Water related diseases are a leading cause of death worldwide. Highly efficient water filtration membrane at reasonable cost is the solution to this problem. A research group in IISc has designed a membrane which can almost eliminate bacterial contamination from water.
The newly designed membrane is made of polyethylene, which has several advantages like low cost, strength, durability and stability. It also prevents biofouling- accumulation of micro-organisms on the membrane. Biofouling blocks the membrane and increases the overall time, cost and energy required for water purification.
The new membrane has a matrix made of polyethylene – a preferred choice to make filtration membranes due to its low cost, strength, durability and stability. To make the three dimensional porous membrane, the scientists mixed the polyethylene oxide (PEO) with polyethylene during the manufacturing process, and later created tiny pores. Biocidal agents are chemical or biological agents used to kill unwanted organisms. A large portion of the porous membrane is covered with graphene oxide sheets which are efficient and safe biocidal agents with potential to kill bacterial contaminants. Unlike other biocidalagents like silver, graphene sheets are non-leaching and non-depleting and thus are safe for use in filtration procedure.
The team tested the antibacterial activity of the membrane on E. coli, a common contaminant of water. The antibacterial activity of graphene oxide is primarily due to its sharp edges. The scissoring and knife cutting effects of graphene oxide leads to physical disruptionof peptidoglycan layer of bacterial cells leading to their death. Graphene oxidesheet coating do not clog the pores of the filtration membrane. So it is capable of improving the membrane efficiency, without any compromise in the flow rate.
The same research group based in IISC has been involved in the development of water filtration membranes. The present membrane is the most robust method and has the greatest antibacterial activity yet.
Dr. Suryasarathi Bose,Assistant Professor at Department of Materials Engineering, Indian Institute of Scienceand one of the authors, believes that this technology would be very useful for commercial use in future. The antibacterial efficiency of the designed membrane is 99% and thus bears great potential to be used in filtration process. The technology involves less cost and can be scaled-up without the need for extensive infrastructure.
About the authors
Dr. Suryasarathi Bose is an Assistant Professor at Department of Materials Engineering, Indian Institute of Science, Bangalore-560012, Karnataka, India. Prof. Giridhar Madras is a Professor at Department of Chemical Engineering, Indian Institute of Science.Prasanna Kumar S Muralis a research scholar at Center for Nano Science and Engineering, Indian Institute of Scienceand Shubham Jain and Sachin Kumar are research scholars at Department of Materials Engineering, Indian Institute of Science, Bangalore-560012, Karnataka, India.
About the study
The paper appeared online in the journal“Nanoscale”