CIESC Journal ›› 2021, Vol. 72 ›› Issue (11): 5779-5789.DOI: 10.11949/0438-1157.20210835

• Energy and environmental engineering • Previous Articles     Next Articles

Potential of phosphorus recovery from sludge-based hydrochar by wet chemical method

Jin XU1,2(),Jiedong ZHU1,2,Juanli LI1,2,Mengqiu LIU1,2,Heluo GONG1,2   

  1. 1.College of Environment and Ecology, Chongqing University, Chongqing 400045, China
    2.Key Laboratory of Three Reservoir Region’s Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
  • Received:2021-06-21 Revised:2021-08-20 Online:2021-11-12 Published:2021-11-05
  • Contact: Jin XU

湿化学法回收污泥水热炭中磷的潜能研究

许劲1,2(),朱杰东1,2,李卷利1,2,刘孟秋1,2,龚河洛1,2   

  1. 1.重庆大学环境与生态学院,重庆 400045
    2.重庆大学三峡库区生态环境教育部重点实验室,重庆 400045
  • 通讯作者: 许劲
  • 作者简介:许劲(1968—),女,博士,教授,xujinglily@ 163.com
  • 基金资助:
    国家自然科学基金区域创新发展联合基金(U20A20326)

Abstract:

Taking the phosphorus-rich sludge hydrothermal charcoal as the research object, the SMT method is used to analyze the phosphorus form distribution, and hydrochloric acid and citric acid are used as extractants to explore the potential of wet chemical recovery of phosphorus. The experimental results show that after hydrothermal carbonization of sludge, the total phosphorus content increased, the organic phosphorus is transformed into inorganic phosphorus, and the non-apatite inorganic phosphorus is transformed into apatite inorganic phosphorus. The forms of phosphorus in hydrochar are mainly inorganic and non-apatite inorganic phosphorus. Acid concentration, liquid-solid ratio and acid leaching time have significant effects on phosphorus leaching from hydrochar. Under the suitable acid leaching conditions (hydrochloric acid concentration 0.3 mol/L, liquid-solid ratio 50 ml/g, acid leaching time 240 min; citric acid concentration 0.1 mol/L, liquid-solid ratio 50 ml/g, acid leaching time 600 min), the phosphorus leaching efficiency of hydrochloric acid and citric acid can reach 94.34% and 88.78%, respectively. The pseudo-second order kinetic model can fit the leaching process of phosphorus in the two acid leaching systems well. Meanwhile, the leaching capacity of metal elements increased gradually with the increase of acid leaching time, and there is a linear correlation with the leaching capacity of phosphorus. The order of leaching capacity from large to small metals is Fe > Ca > Al >Mg. In addition, some heavy metal elements are also leached, and the order of leaching ability is Zn > Mn > Cr > Cu > Pb. After acid leaching, hydrochar has more pore structure, which is expected to be a good adsorption material.

Key words: sludge, hydrochar, phosphorus recovery, hydrochloric acid, citric acid, acid leaching

摘要:

以富含磷的污泥水热炭为研究对象,用SMT法分析磷的形态分布,以盐酸和柠檬酸为浸提剂,探究湿化学法回收磷的潜能。结果表明,污泥经水热碳化后,总磷含量上升,有机磷朝着无机磷转化,非磷灰石无机磷朝着磷灰石无机磷转化,水热炭中磷形态以无机磷和非磷灰石磷为主。适宜酸浸条件下(盐酸浓度0.3 mol/L、液固比50 ml/g、酸浸时间240 min,柠檬酸浓度0.1 mol/L、液固比50 ml/g、酸浸时间600 min),盐酸和柠檬酸对磷的浸出效率分别可达94.34%、88.78%,准二级动力学模型能较好地拟合磷的浸出过程;同时,金属浸出能力随酸浸时间延长而逐渐上升,与磷浸出能力呈线性相关,由大到小依次为Fe>Ca>Al>Mg;重金属浸出能力由大到小依次为Zn>Mn>Cr>Cu>Pb;酸浸残渣有望成为性能良好的吸附材料。

关键词: 污泥, 水热炭, 磷回收, 盐酸, 柠檬酸, 酸浸

CLC Number: