Carbon quantum dots for sustainable water treatment: A critical review on synthesis, properties, challenges and applications in forward osmosis desalination technologies
K S Sonu Ashritha, D. Dsilva Winfred Rufuss
Abstract
• Focus on applications of CQDs in forward osmosis (FO) desalination. • Potential of CQDs to remedy the challenges in FO desalination. • Influence of various types, properties and synthesis techniques of CQDs on FO. • Performance of desalination with CQDs incorporated FO membranes and draw solution. • Other applications and future research prospects of CQDs in desalination. The growing demand for freshwater, aggravated by climate change and population growth has intensified the need for sustainable desalination technologies. Carbon quantum dots (CQDs) have emerged as promising nanomaterials enhancing forward osmosis (FO) desalination processes. This study explores the multifaceted roles of CQDs in water treatment, emphasizing their use as membrane modifiers and draw solutions (DS). The unique properties of CQDs, including high water solubility, hydrophilicity and low toxicity have improved the water flux, reduced membrane fouling, and enhanced chlorine resistance of the FO membrane. Membranes modified with CQDs have enhanced permeability, selectivity, and antifouling properties, while CQDs-based DS have exhibited superior osmotic pressure and low reverse solute flux. This review addresses critical advancements in the synthesis of CQDs and their potential to address the challenges in forward osmosis desalination (including concentration polarization, fouling and reverse solute flux), directly supporting global efforts aligned with the United Nations Sustainable Development Goals (SDGs), particularly SDG 6 (Clean Water and Sanitation) and SDG 12 (Responsible Consumption and Production). The potential of CQDs to address global challenges including water scarcity, pollution, and renewable energy generation positions them as key materials for sustainable technological solutions.