Preparation of a novel polysulfone membrane by incorporated with carbon dots grafted silica from rice husk for dye removal

This study demonstrated the modification of polysulfone (PSf) membrane by incorporating carbon dots (CDs) and silica (SiO2) as additives for membrane's permeability and dye rejection enhancement. Both the CDs and SiO2 were synthesized from rice husk and the carbon dots were impregnated on SiO2 to form CD/SiO2 composite through a hydrothermal synthesis reaction. The impregnation of CDs had shown increment of hydrophilic functional groups with negative surface charge on the SiO2. A series of CD/SiO2 composite embedded ultrafil-tration (UF) membranes was developed. Results revealed that the CD/SiO2 additive was endowed with enhanced membrane properties in terms of pore size, pore distribution, hydrophilicity and negative surface charge. All the modified membranes demonstrated higher permeability and dye rejection. Among the membranes, 1.0 wt% of CD/SiO2 loading showed excellent pure water permeability increment of 111 % due to improved membrane hydrophilicity and enlargement of membrane pores. Notably, the 2.5 wt% of CD/SiO2 membrane showed the highest dye removal of 50.54 % compared to pure PSf membrane of 14.52 % albeit it had similar permeability as the pure PSf membrane. This study had demonstrated a circular economy approach in turning rice husk biomass into useful additives for membrane nanotechnology application.

Automated summary

This study demonstrated the modification of polysulfone membrane with carbon dots and silica to enhance its permeability and dye rejection. The modified membranes showed improved pore size, hydrophilicity, and negative surface charge, with a significant increase in permeability for 1.0 wt% CD/SiO2 loading. Notably, the 2.5 wt% CD/SiO2 membrane exhibited the highest dye removal compared to the pure PSf membrane.