Characterization and spatiotemporal variations of fluorescent dissolved organic matter in leachate from old landfill-derived incineration residues and incombustible waste.

Dissolved organic matter (DOM) influences the bioavailability and behavior of trace metals and other pollutants in landfill leachate. This research characterized fluorescent dissolved organic matter (FDOM) in leachate from an old landfill in Japan during a 13-month investigation. We employed excitation-emission matrix (EEM) fluorescence spectroscopy with parallel factor analysis (PARAFAC) to deconvolute the FDOM complex mixture into three fluorophores: microbial humic-like (C1), terrestrial humic-like (C2), and tryptophan-like fluorophores (C3). These FDOM components were compared with findings from other studies of leachate in landfills with different waste compositions. The correlations among EEM-PARAFAC components, dissolved organic carbon (DOC) concentration, and ultraviolet-visible and fluorescence indices were evaluated. The FDOM in leachate varied spatially among old and extended leachate collected in the landfill and leachate treatment facility. The FDOM changed temporally and decreased markedly in August 2019, November 2019, and April 2020. The strong positive correlation between HIX and %C2 (r = 0.87, ρ = 0.91, p < 0.001)) implies that HIX may indicate the relative contribution of terrestrial humic-like components in landfill leachate. The Fmax of C1, C2, and C3 and the DOC concentration showed strong correlations among each other (r > 0.72, ρ > 0.78, p < 0.001) and positive correlations with leachate level (r > 0.41, p < 0.001), suggesting the importance of hydrological effects and leachate pump operation on FDOM.

Catalytic air oxidation of biogas slurry using Cu sub-nanocluster supported by mesoporous TiZrO4 and protected by SiO2 shell.

Biogas slurry, an inevitable outcome of anaerobic digestion (AD), is a treatment burden for urban environmental management. In this study, two kinds of biogas slurry (slurry J and slurry C), collected from the AD plants in Japan and China, were treated using novel TiZrO4 @Cu and TiZrO4 @Cu@SiO2 multilayered hollow spheres containing Cu sub-nanoclusters as the catalyst. The results showed that the chemical oxygen demand (COD) was removed by 63 % for slurry J and 44 % for slurry C after 5 h. The Cu sub-nanoclusters acted as co-catalysts and active centers, facilitating rapid electron transfer to oxygen molecules and forming highly reactive •O2- and •OH species (Use slurry J as the based solution). These free radicals cleaved the interconnecting bonds between benzene rings, disintegrated the ring structure, formed intermediate compounds such as n-hexylic acid, and ultimately mineralized organic pollutants in biogas slurry into CO2 and H2O. At the same time, TiZrO4 @Cu@SiO2 had excellent stability due to the protection of the SiO2 shell and reduced threefold Cu leaching than TiZrO4 @Cu. The COD removal rate was always 60 % in six cycles in the slurry J. The new catalyst ensured the high performance of catalytic air oxidation at low temperatures, which has significant potential as an environmentally friendly and energy-saving method for organic wastewater treatment.

Valorization of fat balls and primary scum from wastewater treatment: a promising renewable lipid feedstock for biodiesel production.

We investigated the potential of waste materials from wastewater treatment plants (WWTPs) to serve as an alternative lipid feedstock for biodiesel production. The average lipid recoveries from fat balls (46.4%) and primary scum (49.5-54.5%) were higher than the lipid recovery of primary sludge (15.8-16.4%). The yield of biodiesel produced from the extracted lipids ranged from 5.7 to 20.1%. There were considerable site- and season-dependent variations in the characteristics of the lipid waste materials. Radiocarbon analysis indicated the presence of fossil-derived carbon (26.0-42.0%) in the biodiesel obtained from wastewater lipids. Finally, we estimated the potential for biodiesel production from WWTP-derived lipids; about 333.0 metric tons of biodiesel per year could be produced from fat balls and primary scum in Japan. The results indicate that lipid-rich materials from WWTPs represent a valuable alternative feedstock for biodiesel production.

Atomically dispersed copper sites on titanium zirconium oxide accelerate the simultaneous oxidative removal of organic carbon and ammonia from landfill leachate.

