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.
Sci Rep. 2024 Sep 9;14(1):21069. doi: 10.1038/s41598-024-69761-1.
Pyrolysis of animal manure at high temperature is necessary to effectively immobilize heavy metals, while the available phosphorus (P) level in biochar is relatively low, rendering it unsuitable for use as fertilizer. In this study, the pretreatment of swine manure with different potassium (K) sources (KOH, KCO, CHCOOK and CHKO) was conducted to produce a biochar with enhanced P availability and heavy metals immobility. The addition of all K compounds lowered the peak temperature of decomposition of cellulose in swine manure. The percentage of ammonium citrate and formic acid extractable P in biochar increased with K addition compared to undoped biochar, with CHCOOK and CHKO showing greater effectiveness than KOH and KCO, however, water- extractable P did not exhibit significant changes. Additionally, the available and dissolved Si increased due to the doping of K, with KOH and KCO having a stronger effect than CHCOOK and CHKO. X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed that K addition led to the formation of soluble CaKPO and silicate. In addition, the incorporation of K promoted the transformation of labile copper (Cu) and znic (Zn) into the stable fraction while simultaneously reducing their environmental risk. Our study suggest that the co-pyrolysis of swine manure and organic K represents an effective and valuable method for producing biochar with optimized P availability and heavy metals immobility.
高温下对动物粪便进行热解是有效固定重金属的必要手段，然而生物炭中有效磷（P）的含量相对较低，不适合作为肥料使用。本研究采用不同钾源（KOH、KCO、CHCOOK 和 CHKO）对猪粪进行预处理，以生产具有较高 P 有效性和重金属固定性的生物炭。所有 K 化合物的添加均降低了猪粪中纤维素分解的峰值温度。与未掺杂生物炭相比，添加 K 化合物使生物炭中柠檬酸铵和甲酸可提取 P 的比例增加，其中 CHCOOK 和 CHKO 的效果优于 KOH 和 KCO，但水可提取 P 没有明显变化。此外，由于 K 的掺杂，有效和溶解的硅增加，其中 KOH 和 KCO 的效果强于 CHCOOK 和 CHKO。X 射线衍射（XRD）和傅里叶变换红外光谱（FTIR）分析表明，K 的添加导致可溶的 CaKPO 和硅酸盐的形成。此外，K 的掺入促进了不稳定铜（Cu）和锌（Zn）向稳定部分的转化，同时降低了它们的环境风险。我们的研究表明，猪粪与有机 K 的共热解是一种有效且有价值的方法，可生产具有优化 P 有效性和重金属固定性的生物炭。
