| 1. |
- Liang, Jiawei, et al.
(author)
-
Performance and microbial communities of a novel integrated industrial-scale pulp and paper wastewater treatment plant
- 2021
-
In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 278
-
Journal article (peer-reviewed)abstract
- Ltd Paper production generates pulp and paper wastewater (PPW), and it is difficult to remove the high-level pollutants in PPW efficiently. Herein, an efficient industrial-scale pulp and paper wastewater treatment plant (PP-WWTP) that integrated physicochemical and biological processes is investigated and reported. This PP-WWTP treated 2.3 Mt of wastewater with 17,388 ± 1436 mg/L chemical oxygen demand (COD) annually. The PP-WWTP can effectively remove over 99.81% of the COD. In detail, the physical, anaerobic, aerobic and chemical steps accounted for 41.6%, 40.0%, 11.9%, and 6.5% of COD removal, respectively. The microbial communities of the bioreactors removed the pollutants efficiently and contained diverse microbes. Further metagenomic analyses of the bioreactors identified more than 90,000 genes/gene fragments encoding for carbohydrate-active enzymes (CAZys), demonstrating high lignocellulose degradation ability of the bioreactors at molecular level. The xylanase activity assay showed some lignocellulase in the bioreactors were functional. Recycling the residual heat from the PPW along with energy recovered from biological treatment of the PPW, in the form of biogas (20,000 m³/d), could generate more than 1.5 M USD benefits/y. The results of this study demonstrated that the integrated physicochemical and biological process for PPWW treatment could effectively remove pollutants while generating revenue.
|
|
| 2. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Optimizing critical metals recovery and correlative decontamination from MSWI fly ash: Evaluation of an integrating two-step leaching hydrometallurgical process
- 2022
-
In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 368
-
Journal article (peer-reviewed)abstract
- While municipal solid waste incineration (MSWI) fly ash is classified as hazardous waste, it can also serve as an urban mining source for numerous precious metals. Of particular interest are antimony (Sb) and zinc (Zn); the former of which is a strategic and critical metal that is being rapidly depleted, putting society at high risk for supply shortages. In this work, a two-step leaching method for recovering Sb and Zn from MSWI fly ash is proposed. Furthermore, the leaching behavior and adsorption mechanism of Sb in the MSWI fly ash waste stream were also investigated. Results from the first constant pH leaching tests (CPLT) showed that under diluted acidic condition, the maximum amount of Sb released from fly ash was ∼20%. In addition, at pH 4.0, 67% of the fly ash was dissolved, while 79.3% and 12.1% of the Zn and Sb, respectively, were recovered. After optimizing and executing a second Sb leaching procedure (6 M HCl solution at 60 °C), >80% of the Sb was recovered. Thus, the proposed two-step leaching process, consisting of extraction followed by decontamination using a magnetic HAP@CoFe2O4 adsorbent, can eliminate the Sb in fly ash effluent with a removal efficiency >95%. Moreover, this process produces less toxic products and lowers the effluent residue concentration. As such, the two-step process described herein is suggested for Sb and Zn recovery from fly ash; as it not only enables precious metal recovery, but also aids in treating secondary waste streams produced from urban mining.
|
|
| 3. |
- Huang, Hongyun, et al.
(author)
-
Clinical Cell Therapy Guidelines for Neurorestoration (IANR/CANR 2017)
- 2018
-
In: Cell Transplantation. - : SAGE Publications. - 0963-6897 .- 1555-3892. ; 27:2, s. 310-324
-
Research review (peer-reviewed)abstract
- Cell therapy has been shown to be a key clinical therapeutic option for central nervous system diseases or damage. Standardization of clinical cell therapy procedures is an important task for professional associations devoted to cell therapy. The Chinese Branch of the International Association of Neurorestoratology (IANR) completed the first set of guidelines governing the clinical application of neurorestoration in 2011. The IANR and the Chinese Association of Neurorestoratology (CANR) collaborated to propose the current version "Clinical Cell Therapy Guidelines for Neurorestoration (IANR/CANR 2017)". The IANR council board members and CANR committee members approved this proposal on September 1, 2016, and recommend it to clinical practitioners of cellular therapy. These guidelines include items of cell type nomenclature, cell quality control, minimal suggested cell doses, patient-informed consent, indications for undergoing cell therapy, contraindications for undergoing cell therapy, documentation of procedure and therapy, safety evaluation, efficacy evaluation, policy of repeated treatments, do not charge patients for unproven therapies, basic principles of cell therapy, and publishing responsibility.
|
|
| 4. |
|
|
| 5. |
- Li, Yonghong, et al.
