Researchers from India's Haldia Institute of Technology have created a gravity filter using graphene oxide (GO), meant for purifying river water. Using alternative water resources like river water can help address the rising shortage of freshwater resources worldwide. Therefore, the deployment of cost-effective water filtration technologies is imperative for the desalination of river water and purification of polluted water.
Filtration using a gravity filter is a highly popular method for water purification. A gravity filter is a type of pressure filter wherein water passes through the filtering component on the influent side at atmospheric pressure and the whole system is driven by the force of gravity instead of electricity. A major benefit of gravity filters is that they are free from moving components, therefore require less filter maintenance. Another significant advantage of using a gravity-based water filtration system is that the system does not need a power supply. The main drawback, on the other hand, is the low output of purified water. The limitations of filtering technology imply that no one filtration material can remove all pollutants present in water.
The team used smooth and tightly connected GO sheets to create this system. Water quality tests revealed that in terms of efficiency, filters based on graphene oxide outperformed those that did not contain graphene oxide. The level of dissolved oxygen (O2) in the filtered water was higher than in unpurified river water, indicating that microorganisms were removed during filtering.
The use of graphene oxide filters gave a higher efficiency in eliminating arsenic and fluoride from water as compared to filters without graphene oxide. The pH of the filtered water was 6.88, while the unfiltered river water had a pH of 8.47.
The outstanding physical and chemical characteristics of graphene oxide allow the system to act as an effective filtration medium during the desalination process of river water. Graphene oxide also acts as an antibacterial filter medium during water purification. Graphene oxide can be used to create an incredibly thin film with adjustable pores, enabling a high flux of purified water. Two-dimensional sheets of graphene oxide are incredibly light and can withstand significant water pressures. Thanks to the hydrophilic nature of graphene, its large surface area, and its highly porous structure, water can spread uniformly throughout the graphene oxide sheets, thus improving the quality of adsorption. Another benefit of graphene oxide is that it is biocompatible and may be synthesized utilizing a simple process known as Hammer's method.