University of Minnesota, St Paul, MN, USA.
USDA-Agricultural Research Service, St Paul, MN, USA.
Pest Manag Sci. 2018 May;74(5):1206-1212. doi: 10.1002/ps.4530. Epub 2017 Mar 10.
Biochar, a carbon-rich product of biomass pyrolysis, could limit glyphosate transport in soil and remediate contaminated water. The present study investigates the sorption/desorption behavior of glyphosate on biochars prepared from different hardwoods at temperatures ranging from 350 to 900 °C to elucidate fundamental mechanisms.
Glyphosate (1 mg L ) sorption on biochars increased with pyrolysis temperature and was highest on 900 °C biochars; however, total sorption was low on a mass basis (<0.1 mg g ). Sorption varied across feedstock materials, and isotherms indicated concentration dependence. Biochars with a greater fraction of micropores exhibited lower sorption capacities, and specific surface groups were also found to be influential. Prepyrolysis treatments with iron and copper, which complex glyphosate in soils, did not alter biochar sorption capacities. Glyphosate did not desorb from biochar with CaCl solution; however, up to 86% of the bound glyphosate was released with a K HPO solution.
Results from this study suggest a combined impact of surface chemistry and physical constraints on glyphosate sorption/desorption on biochar. Based on the observed phosphate-induced desorption of glyphosate, the addition of P-fertilizer to biochar-amended soils can remobilize the herbicide and damage non-target plants; therefore, improved understanding of this risk is necessary. © 2017 Society of Chemical Industry.
生物炭是生物质热解产生的富碳产物，它可以限制土壤中草甘膦的迁移，并修复受污染的水。本研究调查了不同硬木在 350 至 900°C 温度范围内制备的生物炭对草甘膦的吸附/解吸行为，以阐明其基本机制。
草甘膦（1mg/L）在生物炭上的吸附随热解温度的升高而增加，在 900°C 生物炭上的吸附最高；然而，基于质量的总吸附量较低（<0.1mg/g）。吸附量因原料材料而异，吸附等温线表明浓度依赖性。具有较大微孔分数的生物炭表现出较低的吸附能力，并且还发现特定的表面基团也有影响。与在土壤中与草甘膦络合的铁和铜的预热解处理并没有改变生物炭的吸附能力。草甘膦不会用 CaCl 溶液从生物炭中解吸；然而，用 KHPO 溶液可以释放高达 86%的结合草甘膦。
本研究的结果表明，表面化学和物理约束对生物炭上草甘膦的吸附/解吸有综合影响。基于观察到的草甘膦的磷酸盐诱导解吸，将 P 肥料添加到生物炭改良的土壤中可能会使除草剂重新移动并损害非目标植物；因此，有必要更好地了解这种风险。© 2017 英国化学学会。