Landfill leachate is a refractory wastewater. Low-temperature catalytic air oxidation (LTCAO) has shown considerable potential for leachate treatment owing to its green and simple operation, but the simultaneous removal of chemical oxygen demand (COD) and ammonia from leachate remains challenging. Herein, TiZrO4 @CuSA hollow spheres with high-loading single-atom Cu were synthesized using isovolumic vacuum impregnation and co-calcination methods, and the catalyst was applied to the LTCAO treatment of real leachate. Consequently, the removal rate of UV254 reached 66% at 90 °C within 5 h, while that for COD was 88%. Simultaneously, the NH3/NH4+ (33.5 mg/L, 100 wt%) in the leachate was oxidized to N2 (88.2 wt%), NO2--N (11.0 wt%), and NO3--N (0.3 wt%) owing to the effect of free radicals. The single-atom Cu co-catalyst in TiZrO4 @CuSA exhibited a localized surface plasmon resonance effect at the active center, which could quickly transfer electrons to O2 in water to form O2.- with a high activation efficiency. The degradation products were determined and the deduced pathway was as follows: the bonds joining benzene rings were first broken, and then the ring structure was further opened to produce acetic acid and other simple organic macromolecules, which were finally mineralized to CO2 and H2O.

Effects of water-coal interactions on coal mine water quality in China: a lixiviation experiment and actual water quality investigation.

Water-coal interactions are dominant factors that affect water quality in coal mines. Using lixiviation, the effects of water-coal interactions on pH, salinity, and hazardous elemental enrichment in coal mine water and associated trends were simulated and analyzed. The salinity and hazardous element contents were low in the alkaline solution filtrate. However, the salinity and contents of hazardous elements (As, Cr, Zn, Cu, Mn, Co, Ni, Cd, Pb, U, and Be) in acid solution filtrate increased significantly with a decrease in pH. The pH of the solution filtrate was affected by the mineral composition of the coal, wherein the pyrite content could generally determine the pH. In addition, the spatial distribution and utilization potential of coal mine water quality in China was determined based on water quality data surveys. For water-deficient regions in northern China, particularly in the northwest, the local mine water had high salinity, a high pH, and a low content of hazardous elements; therefore, the reuse of mine water for water consumption is feasible. Conversely, the mine water in the southwest region had high salinity and a low pH and was enriched in harmful elements with potential ecological and health risks. The actual water quality characteristics of the coal mine water matched the results of the laboratory simulation analysis, confirming the effect from water-coal interactions. This work provides a reference for understanding the determinants of coal mine water quality and the potential for water environment protection.

PCDD/Fs and heavy metals in the vicinity of landfill used for MSWI fly ash disposal: Pollutant distribution and environmental impact assessment.

This study focused on the syngenetic control of polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/Fs) and heavy metals by field stabilization/solidification (S/S) treatment for municipal solid waste incineration fly ash (MSWIFA) and multi-step leachate treatment. Modified European Community Bureau of Reference (BCR) speciation analysis and risk assessment code (RAC) revealed the medium environment risk of Cd and Mn, indicating the necessity of S/S treatment for MSWIFA. S/S treatment significantly declined the mass/toxic concentrations of PCDD/Fs (i.e., from 7.21 to 4.25 µg/kg; from 0.32 to 0.20 µg I-TEQ/kg) and heavy metals in MSWIFA due to chemical fixation and dilution effect. The S/S mechanism of sodium dimethyldithiocarbamate (SDD) and cement was decreasing heavy metals in the mild acid-soluble fraction to reduce their mobility and bioavailability. Oxidation treatment of leachate reduced the PCDD/F concentration from 49.10 to 28.71 pg/L (i.e., from 1.60 to 0.98 pg I-TEQ/L) by suspension absorption or NaClO oxidation decomposition, whereas a so-called "memory effect" phenomena in the subsequent procedures (adsorption, press filtration, flocculating settling, slurry separation, and carbon filtration) increased it back to 38.60 pg/L (1.66 pg I-TEQ/L). Moreover, the multi-step leachate treatment also effectively reduced the concentrations of heavy metals to 1-4 orders of magnitude lower than the national emission standards. Furthermore, the PCDD/Fs and heavy metals in other multiple media (soil, landfill leachate, groundwater, and river water) and their spatial distribution characteristics site were also investigated. No evidence showed any influence of the landfill on the surrounding liquid media. The slightly higher concentration of PCDD/Fs in the soil samples was ascribed to other waste management processes (transportation and unloading) or other local source (hazardous incineration plant). Therefore, proper management of landfills and leachate has a negligible effect on the surrounding environment.

Co-incineration effect of sewage sludge and municipal solid waste on the behavior of heavy metals by phosphorus.

