Fabrication of nano-geopolymer filter cartridge for treatment of polluted aqueous solutions with Methylene blue

Methylene blue (MB), a cationic dye, is commonly used in textile manufacturing as a colorific agent for different tissues [1]. Several researchers are attempting for the removal of MB due to its harmful impact on health [2-3]. Fixed-bed adsorption methods have been used for confirming the ability of new synthesized adsorbents. In this study, nano-geopolymer filter was fabricated with combination of Kaolin, sodium hydroxide, sodium silicate and water and then prepared slurry was molded into a ring-disk shape (5 cm in diameter, 0.2 cm thickness). Functional groups and morphological structure was fully characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, Brunner, Emmett, and Teller analysis and energy-dispersive X-ray spectroscopy. Then the media used for filtration were ring-disk shaped nano-geopolymer net. The effects of pH, contact time, dye concentration, sample volume and flow rate are all taken into consideration in detail under ambient conditions. The time-dependent experimental studies showed that the adsorption quantity of methylene blue increases with initial concentration, pH and adsorbent dosage. The study parameters influencing the adsorption processes show that nano-geopolymer filter removed 92% of the MB (initial concentration 10 mg/L) from 100 mL of water with a pH = 6 after 5 min. The adsorption equilibrium and kinetics were studied for experimental data. From these results, it can be considered that the fabricated nano-geopolymer filter from Kaolin sample tested herein is effective in the removal of MB from aqueous solutions and may be used as an alternative to high-cost commercial adsorbents. The filter cartridge made from the nano-geopolymer rings is very resistant and its materials are not dispersed in water.