The effect of particle size of bamboo biochar on the phytoremediation of Salix psammophila C. to multi-metal polluted soil

Abstract

Biochar shows great potential in soil remediation. The benefits of biochar on soil depend onits intrinsic properties and soil characteristics. However, the influence of particle sizes of biochar on soil remediation is not clear. In a pot experiment, we evaluated the effects of bamboo biochar (BBC) particle sizes (P1 < 0.15 mm, 0.15 mm < P2 < 0.25 mm, 0.25 mm < P3 < 0.50 mm) on phytoremediation efficiency of Salix psammophila C. cultivated in multi-metal polluted soil. We added the BBC at 3% (w/w) in tested soil. Next, the BBC was thoroughly mixed with soil and weighting to the pot, and S. psammophila cuttings were planted and grown for six months in the amended soil under model growth condition.Results revealed the addition of different sizes of BBC particles affected soil quality, plant growth, and HMs accumulation in plants. All sizes of BBC treatments improved Cd and Zn accumulation, whereas plants in P2 treatment showed the greatest accumulation, increased by 52.41 and 25.55% compared with the control (1,503 and 19,928 μg·plant⁻¹). Overall, the results indicated BBC enhanced the phytoremediation efficiency of S. psammophila. Plants cultivated in P2 treatment showed the most significant effect on remediating contaminated soil.

Keywords:

• Bamboo biochar
• particle size
• phytoremediation
• Salix psammophila C.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Novelty statement

Biochar and willow (Salix spp.) have been applied as eco-friendly materials for polluted soil remediation. In general, biochar can immobilize heavy metals in soil and reduce metal uptake by plants. However, the effect of particle size of bamboo biochar on the phytoremediation of Salix psammophila to multi-metal polluted soil is little known. In the current study, we observed that bamboo biochar (BBC) (particle sizes: P1 < 0.15 mm, 0.15 mm < P2 < 0.25 mm, 0.25 mm < P3 < 0.50 mm) at 3% application rate improved the amount of Cd and Zn in plants. The BBC of P2 showed the most positive effect on enhancing phytoremediation of Salix to multi-metal polluted soil. The results suggested it is vital to select a suitable particle size of biochar to improve the remediation efficiency of soils polluted by metals. We believe this finding will help to fully understand the different benefits of particle sizes of biochar on soil remediation.

Additional information

Funding

The work was supported by the Key Research and Development Program of Zhejiang Province, China [Grant No. 2018C03047], and Fundamental Research Funds of the Chinese Academy of Forestry (Grant No. CAFYBB2019SZ001) and National Natural Science Foundation of China [Grant No. 32071736].