Atmospheric PM2.5 and Depositions of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Kaohsiung Area, Southern Taiwan

The adsorption of the 17 toxic 2,3,7,8-substituted dioxin congeners onto graphite was investigated using a laboratoryscale fixed-bed adsorption system. First, the morphology and microstructure of graphite were characterized by Scanning Electron Microscopy and Brunauer-Emmer-Teller surface estimation. Removal efficiency of the 17 toxic PCDD/Fs varies from 89.31% to 99.96% and the amount adsorbed on graphite is a linear function of the inlet concentration of PCDD/Fs, as it was varied from 2.3-20.7 ng I-TEQ Nm -3 . Operating over 3 hours, it is observed that the saturation time of fixed-bed adsorbers is less when the inlet concentration is higher. The removal efficiency of dioxin depends on vapour pressure and rises strongly with increasing chlorine substitution number. Removal efficiencies strongly correlate with vapour pressure, with R 2 0.96 for PCDDs and 0.99 for PCDFs, respectively. The removal efficiency of dioxin decreases linearly as the temperature increased (R 2 = 0.99). Possibly, π-π interactions between PCDD/Fs and graphite sheets lead to a high adsorption capacity of dioxin. The high mesopores volume and pore structure of graphite are critical factors when adsorbing dioxin.

Section: The Effect Of Adsorption Temperature On the Removal Pcdd/fsmentioning

confidence: 92%

Section: The Effect Of Adsorption Temperature On the Removal Pcdd/fsmentioning

confidence: 99%

Experimental Study on PCDD/Fs Adsorption onto Nano-Graphite

Lin

et al. 2016

“…Such strong surge poses serious risks to both human health and the natural environment, given the considerable emissions of dust, and a host of organic and inorganic pollutants (Cheruiyot et al, 2016;Lee et al, 2016;Li et al, 2016a;Xu et al, 2018). During conventional cement production Thuong et al, 2014) polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) emerge at the level of 0.99 µg I-TEQ ton -1 clinker.…”

Section: Introductionmentioning

confidence: 99%

Suppression of PCDD/Fs by Raw Meal in Cement Kilns

Lin

Ji²,

Zhan

et al. 2018

Raw meal of the cement production process could probably suppress the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). In this study, these suppression effects were studied and compared during the co-processing of municipal solid waste (MSW) with conventional feed materials such as pure CaCO 3 , and pure CaO. A top suppression efficiency of 96% was achieved for a ratio of MSW to raw meal of 1:15. Moreover, NaCl and CuCl 2 were added to the mix of feed material and MSW, to reveal the impact of additional chlorine and cations on PCDD/F formation. Similarly, the raw meal was mixed with the kiln dust to investigate possible suppression effects of those PCDD/Fs formed through the precursor or the de novo synthesis at a temperature of 350°C. The raw meal suppressed the formation of PCDD/Fs from kiln dust. Furthermore, the raw meal could not suppress the formation of PCDD/Fs on mixtures of kiln dust and NaCl or CuCl 2 , which could be associated with a potential increase in the formation effects of PCDD/Fs on the raw meal. The results can help in potential decision-making on the applicability of certain cement kilns on the co-processing of MSW containing high levels of Cl and Cu.

“…Due to small-scale incinerator, incomplete incineration and high chlorine content in the waste feed, some toxic persistent organic pollutants are generated such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), chlorobenzenes (CBs), chlorophenols (CPs) and polychlorinated biphenyls (PCBs), etc. (Lee et al, 2003;Chen et al, 2013;Cheruiyot et al, 2015;Lee et al, 2016). The PCDD/F emission factors of hospital solid waste incinerator (HSWI) were about 1-2 orders higher than those of municipal solid waste incinerator (MSWI) (Lee et al, 2003;Cheruiyot et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…The principle of flotation is based on the differences in surface hydrophobicity between the particles. The hydrophobicity and lipophilicity nature of PCDD/Fs and other organic contaminants such as PAHs, CBs, CPs and PCBs makes them easy to float into the froths after flotation (Cheruiyot et al, 2015;Lee et al, 2016). The previous report indicated that the flotation process could be successfully applied to substantially decrease the amount of carbon constituents and PCDD/Fs in HSWI fly ash (Liu et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Reburning Treatment of the Froths Obtained after the Flotation of Incinerator Fly Ash

Wei

Liu²,

Liu

et al. 2017

Flotation has been proven to successfully remove most polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) and carbon constituents from hospital solid waste incinerator (HSWI) fly ash. The resultant froths contain large quantities of carbon constituents that can reburn in the incinerator. In this paper, the reburning behavior of froths at temperatures from 800°C to 1200°C was compared with that of HSWI fly ash. Results showed that the destruction efficiency of PCDD/Fs was higher in the froths than in the fly ash at the same reburning temperature. The destruction efficiencies of PCDD/Fs in the froths exceeded 98% at temperatures higher than 1000°C. The volatilization ratio of Pb, Zn, and Cu was lower in the froths than in the fly ash. Furthermore, reburning of the froths can achieve energy recovery of the carbon constituents. Therefore, flotation followed by reburning treatment in a combustion chamber could be a suitable process for the detoxification and reutilization of HSWI fly ash.