(author)
-
Novel strains with superior degrading efficiency for lincomycin manufacturing biowaste
- 2021
-
In: Ecotoxicology and Environmental Safety. - : Elsevier BV. - 1090-2414 .- 0147-6513. ; 209
-
Journal article (peer-reviewed)abstract
- As the antibiotic pollution source in the environment, a large amount of biowastes generated from antibiotic fermentation manufacture needs proper disposal. Recycling the biowaste as resources and nutrients is of great interest. Besides, degradation or removal of antibiotics is indispensable for the reclamation of antibiotic manufacturing biowaste. To establish environmentally friendly disposal strategies for lincomycin manufacturing biowaste (LMB), we screened the microbial strains that could efficiently degrade lincomycin from the antibiotic wastewater treatment plant. Among them, three novel strains were identified as Bacillus subtilis (strain LMB-A), Rhodotorula mucilaginosa (strain LMB-D) and Penicillium oxalicum (strain LMB-E), respectively. LMB-A and LMB-D could degrade 92.69% and 74.05% of lincomycin with an initial concentration of 1117.55 mg/L in 144 h, respectively. The lincomycin degradation products were formed by the breakage of amide bond or losing N-demethyl/thiomethyl group from the pyrrolidine/pyranose ringcata cata catalyzed by the strains. Moreover, LMB-A could decontaminate LMB, and the decontaminated LMB could be used as a nitrogen source to culture salt-resistant bacteria and other useful microorganisms. LMB-A and LMB-D have the potential to be used for the bioremediation of water and soil polluted by lincomycin and its analogs. LMB-E could degrade 88.20% LMB after 144-h cultivation. In summary, this study gives an insight into the green disposal of LMB, and the established strategy has potential application for biotreatment of other antibiotic fermentation manufacturing biowastes.
|
|
| 6. |
- Liang, Jiawei, et al.
(author)
-
Long-term microbiota and performance monitoring of a highly efficient propylene oxide co-production methyl tert-butyl ether production wastewater treatment plant
- 2023
-
In: Journal of Water Process Engineering. - 2214-7144. ; 56
-
Journal article (peer-reviewed)abstract
- A wastewater treatment plant (WWTP) was constructed specifically to treat 543,900 m3 wastewater annually generated by a novel propylene oxide (PO) co-production methyl tert-butyl ether (MTBE) petroleum chemical factory in this study. The WWTP consisted of expanded anaerobic granular sludge beds (EGSBs) and aerobic activate sludge tanks (AASTs), which have been operated for 1340 days. The chemical oxygen demand (COD) and petroleum oils of the WWTP influent were 5140 ± 844 mg/L and 70.08 ± 16.57 mg/L, respectively. The overall removal efficiencies for COD petroleum oils were 94.43% ± 2.36% and 93.46% ± 5.95%, respectively. EGSBs account for 41.48% ± 10.52% of the total COD removal, while AAST contributed to 52.95% ± 10.18%. AAST played a prominent role in the removal of petroleum oils. The optimum COD volume loading rate (VLR) of EGSBs during the operation was 1.83 ± 0.10 kg COD/m3/d, whereas the average COD VLR of AAST was 0.45 ± 0.09 kg COD/m3/d. The composition of dominant microorganisms found in EGSBs and AASTs significantly enhance the performance and efficiency of the WWTP. This study underscores the potential of employing a similar approach for long-term and efficient treatment of industrial complex pollutants, while also highlighting the presence of microbiota with exceptional capability to remove petrochemical contaminants.
|
|
| 7. |
- Mai, Wenning, et al.