The effects of sewage sludge phosphorus (P) content on heavy metal behavior during co-incineration of sewage sludge and municipal solid waste (MSW) were evaluated. Thermogravimetric differential thermal analysis revealed that MSW incineration was mainly caused by organic matter and fixed carbon, while sewage sludge incineration was caused by volatile matter. During co-incineration, the peak weight loss at 460 °C shifted to slightly higher temperatures and the sludge ratio increased, indicating that interaction effects during co-incineration delayed pyrolysis and polymer/fixed carbon incineration. The residual heavy metal ratios after mono-incineration of sewage sludge were higher than those after MSW mono-incineration. The Cl content of MSW (0.757%) was much higher than that of sewage sludge (0.068%), which resulted in the conversion of heavy metals into metal chlorides and then volatilized during MSW mono-incineration. A synergistic effect of co-incineration was evident for Cu, but not for lead (Pb) or cadmium (Cd). X-ray absorption fine structure (XAFS) measurement revealed that Cu in MSW ash was in the form of CuO(s), but was Cu3(PO4)2 in sewage sludge and co-incineration ashes. CuO(s) is relatively unstable and may be transformed to CuO(g) or CuCl(s) before volatilizing at high temperature or in the presence of Cl. Phosphorus has the effect of stabilizing Cu in sewage sludge during co-incineration.

Effective Separation and Recovery of Manganese and Potassium from Biomass Ash by Solvent Extraction.

Manganese (Mn) is considered an important, energy-critical metal due to its leading role in the production of electrochemical energy storage devices. One valuable source of Mn is hyperaccumulator plants used for the phytoremediation of contaminated soil. In this study, stems and leaves of ginger (Zingiber officinale), which accumulate Mn at moderate levels (∼0.2 wt %) and potassium (K) at high levels (>5 wt %), were analyzed to assess the potential of recovering metals from this plant. The extraction behaviors of Mn and K were studied using raw and ash samples (100-600 °C). It was crucial to set an appropriate incineration temperature (300 °C) to selectively extract K (∼96%) and Mn (∼90%) using water and nitric acid over two consecutive steps. Additionally, citric acid, a cost-effective and environmentally friendly solvent, was just as effective (∼85%) as nitric acid in extracting Mn. X-ray absorbance near-edge spectroscopy and X-ray diffraction analysis of the ash before and after extractions were applied to elucidate the extraction mechanism. The results revealed that selective extraction of both compounds was possible due to the change in the oxidative state of Mn(II) (soluble in water) into Mn(III) and Mn(IV) (insoluble in water) during sample incineration. Simultaneously, there were complex reactions associated with the changes within potassium carbonate compounds; however, these did not affect the K extraction efficiency.

Developing a dataset for the expected anthropogenic mercury release in China in response to the Minamata convention on mercury.

This paper contains supplementary data in support of a research paper published [1] regarding the expected anthropogenic mercury release in China in response to the Minamata Convention on Mercury (MCM). The dataset provided within this article contains a set of excel spreadsheets. Each spreadsheet contains filtered (collected) and analysed data, i.e., parameters, collected data, calculated and summarized results for mercury distribution by the category of mineral production, intentional uses, secondary metal production, extraction and combustion, and waste treatment in a specific year. The collected (filtered) data in this article consist of the input factor (IF), activity rate data (ARD), output scenario (OS), initial distribution factor (iDF), and redistribution factor (rDF). IF was from the default IF in the United Nations Environment Programme (UNEP) Toolkit Level 2 and published scientific papers. ARD was obtained from the U.S. Geological Survey database, China Statistical Yearbooks, and published scientific papers. The OS content was from the default OS in the UNEP Toolkit Level 2 and published scientific papers. iDF was from the default distribution factor (DF) in the UNEP Toolkit Level 2 and published scientific papers. rDF was from published scientific paper. The mercury input was calculated using IF and ARD. The mercury release to different media in the initial distribution step was calculated using the mercury input and iDF. The release of mercury to the final sinks in the redistribution step was calculated using the amount of sector-specific treatment/disposal, product or by-product, and rDF. The dataset with combination of the collected (filtered) and analyzed data can contribute to an understanding of differences in anthropogenic mercury release before and after implementation of the MCM, especially considering technology transformation in China. Government policymakers involved in hazardous waste management, especially those working on MCM, and engineers and scientists interested in hazardous waste management may benefit from these data. The data can be used for identifying the environmental impact of anthropogenic mercury release before and after the MCM in China. The data can facilitate the creation of strategic management policies for mercury as the MCM is implemented in China.

