Application of Cellulose-Based Materials as Water Purification Filters; A State-of-the-Art Review

Water scarcity, identified as the most serious global risk by the World Economic Forum, poses significant challenges due to its potential impact over the next decade. This study focuses on addressing the pressing issues of water scarcity and water quality through the use of cellulose-based materials for manufacturing water filters. Industrial wastewater containing dyes and heavy metal ions is a major contributor to water pollution, affecting underground water sources. Copper, mercury, chromium, lead, and tin are among the most common and environmentally damaging heavy metal ions due to their high toxicity, low biodegradability, and persistence in the food chain. Water purification processes are crucial for ensuring safe consumption. Bio-compatible and renewable materials have gained attention for water treatment applications in recent years. Cellulose-based materials, such as cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs), possess unique characteristics including biodegradability, suitable aspect ratio, thermal stability, high strength, stiffness, renewability, and accessibility. This research aims to review the utilization of cellulose-based materials, particularly modified CNC and CNF aerogels, for manufacturing water filters. These materials exhibit high porosity, large specific surface area, and functional groups on their surfaces, making them promising adsorbents for removing water pollutants such as heavy metals, organic dyes, pharmaceutical waste, and oils. Our study demonstrates that modified CNFs and CNCs have shown an exceptional absorption capacity of approximately 98% for heavy metals. By focusing on the specific application of cellulose-based materials for water filtration, this research contributes to the development of effective and sustainable solutions for water purification, addressing the critical challenges posed by water scarcity and pollution.