State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
Chemosphere. 2014 Sep;111:320-6. doi: 10.1016/j.chemosphere.2014.04.043. Epub 2014 May 13.
To investigate the role of the bulk and surface composition of both biochar and biochar-amended soils in the adsorption of Cd(2+), as well as the influence of different biochars added to the soils on Cd(2+) adsorption, swine-manure-derived biochars (BSs) and wheat-straw-derived biochars (BWs) were produced at 300, 450, and 600°C. These biochars were added to a sandy soil to investigate the effect of biochars on the adsorption of Cd(2+) by soil. The significantly higher surface C content of the amended soils compared to their bulk C content suggests that the minerals of the biochar-amended soils are most likely covered primarily by biochars. The maximum adsorption capacity (Qmax,total) of the BSs was 10-15 times higher than that of the BWs due to the high polarity and ash content of the BSs. The polarity ((N+O)/C) of the low-temperature biochars greatly affected their Cd(2+) adsorption. The Qmax,total of the BS-amended soils increased with increasing dose, whereas the Qmax,total of the BW-amended soils showed the opposite behavior, which was attributed to the different surface composition characteristics of the two types of soil. The BSs were more effective in immobilizing Cd(2+) upon application to the soil relative to the BWs. This study elucidates the spatial distribution of biochars in biochar-amended soils and highlights the importance of the surface composition of the investigated samples in Cd(2+) adsorption.
为了研究生物炭及其添加土壤的体相与表面组成在吸附 Cd(2+)方面的作用，以及不同生物炭添加到土壤中对 Cd(2+)吸附的影响，本研究采用猪粪和麦秸分别在 300、450 和 600°C 下制备生物炭（BS 和 BW）。将这些生物炭添加到沙土中，研究生物炭对土壤吸附 Cd(2+)的影响。与生物炭的体相比，添加土壤中生物炭的表面 C 含量显著增加，表明生物炭很可能主要覆盖了生物炭添加土壤的矿物质。BS 的最大吸附量（Qmax,total）比 BW 高 10-15 倍，这是由于 BS 的极性和灰分含量较高。低温生物炭的极性（（N+O）/C）对其 Cd(2+)吸附有很大影响。BS 改性土壤的 Qmax,total 随剂量的增加而增加，而 BW 改性土壤的 Qmax,total 则呈现相反的趋势，这归因于两种土壤的表面组成特征不同。与 BW 相比，BS 更有效地将 Cd(2+)固定在土壤中。本研究阐明了生物炭在生物炭添加土壤中的空间分布，并强调了研究样品表面组成在 Cd(2+)吸附中的重要性。
