新疆某石化污水库周边土壤对锶的吸附特征研究

以新疆某石化污水库周边土壤为例,采用静态吸附试验法研究土壤对Sr2+的吸附特征。通过单因素法研究初始pH值、反应温度、离子强度、时间、Sr2+初始质量浓度等因素对土壤吸附Sr2+的影响,并对吸附机理进行了初步探讨。结果表明,供试土壤对Sr2+有较强的吸附能力,溶液pH值对土壤吸附Sr2+的影响较显著。在3 h左右供试土壤对Sr2+的吸附量达到最大值,3 h后吸附量略有下降,并逐渐稳定。供试土壤对Sr2+的吸附量随溶液离子强度的增加而减小;但当离子浓度大于0.2 mol/L时,土壤对Sr2+的吸附量又呈增加趋势。试验数据拟合结果表明,供试土壤对Sr2+的吸附符合Henry和Fre-undlich方程;在吸附3 h内供试土壤对Sr2+吸附基本可以用一级动力学方程描述。

Adsorption behaviors of strontium on the surrounding soils of a petrochemical sewage in Xinjiang

Adsorption of heavy metals by soils plays a key role in controlling the availability of heavy metals.The retention of heavy metals depends not only on the nature of soil such as the mineral and organic constituents,the composition of the soil solution and its pH,but also on the external factors such as properties of metals,the added cations and anions,the temperature of reactions and the presence of organic or inorganic matters.The objectives of this study were to understand the adsorption behaviour of Sr2+ in various conditions.In present paper,series of experiments were conducted to study the absorption characteristics of Sr2+ in the surrounding soils of a petrochemical sewage reservoir in Xinjiang through static adsorption tests.The effects of adsorption conditions such as pH,temperature,initial concentration of strontium ions,ionic strength and adsorption time on the adsorption capability were investigated.The results indicated that the adsorption capability increases with the increase of temperature and initial concentration of strontium ions.The pH value has significant influence on the soil adsorption of Sr2+.Besides that,the adsorption increases remarkably with the rise of pH.The adsorption performance was optimum when the adsorption equilibrium time of Sr2+ was 3 hours.The adsorption capacity was found to decrease slightly after 3 hours and gradually stabilize.The adsorption behaviour of Sr2+ in the tested soil gradually declined with the increase of ionic concentration under the condition of pH=5,but the soil adsorption of Sr2+ showed an increasing trend when the concentration was greater than 0.2 mol/L.The results of kinetic experiment showed that the adsorption curves of soils for Sr2+ comply to Henry equation and Freundlich equation.Within 3 hours of kinetic adsorption,the removal of Sr2+ can be well described by first order reaction kinetic equation.These results provide a basic data set and theoretical basis for establishing decision making of environmental protection.