Calcium Chelation of Lignin from Pulping Spent Liquor for Water-Resistant Slow-Release Urea Fertilizer Systems

Abstract

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Lignin improves release behavior of slow‐release fertilizers with high content of urea

“…The nearly linear response of the urea release profile of the L/M/U 2:1:4 suggested that the time for its complete release of urea could be greater than 300 h. It was noted that this release experiment was very aggressive, because a complete immersion of the produced materials in water was done. In this aggressive condition, the L/M/U 2:1:4 had a better effect on the urea retention than other urea slow fertilizers containing lignin reported in literatures, for example the Ca‐lignin/urea composites or poly(lactic acid)‐functionalized lignin complex‐coated urea or lignin–urea/hydroxymethylurea/urea–formaldehyde composites . It was noted that in the L/M/U composites, all of the used starting materials (except the urea) did not include any synthetic polymers like poly(lactic acid) but only two natural polymers employed: the lignin and the Mt.…”

Spherical lignin particles: a review on their sustainability and applications

“…176 Also relevant for the fate of lignin particles in soil is the fact that they may possess the same strong chelating properties commonly observed in polyphenolic molecules. 177,178 This may warrant their low mobility in soil due to ionic binding with alkali metals and especially alkaline earth metals (e.g. Na + , K + , Mg 2+ , Ca 2+ ) that are abundant in several types of soil, leading to aggregation and retention of the lignin nanoparticles in the organic and the surface layers of the soil.…”

Structural changes of lignin in biorefinery pretreatments and consequences to enzyme-lignin interactions - OPEN ACCESS

“…Chelation of phenolic and carboxylic OH groups with Ca 2+ and Mg 2+ ions reduces hydrogen bonding between lignin and cellulases and also improves saccharification (Akimkulova et al 2016;Liu et al 2010). This chelation phenomenon also increases hydrophobicity of lignin, and can be used to precipitate lignin from alkaline solutions (Sipponen et al 2016) and so to improve fermentability of lignocellulosic hydrolysates (Palmqvist, Hahn-Hägerdal 2000). Hydroxypropylation blocks covalently the phenolic OH groups while generating new aliphatic OH groups in lignin, and consequently reduces its inhibitory effect on cellulases (Pan 2008;Sewalt et al 1997).…”