Effects of tree harvesting time and tannin cold/hot-water extraction procedures on the performance of spruce tannin biocoagulant for water treatment

This study investigated the effect of seasonal variation (i.e. winter and summer) on tannin extracts from spruce bark as biocoagulants for water treatment applications. Tannins were extracted through three different extraction procedures: cold-water (21 °C), plus hot-water (85 °C) direct °C). 1H nuclear magnetic resonance spectra showed that extractions possessed highest proportion phenols. Electrospray ionization-mass spectrometry indicated a preliminary sufficiently reduced non-phenolic constituents (monosaccharides sugars) in but not summer bark. The synthesis tannin-based coagulants was performed Mannich reaction using formaldehyde ethanolamine. Coagulants with charge densities (3.379 ± 0.012 meq/g) produced obtained extractions. Water experiments demonstrated they effective particle settling. proved tree harvesting season procedure play critical role obtaining high-quality synthesization provide better coagulative performance.