(author)
-
Highly Effective Treatment of Petrochemical Wastewater by a Super-sized Industrial Scale Plant with Expanded Granular Sludge Bed Bioreactor and Aerobic Activated Sludge
- 2019
-
In: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947. ; 360, s. 15-23
-
Journal article (peer-reviewed)abstract
- One industrial scale plant has been constructed for annual treatment of 657,000m3 real petrochemical wastewater of 4649±651mg/l COD and more than 50mg/l petrochemicals. The plant system is divided into four parts, and the treatment process mainly functions in a 2200m3 anaerobic expanded granular sludge bed (EGSB) bioreactor and a 10,000m3 aerobic activated sludge (AS) bioreactor with the hydraulic retention time (HRT) of 62.8h and 133.3h, respectively. The plant has been successfully operated for more than 450days, and the overall COD and petrochemical removal efficiencies of the plant are 85.6±2.5% and 81.5±4.8%, respectively. The removal efficiency of the aerobic AS bioreactor was higher than that of the anaerobic EGSB bioreactor, and most COD and petrochemicals were removed in the aerobic AS bioreactor. Further microbial diversity analysis revealed that the dominant microbes in the EGSB and AS bioreactors were assigned to Proteobacteria and Firmicutes and 4 dominant OTUs related with COD or petrochemicals removal were enriched in the bioreactors, showing that the microbial communities had been adapted to the petrochemical wastewater treatment. Based on the results, the newly built industrial plant exhibited good performance in petrochemical wastewater treatment and enriched microbes towards petrochemical wastewater treatment during operation. This strategy also has potential applications for other industrial wastewater treatment in the future.
|
|
| 8. |
- Schewe, Jacob, et al.
(author)
-
State-of-the-art global models underestimate impacts from climate extremes
- 2019
-
In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
-
Journal article (peer-reviewed)abstract
- Global impact models represent process-level understanding of how natural and human systems may be affected by climate change. Their projections are used in integrated assessments of climate change. Here we test, for the first time, systematically across many important systems, how well such impact models capture the impacts of extreme climate conditions. Using the 2003 European heat wave and drought as a historical analogue for comparable events in the future, we find that a majority of models underestimate the extremeness of impacts in important sectors such as agriculture, terrestrial ecosystems, and heat-related human mortality, while impacts on water resources and hydropower are overestimated in some river basins; and the spread across models is often large. This has important implications for economic assessments of climate change impacts that rely on these models. It also means that societal risks from future extreme events may be greater than previously thought.
|
|
| 9. |
|
|
| 10. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Assessment of copper and zinc recovery from MSWI fly ash in Guangzhou based on a hydrometallurgical process
- 2018
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 76, s. 225-233
-
Journal article (peer-reviewed)abstract
- Fly ash commonly accumulates a significant amount of heavy metals and most of these heavy metals are toxic and easily leached out to the environment, posing risks to human health. Thus, fly ash has been classified as a type of hazardous waste and requires proper treatment before disposal in specific landfill sites for hazardous waste. In this study, a hydrometallurgical process developed to recover copper and zinc performed in pilot scale close to industrial scale followed by a landfill compliance leaching test of the ash residue is evaluated. LIX860N-I and Cyanex 572 gave high selectively for extractions, a yield efficiency of 95% and 61% was achieved for copper and zinc respectively. Results of pilot experiments reveals that the combining metal recovery recycling and landfill disposal of the ash residue in a local regular landfill was demonstrated to be a technically and economically effective strategy. Specifically, the economic and environmental aspects of a scenario, in which the fly ash generated in Guangzhou is processed were systematically assessed. the assessment results show that a 7.15 million US$ of total expense reduction, a less energy cost of 19k GJ as well as 2100 tons less CO2 emissions could be achieved annually comparing to the current alternative, direct disposal of the fly ash as hazardous waste. The results reveal that the hydrometallurgical process has industrial application potential on both economic and environmental aspects and further optimization of the process can give more accurate assessment of the cost and environment effect. In addition, leaching tests and evaluation of solid residue according to the regulations specific to the country should be studied in future.
|
|
| 11. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Assessment of heavy metals mobility and correlative recovery and decontamination from MSWI fly ash: Mechanism and hydrometallurgical process evaluation
- 2021
-
In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 768
-
Journal article (peer-reviewed)abstract
- Fly ash from municipal solid waste incineration (MSWI) enriches many leachable toxic metals which readily migrate into the environment, posing serious risks to the ecosystem and human. In this study, the elements mobility, leaching availability as well as the potential maximum amounts of heavy metals in fly ash were thoroughly evaluated. To decontaminate the toxic elements from resulting fly ash leachates, The aqueous zinc (Zn) was recovered using Cyanex 572, cadmium (Cd) and copper (Cu) were effectively removed through adsorption process by a self-assembled hierarchical hydroxyapatite (HAP) nanostructure. The removal mechanism of Cd, Cu and Zn by leaching, extraction and adsorption was revealed with the results from XRD, ICP-MS and SEM. The results showed that fly ash has a high mobility under maximum availability leaching test (95% of fly ash was dissolved), a recovery rate of 91% for Zn can be obtained using Cyanex 572, and a high adsorption rate (> 95% for both Cu and Cd) was reached using HAP for the pristine fly ash leachate. The outcomes from isothermal and kinetic study revealed that Langmuir isotherm and pseudo-second order model can well describe the Cd and Cu adsorption behavior. Economic assessment suggested that the application of HAP for the removal of Cd and Cu is a technically sound and economically feasible approach. The findings of this study demonstrated that this comprehensive process integrated leaching, solvent extraction and consequential decontamination can be a practical strategy for MSWI fly ash treatment.