The application of multiple advanced chloride removal methods to synthesized Friedel's salt and municipal solid waste incineration bottom ash.

To recycle municipal solid waste incineration bottom ash as a cement raw material, it is important to reduce the Cl concentration in the ash. However, the reduction of chlorides by washing only has limited success due to the presence of insoluble Friedel's salt (FS) in the ash. Although some studies on the decomposition of FS and the application of advanced chloride removal methods to bottom ash have been reported, few studies have compared the effects of different removal methods. Moreover, due to the complex ash composition, it is also necessary to compare the effects on different ashes and pure FS. Therefore, in this study, we applied five advanced chloride removal methods to synthesized FS and two types of bottom ash (FS-High and FS-Low), and compared the effects. For both FS and bottom ash, all methods promoted chloride dissolution more than washing only. For FS, aging was the most effective method, with a Cl removal ratio of 73%. In contrast, for ash FS-High, aging increased the Cl removal ratio to 80% and decreased the Cl content to 2800 mg/kg. The FS-derived peak observed in an X-ray diffraction analysis disappeared following aging. For ash FS-Low, acid washing increased the Cl removal ratio to 64% and decreased the Cl content to 1800 mg/kg. The treatment with the highest removal ratio in each ash had the lowest pH. There was a significant correlation between pH and the Cl removal effect. The Cl remaining after the application of the methods was likely associated with Na.

Mercury emission profile for the torrefaction of sewage sludge at a full-scale plant and application of polymer sorbent.

We evaluated mercury (Hg) behavior in a full-scale sewage sludge torrefaction plant with a capacity of 150 wet tons/day, which operates under a nitrogen atmosphere at a temperature range of 250-350 °C. Thermodynamic calculations and monitoring results show that elemental Hg (Hg0) was the dominant species in both the pyrolysis gas during the torrefaction stage and in the flue gas from downstream air pollution control devices. A wet scrubber (WS) effectively removed oxidized Hg from the flue gas and moved Hg to wastewater, and an electrostatic precipitator (ESP) removed significant particulate-bound Hg but showed a limited capacity for overall Hg removal. Hg bound to total suspended solids had a much higher concentration than that of dissolved Hg in wastewater. Total suspended solid removal from wastewater is therefore recommended to reduce Hg discharge. Existing air pollution control devices, which consist of a cyclone, WS, and ESP, are not sufficient for Hg removal due to the poor Hg0 removal performance of the WS and ESP; a further Hg0 removal unit is necessary. A commercial packed tower with sorbent polymer catalyst composite material was effective in removing Hg (83.3%) during sludge torrefaction.

Liquefied dimethyl ether based multi-stage extraction for high efficient oil recovery from spent bleaching clay.

With the increasing production of spent bleaching clay (SBC), the recovery of the waste oil in SBC is becoming an important and urgent needs for our environment and economy. In this research, we have developed a new effective recovery technique to recover oil from SBC by use of liquefied dimethyl ether (DME). Over 65 wt% oil and 81% wt.% oil are efficiently recovered from SBC under equilibrium single-stage extraction conditions and multi-stage extraction conditions, respectively based on the systematically investigation to the effects of the DME/SBC ratio, extraction time, stirring speed and extraction stage number on oil recovery via a batch extractor. Compared with using other extraction solvents, the extraction solvent DME can be reused without heating and therefore significantly reduce the energy consumption during the oil recovery process. In addition, the quantitative oil extraction relationship is derived from the adsorption equilibrium model and is well verified by experimental results. The results show a great potential for using this oil recovery technique in SBC as well as in the large amount of oily sludge and oil sands.

Microalgae preparation and lipid extraction by subcritical dimethyl ether.

Biodiesel produced from microalgae is a potential alternative due to the high growth rate of microalgae, the possibility of using nonarable land, and high lipid accumulation rate. Microalgae cultivation, cell harvesting and disruption are the important steps before lipid extraction for the biodiesel. In the co-submission article, the details of the whole process cannot be clearly explained. In this regard, we present the details of methods on parameter of photo-bioreactor for cultivating microalgae, flocculation tests to determine optimal flocculant dosage in harvesting, parameter of Dimethyl ether (DME) subcritical extraction device and full-factorial design for investigating the influence of extraction time, initial water content and DME dosage on the extraction performance. It will allow researchers to reproduce these experiments. • The method shows a cell disruption assisted lipid extraction by subcritical dimethyl ether. • Model is built from full-factorial design to investigate multi-factor influence. • Differential scanning calorimetry can be applicable to measure free water content.

