ABSTRACT

Thermal processing has been promoted to recycle phosphorus (P) contained within animal bone. There is a dearth of information on the mechanisms that control P solubility and availability from thermally treated bones. Chemical extraction, XRD, and FTIR were used to elucidate P solubility, and incubation and pot experiments to evaluate P bioavailability from different animal bones, thermal processing methods (pyrolysis vs. combustion), and production temperatures. Pyrolysis resulted in higher formic P than combustion, particularly at temperatures >500°C. Chicken bone showed the highest water-soluble P content (p< 0.001), irrespective of processing methods and temperatures. In contrast, pig bone exhibited the lowest water-soluble P despite its high total P content. The XRD and FTIR studies confirmed higher degree of crystallization for those produced from pig bone, combustion, and higher temperatures (>700°C). Infrared splitting factor and width at 85% of the height of the 604 cm⁻¹ peak were used to assess bioapatite crystallinity, and confirmed a negative correlation between crystallinity and P availability (p< 0.001), indicating the attribution of bioapatite crystallization for low soluble P during combustion and higher temperatures. In low pH soil (pH~4), the addition of thermally treated bones increased Olsen-P and plant P uptake by two- to five-folds compared with unamended soils; however, no significant variation was observed in higher pH soil (pH~7). The finding suggested processing bones below temperatures of 700°C resulted in less crystallinity, thus higher P solubility. The P-fertilizing value of thermally treated bones was more pronounced in lower pH soil.

摘要

已促进热处理以回收动物骨骼中所含的磷 (P)。缺乏关于控制热处理骨骼中 P 溶解度和可用性的机制的信息。化学提取、XRD 和 FTIR 用于阐明 P 的溶解度，并使用孵化和盆栽实验评估来自不同动物骨骼、热处理方法（热解与燃烧）和生产温度的 P 生物利用度。热解导致比燃烧更高的甲酸 P，特别是在温度 > 500°C 时。鸡骨的水溶性磷含量最高（p< 0.001)，与加工方法和温度无关。相比之下，尽管猪骨的总磷含量较高，但其水溶性磷含量最低。XRD 和 FTIR 研究证实，由猪骨、燃烧和更高温度 (>700°C) 生产的那些具有更高的结晶度。604 cm ^-1峰高度的 85% 处的红外分裂因子和宽度用于评估生物磷灰石的结晶度，并证实结晶度与 P 可用性之间存在负相关（p< 0.001)，表明在燃烧和高温期间生物磷灰石结晶对低可溶性 P 的归因。在低 pH 值土壤 (pH~4) 中，与未改良土壤相比，添加热处理骨骼使 Olsen-P 和植物 P 的吸收增加了 2 到 5 倍；然而，在较高 pH 值的土壤（pH~7）中没有观察到显着变化。该发现表明，在低于 700°C 的温度下加工骨头会导致结晶度降低，因此 P 溶解度更高。热处理骨骼的磷肥值在较低 pH 值的土壤中更为明显。