EARTH

[1801-09-09] Assembly of fungus hyphae and nano-hydroxyapatite and its application to the remediation of cadmium and lead-contaminated soils

Zhihui Yang ^1,2, ○Lifen Liang¹, Wei Shi¹, Yunping Tong¹, Liyuan Chai^1,2, Shikang Gao¹, Qi Liao^1,2 (1. Central South University, 2. Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution)

Chairman：Mayumi Ito（Hokkaido University)

Keywords:soil remediation, nano-hydroxyapatite, microbial assembly strategy, bio-nanocomposites

Nano-hydroxyapatite is an effective amendment for in situ immobilization of heavy metals in contaminated soils owing to its large specific surface area and high reactivity. Problems associated with using this phosphate material include excessive dispersion, and resulting in the waste of materials and risks of eutrophication. Therefore, a facile, environment-friendly and scalable microbial assembly strategy has been introduced for the fabrication of fungus hyphae-assembled nano-hydroxyapatite bio-nanocomposites which displayed a promising immobilization performance toward Cd-Pb contaminated soil remediation. According to SEM, XRD and FT-IR analyses, hydroxyapatite nanoparticles were indeed assembled onto the fungus hyphae macrospheres. In terms of the selection of filamentous fungus, Aspergillus niger was superior to Penicillium Chrysogenum F1 based on the immobilization performance of amendments, which may be closely related to the difference in their assembly capacity. Compared to the simplex nano-hydroxyapatite, Aspergillus niger hyphae-assembled nano-hydroxyapatite bio-nanocomposite (ANHP) exhibited much better Cd and Pb immobilization performance in soils with varying degrees of cadmium and lead contamination, revealing the superiority of microbial assembled nano-hydroxyapatite. Under the same dosage of ANHP, the immobilization efficiency of DTPA-extractable Cd increased with the aggravation of soil pollution, while the DTPA-extractable Pb decreased gradually. The mechanism may involve competitive adsorption between Cd and Pb for the active sites on the hydroxyapatite (HAP) surface. Thus, the ANHP can be recognized as a promising soil amendment candidate for cadmium and lead contaminated soil remediation.