|
|
| 12. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Comparative study of the application of traditional and novel extractants for the separation of metals from MSWI fly ash leachates
- 2018
-
In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 172, s. 143-154
-
Journal article (peer-reviewed)abstract
- Municipal Solid Waste Incineration (MSWI) fly ash often has to be managed as a hazardous waste due to its content of toxic metals in leachable forms. Some of the metals are also quite valuable and should not be lost in a landfill. In the present work a novel commercial extractant, Cyanex 572, was applied for selective separation of zinc from other metals in an ash leachate and its efficiency was compared to that of Cyanex 923 and Cyanex 272. Cyanex 572 was found to be more selective towards zinc than the other extractants and gave less co-extraction of other metals. Furthermore, the configurations of the complexes formed between metal ions and the respective extractants were investigated using both experimental data and theoretical modelling. Hydrometallurgical processes based on the use of Cyanex 572 and Cyanex 923, respectively, were tested and gave zinc recovery yields of 91% and 76%, respectively. Extraction with Cyanex 923 is not pH dependent like those of the other extractants, however it does extract part of the acid as well as the metal ions. The stripping processes, i.e. the recovery of extracted metal ions from the organic phases, are simpler with Cyanex 572 than with Cyanex 923 and create less secondary waste. These results show that Cyanex 572 can be an economically and environmentally suitable extractant for the recovery of zinc and other metals from MSWI fly ash. Further work to verify this includes modelling of the number of mixer settler stages needed for the extraction and stripping steps, as well as demonstration of the entire process in a pilot scale mixer settler set up.
|
|
| 13. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Comprehensive evaluation of the effectiveness on metals recovery and decontamination from MSWI fly ash by an integrating hydrometallurgical process in Guangzhou
- 2020
-
In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 728
-
Journal article (peer-reviewed)abstract
- Municipal solid waste incineration (MSWI) fly ash generally contains substantial toxic elements which can be easily released into the environment, giving rise to serious environmental contaminations. In order to dispose of these harmful fly ashes safely and feasibly, an advanced and reliable strategy is needed. This work presented an integrated method designed for recycling of valuable copper (Cu) and zinc (Zn) through hydrochloric acid leaching and sequential extraction (using LIX 860N-I and Cyanex 572 for Cu and Zn as extractants, respectively) and clean-up of cadmium (Cd) and lead (Pb) in consequential waste effluent by adsorption with a versatile material – bundle-like hydroxyapatite (B-HAP). The method was applied in the pilot scale tests with recovery yields of 95% and 61% for Cu and Zn, respectively. Additionally, satisfied removal efficiencies of Cd and Pb (over 95% for both) were realized, reaching the acceptable emission level for Cd and Pb in China. A scenario based on the latest MSW data in 2018 in Guangzhou was assessed through the integrated pilot experiment. The evaluation demonstrates a reduction of a $ 20.8 million cost; over 48.2 k GJ of energy consumption and 5800 tons of CO2 emission can be reduced in 2018, comparing to that landfilled in hazardous waste sites, which reveals great benefits. The valuable metal recovery in combination with decontamination of toxic elements/substances as a complete and combined process gives a promising fly ash treatment strategy in future.
