scholarly journals Effects of pyrolysis temperature on biochar’s characteristics and speciation and environmental risks of heavy metals in sewage sludge biochars

2022 ◽  
pp. 102288
Author(s):  
Xin Zhang ◽  
Baowei Zhao ◽  
Hui Liu ◽  
Yue Zhao ◽  
Liujun Li
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Pyrolysis Temperature ◽  
Environmental Risks

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.

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

Removal of Heavy Metals from Aqueous Solution Using Biochar Derived from Biomass and Sewage Sludge

2015 ◽  
Vol 768 ◽  
pp. 89-95 ◽  
Author(s):  
Han Qiao Liu ◽  
Xian Xu ◽  
Zhen Hua Wu ◽  
Guo Xia Wei ◽  
Lei Sun
Keyword(s):  
Heavy Metals ◽  
Aqueous Solution ◽  
Sewage Sludge ◽  
Heating Rate ◽  
Pyrolysis Temperature ◽  
Optimum Conditions ◽  
Solution Ph ◽  
Adsorption Time ◽  
Mixed Aqueous Solution ◽  
Removal Of Heavy Metals

Biochar, a production of cotton/sludge pyrolysis, was used as an adsorbent for the removal of heavy metals from aqueous solutions. In this paper, it was assessed that the effect of biochar produced parameters including pyrolysis temperature and heating rate, adsorption time, solution pH and biochar modification on removal of Cd from aqueous solution, and the removal effect of heavy metals from mixed aqueous solution was also studied. The results showed that the optimum conditions were pyrolysis temperature of 550°C, heating rate of 5°C/min, adsorption time of 90min, biochar dosage of 10g/L and solution pH=6, respectively. And the effect was a little increased when the biochar were impregnated with chemicals. About 99% Cd, Pb and Zn were removed from aqueous solution using biochar under the optimum conditions.

scholarly journals Influence of Temperature on Characteristics of Particulate Matter and Ecological Risk Assessment of Heavy Metals during Sewage Sludge Pyrolysis

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5838
Author(s):  
Binbin Li ◽  
Haihong Fan ◽  
Songxiong Ding ◽  
Yixuan Luan ◽  
Yiming Sun
Keyword(s):  
Heavy Metals ◽  
Risk Assessment ◽  
Particulate Matter ◽  
Sewage Sludge ◽  
Ecological Risk ◽  
Ecological Risk Assessment ◽  
Pyrolysis Temperature ◽  
Inorganic Particles ◽  
Different Temperatures ◽  
Influence Of Temperature On

The formation process of Particulate Matter (PM) during sludge pyrolysis at different temperatures (300–700 °C) and the ecological risks of heavy metals were studied. The results showed that the particulate matter is mainly condensed on the quartz film in a carbon-based organic matter when the pyrolysis temperature was between 200–500 °C in a volatilization process. Inorganic particles was found in the particulate matter when the temperature was raised to 500–700 °C in a decomposition stage. Heavy metals were enriched in particulate matter with increase in pyrolysis temperature. When the temperature reached 700 °C, the concentration of Pb and Cd in the particulate matter significantly increased. The ecological risk assessment showed that heavy metals in the sewage sludge had considerable ecological toxicity. When the pyrolysis temperature reached 700 °C, the ecological toxicity of those heavy metals enriched in the particulate matter decreased considerably.

Fraction Distribution Changes of Heavy Metals in Co-Pyrolysis of Sewage Sludge and Corn Straw

2011 ◽  
Vol 236-238 ◽  
pp. 187-191 ◽  
Author(s):  
Qiu Rong Zhang ◽  
Shuang Quan Zhang ◽  
Ting Ting Pan
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Sequential Extraction ◽  
Pyrolysis Temperature ◽  
Extraction Procedure ◽  
Sequential Extraction Procedure ◽  
Residual Fraction ◽  
Corn Straw ◽  
Icp Ms ◽  
Fraction Distribution

Maiz’s short sequential extraction procedure was used to extract the heavy metals in the carbon residues made from sewage sludge by co-pyrolysis with corn straw. The content of heavy metals in the residues was determined by ICP-MS to study the fraction distribution changes of heavy metals. It is concluded that the content of mobile and mobilization heavy metals exsisted in the residue decrease and the content of residual heavy metals increase due to the co-pyrolysis. The co-pyrolysis temperature has great effect on the fraction distribution changes of heavy metals. The content of residual fraction for Cr, Ni, Pb is up to the top at 700°C and for Cd、Cu、Zn is at 500°C. The carbon residues are unhazardous and safe.

scholarly journals Experimental Investigation into the Effect of Pyrolysis on Chemical Forms of Heavy Metals in Sewage Sludge Biochar (SSB), with Brief Ecological Risk Assessment

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 447
Author(s):  
Binbin Li ◽  
Songxiong Ding ◽  
Haihong Fan ◽  
Yu Ren
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Ecological Risk ◽  
Pyrolysis Temperature ◽  
Potential Ecological Risk ◽  
Experimental Investigations ◽  
Chemical Forms ◽  
Bcr Sequential Extraction ◽  
Measurement Results ◽  
Sequential Extraction Method

Experimental investigations were carried out to study the effect of pyrolysis temperature on the characteristics, structure and total heavy metal contents of sewage sludge biochar (SSB). The changes in chemical forms of the heavy metals (Zn, Cu, Cr, Ni, Pb and Cd) caused by pyrolysis were analyzed, and the potential ecological risk of heavy metals in biochar (SSB) was evaluated. The conversion of sewage sludge into biochar by pyrolysis reduced the H/C and O/C ratios considerably, resulting in stronger carbonization and a higher degree of aromatic condensation in biochar. Measurement results showed that the pH and specific surface area of biochar increased as the pyrolysis temperature increased. It was found that elements Zn, Cu, Cr and Ni were enriched and confined in biochar SSB with increasing pyrolysis temperature from 300–700 °C; however, the residual rates of Pb and Cd in biochar SSB decreased significantly when the temperature was increased from 600 °C to 700 °C. Measurement with the BCR sequential extraction method revealed that the pyrolysis of sewage sludge at a suitable temperature transferred its bioavailable/degradable heavy metals into a more stable oxidizable/residual form in biochar SSB. Toxicity of heavy metals in biochar SSB could be reduced about four times if sewage sludge was pyrolyzed at a proper temperature; heavy metals confined in sludge SSB pyrolyzed at about 600 °C could be assessed as being low in ecological toxicity.

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