Effects of pyrolysis temperature on properties of swine manure biochar and its environmental risks of heavy metals

2020 ◽  
Vol 152 ◽  
pp. 104945
Author(s):  
Feiyue Li ◽  
Xuan Wu ◽  
Wenchao Ji ◽  
Xiangyang Gui ◽  
Yihan Chen ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Pyrolysis Temperature ◽  
Swine Manure ◽  
Environmental Risks

scholarly journals Speciation and environmental risk of heavy metals in biochars produced by pyrolysis of chicken manure and water-washed swine manure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andong Wang ◽  
Dongsheng Zou ◽  
Xinyi Zeng ◽  
Bin Chen ◽  
Xiaochen Zheng ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Risk Assessment ◽  
Heavy Metal ◽  
Environmental Risk ◽  
Metal Toxicity ◽  
Pyrolysis Temperature ◽  
Swine Manure ◽  
Chicken Manure ◽  
Toxicity Characteristic Leaching Procedure ◽  
Leaching Procedure

AbstractThis study was conducted to investigate the speciation, bioavailability and environmental risk of heavy metals (HMs) in chicken manure (CM) and water-washed swine manure (WSM) and their biochars produced at different pyrolysis temperatures (200 to 800 °C). As the pyrolysis temperature increased, the remaining proportion, toxicity characteristic leaching procedure (TCLP), HCl and diethylenetriamine pentaacetic acid (DTPA) of HMs gradually declined. This result proved that the speciation of HMs in chicken manure biochars (CMB) and water-washed swine manure biochars (WSMB) was influenced by pyrolysis temperature. The proportions of stable fractions were enhanced with increased pyrolysis temperature and weakened the HM validity for vegetation at 800 °C. Finally, the results of the risk assessment showed that the environmental risk of HMs in CMB and WSMB decreased with increasing pyrolysis temperature. Therefore, pyrolysis at 800 °C can provide a practical approach to lessen the initial and underlying heavy metal toxicity of CMB and WSMB to the environment.

scholarly journals Effect of temperature on pyrolysis of sewage sludge: biochar properties and environmental risks from heavy metals

2021 ◽  
Vol 237 ◽  
pp. 01040
Author(s):  
Zhipu Wang ◽  
Shun Liu ◽  
Kai Liu ◽  
Shibo Ji ◽  
Mingming Wang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Pyrolysis Temperature ◽  
Environmental Risks ◽  
Effect Of Temperature ◽  
Ecological Risks ◽  
Average Pore ◽  
Leaching Potential ◽  
Ph Values ◽  
Increasing Temperature

Biochars were prepared via the pyrolysis of sewage sludge at temperatures ranging from 350–550 °C. The properties and behaviors of heavy metals in the biochars were investigated. The results indicated that the pH values and ash contents of the biochars increased, while biochar yield and C, H, and N contents decreased with the increasing temperature. A high pyrolysis temperature contributed to a developed biochar pore structure. The specific surface area and pore volume of the biochars increased, while the average pore width decreased, with the increasing temperature. Heavy metals in the biochars were further enriched with the increasing temperature. TCLP tests demonstrated that the leaching potential of heavy metals from the biochars significantly decreased with the increasing temperature, indicating the decrease of potential ecological risks of heavy metals to the environment. Additionally, BCR tests confirmed the transformation of heavy metals from mobile fractions (F1 and F2) to stable fractions (F3 and F4). The evaluation results showed that a high pyrolysis temperature can effectively inhibit the ecological risks of heavy metals in the biochars. Thus, the conversion of sewage sludge into biochar via pyrolysis is a promising method for the safe disposal of sewage sludge.

scholarly journals Release Behaviors of Arsenic and Heavy Metals from Arsenic Sulfide Sludge during Simulated Storage

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 130 ◽  
Author(s):  
Liwei Yao ◽  
Xiaobo Min ◽  
Yong Ke ◽  
Yunyan Wang ◽  
Yanjie Liang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Preventive Measures ◽  
Oxidation Process ◽  
Ferrous Metal ◽  
Environmental Risks ◽  
Arsenic Sulfide ◽  
Drying Process ◽  
Secondary Pollution ◽  
Release Ratio ◽  
Natural Drying

Non-ferrous metal smelting enterprises produce hundreds of thousands of tons of arsenic sulfide sludge (ASS) each year in China. Most of the ASS are stored at the companies without enough preventive measures. During the storage and natural drying process, arsenic sulfide is easily oxidized, thereby causing secondary pollution and increasing environmental risks. In this paper, experiments of simulated storage were used to study the release characteristics of heavy metals. During the simulated storage, the release concentrations of As, Pb, and Cd increased rapidly at first and then slowly. Although the total amount of arsenic released was the largest, the release ratio was in the order of Cd > Pb > As. The effects of different atmospheres and conditions on the release of arsenic and heavy metals were explored. The more the H2SO4 in the sludge, the higher the release concentration, and the addition of an appropriate amount of Ca(OH)2 is beneficial for reducing the release of heavy metals. Finally, SEM, XRD and TG-DTG techniques were carried out to confirm that the release of heavy metals was caused by the oxidation process resulting from the residual H2SO4 in the ASS and the air.

scholarly journals Tracing heavy metals in ‘swine manure - maggot - chicken’ production chain

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Wanqiang Wang ◽  
Wenjuan Zhang ◽  
Xiaoping Wang ◽  
Chaoliang Lei ◽  
Rui Tang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Swine Manure ◽  
Production Chain
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