|
|
| 14. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Highly efficient recovery and clean-up of four heavy metals from MSWI fly ash by integrating leaching, selective extraction and adsorption
- 2019
-
In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 234, s. 139-149
-
Journal article (peer-reviewed)abstract
- Municipal solid waste incineration (MSWI) fly ash contains significant amounts of heavy metals (e.g., Cd, Cu, Pb and Zn) and is therefore considered to be a hazardous waste requiring proper treatment prior to its disposal. In this work, an integrated hydrometallurgical process for treatment of MSWI fly ash was evaluated. Valuable metals, e.g. Cu and Zn, were first recovered by combining leaching and extraction sequentially. In the next step, the t removal of Cd and Pb from the remaining leachate using four types of iron-based adsorbents was evaluated. The leaching was optimized with respect to pH, leaching time and liquid to solid ratio. A test done under optimal conditions gave metal releases of 100% and 80% for Cu and Zn as well as 100% and 85% for Cd and Pb, respectively. The resulting leachate was contacted with organic phases based on kerosene containing the extractants LIX860N–I for Cu extraction and Cyanex 572 for Zn extraction in two consecutive steps. Efficient extractions were achieved, thus demonstrating that the combination of leaching and extraction can be successfully used for the recovery of Cu and Zn. Adsorption of heavy metal ions on various iron based sorbents to detoxify the aqueous effluent from the extraction showed good removal efficiency (more than 95%) for both Cd and Pb. The results of this study show that the proposed integrated process is a promising tool that can be used in the strategy for metal recovery and detoxification of MSWI fly ash.
|
|
| 15. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Leaching optimization of municipal solid waste incineration ash for resource recovery: A case study of Cu, Zn, Pb and Cd
- 2016
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 48, s. 315-322
-
Journal article (peer-reviewed)abstract
- Ash from municipal solid waste incineration (MSWI) may be quite cumbersome to handle. Some ash fractions contain organic pollutants, such as dioxins, as well as toxic metals. Additionally, some of the metals have a high value and are considered as critical to the industry. Recovery of copper, zinc and lead from MSWI ashes, for example, will not only provide valuable metals that would otherwise be landfilled but also give an ash residue with lower concentrations of toxic metals.In this work, fly ash and bottom ash from an MSWI facility was used for the study and optimization of metal leaching using different solutions (nitric acid, hydrochloric acid and sulfuric acid) and parameters (temperature, controlled pH value, leaching time, and liquid/solid ratio). It was found that hydrochloric acid is relatively efficient in solubilizing copper (68.2 ± 6.3%) and zinc (80.8 ± 5.3%) from the fly ash in less than 24 h at 20 °C. Efficient leaching of cadmium and lead (over 92% and 90% respectively) was also achieved. Bottom ash from the same combustion unit was also characterized and leached using acid. The metal yields were moderate and the leachates had a tendency to form a gelatinous precipitate, which indicates that the solutions were actually over-saturated with respect to some components. This gel formation will cause problems for further metal purification processes, e.g. solvent extraction.
|
|
| 16. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Mixer-settler system for the recovery of copper and zinc from MSWI fly ash leachates: An evaluation of a hydrometallurgical process
- 2017
-
In: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 148, s. 595-605
-
Journal article (peer-reviewed)abstract
- Municipal Solid Waste Incineration (MSWI) fly ash contain large amounts of leachable heavy metals, and thus is classified as hazardous waste. The increased amounts of fly ash generated cause environmental issues and accumulation of valuable metals in landfills which contribute to an increased interests to recognize the ash as an urban mining target of metal resources. The high leachability of fly ash metal compounds could instead be seen as a benefit since it opens a path for metal recovery. This study reports a new potential hydrometallurgical process based on combining leaching and sequential solvent extraction to recover copper and zinc from MSWI fly ash. The investigations were carried out at bench scale and laboratory pilot scale. The pilot scale unit, operated as a counter-current mixer-settler system. The separation of copper and zinc from the acidic ash leachate was achieved using LIX860N-I and Cyanex 923, two commercial extraction reagents, respectively. The phase contact time to reach equilibrium, number of mixer-settler stages of the system and liquid to organic ratios were investigated for optimization. Removal of co-extracted metals, e.g. cadmium, iron and lead to obtain higher purity of zinc solution, was carried out using either cementation before the zinc extraction, or selective stripping with different stripping agents sequentially after extraction. An efficient recovery of the copper and zinc present in an ash leachate, more than 90% and 99% respectively, was achieved sequentially in a mixer-settler system, which comprised of two stages for copper extraction and three stages for zinc extraction. Moreover, the removal of the toxic metals lead and cadmium is reported.