Dechlorination of short-chain chlorinated paraffins by the metal sodium dispersion method.

Short-chain chlorinated paraffins (SCCPs) are listed in Annex A (elimination) of the Stockholm Convention on persistent organic pollutants, and products containing SCCPs require detoxification. In the present study, the metal sodium (Na) dispersion method was applied to a wax sample containing SCCPs (58%, C10-C13 and Cl5-Cl9) to assess the dechlorination effect. Effective dechlorination of SCCPs was confirmed using 2-L and 20-L reaction systems. The initial concentrations of the wax (5, 10, 20, 30%), reaction time (10, 30, 60, 120, 180 min), and the ratios of the amount of Na dispersion and the initial amount of the wax containing SCCPs (Na/wax ratios; 3.9, 4.4, 5.2) were tested. The destruction efficiency of SCCPs was over 99.999% after 10 min of reaction at 90 °C under several conditions. The initial concentrations of the wax and the Na/wax ratios did not affect the results. The ultralow SCCP contents in exhaust gas from the reaction tank demonstrated a destruction removal efficiency of over 99.999999%. Trace levels of polychlorinated dibenzo-p-dioxins and furans, dioxin-like polychlorinated biphenyls, hexachlorobenzene, and pentachlorobenzene in the wax sample and treated materials (oil, water, and gas) met various regulatory values or exhibited the same levels as the environmental background. After dechlorination of the SCCPs, the main reaction products in the reaction liquid and final oil phase were identified as aliphatic compounds. The metal Na dispersion method was found to be an effective and decontaminated destruction technique for application to SCCPs in liquid-like samples with no formation of hazardous organic byproducts.

Effect of pH on the performance of an acidic biotrickling filter for simultaneous removal of H2S and siloxane from biogas.

Acidic biotrickling filters (BTF) can be used for simultaneous removal of hydrogen sulfide (H2S) and siloxane from biogas. In this study, the performance of a BTF under different acidic pH conditions was investigated. The removal profile of H2S showed that 90% of H2S removal was achieved during the first 0.4 m of BTF height with down-flow biogas. Decamethylcyclopentasiloxane (D5) removal decreased from 34.5% to 15.6% when the pH increased from 0.88 to 3.98. Furthermore, the high partition coefficient of D5 obtained in under higher pH condition was attributed to the higher total ionic strength resulting from the addition of sodium hydroxide solution and mineral medium. The linear increase in D5 removal with the mass transfer coefficient (kL) indicated that the acidic recycling liquid accelerated the mass transfer of D5 in the BTF. Therefore, the lower partition coefficient and higher kL under acidic pH conditions lead to the efficient removal of D5. However, the highly acidic pH 0.9 blocked mass transfer of H2S and O2 gases to the recycling liquid. Low sulfur oxidation activity and low Acidithiobacillus sp. content also deteriorated the biodegradation of H2S. Operating the BTF at pH 1.2 was optimal for simultaneously removing H2S and siloxane.

Influence of water content and cell disruption on lipid extraction using subcritical dimethyl ether in wet microalgae.

Subcritical dimethyl ether, a green solvent, was used to extract lipids from microalgae. The effect of the water content on the process was firstly investigated. Secondly, microalgal samples were subjected to five cell disruptions, and the effects on raw lipid and fatty acid methyl ester, and its profile were evaluated. Among them, heating, microwave, and ultrasonic treatments greatly improved extraction. Mechanism analysis revealed the improvements by the three treatments were due to increased cell wall permeability rather than to complete cell disruption. After the extraction, microalgal cells with lipid being well-extracted were shriveled with extensive surface folds, indicating a loss of intracellular substances, but the cell structure was undamaged. As for dewatering performance, extraction process removed almost all of the free water but left bound water. Finally, the potential of the residues after lipid extraction to serve as solid fuel was evaluated by combustion characteristics and heating value calculation.

Mitigation of bromine-containing products during pyrolysis of polycarbonate-based tetrabromobisphenol A in the presence of copper(I) oxide.

