Preparation Of Polymer Porous Materials Based On Blast Furnace Nickel-iron Slag And Study On Adsorption Properties Of Cu(?), Pb(?), Cr(?) Ions

The rapid grow of our country's economy is inseparable from the development of the industrialization process.The pollution caused by the heavy metal-containing wastewater discharged from the industrial process has caused a serious threat to the ecological environment and human health.Adsorption technology is an effective and promising method for the treatment of heavy metal wastewater.Due to its zeolite-like structure,geopolymer materials can efficiently remove heavy metals through ion exchange and adsorption.This paper proposes to use blast furnace nickel-iron slag to prepare porous geopolymer materials with rich pore structure and high specific surface area,and to adsorb Cu(?),Pb(?),Cr(?)and other heavy metal ions in wastewater.The influences of sodium silicate modulus and content,water-cement ratio,H₂O₂content,and SDS content on porous materials were studied,and its heavy metal ion adsorption performance and adsorption kinetics were investigated.The main conclusions are as follows:(1)The research on the preparation of blast furnace nickel-iron slag geopolymer porous material showed that when the water glass modulus was 1.4,the water glass content was 10%,the water-cement ratio was 0.30,the H₂O₂conten was 1.25%and the SDS conten was 0.04%,The compressive strength of the geopolymer porous material at 7 days was 2.7 MPa,the bulk density was 0.7374 g/cm³,the porosity was 67.2%,the pore distribution was relatively uniform,and the average pore diameter was 36.85 um.(2)The experimental research on the adsorption of Cu(?),Pb(?),Cr(?)ions by polymer porous materials based on blast furnace nickel-iron slag showed that with the increase of adsorbent dosage,the ion removal rate of Cu(?)Pb(?),Cr(VI)had a rapid increase and then a gentle trend.However the adsorption capacity showed a gradually decreasing trend.Considering the removal rate of heavy metal ions and the adsorption capacity of the adsorbent,the corresponding removal rate of Cu(?),Pb(?),Cr(?)ions could reach 95.1%,90.0%,92.8%when the optimum dosage was 0.5 g,0.1g and 0.5 g.The pH of the initial solution also had a great impact on the removal rate of Cu(?),Pb(?),Cr(?)ions.As for Cu(?)and Pb(?),when pH<2,a large amount of H⁺and heavy metal ions existed in the solution,and the competitive adsorption had a negative impact on the adsorption.With the pH of the solution increasing,the removal rate of heavy metals continued to increase.When pH=5,the maximum removal rates of Cu(?)and Pb(?)were 91.3%and 93.1%,respectively.As for Cr(?)ions,when pH<2,Cr(?)ions existed in the form of HCr O₄^-,and the adsorbent had a strong affinity for it,so the removal rate could reach 96.5%.When pH>2,Cr(?)ions mainly existed in the form of Cr O₄^2-,but OH^-and Cr O₄^2-had competitive adsorption,which lead to the continuous decrease of removal rate and adsorption capacity.(3)The analysis of adsorption kinetics and adsorption isotherm showed that the Cu(?)and Pb(?)ions of the blast furnace nickel-iron slag based on polymer porous material could be described by a pseudo-second-order kinetic model,and Cr(?)conformed to the first-order kinetics.And all conform to the Langmuir model,and the calculated maximum theoretical adsorption of Cu(?),Pb(?)and Cr(?)were 32.73mg/g,156.98 mg/g and 21.88 mg/g,respectively.It showed that the surface of the geopolymer porous material adsorbed Cu(?),Pb(?),Cr(?)ions were mainly by monolayer.