|
|
| 17. |
- Tang, Jinfeng, 1984
(author)
-
Recovery of copper and zinc in ashes from municipal solid waste combustion
- 2015
-
Licentiate thesis (other academic/artistic)abstract
- The amount of municipal solid waste incineration (MSWI) fly ash has increased in many parts of the world in recent years. Ashes from municipal solid waste incineration (MSWI) may be a cumbersome waste to handle since containing significant amounts of leachable hazardous metal species and must be landfilled in special sites at high costs. Recovery of e.g. copper, zinc and lead from MSWI ashes may not only recover valuable metals that would otherwise be land filled, but also reduce the toxicity of the ash and thereby make it possible to use a less expensive landfill option or perhaps even to utilize the ash residue as a construction material.The work presented here discusses the development and evaluation of a metal recycling process for MSWI fly ash based on acid leaching and solvent extraction; fly ash and bottom ash from an MSWI facility was used for studying and optimization of metal leaching using different solutions (nitric acid, hydrochloric acid and sulfuric acid) and parameters (temperature, controlled pH value, leaching time, and liquid/solid ratio). It was shown that hydrochloric acid is relatively efficient in solubilizing copper (75.3 ± 3.0%), zinc (80.8 ± 5.3%) from the fly ash in less than 24 hours at 20°C. Efficient leaching of cadmium and lead (over 92% and 90% respectively) was also achieved.After leaching, a selective solvent extraction to recover Cu using an oxime (LIX860-I) followed by a Zn extraction with phosphine oxides (Cyanex 923) were carried out sequentially. Both extraction reagents gave good yields and stripping of Cu and Zn is also possible in a single step using sulfuric acid or nitric acid respectively. The extraction of Cu was selective but a significant amount of other metals, such as Fe, were co-extracted together with Zn. It was shown that it is possible to decrease the contamination of Fe by adjusting the extraction parameters (e.g. adjusting the concentration of nitric acid solution for stripping) or by cleaning the final solution by cementation. A metal recycling process for MSWI fly ash is suggested based on the results from this study.
|
|
| 18. |
- Tang, Jinfeng, 1984
(author)
-
Removal and Recovery of Metals from Municipal Solid Waste Incineration ashes by a Hydrometallurgical Process
- 2017
-
Doctoral thesis (other academic/artistic)abstract
- Municipal Solid Waste Incineration (MSWI) fly ash contains significant amounts of leachable metals, and is therefore considered to be a hazardous waste. The increased amounts of fly ash generated cause environmental issues, management costs and accumulation of valuable metals in landfills. All these factors contribute to an increased interests to recognize the ash as an urban mining target of metal resources. Metals recovery, e.g. copper, zinc from fly ash, is not only beneficial for the availability of valuable metals that otherwise would be lost, but it can also decrease the amount of potentially soluble and toxic metal compounds in the ash residue, making it possible to landfill the ash at a lower cost.A hydrometallurgical process for recovery of copper and zinc from MSWI ash is presented in this thesis. A process consisting of leaching followed by sequential solvent extraction of metals was developed. With respect to leaching efficiency and feasibility, it was found that hydrochloric acid is the best option for recovery if copper and zinc from the fly ash, in addition, efficient leaching of cadmium and lead was also achieved.LIX860N-I, a commercial extractant was chosen for the copper extraction. No third phase formations or phase separation problems were observed. The copper extraction gave a good extraction yield with high selectivity. The extracted copper in organic phase can be stripped in a one stage process using a selected sulfuric acidic solution (1.5M). Zinc extraction followed the copper extraction by extracting the raffinate using Cyanex 272, Cyanex 572 or Cyanex 923. Cyanex 923 showed the highest efficiency and no pH adjustment of the aqueous phase was needed. However, this extractant co-extracts iron, cadmium and lead with the zinc. Cyanex 572, a novel phosphorus-based chelating extractant is less effective, but more selective for zinc extraction compared to Cyanex 923. Selective stripping processes were suggested for zinc extraction using Cyanex 572 and Cyanex 923 respectively.Laboratory pilot scale experiments using mixer-settler systems were carried out based on the batch experiment results. McCabe Thiele diagrams were used to model the processes with respect to the number of stages needed for conducting the extractions in mixer-settler systems. The solvent extraction process was then demonstrated in pilot size mixer settler equipment consisting of two stages for copper extraction and three stages for zinc extraction and gave a recovery of 90% of the copper and ~100% of the zinc in the leachate.
