粘土质白云岩去除水中铜离子的效果及其机制

利用静态吸附实验研究了溶液pH值、反应时间、初始Cu2+浓度等因素对凹凸棒石粘土矿中粘土质白云岩去除Cu2+效 果的影响，将准一级、准二级、Elovich动力学方程与反应动力学进行拟合，再利用Langmuir、Freundlich等温方程对实验数 据进行等温式拟合，并与普通白云岩和凹凸棒石粘土进行了对比研究。结果表明，粘土质白云岩相对于其他两种材料受pH 影响较小，且在pH3~5范围内对Cu2+去除率均大于85%，最佳pH为5；对Cu2+的去除符合准二级动力学模型，粘土质白云 岩对铜的去除速率和去除率均最高；等温数据符合Freundlich模型，对Cu2+的最大去除量（pH=5，30℃）为186.2×10-3。粘 土质白云岩去除水中Cu2+的主要机制为矿物水化与溶解引起的表面沉淀及凹凸棒石与新生碱式碳酸铜[Cu2CO3(OH)2]胶体的静 电吸附。粘土质白云岩中纳米凹凸棒石与亚微米多孔白云石共生，具有较高的化学反应活性，除Cu2+效果明显优于普通白 云岩和凹凸棒石粘土，在处理含Cu2+废水方面具有潜在应用价值。
In comparison to common dolomite and palygorskite clay, the effects of parameters such as pH, contact time, initial concentrationofcopperonremovalofcopperionsusingclayeydolomiteinpalygorskiteclaydepositwasinvestigatedusingstatic adsorptionexperiments.Thekineticsofcopperremovalwasdiscussedbythepseudo-first-order,thepseudo-second-orderandthe Elovichmodel,andthesorptionisothermwasanalyzedbyLangmuirandFreundlichisothermequations.Theresultsshowthatthe effectofpHontheremovalofcopper(II)ionbyclayeydolomitewaslessthantheothertwo.Morethan85%ofcopper(II)ionswere removedinthepHrangeof3to5andtheoptimumpHis5.Thekineticdataoftheremovalofcopperbyclayeydolomitefittedthe pseudo-second-orderkineticmodelverywell.Theremovalrateaswellastheefficiencywasthehighest.Theisothermdatacanbe described by the Freundlich model and the removal capacity was 186.2×10-3. The removal mechanisms were mainly surface precipitationinducedbythemineral-waterinteractionsandelectrostaticattractionbetweenpalygorskiteandthenewlyformedcolloid [Cu2CO3(OH)2].Thepresentstudyconcludesthatclayeydolomiteismoreeffectivebecauseoftheintergrowthofnanoscalepalygorskite andsub-micronporousdolomite,leadingtothehigh-efficientremovalofcopperionsthanthecommondolomiteandpalygorskiteclay, anditpossessesthepotentialfortreatingcopperwastewater.