Study on adsorption of Cu(Ⅱ)on 4A zeolite synthesized by aluminum extraction residue by fly ash
The 4A zeolite has become an excellent adsorption material for the treatment of heavy metal wastewater,due to its good cation-exchange ability.In order to achieve the goal of"using waste treat waste",the geopolymer was prepared from the aluminum extraction residue by fly ash,and then the shaped 4A zeolite was synthesized by hydrothermal in-situ conver-sion.The 4A zeolite was characterized by XRD,FT-IR,SEM,BET,TGA.The effects of adsorption time,initial concentration of Cu(Ⅱ),amount of adsorbent and pH value of solution on its adsorption properties were investigated,and the adsorption process was studied by combining the kinetic equation and adsorption isotherm model.The results showed that the synthe-sized 4A zeolite had developed pores and more micropores.The total specific surface area was 71.85 m2/g,of which the spe-cific surface area of micropores was 53.91 m2/g,and the micropores were mainly concentrated in about 1.3 nm.The optimal conditions for adsorption of Cu(Ⅱ)by the shaped 4A zeolite were as follows:the adsorption time was 240 min,the initial concentration of Cu(Ⅱ)was 100 mg/L,the amount of adsorbent was 2.0 g/L,and pH was 6～9,the adsorption capacity could achieve 32.97 mg/g,and the removal efficiency of Cu(Ⅱ)was 65.93%.The adsorption process conformed to the pseudo-second order kinetic model,which was mainly chemisorption.Langmuir model had better fitting effect,indicating that the adsorption process of Cu(Ⅱ)on synthetic 4A zeolite was monolayer absorption,and the maximum adsorption ca-pacity of Cu(Ⅱ)obtained by fitting was 37.05 mg/g.
aluminum extraction residue by fly ashshaped 4A zeoliteCu(Ⅱ)adsorptionpseudo-second order kinetics equationLangmuir model
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