Preparation Of Nano Iron Material Loaded On Windmill Biochar And Its Removal Effect On Cd,As And Tetracycline In Water

In recent years,due to the rapid development of mining,metallurgy and other industries,heavy metals continue to enter the environment.At the same time,antibiotics are also widely used in the environment due to excessive use of medicine,animal husbandry and aquaculture.After long-term accumulation and biological chain transfer of heavy metals and antibiotics in the environment,the ecological risk and harm to human health have become increasingly prominent.With the extensive promotion and application of constructed wetland technology,a large number of wetland plants have been introduced and applied to the advanced treatment of urban sewage.However,most of the wetland plant harvest has not been properly disposed and effectively utilized,resulting in a great waste of carbon resources,and the preparation of biochar is an effective way to make full use of the rich carbon resources of wetland plant system.Biochar is a new,cheap and efficient environmental functional material with highly developed pore structure and efficient adsorption performance.It is widely used,especially for controlling heavy metal and antibiotic pollution in water.Therefore,it is of great scientific and practical significance to study the preparation and modification of wetland plant-based biochar and its application in water pollution control of heavy metals and antibiotics.In this paper,nano zero valent iron（CBC-NZVI）loaded on wetland plant-based biochar was prepared by using grape seed extract as reducing agent.The removal efficiency and mechanism of Cd,As and tetracycline hydrochloride in water by CBC-NZVI were systematically studied,and a batch of scientific data were obtained,which provided technical support and theoretical basis for the high value utilization of wetland plant resources and the treatment of heavy metal and antibiotic pollution in water.The main results are as follows:（1）Using grape seed extract as reducing agent,nano iron（CBC-NZVIi）loaded on windmill biochar was prepared.Physical and chemical characterization（TEM,Mapping,BET,FTIR,XPS）showed that nano iron（NZVI）was successfully loaded on the surface of biochar.After loading,NZVI had better stability and dispersion,and the pore structure of biochar was optimized by loading nano iron,After loading,the specific surface area and pore volume of CBC-NZVI are 14.7442 m²/g and 12.751 cm³/g respectively,which are about three times larger than those of CBC.The active groups are also more abundant.The coexistence of ferritin in the form of Fe⁰,Fe²⁺,Fe³⁺stimulates the activity,which is conducive to the adsorption,degradation and removal of Cd²⁺,As³⁺,tetracycline hydrochloride.（2）The removal amount of Cd²⁺by CBC-NZVI increases with the extension of reaction time,with the increase of dosage,with the increase of initial ion concentration,and with the increase of pH.the effect of temperature on the removal amount is not obvious;The removal amount of As³⁺by CBC-NZVI increases with the extension of reaction time,then tends to equilibrium,increases with the increase of dosage,increases with the increase of initial ion concentration,and increases with the increase of pH.the effect of temperature on the removal amount is not obvious;The removal amount of tetracycline hydrochloride by CBC-NZVI increased rapidly with the increase of reaction time,and then tended to equilibrium.It increases with the increase of dosage,initial ion concentration,temperature and pH.（3）The optimal removal conditions of Cd²⁺by CBC-NZVI were as follows:dosage 0.2 g,initial concentration 500 mg/L,pH 8.0,temperature 45℃,reaction time 120 min,and the maximum removal rate was 99.341 mg/g;The optimal conditions for As³⁺removal were as follows:dosage 0.5 g,initial concentration 500 mg/L,pH 8.0,temperature 45℃,reaction time 120 min,and the maximum removal rate was 103.78 mg/g;The optimal removal conditions of tetracycline hydrochloride were as follows:dosage 0.8 g,initial concentration 500 mg/L,pH 7.0,temperature 65℃ and reaction time 120 min.the maximum removal rate of tetracycline hydrochloride was 102.5245 mg/g;The Freundlich model is the most suitable model to describe the adsorption of As³⁺,Cd²⁺and tetracycline hydrochloride by CBC and CBC-NZVI..（4）The removal of Cd²⁺in solution by cbc-nzvi is mainly due to the reaction of FeO with water to form OH-,which then forms Cd（OH）₂ precipitation with Cd²⁺;For the removal of As³⁺in solution by CBC-NZVI,on the one hand,As³⁺is partially oxidized to As⁵⁺by FeOOH on the surface of NZVI;on the other hand,Fe²⁺/Fe³⁺is polymerized to form iron（hydrogen）oxide to realize the coprecipitation of As³⁺/As⁵⁺;The removal of tetracycline hydrochloride by CBC-NZVI is mainly through cation exchange and electrostatic interaction to achieve the combination of tetracycline hydrochloride and CBC,The original battery system was formed by Fe⁰ and biochar0.The hydrogen[H]was transformed into atomic hydrogen[H]by electron transmission on the surface of CBC on the cathode,which promoted the degradation of tetracycline hydrochloride.