Evaluation of the toxicity of textile effluent treated by electrocoagulation

Abstract

Textile effluents are complex, making it difficult to choose an effective treatment. The textile effluent toxicity in Lactuca sativa after pulsed current (PC) electrocoagulation (EC) was evaluated in this study. The EC was performed using 304 stainless steel electrodes in batch mode. Parameters monitored included pH, temperature, color, and turbidity. Additionally, the process residue was subjected to energy-dispersive X-ray fluorescence (XFR) to determine the elements present. The process achieved proportional color and turbidity removal ranging from 97 to 99% and from 74 to 85%, respectively. Chemical oxygen demand (COD) and total nitrogen removal were 81 and 49%, respectively, in a 50 min time-lapse. The process generated approximately 1.7 kg of solid residue/m3 treated effluent. The XFR results revealed the presence, mainly, of Fe, Cr, and Ni ions in the residue, as well as chlorine. The germination index (GI) and relative growth values showed that EC reduced effluent toxicity slightly, indicating the need for complementary treatment. HIGHLIGHTS A lower energy consumption electrocoagulation process by the pulsed current was studied for textile wastewater treatment.; The color and turbidity removal were modeled under the influence of stirring rate, pulse frequency, and inter-electrode distance.; XRF analysis to determine the electrochemical residue composition is essential for the process's understanding.;

Keywords

• current density
• dye removal
• electrochemical process
• electrocoagulation residue
• germination index
• lactuca sativa toxicity