Zhou Yihui, Xu Tao, Ou Jinhua, Zou Gege, Lei Xiping, Hu Bonian, Yu Gang
College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China E-mail:
Hunan Zihong Ecology Technology Co., Ltd, Changsha 410082, China.
Water Sci Technol. 2020 Nov;82(9):1950-1960. doi: 10.2166/wst.2020.466.
A novel sinusoidal alternating current coagulation (SACC) technique was used to remove the Zn from wastewater in the present study. The response surface methodology was used to analyze the effect of current density, time, initial pH and initial Zn concentration in order to obtain the optimum removal efficiency and to lower energy consumption. The results show that SACC with a current density of 0.31 A·m applied to treat wastewater containing 120 mg·dm Zn at pH = 9 for 21.3 min can achieve a removal efficiency of Zn of 98.80%, and the energy consumption is 1.147 kWh·m. The main component of flocs produced in SACC process is FeOOH·4HO (HFO). Large specific surface area and good adsorption performance of HFO are demonstrated. There is strong interaction between Zn and HFO. Zn is adsorbed and trapped by HFO and then co-precipitated. Freundlich adsorption isotherm model and pseudo-second order kinetics model explained the Zn adsorption behavior well. The Zn adsorption on HFO is an endothermic and spontaneous process.
在本研究中，采用一种新型正弦交变电流混凝（SACC）技术去除废水中的锌。运用响应面法分析电流密度、时间、初始pH值和初始锌浓度的影响，以获得最佳去除效率并降低能耗。结果表明，在pH = 9时，采用0.31 A·m²的电流密度对含120 mg·dm⁻³锌的废水处理21.3分钟，锌的去除效率可达98.80%，能耗为1.147 kWh·m⁻³。SACC过程中产生的絮体主要成分是FeOOH·4H₂O（HFO）。结果表明HFO具有较大的比表面积和良好的吸附性能。锌与HFO之间存在强烈的相互作用。锌被HFO吸附并捕获，然后共沉淀。Freundlich吸附等温线模型和伪二级动力学模型能很好地解释锌的吸附行为。锌在HFO上的吸附是一个吸热且自发的过程。
