Research On The Adsorption Of Heavy Metal Ions By Electrolytic Manganese Slag-based Analcite And Its Chitosan Composites

Electrolytic manganese slag refers to the solid waste residue produced during the process of developing manganese ore.With the rapid development of industrialization in China,In order to reduce the environmental pollution caused by industrial byproducts,the comprehensive utilization of waste resources has become an urgent topic for environmental protection.As a silicate mineral with high utilization value,the comprehensive utilization of electrolytic manganese slag is mainly focused on the preparation of building materials and agricultural utilization,lack of relatively perfect technical means.Therefore,if use electrolytic manganese slag as raw material,synthesize and then further modify high-performance adsorption material,which not only solves the disposal problem of electrolytic manganese slag,but also reduces the pollution risk in the treatment process,and at the same time realizes the effective utilization of solid waste.In this paper,electrolytic manganese slag is used as resource utilization objects.Firstly,after its pretreatment,the electrolytic manganese slag base analcime is obtained by hydrothermal synthesis method,and the adsorption characteristics of heavy metal Pb(II)are discussed.Then,the synthesized electrolytic manganese slag-based analcime is further cross-linked with chitosan to prepare electrolytic manganese slagbased/chitosan composites,systematically and theoretically study the preparation process of the composites.Finally,further reveal the adsorption properties of the composites to heavy metals Pb(II),Cu(II),Cr(III)and Zn(II).The main research contents and achievements are as follows:(1)Electrolytic manganese slag after the oxidation-weak acid complexing,alkalimelt activation as pretreatment,the iron removal rate was 85.7%,the best activation temperature is 850 ℃,add silicon source(Si:Al=3:1)and aluminum source(Si:Al=4:1)respectively,under the condition of 180 ℃ hydrothermal synthesis to obtain two kinds of analcime product ANA-S and ANA-A,both has the difference in particle size and morphology,but all have good thermal stability.(2)ANA-S has better adsorption performance for Pb(II).The adsorption capacity of Pb(II)by two electrolytic manganese slag-based analcime adsorbents are 161.29mg/g(ANA-A)and 185.19mg/g(ANA-S),and the removal rates are 93.69 %(ANA-A)and 95.47 %(ANA-S),When the initial concentration of Pb(II)is 100 mg/L,the removal rates are 93.69 %(ANA-A)and 95.47 %(ANA-S).The adsorption of Pb(II)by the two kinds of analcime are both single molecular layer chemisorption.(3)Use response surface method to obtaine the optimum process of composite chitosan: the stirring time is 1.2h,the dosage of chitosan is 9.2g and the acetic acid concentration is 2.3%.The particle size distribution of the composites is concentrated in the range of 6.57～12.8μm,The interior is a one-dimensional pore structure dominated by micropores,and the saturation of Pb(II)of the composite material is243.57 mg/g.(4)The optimal conditions for Pb(II)adsorption of composites are p H=5.6,initial concentration 82.88 mg/L,reaction time 2h,composite dosage 4 g/ L,and reaction temperature 298 K.The adsorption model fitting results show that the adsorption of Pb(II),Cr(III),Cu(II)and Zn(II)by the composite materials is mainly single molecular layer chemisorption.(5)The composite material has the best adsorption performance of heavy metal Pb(II).Saturation adsorption capacity are Pb(II)243.57mg/g > Cu(II)227.27mg/g >Cr(III)144.93mg/g > Zn(II)99.01mg/g respectively,when the initial concentration is100 mg/ L,the equilibrium adsorption amount are Pb(II)28.59mg/g > Cr(III)22.63mg/g > Cu(II)20.05mg/g > Zn(II)20.17 mg/g respectively.