Study On Lead Removal Characteristics And Mechanism Of Steel Slag-Manganese Slag Composite Particles (SS-MS)

Heavy metal iron pollution in water has been attracting much attention,among which the treatment of lead-containing wastewater is a major problem in the environmental industry.At present,adsorption method with the advantages of simple operation,good removal effect is the most widely used,and what kind of material is used to prepare adsorbent is the key point in many studies.Steel slag has large specific surface area and high alkalinity,it is regarded as a good adsorbent material.Manganese slag is an acidic waste produced by manganese ore powder during the leaching of manganese sulfate in acidic solution.It has a large specific surface area and contains a higher sulfate component to promote the hydration of steel slag and can be used as an additive to the adsorbent.This paper selects steel slag as the base material to prepare steel residue-manganese slag composite particles（SS-MS）with manganese residue,and studies its adsorption performance to lead-containing aqueous solution.Based on the analysis of the physical and chemical properties of steel slag and manganese slag,high-performance SS-MS were prepared by compounding.In this paper,the chemical composition and physical structure of different state of adsorption materials were analyzed and compared by characterization methods such as XRF,XRD,BET,and the results can be revealed:the SS-MS（manganese residue is 20%）with the best adsorption effect after the two are compounded,with a larger specific surface area of 22.013 m²/g,and new components of Mg Fe Si O₄and Ca Fe₂O₅are formed,giving the composite particles high strength and alkalinity.Through static adsorption experiments,the best adsorption system for SS-MS was obtained.The research shows that the experimental temperature has little effect on the removal of Pb²⁺,and the optimum solid-liquid ratio of composite particles to remove Pb²⁺is SS-MS/lead-containing water sample=1:20;In the adsorption system,the removal efficiency of Pb²⁺can reach more than 99%when the initial concentration is 500 mg/L lead-containing water sample and the initial p H is 7-9 and the adsorption time is 25 min in the stirring speed range of 100 to 300r/min;The concentration of other heavy metals leaching in water samples after SS-MS adsorption meets the wastewater discharge standards of China.Drawing on the classic adsorption model and kinetic model,the isothermal adsorption mechanism of SS-MS was explored.According to the Langmuir isothermal adsorption equation and Mc Kay’s secondary kinetic equation,it can be seen that the adsorption mechanism of SS-MS to Pb²⁺is a single-layer adsorption,the adsorption rate is mainly chemical adsorption,and the theoretical saturation adsorption amount Q_max=69.93 mg/g.Through the dealkali adsorption comparison experiments of SS-MS and the characterization and analysis of SEM,XRD and SEM-EDS,it can be seen that the main adsorption mechanisms of SS-MS are electrostatic surface adsorption and chemical precipitation,and the two promote each other.The dynamic adsorption rule of SS-MS was studied by dynamic adsorption experimental means and Thomas,Yoon-Nelson and BDST models.Through dynamic adsorption experiments,it can be seen that with the decrease of the initial concentration and the increase of the high adsorption column,the adsorption capacity is in a trend of strengthening,and the adsorption capacity has reached high under appropriate environmental conditions.The experimental data prediction is carried out using Thomas,Yoon-Nelson and BDST models,the correlation coefficient R²>0.92 of the Thomas model and the Yoon-Nelson model,and the correlation coefficient R²value of the BDST model at h=5 cm is 0.99789.The research of SS-MS will break through the shortcomings of traditional steel slag as adsorption material,and will also change the damage that a single use of manganese slag as an adsorption material will increase heavy metals.The study of the static and dynamic adsorption mechanism of SS-MS will promote the industrialization application of SS-MS,it provides a certain theoretical basis for the resource utilization of steel slag and manganese slag.