Removal of natural organic matter from surface water sources by nanofiltration and surface engineering membranes for fouling mitigation – A review

Given that surface water is the primary supply of drinking water worldwide, the presence of natural organic matter (NOM) in surface water presents difficulties for water treatment facilities. During the disinfection phase of the drinking water treatment process, NOM aids in the creation of toxic disinfection by-products (DBPs). This problem can be effectively solved using the nanofiltration (NF) membrane method, however NOM can significantly foul NF membranes, degrading separation performance and membrane integrity, necessitating the development of fouling-resistant membranes. This review offers a thorough analysis of the removal of NOM by NF along with insights into the operation, mechanisms, fouling, and its controlling variables. In light of engineering materials with distinctive features, the potential of surface-engineered NF membranes is here critically assessed for the impact on the membrane surface, separation, and antifouling qualities. Case studies on surface-engineered NF membranes are critically evaluated, and properties-to-performance connections are established, as well as challenges, trends, and predictions for the field's future. The effect of alteration on surface properties, interactions with solutes and foulants, and applications in water treatment are all examined in detail. Engineered NF membranes containing zwitterionic polymers have the greatest potential to improve membrane permeance, selectivity, stability, and antifouling performance. To support commercial applications, however, difficulties related to material production, modification techniques, and long-term stability must be solved promptly. Fouling resistant NF membrane development would be critical not only for the water treatment industry, but also for a wide range of developing applications in gas and liquid separations

Efficient pollutant removal using tetrahydrofuran functionalized carbon nitride nanosheets with enhanced photocatalytic performance

Photocatalysis offers a green and promising strategy for light-driven pollutant degradation to address water pollution. Yet, challenges in conversion efficiency and cost-efficiency propel the search for effective metal-free photocatalysts. Here, we employ a ball milling technique using organic solvent molecules to enhance the exfoliation of g-C3N4 nanosheets. Incorporating tetrahydrofuran, with its distinctive five-membered monooxygenase ring structure, endows exfoliated CN nanosheets (TCN) with remarkable electron-donating capabilities, expanding specific surface area and active sites, essential for intricate photocatalytic reactions. Comparative assessments unequivocally establish TCN's superiority, revealing a remarkable 3.6-fold enhancement in RhB dye degradation and a remarkable 99.7 % removal efficiency. TCN demonstrates rapid, complete reduction of heavy metal ions (Cr6+) under natural sunlight within 10 min and exhibits a significant 2.3-fold antibiotic degradation enhancement over pristine CN. This pioneering work unveils the mechanisms behind TCN's superior photocatalytic performance, offering insights into designing advanced photocatalysts for crucial water purification applications