Influence of fertilizers on fluoride accumulation in tea leaves and its remediation using polyphenol–Ce adsorbents

Abstract

Fluoride accumulation in tea leaves has been an issue of concern because tea is currently one of the most popular beverages in the world. Unfortunately, the fertilizers used to promote the growth of tea trees inevitably cause significant fluoride accumulation in tea leaves. Here, we disclose that the use of plant polyphenol–Ce hybrid materials as chelating adsorbents effectively suppressed the accumulation of fluoride in tea leaves when compound fertilizers were applied during the growing period of tea plants. The adjacent phenolic hydroxyls of plant polyphenols were able to chelate with the Al³⁺ in the soil and prevent the formation and absorption of AlF_x complexes in tea trees. The adsorbents can effectively absorb F⁻ via positively charged Ce⁴⁺ based on electrostatic attraction. In field plot experiments, the fluoride accumulation in tea leaves was substantially reduced up to 74.75% when the compound fertilizers were used accompanied by the polyphenol–Ce adsorbents.