|
|
| 19. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Resource recovery from municipal solid waste ash
- 2014
-
In: Proceedings of the 29th International Conference on Solid Waste Technology and Management, Philadelphia, PA U.S.A., March 30-April 2, 2014. - 1091-8043. ; , s. 352-361
-
Conference paper (other academic/artistic)abstract
- Ashes from municipal solid waste incineration (MSWI) may be a cumbersome waste to handle. Some ash fractions contain organic pollutants, such as dioxins, as well as heavy metals. Additionally, some of the metals have a high value and are considered as critical to the industry. Recovery of e.g. copper and zinc from MSWI ashes will not only recover valuable metals that would otherwise be land filled, but also reduce the toxicity of the ash and thereby make it less cumbersome to handle.Such processes are presently being investigated by the Industrial Materials Recycling group at Chalmers University of Technology. The processes are primarily based on acid leaching of the ash combined with selective solvent extraction. The work on recovery process development is supported by investigations of the chemical speciation of metals, i.e. identification of metal compounds, in ashes by, e.g. synchrotron based X-ray absorption spectroscopy (XAS).The presentation will give an introduction to the validation of an optimized leaching process for MSWI and speciation results for Cu and Zn, as well as discuss the promising results that have been obtained using the suggested recovery processes for these metals.
|
|
| 20. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Solvent extraction separation of copper and zinc from MSWI fly ash leachates
- 2015
-
In: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 44, s. 147-154
-
Journal article (peer-reviewed)abstract
- Fly ash from combustion of municipal solid waste (MSW) contains significant amounts of metals, some of which are valuable and some of which are potentially toxic. This type of ash is most often stabilized and landfilled which means that the metals will be difficult to reclaim at a later stage. In recent years efforts have been made to develop feasible methods to recover selected metals, such as Zn, from MSW fly ash. If this would be possible, a significant amount of valuable metals could be re-inserted in the industrial material loops.This paper describes the development and evaluation of a process for recovery of Cu and Zn from MSW combustion fly ash based on hydrochloric acid leaching followed by two solvent extraction processes, one for each metal. The separation of Cu from the acid leachate was done using an aldoxime extractant, LIX860N-I, in kerosene and a mixture of phosphine oxides, Cyanex 923, also in kerosene, was used for extraction of Zn from the Cu-depleted aqueous phase. The extraction of Cu was selective, but a significant amount of other metals, such as Fe and Pb, were co-extracted together with Zn. It was shown that it is possible to decrease the contamination of Fe by using a suitable concentration of nitric acid solution for stripping or by removing the contaminating metals through cementation.The suggested process was tested for two MSW combustion fly ashes in laboratory scale experiments and gave Cu yields of 69-87% and Zn yields of 75-80% based on the contents in the ash.
|
|
| 21. |
- Tang, Jinfeng, 1984, et al.
(author)
-
Source analysis of municipal solid waste in a mega-city (Guangzhou): Challenges or opportunities?
- 2018
-
In: Waste Management and Research. - 1096-3669 .- 0734-242X. ; 36:12, s. 1166-1176
-
Journal article (peer-reviewed)abstract
- Rapid economic development accelerates the generation of municipal solid waste (MSW), and thereby calls for an effective and reliable waste management strategy. In the present work, we systematically investigated the status of MSW management in a mega-city of China (Guangzhou). The data were collected from literatures, government statistics and field sampling work. It can be found that a combination of waste sorting by individual residents and a necessary quantity of sanitation workers is one of the most feasible strategies to achieve a sustainable waste management. With implementation of that integrated strategy, approximately 0.03 million tons of metal, 0.24 million tons of paper, as well as 0.46 million tons of plastics can be recycled/recovered for further processing. A cost reduction of 70 million US$ is achieved in comparison with the un-optimized system due to the sale revenue of recyclable materials and the saving from waste disposal fees. The values of environmental assessment were expressed as environmental load units. The developed scenarios could decrease the environmental cost, namely, 0.66 million US$. Based on the studies, waste sorting is urgently needed in Guangzhou. However, to make the proposed strategy to be more economically feasible, the sorting should be performed individually as well as with public participation. The establishment of a win–win situation for all stakeholders is an effective path for the improvement of the integrated waste management system.
|
|
| 22. |
- Wang, Yan, et al.
