Effect of aging on stabilization of Cd and Ni by biochars and enzyme activities in a historically contaminated alkaline agricultural soil simulated with wet–dry and freeze–thaw cycling

Natural aging alters the surface physicochemical properties of biochars, which can affect the retention of heavy metals. This work investigated the effect of biochar aging on stabilization of heavy metals (Cd and Ni) and soil enzyme activities simulated with laboratory wet–dry (WD) and freeze–thaw (...

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Vydáno v:Environmental pollution (1987) Ročník 268; číslo Pt A; s. 115846
Hlavní autoři: Yang, Kai, Wang, Xilong, Cheng, Hefa, Tao, Shu
Médium: Journal Article
Jazyk:angličtina
Vydáno: England Elsevier Ltd 01.01.2021
Témata:
Accelerated aging
agricultural soils
beta-fructofuranosidase
Biochar
Cadmium
carbonates
catalase
Charcoal
corn straw
Enzyme activity
freeze-thaw cycles
Heavy metal stabilization
phytoaccumulation
pollution
Soil
soil enzymes
Soil Pollutants - analysis
Soil remediation
urease
wheat straw
Heavy metal stabilization
Soil remediation
Cadmium
Enzyme activity
Accelerated aging
Biochar
ISSN:0269-7491, 1873-6424, 1873-6424
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Shrnutí:Natural aging alters the surface physicochemical properties of biochars, which can affect the retention of heavy metals. This work investigated the effect of biochar aging on stabilization of heavy metals (Cd and Ni) and soil enzyme activities simulated with laboratory wet–dry (WD) and freeze–thaw (FT) cycling. A wheat straw (WS) biochar and a corn straw (CS) biochar were subjected to 30 WD or FT cycles, and Cd- and Ni-contaminated alkaline soils amended with the two fresh biochars (at 5% w/w) were subjected to 30-day constant moisture incubation and 30 WD or FT cycles. WD and FT aging caused slight reduction in the pH of the biochars, significant increases in their O contents and surface areas, and formation of new carbonate minerals. WS biochar was more effective than CS biochar at reducing the phytoavailable Cd in the soil, with reduction of 12.1%, 14.6%, and 12.9% under constant moisture incubation, WD aging, and FT aging, respectively. Reduction in phytoavailability of Ni by the addition of biochars was observed only under WD aging, by 17.0% and 18.5% in the presence of WS and CS biochars, respectively. Biochar amendment also reduced the distribution of Cd in the acid soluble and reducible fractions in all aging regimes. The addition of biochars decreased catalase activity in almost all aging regimes and invertase activity under FT aging, but increased urease activity under FT aging. Comparison of the enzyme activities in the soils amended with biochars under constant moisture and accelerated aging conditions indicates WD aging significantly decreased the activities of catalase, invertase, and urease in all treatments, while FT aging significantly increased urease activity in all treatments. These findings suggest that biochars can stabilize Cd in alkaline soils under changing environmental conditions, although the activities of some soil enzymes could be negatively impacted. [Display omitted] •Aging of biochars was simulated with wet–dry (WD) and freeze–thaw (FT) cycling.•Biochar reduced phytoavailable Cd and Ni in alkaline soil under WD and/or FT aging.•Biochar promoted the distribution of Cd into the residual fraction of alkaline soil.•Effect of biochar on enzyme activities varied with enzyme type and aging conditions.•Crop straw biochars hold promise for long-term immobilization of Cd in alkaline soils. Crop straw biochars stabilized Cd in a historically contaminated alkaline agricultural soil under accelerated aging, and thus hold promise for long-term immobilization of Cd under field conditions.
Bibliografie:ObjectType-Article-1
SourceType-Scholarly Journals-1
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content type line 23
ISSN:0269-7491
1873-6424
1873-6424
DOI:10.1016/j.envpol.2020.115846