砂样钢渣对酸性Cr(Ⅵ)的吸附动力学与机理研究

Study on absorption dynamics and mechanism of sand-steel-slag to acidic Cr( Ⅵ)

以砂样钢渣作为吸附剂,研究了去除废水中Cr6＋的工艺条件和机理。结果表明,最佳工艺条件分别为：p H值0.8--1.5,温度为20℃--25℃,钢渣投放量为5 g,废水初始体积以150--200 m L为宜。铬去除量与钢渣水溶液静置时间呈线性关系,且颗粒内扩散模型、准一级和二级速率方程、Langmuir和Freundlich吸附等温模型拟合曲线的相关系数较大,属于单分子层的吸附方式并具有较好的吸附性。通过机理分析可知,砂样钢渣对Cr6＋的吸附过程分为还原（降毒）、水化、沉淀、吸附等4个阶段,钢渣最大吸附量为45.872 mg/g,占砂样钢渣的比例较小。钢渣完成吸附铬后,仍可用来配制砂浆、混凝土等。

Taking the sand-steel-slag as an adsorbent, the process conditions and mechanisms of acidic Cr6＋ removal in waste water was studied. The results show that the optimal removal conditions are pH of 0. 8--1. 5, temperature of 20℃ --25℃, sand-steel-slag adsorbent of 5g and the initial waste water input of 150--200mL. Cr6＋ removal amount has a linear relation-ship with slag solution stewing time, the correlative coefficients of the intra-particle diffusion model, quasi-one rate equation, quasi-two rate equation, Langmuir and Freundlich isotherm model are greater, which is monolayer adsorption mode and has bet-ter adsorption. The mechanism analysis show that the adsorption process of sand-steel-slag to acidic Cr6＋ can be divided into 4 stages：reduction phase （ lowering drug） , hydration phase, precipitation phase, adsorption stage. The maximum adsorption ca-pacity of sand-steel-slag is 45. 872mg/g, accounting for a smaller proportion of sand-steel-slag, so it can be used to pre-pare mortar and concrete, etc. after adsorption.