铁改性刺梨生物炭对硒的吸附效应及机理研究OA

Rosa roxburghii is an economic shrub of Rosa.Rosa roxburghii planting has become an important measure in industrial poverty alleviation.Selenium(Se)is an essential micronutrient for the growth of plant and animal and human health,whereas it is also an environmental pollutant in aquatic environment when exceeding the limit.Rosa roxburghii biochar(BBC)and Fe-modified Rosa roxburghii biochar(Fe-BBC)was prepared from Rosa roxburghii litter and the removal capacity and preliminary mechanisms of two kinds of biochar in the Se(Ⅳ)adsorption was studied in detail.The kinetics and isotherm adsorption of Se(Ⅳ)of two biochar were compared and the involved mechanism,including changes of physicochemical properties and surface functional groups of the biochar were investigated by X-ray diffraction(XRD),Scanning electron microscope(SEM)and Fourier-transform composite(FT-IR)in Se(Ⅳ)adsorption experiments.The results showed that:(1)Compared with the original biochar,the physicochemical properties of Fe-BBC were significantly changed,of which the pH decreased and the mass fraction of ash increased.(2)The adsorption of Fe-BBC for Se(Ⅳ)was mainly multilayer chemisorption.The adsorption of Se(Ⅳ)by Fe-BBC fitted in the Freundlich model,and the maximum adsorption capacity was 11.05 mg·g-1.The adsorption of Se(Ⅳ)by BBC and Fe-BBC conformed to the quasi second-order kinetic model.The BBC and Fe-BBC reached the adsorption equilibrium after 3 h and 30 min.(3)SEM,XRD and FT-IR analysis confirmed that the Fe element was successfully loaded on Rosa roxburghii biochar.The results of XRD showed that there were characteristic peaks of Fe3O4 at 35.5 ° and 62.9 °.FT-IR showed that the characteristic absorption peak of Fe-O vibration(580-620 cm-1)appeared at 595 cm-1.(4)The chloride,nitrate,and sulfate did not affect the removal of Se(Ⅳ),whereas carbonate reduced the adsorption efficiency due to the adsorption sites competition.Fe-BBC can be recycled for further use after desorption.To sum up,Fe-modified Rosa roxburghii biochar is a potential adsorbent for adsorbing the Se(Ⅳ)in aqueous solution.