Loading…
Structural study and metal speciation assessments of waste PCBs and environmental implications: Outlooks for choosing efficient recycling routes
[Display omitted] •The PCBs recycling challenge is solvable by waste characterization assessment.•The metals content indicated that PCBs were as a potent metallic reservoir.•Most metals were in residual fraction, which need harsh leaching agent.•The environmental risk was assessed using indexes of R...
Saved in:
| Published in: | Waste management (Elmsford) 2022-09, Vol.151, p.181-194 |
|---|---|
| Main Authors: | , |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Get full text |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | [Display omitted]
•The PCBs recycling challenge is solvable by waste characterization assessment.•The metals content indicated that PCBs were as a potent metallic reservoir.•Most metals were in residual fraction, which need harsh leaching agent.•The environmental risk was assessed using indexes of RAC, ICF, GCF, Er, and PERI.•The leaching tests (WET, TCLP, and SPLP) demonstrated WET was an aggressive method.
Environmental protection from risks and disposal management of discarded mobile phone printed circuit boards (MPhPCBs) is a global issue. Although recycling is proposed as a solution, it is challenging to choose a sustainable method due to the insufficient recognition from extreme structural heterogeneity of these wastes based on their types. To this end, a thorough study on the structural characterization of PCBs using different analyses and metal speciation by sequential extraction procedure were performed. Understanding these information is an essential step in order to choose efficient methods to maximize selective recycling of metals and minimize environmental implications. PCBs were found to be potent metallic reservoirs after all metal content of PCBs were precisely measured. The structural analysis results of the sample included identification of different phases, functional groups, 45.1 % of the crystalline and 54.9 % of amorphous, the mesoporous nature (pore diameter mean ∼ 7.24 nm), hydrophobic property (contact angle ∼93.4°), the positive ζ-potential of particles at pH < (isoelectric point ∼5.4) and vice versa, and the particle size that were not oversized. The metal speciation outcome indicated over 80 % of the total content of elements such as Si, Sn, Ag, Au, Sr, Al, Cr, Nd, Ca, Ba, and P was in a solid crystal structure/residual fraction, which were hard recycled. The assessment of contamination levels of waste indicated the considerable contamination for the environment at global contamination factor ∼27.7, the moderate ecological risk at potential ecological risk assessment ∼82.9, and threats to public health. In addition, the metals of Pr, Mn, and Zn pose high risks because of their risk assessment code values of 42.7 %, 36.7 %, and 33.1 %, respectively. Leaching tests proved Waste Extraction Test was an aggressive method. ANC4 proposed high level of H+ consumption are required for metal leaching in future works. |
|---|---|
| ISSN: | 0956-053X 1879-2456 |
| DOI: | 10.1016/j.wasman.2022.07.036 |