Simultaneous degradation and dechlorination of poly (vinyl chloride) by a combination of superheated steam and CaO catalyst/adsorbent

Nishibata, Haruka; Uddin, Md. Azhar; Kato, Yoshiei

doi:10.1016/j.polymdegradstab.2020.109225

Cited by 34 publications

(8 citation statements)

References 46 publications

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“…There are reports on the catalytic acceleration of the PVC waste dechlorination in the presence of various substances [ 114 , 118 , 119 , 120 , 121 , 122 ]. The process of dechlorination, by binding chlorine and HCl, is also influenced by additional substances, such as Na 2 CO 3 , KOH, NaOH, NH 3 ·H 2 O, CaO and NaHCO 3 [ 87 , 100 , 101 , 123 , 124 , 125 , 126 , 127 , 128 ].…”

Section: Pvc Recyclingmentioning

confidence: 99%

A Brief Review of Poly(Vinyl Chloride) (PVC) Recycling

2022

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Bearing in mind the aspiration of the world economy to create as complete a closed loop of raw materials and energy as possible, it is important to know the individual links in such a system and to systematise the knowledge. Polymer materials, especially poly(vinyl chloride) (PVC), are considered harmful to the environment by a large part of society. The work presents a literature review on mechanical and feedstock recycling. The advantages and disadvantages of various recycling methods and their development perspectives are presented. The general characteristics of PVC are also described. In conclusion, it is stated that there are currently high recycling possibilities for PVC material and that intensive work is underway on the development of feedstock recycling. Based on the literature review, it was found that PVC certainly meets the requirements for materials involved in the circular economy.

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Section: Pvc Recyclingmentioning

confidence: 99%

A Brief Review of Poly(Vinyl Chloride) (PVC) Recycling

2022

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“…Catalytic dehydrochlorination is one of the promising directions [ 10 ]. At the same time, dehydrochlorination of PVC under the action of bases or alkalies remains the main reaction for this purpose [ 13 , 14 , 15 , 16 , 17 , 18 ]. Thus, hydrothermal treatment of a PVC powder in 1% aqueous solutions of NaOH [ 13 ] or Cu(NO 3 ) 2 [ 14 , 15 ] at a temperature up to 240 °C and a corresponding pressure leads to the removal of 94% and 98% chlorine from PVC, respectively; high degrees of chlorine removal from PVC (95–97%) were also achieved upon heating (170 °C and 200 °C) of the mixtures of PVC powders and Zn or Ca oxides [ 16 , 17 ], which, being the bases, served as dehydrochlorinating agents.…”

Section: Introductionmentioning

confidence: 99%

Porous Carbon–Carbon Composite Materials Obtained by Alkaline Dehydrochlorination of Polyvinyl Chloride

et al. 2022

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Porous carbon–carbon composite materials (PCCCM) were synthesized by the alkaline dehydrochlorination of polyvinyl chloride solutions in dimethyl sulfoxide containing the modifying additives of a nanostructured component (NC): graphite oxide (GO), reduced graphite oxide (RGO) or nanoglobular carbon (NGC), with subsequent two-step thermal treatment of the obtained polyvinylene–NC composites (carbonization at 400 °C and carbon dioxide activation at 900 °C). The focus of the study was on the analysis and digital processing of transmission electron microscopy images to study local areas of carbon composite materials, as well as to determine the distances between graphene layers. TEM and low-temperature nitrogen adsorption studies revealed that the structure of the synthesized PCCCM can be considered as a porous carbon matrix in which either carbon nanoglobules (in the case of NGC) or carbon particles with the “crumpled sheet” morphology (in the case of GO or RGO used as the modifying additives) are distributed. Depending on the features of the introduced 5–7 wt.% nanostructured component, the fraction of mesopores was shown to vary from 11% to 46%, and SBET—from 791 to 1115 m2 g−1. The synthesis of PCCNC using graphite oxide and reduced graphite oxide as the modifying additives can be considered as a method for synthesizing a porous carbon material with the hierarchical structure containing both the micro- and meso/macropores. Such materials are widely applied and can serve as adsorbents, catalyst supports, elements of power storage systems, etc.

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“…Steam assisted low-temperature pyrolysis can enhance the dehydrochlorination reaction. 5,6 Recently, Nishibata et al 7 investigated dechlorination of PVC plastics using a combination of superheated steam and CaO to achieve a higher extent of dechlorination. Wet treatment in a glycol/NaOH mixture is also an effective method to remove chlorine instead of lowtemperature pyrolysis pretreatment.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Westerhout et al estimated that at least 2% of chlorine went to the next pyrolysis stage. Steam assisted low-temperature pyrolysis can enhance the dehydrochlorination reaction. , Recently, Nishibata et al investigated dechlorination of PVC plastics using a combination of superheated steam and CaO to achieve a higher extent of dechlorination. Wet treatment in a glycol/NaOH mixture is also an effective method to remove chlorine instead of low-temperature pyrolysis pretreatment. , Although these new technologies have been developed, capture of chlorine by solid adsorbents during pyrolysis or in subsequent upgrading plastic derived oil is still the dominant technology for reducing chlorine to the required criteria because of its easy operation and low cost …”

Section: Introductionmentioning

confidence: 99%

Understanding the Dechlorination of Chlorinated Hydrocarbons in the Pyrolysis of Mixed Plastics

Jiang

Monsalve²,

Clough

et al. 2021

ACS Sustainable Chem. Eng.

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The dechlorination of chlorine containing hydrocarbons in pyrolysis vapor is poorly understood.In order to shed new light on the dechlorination mechanism, a model mixture composing of isooctane doped with 2-chlorobutane, 2-chloroethylbenzene, and chlorobenzene was used to study the dechlorination of chlorinated hydrocarbons by alkali adsorption. These three chlorinated hydrocarbons were selected as they can be typically produced from the pyrolysis of mixed plastic waste containing polyvinyl chloride (PVC). The mixture is pumped continuously through a Na2CO3 or CaCO3/alumina bed, and GC-MS is used to identify the dechlorination products and to follow the dechlorination reactions. When chlorine is bonded to an aliphatic carbon with an adjacent aliphatic hydrogen, the chlorinated compound firstly undergoes a dehydrochlorination reaction to form HCl and olefins, and subsequently the HCl is reacted with the alkali in the absorbents. In our experiments, 2-chlorobutane is converted to 2-butene, and 2chloroethylbenzene is converted to styrene. The formation of HCl and subsequent reaction with

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Simultaneous degradation and dechlorination of poly (vinyl chloride) by a combination of superheated steam and CaO catalyst/adsorbent

Cited by 34 publications

References 46 publications

A Brief Review of Poly(Vinyl Chloride) (PVC) Recycling

A Brief Review of Poly(Vinyl Chloride) (PVC) Recycling

Porous Carbon–Carbon Composite Materials Obtained by Alkaline Dehydrochlorination of Polyvinyl Chloride

Understanding the Dechlorination of Chlorinated Hydrocarbons in the Pyrolysis of Mixed Plastics

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