铜渣基化学键合陶瓷材料吸附Cr(VI)的性能及机理

Adsorption properties and mechanism of Cr(VI) using copper slag-based chemically bonded ceramics

摘要:

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），对废水中的Cr(Ⅵ)进行吸附处理。考察了吸附剂添加量、Cr(Ⅵ)初始浓度及pH等因素对Cr(Ⅵ)吸附效果的影响，并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200 mg/L、pH=1、吸附剂投加量为0.4 g时，在240 min内达吸附平衡，Cr(Ⅵ)去除率可达93%以上，最大理论吸附容量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，Cr(Ⅵ)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。其吸附机制主要是还原、吸附等双重作用的结果。 6次吸附-解吸实验后，其吸附容量保持初次吸附容量的75%以上 。

Abstract:

Copper slag based chemically bonded ceramics (CSCBC) prepared through the alkali activation of copper slag was used to adsorb Cr(Ⅵ) ions in the waste water. The influence of the addition amount of adsorbent, initial concentration of Cr(Ⅵ) and pH on the adsorption efficiency was investigated, and the adsorption mechanism was discussed by the adsorption kinetics and thermodynamics analysis and characterization of adsorbent before and after adsorption. The result showed that the adsorption equilibrium can be reached within 120min, the removal rate was up to 93% and the maximum theoretical adsorption capacity was 25.3mg/g at the optimal condition (adsorbent addition amount: 0.4g, initial concentration of Cr(Ⅵ): 100 mg/L, pH: 1.0) . CSCBC has higher adsorption capacity than the same type adsorbents such as biochar-based iron oxide composites, FeS composite and Cr(Ⅵ)able metal 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 can be explained from two aspects of reduction and physical adsorption. The adsorption capacity remained 75% of the initial adsorption capacity after 6 adsorption-desorption experiments.