Rokneddini M, Mokhtarani N, Rajabi M M. Simultaneous Removal of Nitrate and Sulfate from Polluted Water by Combining Electrokinetic Process With PRB Containing Zero-Valent Iron Nanoparticles. MCEJ 2024; 24 (3) :15-27
URL:
http://mcej.modares.ac.ir/article-16-59787-en.html
1- Civil and Environmental Engineering Faculty, Tarbiat Modares University
2- Associate Professor, Civil and Environmental Eng. Faculty, Tarbiat Modares University , mokhtarani@modares.ac.ir
Abstract: (300 Views)
Nitrates and sulfates are commonly present as common pollutants in most natural waters. Sometimes, human activities such as excessive use of chemical fertilizers, lack of proper control over water sources, and improper treatment of industrial wastewater cause an increase in the concentration of these types of pollutants in surface and groundwater. This study focuses on the efficient removal of nitrates and sulfates from contaminated water using a combination of permeable reactive barriers (PRB) containing zero-valent iron nanoparticles (nZVI) and an electrokinetic (EK) process. In this research, which was carried out on a laboratory scale, by using the PRB system, the nitrate, and sulfate in the polluted groundwater were removed, and simultaneously, with the help of the EK process, the early saturation of the bed was prevented and system performance time is increased. To check the system efficiency, various parameters on the system performance were investigated, and the optimal conditions were determined to grow the system performance time. Additionally, the experiments were repeated using PRB containing granular activated carbon for comparison. The results reveal that the substrate containing nZVI exhibited superior performance in removing nitrates and sulfates from groundwater compared to the modified activated carbon. According to the results, the best system performance was obtained at pH 7, initial nitrate concentration of 200 mg/L, initial sulfate concentration of 450 mg/L, 2.14 gr of nZVI per Kg of sand, and a potential difference of 20 volts. Under these conditions, the use of the PRB containing nZVI not only extended the system operation time by 35 hours for sulfate removal and 30 hours for nitrate removal but also increased the system's removal efficiency by 13% for sulfate and 10% for nitrate after 80 consecutive hours of use, compared to the PRB containing modified activated carbon. Overall, this research contributes to the development of more effective strategies for the simultaneous removal of nitrate and sulfate from contaminated groundwater, using a combination of PRB with nZVI and the EK process.
Article Type:
Original Research |
Subject:
Environment Received: 2022/02/22 | Accepted: 2024/02/28 | Published: 2024/08/31