Preparation Of Polypyrrole Modified Fruit Charcoal And Study On Fluoride Adsorption In Water

Fluorine pollution of groundwater is one of the most serious pollution problems in the world.Excessive intake of fluoride will cause harm to the body,such as skeletal fluorosis,dental fluorosis and other diseases.Therefore,the concentration of fluoride ion in drinking water,natural water and water after sewage treatment should not be too high.In the water treatment,the adsorption method has the advantages of simple operation,low processing cost and stable removal effect,so it is widely used.The rapid development of grape,red jujube and other characteristic forest and fruit industry in Xinjiang leads to a large number of pruned fruit branches waste can not be recycled,so how to make these waste resources utilization is also the current focus of environmental field.In this study,grapevine and jujube branches were used as raw materials to prepare biochar,and Pyrrole was used to modify it.A new adsorption material with good fluoride removal effect,low cost and wide application range was prepared.The effects of various factors on the removal of fluorine by biomass carbon were discussed.The surface morphology and components of biochar were analyzed by BET,SEM and elemental analyzer,and the mechanism of adsorption and removal of fluoride ions by biochar was revealed.This paper provides a reference basis for the application of biomass carbon in water treatment and fluoride removal.The following results were obtained:（1）Polypyrrole was successfully loaded on the surface of both biochar;When Py:Fe Cl₃（molar concentration ratio）is 1:1,PPy/GBC has the best fluoride removal effect.When Py:Fe Cl₃（molar concentration ratio）is 1:2,PPy/ZBC has the best fluoride removal effect.When the fluorine solution was10mg/L and the dosage was 10 g/L,PPy/GBC reached adsorption equilibrium in 3 h,and the fluoride removal rate was more than 90%.While PPy/ZBC was 6 h;The highest fluoride removal rate was 84.52%.The p H range of PPy/GBC was 4.0～9.0.The p H range of PPy/ZBC was 2.0～8.0.The removal of fluoride was not affected by chloride ion and sulfate ion.Bicarbonate and carbonate will change the p H of the solution,which will have a certain influence on the adsorption,and the higher the ion concentration,the greater the influence.When biochar is used to adsorb fluoride ions,reducing the concentration of bicarbonate and carbonate is beneficial to the removal of fluoride.（2）The load of PPy decreased the specific surface area of GBC and ZBC adsorption materials,but the fluoride removal effect increased,indicating that physical adsorption is not the main way of fluoride removal.The p H of PPy/GBC and PPy/ZBC is widely applicable,which can better adapt to the water environment.The loading of PPy improved the fluoride removal effect of biochar,and the fluoride removal effect of PPy/GBC was better than that of PPy/ZBC,which indicated that the removal effect of fluoride ions was better by using grape vine as raw material and pyrrole as modifier.（3）The pseudo-second-order kinetic model has a higher fitting degree for the adsorption process of F^-,and the adsorption process is mainly chemical adsorption;The fitting degree of Langmuir model was better than that of Freundlich model,which proved that monolayer uniform adsorption dominated the adsorption of F^-on PPy/GBC and PPy/ZBC materials.The R²value of Freundlich model was also greater than 0.9,which proved that multi-layer non-uniform adsorption also existed in the adsorption process.In conclusion,the polypyrrole modified grapevine charcoal has good fluoride removal effect,low cost,simple preparation and better adaptability to the environment.It is a kind of adsorption material with application prospect.