Phosphorus speciation in sewage sludge and the sludge-derived biochar by a combination of experimental methods and theoretical simulation
Phosphorus speciation in sewage sludge and the sludge-derived biochar by a combination of experimental methods and theoretical simulation
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实验方法与理论模拟相结合研究污水污泥和污泥生物炭中的磷形态
DOI：
10.1016/j.watres.2018.04.039
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发表时间：
2018
期刊：
影响因子：
12.8
通讯作者：
Yiming Cao
中科院分区：
文献类型：
--
作者：
Mi Li;Yuanyuan Tang;XiaoYing Lu;Zuotai Zhang;Yiming Cao
污泥是城市污水处理过程中不可避免的副产物，将污泥转化为高附加值的生物炭是污泥资源化利用的有效策略。磷形态的表征对于控制污泥及其衍生生物炭的实际应用和环境行为具有重要意义。磷的迁移性和生物有效性与磷的形态存在密切相关，但磷形态存在的知识空白需要通过现有的实验方法和技术以及理论预测等系统研究来缩小。为了全面了解磷的形态，本研究进行了一系列的研究相结合的传统分馏的P考虑主要伴生元素（Al，Ca，Fe），先进的分析技术（溶液和固态31 P核磁共振（NMR），X射线衍射（XRD）），和理论模拟方面的主要元素在不同的酸碱萃取剂的溶解度。结果表明，Ca和Fe主要被HCl萃取，而P和Al都是NaOH和HCl可溶的。无机正磷酸盐被检测到的主要分子构型的P从solution 31 P NMR光谱，而钙和铝的正磷酸盐的存在被揭示了由固态31 P NMR。此外，通过污泥和生物炭的XRD图谱进一步证明了贫结晶AlPO 4矿物。最后，在上述结果的基础上，对含磷矿物进行了理论模拟，结果表明污泥和生物炭中均存在磷钙石/磷铍石和无定形Ca 3（PO 4）2。本研究不仅探讨了污泥及其生物炭中磷的形态分布，而且为进一步研究磷的形态分布提供了方法学依据。通过对磷的环境行为的深入研究，为磷在废物综合管理中的再循环提供了基础知识。
Sewage sludge is an inevitable byproduct from municipal wastewater treatment processes and conversion of sewage sludge into high value-added biochar is an effective strategy for resource utilization of sewage sludge. The characterization on P speciation is important to control the practical applications and environmental behavior of the sewage sludge and its derived biochar. The mobility and bioavailability of P is closely related to its speciation, but knowledge gap in P speciation is still existed which needs to be narrowed by a systematic study including existing experimental methods and techniques as well as theoretical prediction. To achieve a comprehensive understanding of P speciation, this study conducted a series of research combining conventional fractionation of P with consideration of major concomitant elements (Al, Ca, Fe), advanced analytical techniques (solution and solid-state31P nuclear magnetic resonance (NMR), X-ray diffraction (XRD)), and theoretical simulation with respect to solubility of major elements in different acid-base extractants. Results showed that Ca and Fe were dominantly extracted by HCl whereas P and Al were both NaOH- and HCl-soluble. Inorganic orthophosphates were detected as predominant molecular configurations of P from solution31P NMR spectra, while the existence of calcium and aluminum orthophosphates was revealed by solid-state31P NMR. Moreover, the poor-crystalline AlPO4mineral was further evidenced by XRD patterns of the sewage sludge and biochar. Finally, a theoretical simulation of P-containing minerals was performed on the basis of results above, which suggested the existence of variscite/berlinite and amorphous Ca3(PO4)2in the sludge and biochar. This study does not only explore the P speciation in the sewage sludge and its derived biochar, but also provides a methodology for further research on P speciation. Through the intensive study on the environmental behavior of P, this work might further contribute to the fundamental knowledge basis for the recycle of P during integrate waste management.