化工学报 ›› 2020, Vol. 71 ›› Issue (7): 3288-3295.DOI: 10.11949/0438-1157.20200042

• 能源和环境工程 • 上一篇    下一篇

污泥水热碳化中磷的形态变化及金属浸出行为

方俊华(),唐琦,李杨,李遥瑶,吕秋颖,范准,周健,许劲   

  1. 重庆大学三峡库区生态环境教育部重点实验室,重庆 400045
  • 收稿日期:2020-01-13 修回日期:2020-03-24 出版日期:2020-07-05 发布日期:2020-07-05
  • 通讯作者: 方俊华
  • 作者简介:方俊华(1965—),男,博士,副教授,1400525812@qq.com
  • 基金资助:
    科技部国家重大专项子课题(2017ZX07401001-02)

Morphology of phosphorus and metal extraction behavior in sewage sludge during hydrothermal carbonization treatment

Junhua FANG(),Qi TANG,Yang LI,Yaoyao LI,Qiuying LYU,Zhun FAN,Jian ZHOU,Jin XU   

  1. Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
  • Received:2020-01-13 Revised:2020-03-24 Online:2020-07-05 Published:2020-07-05
  • Contact: Junhua FANG

摘要:

在不同温度下进行污泥水热碳化实验,利用Hedley顺序提取法探究水热炭中磷的形态变化,并结合钙、铁、铝的浸出行为进一步解释含磷物质的形态分布。结果表明,磷主要富集在水热炭中,水热碳化促进有机磷(Po)向无机磷(Pi)转化,NaOH溶解态磷(NaOH-P)转化为HCl溶解态磷(HCl-P)和残渣态(Res-P)。污泥和水热炭中Ca、Fe主要以HCl溶解态为主;Al则由NaOH溶解态转化为 HCl溶解态。并且水热碳化过程促使污泥中磷形态从磷酸铝盐(Al-P)、磷酸铁盐(Fe-P)向磷酸钙盐(Ca-P)、磷酸镁盐(Mg-P)转化。通过理论分析,水热炭中Al-P可能以Al2PO43+和AlHPO4+络合物为主;羟基磷灰石是Ca-P的主要存在形态;部分磷酸盐可能被铁氧化物或氢氧化物固定。为后续水热炭的回收利用提供理论基础。

关键词: 污泥, 水热炭, 磷, 形态, 金属, 浸取

Abstract:

Hydrothermal carbonization (HTC) treatment of sewage sludge was conducted at different temperatures. The conventional fractionation of phosphorus in hydrochar was investigated by Hedley fractional extraction method, and to achieve a comprehensive understanding of the morphology of phosphorus-containing substances with consideration of Ca, Fe, Al. The results showed that phosphorus was mainly concentrated in the hydrochar. organophosphorus (Po) almost transformed into inorganic phosphorus (Pi), and NaOH-extractable P (NaOH-P) converted to HCl-extractable P (HCl-P) and residue state (Res-P) in the process of HTC. Ca and Fe in the sludge and hydrochar were dominantly extracted by HCl whereas Al was transformed from NaOH-soluble to HCl-soluble. Moreover, the HTC process promoted the transformation of phosphorus form aluminum phosphate (Al-P) and iron phosphate (Fe-P) to calcium phosphate (Ca-P) and magnesium phosphate (Mg-P). Finally, a theoretical simulation of P-containing minerals suggested the existence of Al2PO43+ and AlHPO4+ complex in the hydrochar. Hydroxyapatite was the main existing form of Ca-P. Part of the phosphate may be fixed by iron oxides or hydroxides. This work provides a theoretical basis for the subsequent recycling of hydrochar.

Key words: sewage sludge, hydrochar, phosphorous, morphology, metal, extraction

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