(author)
-
Bimetallic hybrids modified with carbon nanotubes as cathode catalysts for microbial fuel cell: Effective oxygen reduction catalysis and inhibition of biofilm formation
- 2021
-
In: Journal of Power Sources. - Amsterdam, Netherlands : Elsevier. - 0378-7753 .- 1873-2755. ; 485
-
Journal article (peer-reviewed)abstract
- As a promising energy conversion equipment, the performance of microbial fuel cell (MFC) is affected by slow kinetics of oxygen reduction reaction (ORR). It is of great significance to explore electrocatalysts with high activity for sustainable energy applications. Herein, we synthesize the in-situ grown carbon nanotubes decorated electrocatalyst derived from copper-based metal organic frameworks (MOFs) co-doped with cobalt and nitrogen (CuCo@NCNTs) through straightforward immersion and pyrolysis process. The carbon nanotubes produced by metallic cobalt and high-activity bimetallic active sites formed by nitrogen doping enable CuCo@NCNTs to have the best oxygen reduction reaction (ORR) performance in alkaline electrolyte, with limit current density of 5.88 mA cm-2 and onset potential of 0.91 V (vs. RHE). Moreover, CuCo@NCNTs nanocomposite exhibits obvious antibacterial activity, and inhibiting the biofilm on cathode surface in antibacterial test and biomass quantification. The maximum power density (2757 mW m-3) of MFC modified with CuCo@NCNTs is even higher than Pt/C catalyst (2313 mW m-3). In short, CuCo@NCNTs nanocomposite can be an alternative cathode catalyst for MFC.
|
|
| 23. |
- Wartenburger, Richard, et al.
(author)
-
Evapotranspiration simulations in ISIMIP2a-Evaluation of spatio-temporal characteristics with a comprehensive ensemble of independent datasets
- 2018
-
In: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 13:7
-
Journal article (peer-reviewed)abstract
- Actual land evapotranspiration (ET) is a key component of the global hydrological cycle and an essential variable determining the evolution of hydrological extreme events under different climate change scenarios. However, recently available ET products show persistent uncertainties that are impeding a precise attribution of human-induced climate change. Here, we aim at comparing a range of independent global monthly land ET estimates with historical model simulations from the global water, agriculture, and biomes sectors participating in the second phase of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP2a). Among the independent estimates, we use the EartH2Observe Tier-1 dataset (E2O), two commonly used reanalyses, a pre-compiled ensemble product (LandFlux-EVAL), and an updated collection of recently published datasets that algorithmically derive ET from observations or observations-based estimates (diagnostic datasets). A cluster analysis is applied in order to identify spatio-temporal differences among all datasets and to thus identify factors that dominate overall uncertainties. The clustering is controlled by several factors including the model choice, the meteorological forcing used to drive the assessed models, the data category (models participating in the different sectors of ISIMIP2a, E2O models, diagnostic estimates, reanalysis-based estimates or composite products), the ET scheme, and the number of soil layers in the models. By using these factors to explain spatial and spatio-temporal variabilities in ET, we find that the model choice mostly dominates (24%-40% of variance explained), except for spatio-temporal patterns of total ET, where the forcing explains the largest fraction of the variance (29%). The most dominant clusters of datasets are further compared with individual diagnostic and reanalysis-based estimates to assess their representation of selected heat waves and droughts in the Great Plains, Central Europe and western Russia. Although most of the ET estimates capture these extreme events, the generally large spread among the entire ensemble indicates substantial uncertainties.
|
|
| 24. |
- YanHui, Fan, et al.
(author)
-
The rates and patterns of insertions, deletions and substitutions in mouse and rat inferred from introns
- 2008
-
In: Chinese Science Bulletin. - : Elsevier BV. - 1001-6538 .- 1861-9541 .- 2095-9273 .- 2095-9281. ; 53:18, s. 2813-2819
-
Journal article (peer-reviewed)abstract
- The rates and patterns of InDel (insertions and deletions) and substitution in rodent (mouse and rat) have been studied. The result reveals that deletions occur more frequently than insertions, and single nucleotide insertion and deletion are the most frequent in both mouse and rat. The frequencies of both deletions and insertions decrease rapidly with increasing InDels length, and the size distributions of both insertions and deletions can be described well by power-law. There are more AT-->G than GC-->AT substitutions in the introns of rat. However, there are more GC-->AT than AT-->GC substitutions in the introns in mouse. The deletion bias found in introns in mouse and rat supports the prediction that intron insertions are more deleterious than deletions because of reduced transcription and splicing efficiency. The patterns of substitution suggest that both composition and GC content are not equilibrium in the introns in rodents.
|
|
