Scientists explore sustainable use of fly ash for water treatment

Fly ash, often laden with toxic chemicals, pollutants, and soluble metal oxides, poses a significant environmental threat, causing damage to soil, water, and air. "Transportation across continents increases and rapid industrialization continues leading to surge in the energy consumption. Unfortunately, this has given rise to environmental concerns, with waste fly ash being discarded in alarming quantities - up to 1 billion tons annually," the study authors wrote.

Their literature review examines the potential of fly ash as a cost-effective and environmentally sustainable material for addressing global water scarcity. With over a billion people lacking access to fresh water, the need for innovative and affordable water treatment solutions is urgent. The authors emphasize the potential of fly ash in this context, highlighting its ability to replace conventional materials used in water purification processes.

The study draws on research published from 2015 to 2023, focusing on advancements in utilizing fly ash in water treatment. "Among these materials, fly ash stands out as a notable contributor to this field. Fly ash consists of fine particles expelled from the boiler with flue gases during combustion of coal, wood, rice husk, bagasse, or other combustible materials," the authors noted.

A key finding is that fly ash can be transformed into low-cost, high-performance ceramic membranes for wastewater treatment. These membranes exhibit durability, hydrophilicity, and high permeability, offering efficient solutions for industrial applications. Additionally, fly ash shows promise in photocatalysis, Fenton processes, and as support materials for membranes and electrodes, all of which align with sustainable practices.

The research highlights regional contributions to global fly ash production, with coal combustion in China accounting for 46%, sugarcane bagasse in Brazil at 41%, and notable contributions from rice husk and wood pulp industries in India, the United States, and Brazil. These statistics underscore the global scope of the issue and the potential impact of repurposing fly ash.

While significant progress has been made, the authors call for further research to address gaps in knowledge and expand the practical applications of fly ash in water treatment. "Addressing these gaps will contribute to the practical application of fly ash materials, paving the way for a more sustainable and effective approach to water treatment," they concluded.

Research Report:Fly ash as zero cost material for water treatment applications: A state of the art review