Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake/Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huai'an, 223300, China.
Advanced Technology Center (ATC) Building, Global Centre for Environmental Remediation, Faculty of Science, The University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia.
J Hazard Mater. 2019 Dec 15;380:120870. doi: 10.1016/j.jhazmat.2019.120870. Epub 2019 Jul 13.
Co-pyrolysis of straws with manures has been found effective to mitigate heavy metal risks in manure-derived biochars. This study further investigated co-pyrolysis strategy on the levels, species and risks of metals (Cu, Zn, Cr, Ni, Pb, and Cd) carried by manure-based biochars through co-pyrolyzing swine manure (SM) and corn straw (CS) with different mixture ratios (1:0, 0:1, 3:1, 1:1, and 1:3, w/w) at 300 ℃, 500 ℃ and 700 ℃. The total heavy metals in SM biochars were significantly reduced by CS addition except when SM/CS ratio was 3:1 at 300 ℃. Notably, CS addition increased stable Ni, Zn, Cu, Pb and Cd, but simultaneously mobilized part of Ni, Zn, Cu and Pb in SM biochars, especially at higher CS ratio and higher temperature. Co-pyrolysis converted less stable Cd to more stable Cd at all pyrolysis conditions, with higher CS ratio and higher temperature more effective. Overall, higher temperature (700 ℃) and higher addition ratio of CS (SM/CS 1:3) were more favorable for mitigating the potential ecological index of biochar-bearing Cd, Cu and Zn, the dominating risky contributor to SM biochars, hence more effective to mitigate the overall environmental risks of heavy metals in the derived SM biochars.
秸秆与粪肥的共热解已被证明可以有效降低粪肥衍生生物炭中重金属的风险。本研究通过不同比例（1:0、0:1、3:1、1:1 和 1:3，w/w）在 300℃、500℃和 700℃下共热解猪粪（SM）和玉米秸秆（CS），进一步研究了共热解策略对粪肥基生物炭中携带的金属（Cu、Zn、Cr、Ni、Pb 和 Cd）的水平、形态和风险的影响。除了 300℃时 SM/CS 比例为 3:1 外，CS 的添加显著降低了 SM 生物炭中的总重金属含量。值得注意的是，CS 的添加增加了稳定的 Ni、Zn、Cu、Pb 和 Cd，但同时也使部分 Ni、Zn、Cu 和 Pb 在 SM 生物炭中变得更具移动性，尤其是在更高的 CS 比例和更高的温度下。共热解在所有热解条件下将不稳定的 Cd 转化为更稳定的 Cd，CS 比例更高、温度更高更有效。总的来说，更高的温度（700℃）和更高的 CS 添加比例（SM/CS 1:3）更有利于降低生物炭中 Cd、Cu 和 Zn 的潜在生态指数，这是 SM 生物炭中主要的风险贡献者，从而更有效地降低衍生自 SM 的生物炭中重金属的整体环境风险。
