铜渣基化学键合陶瓷材料吸附Cr(Ⅵ)的性能及机理

Adsorption of Cr(Ⅵ)by copper slag based chemically bonded ceramics:Property and mechanism

以富含铁的铜渣(CS)为原料,在碱激发条件下制备了铜渣基化学键合陶瓷材料(CSCBC),将其用于废水中Cr(Ⅵ)的吸附。考察了吸附剂投加量、Cr(Ⅵ)初始质量浓度及溶液pH对Cr(Ⅵ)吸附率的影响。通过吸附动力学和热力学分析,结合吸附前后吸附材料结构表征,对其吸附机理进行了探讨。结果表明,当Cr(Ⅵ)初始质量浓度为100 mg/L、pH=1、吸附剂投加量为8 g/L时,在120 min内达吸附平衡,Cr(Ⅵ)吸附率在99%以上。Langmuir等温吸附模型计算所得最大理论吸附容量为25.3 mg/g。与生物炭基铁氧化物复合材料、FeS复合材料、铁掺杂吸附剂等同类型吸附剂相比,CSCBC对Cr(Ⅵ)的吸附容量明显提高。CSCBC对Cr(Ⅵ)的吸附过程符合准一级动力学模型和Langmuir等温吸附模型。其吸附机制主要是物理吸附和化学吸附同时作用的结果。6次吸附-解吸后,其吸附容量保持初次吸附容量的75%以上。

Copper slag based chemically bonded ceramic material(CSCBC)was prepared from iron-rich copper slag under alkali excitation,and was used to adsorb Cr(Ⅵ)in the waste water.The effects of addition amount of adsorbent,initial mass concentration of Cr(Ⅵ)and pH of the solution on the adsorption rate of Cr(Ⅵ)were investigated.The adsorption mechanism was discussed by the adsorption kinetics,thermodynamics analysis and characterization of adsorbent before and after adsorption.The results showed that the adsorption equilibrium could be reached within 120 min,the adsorption rate of Cr(Ⅵ)was up to 99%under the optimal conditions[adsorbent addition amount of 8 g/L,initial mass concentration of Cr(Ⅵ)of 100 mg/L and p H=1].The maximum theoretical adsorption capacity of 25.3 mg/g was obtained by Langmuir isothermal adsorption model calculation.CSCBC had higher adsorption capacity of Cr(Ⅵ)than the same type adsorbents such as biochar-based iron oxide composites,FeS composite and ion doped adsorbent.The adsorption process of Cr(Ⅵ)by CSCBC was in accordance with the quasi-first order kinetic model and Langmuir isotherm adsorption model.The adsorption mechanism could be explained from two aspects of reduction and physical adsorption.The adsorption capacity remained more than 75%of the initial adsorption capacity after 6 adsorption-desorption experiments.