Modified Lignin for Micronutrient Chelation.

Abstract

Micronutrients are essential for plants. Micronutrient chelates offer a means of minimizing the chemical reaction of metals ions in solution and soil, which improves the bioavailability of micronutrients to contribute to plants growth. Those synthetic chelates are achieved by combining a chelating agent with a metal through coordinate bonding.

EDTA is the most common chelating agent in current synthetic micronutrients fertilizers. However, since the chelating agent is foreignto the plant, it will eventually release back into environments that may cause new concerns, like biological toxicity, etc. Besides of it, some researchers also doubt that EDTA would affect trace element sorption by leaf cuticles and slow nutrient absorption into leaves since the narrow size (0.3 nm) and negative charge of aqueous pores may hinder the diffusion of anionic, high molecular weight species such as EDTA.

The lignin is a naturally abundant, low-cost, environmentally friendly polymer, as well as one of main by-products from the paper industry. Recently, many researchers have proved that lignin is a potential absorption ability for metals due to its multiple appropriate functional groups, such as phenolic hydroxyl, aliphatic hydroxyl, carbonyl, etc.

Thus, the objective of this research is to utilize lignin as a highly functional chelate agent for micronutrient iron.