Sustainable tannin-based coagulants synthesized through Mannich reaction using melamine as an amine source for water treatment applications

This study explored the potential of melamine, as nitrogenating source for cationization pulverized quebracho and spruce tannins. The influence modification conditions on properties coagulants was studied by varying formaldehyde melamine ratios with different activation times temperatures. Based considerations charge density shelf life, most viable modifications were established synthesized a 1:0.52 to molar ratio at 70 °C. At optimal conditions, 2.22 meq/g 1.04 meq/g, respectively, residual content in low. developed synthesis this demonstrated clear advantage over previous methods due rapid step. X-ray photoelectron spectroscopy (XPS) confirmed emergence an amine which signifies successful Mannich reaction coagulant. Although °C (5-min time), average molecular weight could not be determined these conditions. Nevertheless, electrospray ionization mass spectrometry (ESI-MS) matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) measurements revealed that tannin-based obtained lower temperatures (23 45 °C) possessed low (approx. 800–900 Da). Furthermore, ESI-MS MALDI-TOF spectra showed resulted depolymerisation tannin, leading reduction units higher fractions coagulant, contrasted tannin. Jar test experiments surface industrial process waters tannin enhanced particle settling effectively.