Degradation of brominated flame retardant in computer housing plastic by supercritical fluids

Wang, Yanmin; Zhang, Fu-Shen

doi:10.1016/j.jhazmat.2011.12.055

Cited by 87 publications

(35 citation statements)

References 25 publications

(36 reference statements)

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“…Wath et al (2015) used two organic solvents (N-methyl-2-pyrrolidone (NMP) and dimethyl sulfoxide (DMSO)) as supercritical fluids for degradation of waste PCBs, obtaining better results for the debromination with NMP. Additionally, Wang and Zhang (2012) showed the excellent efficiencies obtained using different supercritical fluids (water (97.6%) > methanol (69.2%) > isopropanol (63.6%) > acetone (46.8%)) for the debromination of computer housing plastic at 400 o C for 60 minutes.…”

Section: Introductionmentioning

confidence: 91%

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

2017

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Degradation of brominated flame retardants present in printed circuit boards (PCBs) was tested using subcritical water in a high pressure reactor. Debromination experiments were carried out in a batch stirred reactor at three different temperatures (225 ºC, 250 ºC and 275 ºC) keeping a solid to liquid (S/L) ratio of PCB:water=1:5 during 180 min. Results indicated that debromination efficiency was increased with temperature (18.5 to 63.6% of bromine present in the original PCB was removed).Thermal decomposition of the debrominated materials was studied and compared with that of the original PCB. Thermogravimetric analyses were performed at three different heating rates (5, 10 and 20 K min -1 ), studying both the pyrolysis (inert atmosphere) and combustion (in air). Pyrolysis runs of the debrominated materials were also performed in a quartz horizontal laboratory furnace at 850 ºC, in order to study the emission of pollutants. More than 99% of the bromine was emitted in the form of HBr and Br 2 . Emissions of polycyclic aromatic hydrocarbons (PAHs) and bromophenols (BrPhs) decreased with the increase in the treatment temperature; naphthalene (10800 -18300 mg kg -1 original sample) and monobrominated phenols (12.8 -16.9 mg kg -1 original sample) were the most abundant compounds.

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Section: Introductionmentioning

confidence: 91%

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

2017

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“…In recent years, supercritical fluid (SCF) has been investigated as an environmentally friendly technology to solve environmental problems related with waste electrical and electronic equipment [17][18][19]. SCFs such as water [20], methanol [21] and acetone [22] have extraordinary properties (e.g. low viscosity, high mass transport coefficient, high diffusivity, and high solubility etc.)…”

Section: Introductionmentioning

confidence: 99%

Innovative leaching of cobalt and lithium from spent lithium-ion batteries and simultaneous dechlorination of polyvinyl chloride in subcritical water

Liu

Zhang

2016

Journal of Hazardous Materials

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h i g h l i g h t s• A co-treatment process for recovery of Co and Li and simultaneous detoxification of PVC in subcritical water was proposed.• PVC was used as a hydrochloric acid source.• More than 95% Co and nearly 98% Li were leached under the optimum conditions.• Neither corrosive acid nor reducing agent was used.• The co-treatment process has technical, economic and environmental benefits over the traditional recovery processes. a r t i c l e i n f o In this work, an effective and environmentally friendly process for the recovery of cobalt (Co) and lithium (Li) from spent lithium-ion batteries (LIBs) and simultaneously detoxification of polyvinyl chloride (PVC) in subcritical water was developed. Lithium cobalt oxide (LiCoO 2 ) power from spent LIBs and PVC were co-treated by subcritical water oxidation, in which PVC served as a hydrochloric acid source to promote metal leaching. The dechlorination of PVC and metal leaching was achieved simultaneously under subcritical water oxidation. More than 95% Co and nearly 98% Li were recovered under the optimum conditions: temperature 350• C, PVC/LiCoO 2 ratio 3:1, time 30 min, and a solid/liquid ratio 16:1 (g/L), respectively. Moreover, PVC was completely dechlorinated at temperatures above 350• C without any release of toxic chlorinated organic compounds. Assessment on economical and environmental impacts revealed that the PVC and LiCoO 2 subcritical co-treatment process had significant technical, economic and environmental benefits over the traditional hydrometallurgy and pyrometallurgy processes. This innovative co-treatment process is efficient, environmentally friendly and adequate for Co and Li recovery from spent LIBs and simultaneous dechlorination of PVC in subcritical water.

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“…In our previous works [12], supercritical fluids were employed for debromination and recovery of oil from waste plastic containing brominated flame retardant in computer housing, where the retardant was in additive type [13]. This type of brominated flame retardant could be quickly extracted by supercritical organic fluids.…”

Section: Introductionmentioning

confidence: 99%

Degradation of brominated epoxy resin and metal recovery from waste printed circuit boards through batch sub/supercritical water treatments

Xing

Zhang

2013

Chemical Engineering Journal

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123

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h i g h l i g h t s" This work provides an efficient and green approach for waste printed circuit boards recycling. " Debromination of brominated epoxy resins and recycling of metals was simultaneously achieved. " Brominated epoxy resins can be completely decomposed by sub/SCW treatments. " Glass fibers and copper foils in WPCBs were liberated and could be easily separated by crushing after sub/SCW treatment. a r t i c l e i n f o b s t r a c tWaste printed circuit boards (WPCBs) contain high amount of brominated flame retardants and heavy metals which may bring a series of environmental and health problems. In the present study, an effective and benign process using sub-and supercritical water (sub/SCW) to simultaneously degrade brominated epoxy resin and recover metals from WPCBs was developed. Experiments were performed in a batch-type reactor with temperatures ranging from 200 to 400°C, water adding amounts from 10 to 40 ml and holding times from 30 to 240 min. The results showed that brominated epoxy resins (BERs) could be quickly and efficiently decomposed under sub/SCW condition. The debromination rate was 97.8% by controlling the temperature, water adding amount and holding time at 400°C, 40 ml and 120 min, respectively. Most of the bromine was changed into HBr and around 97.7% was enriched in water. Meanwhile, bromine-free oil was obtained of which the main compositions were phenol (58.5%) and 4-(1-methylethyl)-phenol (21.7%). After the sub/SCW treatments, the glass fibers and copper foils in the residue can be easily liberated and recovered respectively. The copper recovery rate reached 98.11% in the purities of 96.74% (grain size >2.0 mm) and 92.74% (0.147-2.0 mm). This study provides an efficient and green approach for WPCBs recycling.

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Degradation of brominated flame retardant in computer housing plastic by supercritical fluids

Cited by 87 publications

References 25 publications

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

Emissions of brominated compounds and polycyclic aromatic hydrocarbons during pyrolysis of E-waste debrominated in subcritical water

Innovative leaching of cobalt and lithium from spent lithium-ion batteries and simultaneous dechlorination of polyvinyl chloride in subcritical water

Degradation of brominated epoxy resin and metal recovery from waste printed circuit boards through batch sub/supercritical water treatments

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