Study On Performance And Preparation Of Arsenic Adsorption Material Based On Biochar

The rapid development of industry has led to the continuous discharge of wastewater containing heavy metals into the environment,so heavy metal pollution has become a worldwide environmental problem,especially in developing countries.Arsenic can be absorbed by human body and animal,bringing about potentially damaging effects.Long term exposure to heavy metals in the aqueous phase may cause cardiovascular,lung,immune,neurological,endocrine disorders and cancer,even if the concentration of pollutants is low.Therefore,we urgently need efficient and environmentally friendly arsenic adsorbents to properly treat arsenic wastewater.In this paper,firstly,the waste scallion sheathing was used as biomass and pretreated with ferric chloride.Then,the Fe-BC magnetic biochar composite is prepared via high-temperature pyrolysis in muffle furnace,which is used to remove As(?)in water.The results of FTIR and SEM showed that the Fe-BC nanocomposites were successfully prepared;the XRD patterns showed that Fe3O4 and Fe2O3 were formed;VSM test shows that the material has good magnetic separation performance.The data of batch adsorption experiments show that under the condition that the pH of the solution is 6 and the dosage of the adsorbent is 2 mg/mL,the Fe-BC adsorption of As(?)in the water body basically reaches dynamic equilibrium within 200 min,and its anti-interference Strong ionic capacity(except for high concentration of PO43-).In addition,the adsorption kinetics of Fe-BC was studied,and it was found that the pseudo second order model fits the adsorption behavior of Fe-BC better,that is,Fe-BC mainly reacts with arsenic ions in sewage,thereby removing As(?)in the sewage.At the same time,Fe-BC uses Langmuir adsorption isotherm model to fit the maximum adsorption capacity of 37.24 mg/gIn the above study,It is found that the agglomeration of iron oxide on the surface of the material is serious.In order to improve the morphology of the adsorption material,this part uses solvothermal method to prepare the uniform size and regular structure of Fe3O4 nanoparticles.To solve the problem of the dispersion of Fe3O4,firstly,the scallion sheathing was pyrolyzed to prepare biochar.Then,Fe3O4 was successfully loaded on flat surface of biochar via solvothermal method to prepare Fe3O4/BC magnetic biochar composite material which can achieve magnetic separation.In addition,the effects of biochar acid-base treatment on the physical and chemical properties and adsorption properties of the composite were also investigated.The results of FTIR and XRD showed that the composite was successfully prepared;TEM showed that Fe3O4 was uniformly loaded on the surface of biochar;VSM test showed that the composite was magnetic and could be recovered by magnetic separation.The data of batch adsorption experiments show that under the conditions of pH of solution 6 and the amount of adsorbent being 2 mg/mL,Fe3O4/BC adsorbed As(?)in aqueous solution water basically reached dynamic equilibrium within 30 min.Fe3O4/BC has strong anti-interference ion ability(except for high concentration of PO43-),good recycling performance.In addition,the adsorption kinetics of Fe3O4/BC was studied,and it was found that the pseudo second order model fits the adsorption behavior of Fe3O4/BC better,that is,Fe3O4/BC mainly reacts with arsenic ions in sewage,thereby removing As(?)in the sewage.At the same time,the maximum adsorption capacity of Fe3O4/BC using Langmuir adsorption isotherm model is 39.47 mg/gIn the above study,we found that scallion sheathing based biochar can effectively improve the dispersion of Fe3O4,and Fe3O4/BC has a strong magnetic property.After use,it can be recovered through magnetic separation to prevent secondary pollution.However,Fe3O4/BC is prepared by solvothermal method,which requires high equipment and complex process,and the maximum adsorption capacity of Fe3O4/BC(39.47 mg/g)is low.It has been reported that hydrated iron oxide has high arsenic adsorption efficiency,and the preparation method is simple.In order to obtain a higher adsorption performance and low price arsenic adsorbent,biochar(BC)is used as the matrix material,and in-situ growth method is used to prepare coral like hydrated iron oxide biochar composite arsenic removal agent(BC/HFO).Coral-like hydrated ferric oxide biochar composite was successfully prepared by adjusting the proportion of iron salt and biochar The data of batch adsorption experiments show that under the conditions of pH 5-9 and adsorbent dosage of 1 mg/mL,BC/HFO adsorption of As(?)in water basically reached dynamic equilibrium within 30 min.BC/HFO has strong anti-interference ion ability(except for high concentration of PO43-),good recycling performance.The adsorption kinetics of BC/HFO was studied,and it was found that the pseudo second order model fits the adsorption behavior of BC/HFO better,that is,BC/HFO mainly reacts with arsenic ions in sewage,thereby removing As(III)in the sewage.At the same time,the maximum adsorption capacity of BC/HFO using Langmuir adsorption isotherm model is 104.55 mg/g.The results show that BC/HFO composite not only has low cost,simple preparation method,good regeneration performance,but also has excellent adsorption performance in a wide range of pH and a great application prospect in removal of arsenic wastewater.