Kaolin-based Geopolymer Removes Toxic Dye From Wastewater
Researchers have developed an efficient and sustainable adsorbent based on South African kaolin clay. The kaolin-based geopolymer (KBG) has a high-dye-removal capacity for crystal violet (CV), making it an ideal solution for wastewater treatment.
CV is a cationic dye commonly discharged by the textile and paper industries into wastewater. Besides being carcinogenic and harmful to the environment, it also takes a long time to degrade. Membrane separation, chemical precipitation, and other traditional wastewater treatment methods can trap CV. However, they are expensive and, worse, become a source of secondary pollutants.
In a recent study published in Chemistry, the team demonstrated how the KBG is an ideal option for treating wastewater. Despite its modest adsorption capacity compared to that of other geopolymer systems, KBG is cost-effective and environmentally friendly.
To develop this new geopolymer, the team used sodium hydroxide to activate the South African kaolin clay. Then, they mixed it with hydrogen peroxide to remove residual organics and enhance pore formation.
The material underwent drying, grinding, and characterization using several analytical techniques. Fourier Transform Infrared Spectroscopy revealed any changes in aluminosilicate bonding, while Scanning Electron Microscopy paired with Energy-Dispersive Spectroscopy provided insight into the porous network and elemental makeup.
In addition, surface area was determined through Brunauer–Emmett–Teller analysis, and X-ray Diffraction verified the conversion of crystalline kaolin into an amorphous geopolymer.
The team conducted batch adsorption studies to assess the CV uptake of KBG under varying conditions. They also ran parallel tests in distilled and natural river water to support further testing.
In the end, KBG achieved a maximum adsorption capacity of 7.27 mg/g. This figure is higher than that of clay- and fly ash-based geopolymers but lower than that of geopolymers derived from metakaolin, rice husk, pozzolan, and charcoal. Nonetheless, KBG can remove CV from wastewater in a much more sustainable manner.
Read the full article here to learn more about the kaolin-based geopolymer.
Aqua Solutions is a trusted source of laboratory water purification systems. We provide Type I and Type II water, reverse osmosis solutions, and hydrogen generator support. Learn more about our products at https://www.aquaa.com.