Polycarbonate (PC) is an engineering thermoplastic that is widely used in electrical and electronic equipment. This plastic often contains tetrabromobisphenol A (TBBA), the most common brominated flame retardant. Thermal degradation of the PC-TBBA leads to generation of numerous bromo-organic products in the pyrolytic oil, hindering its appropriate utilization, as well as corrosive hydrogen bromide gas. The purpose of this study was to experimentally investigate and compare the pyrolysis products of PC-TBBA and PC-TBBA + Cu2O at various temperatures, with an emphasis on the yield and distribution of brominated compounds. In pyrolysis of PC-TBBA + Cu2O, at the maximum degradation temperature (600 °C), as much as 86% of total Br was trapped in the residue, while 3% and 11% were distributed in the condensate and gas fractions, respectively. In contrast, the distribution of Br from non-catalytic pyrolysis of PC-TBBA (600 °C) was 0.5% residue, 40% condensate, and 60% gas. The results of this study revealed that in the presence of Cu2O, organo-bromine products were most likely involved in Ullman-type coupling reactions, leading to early cross-linking of the polymer network that efficiently hinders their vaporization. HBr in the gas fraction was suppressed due to effective fixation of bromine in residue in the form of CuBr.

Effective lipid extraction from undewatered microalgae liquid using subcritical dimethyl ether.

BACKGROUND: Recent studies of lipid extraction from microalgae have focused primarily on dewatered or dried samples, and the processes are simple with high lipid yield. Yet, the dewatering with drying step is energy intensive, which makes the energy input during the lipid production more than energy output from obtained lipid. Thus, exploring an extraction technique for just a thickened sample without the dewatering, drying and auxiliary operation (such as cell disruption) is very significant. Whereas lipid extraction from the thickened microalgae is complicated by the high water content involved, and traditional solvent, hence, cannot work well. Dimethyl ether (DME), a green solvent, featuring a high affinity for both water and organic compounds with an ability to penetrate the cell walls has the potential to achieve this goal. RESULTS: This study investigated an energy-saving method for lipid extraction using DME as the solvent with an entrainer solution (ethanol and acetone) for flocculation-thickened microalgae. Extraction efficiency was evaluated in terms of extraction time, DME dosage, entrainer dosage, and ethanol:acetone ratio. Optimal extraction occurred after 30 min using 4.2 mL DME per 1 mL microalgae, with an entrainer dosage of 8% at 1:2 ethanol:acetone. Raw lipid yields and its lipid component (represented by fatty acid methyl ester) contents were compared against those of common extraction methods (Bligh and Dryer, and Soxhlet). Thermal gravimetry/differential thermal analysis, Fourier-transform infrared spectroscopy, and C/H/N elemental analyses were used to examine differences in lipids extracted using each of the evaluated methods. Considering influence of trace metals on biodiesel utilization, inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectroscopy analyses were used to quantify trace metals in the extracted raw lipids, which revealed relatively high concentrations of Mg, Na, K, and Fe. CONCLUSIONS: Our DME-based method recovered 26.4% of total raw lipids and 54.4% of total fatty acid methyl esters at first extraction with remnants being recovered by a 2nd extraction. In additional, the DME-based approach was more economical than other methods, because it enabled simultaneous dewatering with lipid extraction and no cell disruption was required. The trace metals of raw lipids indicated a purification demand in subsequent refining process.

Bromination of Carbon and Formation of PBDD/Fs by Copper Bromide in Oxidative Thermal Process.

Brominated aromatic compounds are unintentionally generated during various thermal processes, including municipal solid waste incineration, electric-waste open burning, and secondary copper smelting. Copper (Cu) plays an important role in the formation of brominated aromatic compounds. In the present study, the thermochemical behaviors of Cu and Br in model samples, including copper bromide (CuBr2) and activated carbon, were studied using in situ X-ray absorption near-edge structure (XANES) and thermogravimetry. Quantification of polybrominated dibenzo-p-dioxins/furans (PBDD/Fs) was also conducted by gas chromatograph-high resolution mass spectrometer. Three key reactions were identified: (i) the reduction of CuBr2 to CuBr (room temperature to 300 °C), (ii) the generation of Br bonded with aromatic carbon (150-350 °C), and (iii) the oxidation of copper (>350 °C). Maximum amounts of PBDD/Fs were found in residual solid phase after heating at 300 °C. The analytical results indicated the direct bromination of aromatic carbon by the debromination of copper bromides (I, II) and that CuBr and CuO acted as catalysts in the oxidation of the carbon matrix. The bromination mechanisms revealed in this study are essential to the de novo formation of PBDD/Fs and other brominated aromatic compounds.