| With the development of economy,the pollution of water body by inorganic heavy metals and organic dyes is becoming more and more serious,and the problem of water environment pollution control has also been paid more and more attention.Adsorption is one of the most advantageous treatment methods to remove heavy metals and dye pollution in water,and the preparation of adsorption materials is the key to the removal of pollutants.In recent years,biomass-based adsorption materials have been widely used in pollution control and other fields due to the advantages of wide sources,low cost,biodegradability and easy modification.In this paper,using cheap and readily available biomass such as gelatin and chitosan,microspheres were prepared by neutralization titration method,caffeic acid was modified to the surface of microspheres by amidation reaction,and gelatin-based aerogel microspheres were prepared by freezedrying method.GC1 and caffeic acid-modified gelatin-based aerogel microspheres GC2.The prepared aerogel microspheres were analyzed by means of scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),automatic physical and chemical adsorption(BET),Zeta potential,and thermogravimetric analyzers(TG,DTG).The results showed that both GC1 and GC2 microspheres exhibited a three-dimensional interpenetrating network structure with mesoporous structure,and the specific surface areas were 166.2 m2/g and 148.8 m2/g,respectively.The adsorption material GC2 was used for the removal of heavy metal Cr(Ⅵ)in water.The results showed that the removal rate of Cr(Ⅵ)by GC2 microspheres reached99.6% at pH=2,and the maximum adsorption capacity reached 310.633 mg/g.It has a good adsorption-reduction synergy,and can partially reduce Cr(Ⅵ)on the surface of the solution and adsorbent to Cr(Ⅲ),and the removal rate can still reach more than91.8% after 5 cycles of use.It also shows good adsorption effect on lead ions and copper ions,and can be used for the removal of heavy metal anions and cations in water.The research on the adsorption of dyes by the two materials showed that the removal rate of the new carmine dye(AR18)by GC1 and GC2 aerogel microspheres at pH=1-3 could reach more than 99.5% due to electrostatic force,and GC2 at pH=1-3.When pH = 4-8,the removal rate can still be maintained above 90% due to π-πconjugation,and GC2 microspheres are sensitive to acidic golden yellow 2(AO2),methyl orange(MO),Congo red at pH = 6 The removal rate of four dyes(CR)and direct blue(DB)can reach more than 92%;the maximum adsorption capacity of AR18 can reach 627.062 mg/g.Both materials showed good regeneration capacity,and their adsorption capacity remained unchanged after 5 reuses.The two materials can simultaneously remove AR18 and Cr(Ⅵ)at low pH,and can simultaneously remove AR18,Pb(Ⅱ)and Cu(Ⅱ)under neutral pH conditions,so they can be used for simultaneous removal of heavy metal ions and dyes in wastewater. |
