By Marcus Gay, NM WRRI Student Program Coordinator
Alireza Bandegi is a PhD student at NMSU in the Department of Chemical and Materials Engineering. In June, he received an NM WRRI Student Water Research Grant entitled, Electrochemical-assisted ultrafiltration membranes for simultaneous removal of As, Cd and Cr. The purpose of the study is to produce new types of electro-responsive membranes (ERMs) to electrochemically and reductively remove heavy metals from contaminated water.
The concentration of heavy metals has increased in many drinking water sources partially due to natural geological formations and also due to poor wastewater management practices. During the treatment of industrial wastewaters, toxic heavy metals of concern include cadmium (Cd), arsenic (As), and especially chromium (Cr). Cr (VI) is highly soluble and mobile because of its neutral pH, and due to the high toxicity of Cr (VI), the US EPA set the maximum concentration level (MCL) for total chromium in drinking water at 100 ppb. The New Mexico state groundwater standard for total chromium in drinking water is 50 ppb. However, high levels of chromium (250 ppb, five times higher than state groundwater standard) have recently been found in a water source in New Mexico.
Low pressure demands and wide range of chemical stability have caused ultrafiltration (UF) membranes to be widely used in water treatment processes, however, Cr (VI) removal by typical UF membranes is very limited due to the maximum rejection of 20%. Decreasing the pore size of the membrane and incorporating a charged surface can increase the heavy metal ions rejection by UF membranes.
As Alireza explains, “The biggest challenge in membrane technology is increasing the flow rate while decreasing the energy requirements used to push the fluid through the membrane. In this research, I synthesize the porous polymeric membrane using the self-assembly of block copolymers. By polymerizing the precursor in the system and removing the surfactant, I can successfully make membranes with porous structures in the nanometer size range. Consequently, the efficiency of the membrane for wastewater treatment will be improved by controlling and adjusting the size and orientation of pores within the membrane. We expect to increase the efficiency of typical polysulfone UF membrane with maximum rejection of 20% to more than 90% with our new electro-responsive UF membrane. Our new electrically conductive UF membrane is a scalable and cost-effective alternative to traditional heavy metals removal, and increases the availability of the clean drinking water which will improve human health.”
Alireza expects to complete his studies and graduate from NMSU with a PhD in Chemical Engineering in 2021. He is working under the guidance of his faculty advisor Dr. Reza Foudazi, Associate Professor of Chemical and Material Engineering at NMSU. Alireza received his BS and MS degrees in Chemical Engineering from Iran University of Science and Technology located in his home country of Iran. Alireza wants to pursue a career in research and teaching, and is especially interested in the enormous potential for research in the fields of nano- and micro-structured material.