School of Materials Science and Engineering, University of New South Wales, NSW 2052, Australia.
School of Applied and Biomedical Sciences, Faculty of Science and Technology, Federation University, Churchill, VIC 3842, Australia.
Waste Manag. 2017 Sep;67:131-142. doi: 10.1016/j.wasman.2017.05.052. Epub 2017 Jun 7.
Municipal solid waste (MSW) generation has been growing in many countries, which has led to numerous environmental problems. Converting MSW into a valuable biochar-based by-product can manage waste and, possibly, improve soil fertility, depending on the soil properties. In this study, MSW-based biochars, collected from domestic waste materials and kerbsides in two Sydney's regions, were composted and pyrolysed at 450°C, 550°C and 650°C. The characteristics of the organic components and their interactions with mineral phases were investigated using a range of analytical techniques, with special attention given to polycyclic aromatic hydrocarbons and heavy metal concentrations. The MSW biochar prepared at 450°C contained the most complex organic compounds. The highest concentration of fixed C, indicating the stability of biochar, was detected in the high-temperature-biochar. Microscopic analysis showed development of pores and migration of mineral phases, mainly Ca/P/O-rich phases, into the micro-pores and Si/Al/O-rich phases on the surface of the biochar in the MSW biochar produced at 550°C. Amalgamation of organic phases with mineral compounds was observed, at higher pyrolysis temperatures, indicating chemical reactions between these two phases at 650°C. XPS analysis showed the main changes occurred in C and N bonds. During heat treatment, N-C/C=N functionalities decomposed and oxidized N configurations, mainly pyridine-N-oxide groups, were formed. The majority of the dissolved organic carbon fraction in both MSW biochar produced at 450°C and 550°C was in the form of building blocks, whereas LMW acids was the main fraction in high-temperature-biochar (59.9%).
城市固体废物（MSW）的产生在许多国家都呈增长趋势，这导致了许多环境问题。将 MSW 转化为有价值的生物炭基副产品，可以管理废物，并且可能根据土壤特性提高土壤肥力。在这项研究中，从两个悉尼地区的家庭垃圾和路边收集的基于 MSW 的生物炭，在 450°C、550°C 和 650°C 下进行堆肥和热解。使用一系列分析技术研究了有机成分的特性及其与矿物相的相互作用，特别关注多环芳烃和重金属浓度。在 450°C 下制备的 MSW 生物炭含有最复杂的有机化合物。在高温生物炭中检测到固定 C 的最高浓度，表明生物炭的稳定性。微观分析表明，在 550°C 下产生的 MSW 生物炭中，矿物相主要是富 Ca/P/O 相和富 Si/Al/O 相进入微孔隙和表面的微孔，以及矿物相的迁移。在较高的热解温度下观察到有机相与矿物化合物的融合，表明这两个相在 650°C 时发生了化学反应。XPS 分析表明主要变化发生在 C 和 N 键上。在热处理过程中，N-C/C=N 官能团分解，氧化 N 构型，主要形成吡啶-N-氧化物基团。在 450°C 和 550°C 下产生的两种 MSW 生物炭中，大部分溶解有机碳馏分呈结构单元形式，而在高温生物炭中，低分子量酸是主要馏分（59.9%）。
