Xie Jing-Ru, Chen Ben-Shou, Zhang Jin-Zhong, Liu Jiang
Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Resources and Environment, Southwest University, Chongqing 400715, China.
Chongqing Chemical Engineering Vocational College, Chongqing 400020, China.
Huan Jing Ke Xue. 2016 Jun 8;37(6):2187-2194. doi: 10.13227/j.hjkx.2016.06.023.
In order to develop highly efficient and low-cost treatment technique for heavy metal wastewater and promote the resource utilization of sepiolite, natural sepiolite was modified by using thioglycollic acid and characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), specific surface, Zeta potential and infrared spectrum (IR) analysis, and the adsorption kinetic and thermodynamic characteristics of the modified sepiolite to Hg(Ⅱ) in water were studied by static adsorption experiments. The results showed that sulfydryl groups were grafted onto sepiolite, and the surface of the modified sepiolite became smoother with more gaps and negative charges to improve the adsorption ability for Hg(Ⅱ). The optimal pH for Hg(Ⅱ) adsorption on the modified sepiolite was 6, and the adsorption process reached equilibrium in 60 min at 30℃. This process could be described by the pseudo second-order kinetic equation, and the initial adsorption rate constant was 0.063 mg·(g·min). The adsorption thermodynamic characteristics could be well described by Langmuir isothermal adsorption model, and the maximum adsorption capacity was 3.256 mg·g. The investigation revealed that the adsorption process was a spontaneous endothermic process, resulting in physical adsorption and chemical adsorption, which was dominated by physical adsorption.
为开发高效低成本的重金属废水处理技术并促进海泡石的资源利用，采用巯基乙酸对天然海泡石进行改性，通过扫描电子显微镜（SEM）、X射线衍射（XRD）、比表面积、Zeta电位及红外光谱（IR）分析对其进行表征，并通过静态吸附实验研究改性海泡石对水中Hg(Ⅱ)的吸附动力学和热力学特性。结果表明，巯基接枝到海泡石上，改性海泡石表面更光滑，孔隙增多且带负电荷，提高了对Hg(Ⅱ)的吸附能力。改性海泡石吸附Hg(Ⅱ)的最佳pH为6，在30℃下吸附过程60 min达到平衡。该过程可用准二级动力学方程描述，初始吸附速率常数为0.063 mg·(g·min)。吸附热力学特性可用Langmuir等温吸附模型很好地描述，最大吸附容量为3.256 mg·g。研究表明，吸附过程是一个自发的吸热过程，兼有物理吸附和化学吸附，以物理吸附为主。
