesized by referring to the preparation method of array iron oxyhydroxide mentioned above and reducing them to NZVI by hydrogen gas.SEM and TEM tests showed that the rod-like NZVI with a diameter of 50～80nm was uniformly distributed on the surface of cotton fiber,and the silica coating formed a transparent shell layer with a diameter of 10～20nm,which effectively prevented the oxidation of NZVI on the surface.Additional,the optimal adsorption conditions of FSC were investigated from the aspects of concentration,p H value,interfering ions and temperature.The results exhibite that the maximum adsorption capacity of the prepared material can reach about 65mg/g at the initial concentration of 300mg/L and p H of 2.8～4.This work makes full use of the synergistic effect of each component,that is,NZVI plays a leading role,silicon acts as a protective layer,and cotton fiber acts as a substrate to fix nanoparticles,so as to achieve the optimum adsorption of arsenic by FSC.3.In order to reduce the use of hazardous chemicals and simplify the experimental operation process,bimetallic oxides were loaded on rice husk biochar by one-step hydrothermal method and calcination method using waste rice husk as raw material.SEM,XPS,FTIR and XRD were used to characterize each stage of composite synthesis,and the changes of morphology,crystal phase and chemical elements in the preparation process of the material were explored.The results showed that the MFA/RB composite was successfully prepared.Through the study of different p H values,reaction time,initial concentration,interference ions and other factors,the adsorption effect of adsorbent on low concentration arsenic solution was further discussed,and the experimental data were fitted to the adsorption isotherm and kinetic model.The results were more consistent with the Ferundlich model and the qseudo-first-order kinetic model.This indicates that the adsorption process takes place in the heterogeneous layer and physical adsorption is the main process.The recovery and regeneration experiment showed that the recovery time of synthetic materials by magnet was only 10s.Under the very low pollutant concentration,the first arsenic removal rate could reach 75%.After five times of elution and regeneration,the removal rate was still above30%,realizing the simple recovery and reuse process of synthetic materials.