Ultrasonic‐Assisted Nitrate Anion Incorporation in Triaminoguanidium Chloride Based Covalent Organic Polymer for Methylene Blue Dye Adsorption

Terephthalaldehyde-triaminoguanidium chloride covalent organic polymer, Te-TG_Cl COP can facilely be incorporated with NaNO₃ by sonication. Te-TG_Cl COP incorporated with NaNO₃ via ultrasonication adsorbs Methylene Blue (MB) dye. Te-TG_Cl COP alone shows negligible adsorption capacity for MB, however, when treated with NaNO₃, its adsorption capacity emerges slightly. Moreover, ultrasonication of the NaNO₃ treated COP, Te-TG-NaNO₃ COP shows dramatic increase in its adsorption capacity for MB (q_e for Te-TG_Cl COP ≈0 mg g^-1; for Te-TG-NaNO₃=17.65 mg g^-1). Emergence of MB dye adsorption property in Te-TG-NaNO₃ COP composite may be attributed primarily to the electrostatic interaction of MB dye molecules with nitrate anions and the sonochemical effect caused fibrous morphological structure of the adsorbent material. The kinetics of MB dye adsorption onto Te-TG-NaNO₃ COP composite exhibits an excellent fit for the pseudo-second order model, suggesting the rate-determining step to be chemisorption. Homogeneous monolayer adsorption of MB dye onto Te-TG-NaNO₃ COP composite can be suggested as the Langmuir isotherm model seemed to be fitted well.