Kumar Amit, Basu D
Department of Civil Engineering, Motilal Nehru National Institute of Technology Allahabd, Prayagraj, 211004 India.
J Environ Health Sci Eng. 2023 Apr 28;21(1):255-275. doi: 10.1007/s40201-023-00859-w. eCollection 2023 Jun.
This study aims to evaluate the performance of rotating aluminum electrodes in the electrocoagulation reactor for removing hexavalent chromium (Cr from synthetic tannery wastewater. Taguchi and Artificial Neural Network (ANN) based models were developed to obtain the optimum condition for maximum Cr removal. The optimum working condition obtained by Taguchi approach for the maximum Cr removal (94%) was: Initial Cr concentration (Cr ) = 15 mg/L; Current Density (CD) = 14.25 mA/cm; Intial pH = 5; Rotational Speed of Electrode (RSE) = 70 rpm. In contrast, the optimal condition for maximum Cr ions removal (98.83%) obtained from the BR-ANN model was: Cr = 15 mg/L; CD = 14.36 mA/cm; pHi = 5.2; RSE = 73 rpm. Compared to the Taguchi model, the BR-ANN model outperformed in terms of providing higher Cr removal (+ 4.83%); reduced energy demand (-0.035 KWh/gm Cr remove); lower error function value (χ = -7.9674 and RMSE = -3.5414); and highest R value (0.9991). The data for the conditions 91,007 < Re < 227,517 and Sc = 102.834 were found to fit the equation for the initial Cr concentration of 15 mg/l; Sh = 3.143Re Sc. The Cr removal kinetics was best described by Pseudo 2 Order model, as validated by high R and lower error functions value. The SEM and XRF analysis confirmed that Cr was adsorbed and precipitated along with metal hydroxide sludge. The rotating electrode led to lower SEEC (10.25 kWh/m), as well as maximum Cr removal (98.83%), compared to EC process with stationary electrodes.
本研究旨在评估旋转铝电极在电凝聚反应器中去除合成制革废水中六价铬（Cr）的性能。基于田口方法和人工神经网络（ANN）开发了模型，以获得最大程度去除Cr的最佳条件。通过田口方法获得的最大Cr去除率（94%）的最佳工作条件为：初始Cr浓度（Cr ）=15mg/L；电流密度（CD）=14.25mA/cm²；初始pH=5；电极转速（RSE）=70rpm。相比之下，从BR-ANN模型获得的最大Cr离子去除率（98.83%）的最佳条件为：Cr =15mg/L；CD=14.36mA/cm²；pHi=5.2；RSE=73rpm。与田口模型相比，BR-ANN模型在提供更高的Cr去除率（+4.83%）、降低能源需求（-0.035KWh/gm Cr去除）、更低的误差函数值（χ=-7.9674和RMSE=-3.5414）以及最高的R值（0.9991）方面表现更优。发现条件91,007＜Re＜227,517和Sc=102.834的数据符合初始Cr浓度为15mg/l的方程；Sh=3.143Re Sc。Cr去除动力学最好用伪二级模型描述，高R值和较低的误差函数值验证了这一点。扫描电子显微镜（SEM）和X射线荧光光谱（XRF）分析证实，Cr与金属氢氧化物污泥一起被吸附和沉淀。与使用固定电极的电凝聚工艺相比，旋转电极导致更低的特定能耗（SEEC）（10.25kWh/m³）以及最大的Cr去除率（98.83%）。
