scholarly journals Residual and ecological risk assessment of heavy metals in fly ash from co-combustion of excess sludge and coal

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yao Tang ◽  
Jingshi Pan ◽  
Biqing Li ◽  
Suying Zhao ◽  
Liguo Zhang

AbstractCo-combustion of municipal excess sludge (ES) and coal provides an alternative method for disposing ES. The present study aims to investigate the residual and ecological risk of heavy metals in fly ash from co-combustion of ES and coal. The total concentration and speciation distribution of heavy metals, characterization of SEM, EDX, XRD and leaching test were carried out to assess the fly ash in this study. The results showed that the total concentrations of Cu, Zn and Mn were higher than others in fly ash, and most heavy metals were concentrated in fine particles. For Cd, Cr and Pb, the percentages of speciation of F4 and F5 were all over 90%, suggesting the relatively lower leaching toxicity. The leaching percent of all heavy metals was lower than 5% by two diluted HNO3 solutions for fly ash. The potential ecological risks increased with the decrease of particle size of fly ash, and Cd accounted for the main fraction for ecological risk despite of lower concentration in comparison to other measured heavy metals.

2012 ◽  
Vol 531 ◽  
pp. 292-295
Author(s):  
Hai Ying Zhang ◽  
Guo Liang Yuan ◽  
Guo Xian Ma

The characteristics and leaching behavior of heavy metals in fly ash, sampled from one MSWI (municipal solid waste incineration) plant in Shanghai China, were investigated. The results indicated that the main elements of fly ash were Fe, K, Na, Cl, Si, Ca, Al, and the total fraction of heavy metals was in the range of 0.8 % - 2.0%. Hence, MSWI fly ash was considered to be one kind of hazardous waste due to its potential environmental risk. Leaching toxicity was performed on fly ash samples from the MSWI plant in Shanghai China. Leaching toxicity of the heavy metals by the ALT (available leaching toxicity) procedure exceeded that by the HVEP (horizontal vibration extraction procedure) standard. Leaching concentrations of Ni, Zn, Cd and Pb exceeded the limit of hazardous waste identification standard. Hence, fly ash is a hazardous waste.


2018 ◽  
Vol 40 (26) ◽  
pp. 3502-3511 ◽  
Author(s):  
Tengtun Xu ◽  
Li’ao Wang ◽  
Yunmin Zeng ◽  
Xue Zhao ◽  
Lei Wang ◽  
...  
Keyword(s):  
Fly Ash ◽  

2017 ◽  
Vol 18 ◽  
pp. 01022
Author(s):  
Săndica Liliana Gherghe ◽  
Ildiko Anger ◽  
Georgiana Moise ◽  
Roxana Trusca

This article presents the characterization of the Romanian bentonite and fly ash, using different techniques: FAAS, XRD, FT-IR, SEM and EDAX and their evaluation as sorbents for heavy metals immobilization in polluted soils coming from mining and metallurgical activities. The applicability of bentonite and fly ash for Pb (II) and Zn (II) immobilization was studied using aqueous solutions of these metals. The influence of the pH and contact time were studied. The results shown that the Romanian bentonite and fly ash could be used for Pb (II) and Zn (II) immobilization in polluted soils from brownfields.


2022 ◽  

<p>The concentrations and comparisons of total and available metals Cd, Cr, Ni, Pb and the metalloid As were examined in two adjacent acid forest soils in Greece under oak and beech together with the dependency of their availability. It was found that the soil in the beech plot had higher concentrations of total elements with the exception of the litter layer (L) where most metals did not differ. It is probable that the parent material of the beech soil contained some metamorphic mafic material. The surface soils for both stands were moderately enriched with Pb, Cd and As, whereas for Cr and Ni the enrichment was minimal. The concentrations of available elements (extracted with DTPA) were higher in the beech soil. The availability of most metals was affected by the pH, the organic C, the ratio of C/N and the total concentration of the metals. Through a Principal Component Analysis (PCA) analysis, it was found that 63-75% of the concentrations variance of the available metals was explained. The percentages of available metals with regard to their total concentrations in soils were higher in the beech plot in the FH layer but in the mineral layers, they did not differ apart from Pb. The concentrations of the metals in the leaves of both species in three consecutive years did not differ with the exception of Cd, the concentration of which was higher in the beech leaves.</p>


Author(s):  
Virendra Kumar Yadav ◽  
Nisha Choudhary ◽  
Samreen Heena Khan ◽  
Parth Malik ◽  
Gajendra Kumar Inwati ◽  
...  

Nanotechnology is one of the most reliable techniques for the remediation of heavy metals. As nanoparticles have a higher surface area to volume, ratio, and high surface energies, so nano-based absorbents are very efficient. Adsorption technique is the most preferred for the remediation of wastewater pollutants. In the current study, a comparative study was done between bio sorbents, nanosorbents and bio nanosorbents. The chapter studies with the synthesis and characterization of the bio sorbents, bionanosorbents, their mechanism of sorption, their synthesis, in addition, application for the remediation of heavy metals from wastewater. The fly ash is an industrial byproduct. Biosorbents have immense applications in the field of bioremediation of heavy metals. Further, their components have also enhanced removal efficiency from the wastewater.


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