The continuous depolymerization of filled polytetrafluoroethylene with a continuous process

Walt, I.J. van der; Grunenburg, A. T.; Nel, J.T.; Maluleke, G. G.; Bruinsma, O.S.L.

doi:10.1002/app.27380

Cited by 8 publications

(4 citation statements)

References 9 publications

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“…7 However, the manufacture of various PTFE products causes the generation of a large amount of waste. [8][9][10] Hence, studies on the degradation of waste PTFE materials are considered a matter of considerable importance. [11][12][13][14][15][16][17] Hlavaty and Kavan found that PTFE could react with alkali metals in organic solvents and produce highly reactive polyynes and metal fluorides.…”

Section: Introductionmentioning

confidence: 99%

Molybdenum oxide nanoparticles: preparation, characterization, and application in heterogeneous catalysis

et al. 2011

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An adduct behaviour of ammonium molybdate tetrahydarte (AMT) with polytetrafluoroethylene (PTFE) resulted in three significant benefits: (a) a much lower degradation temperature (DT m , 82 K) of the PTFE in the adduct and a much lower final residual mass (DRM, 39%) of the adduct compared to the theoretical prediction, (b) the formation of MoO 3 and MoO 2 nanoparticles, and (c) the shuttleshaped MoO 2 nanoparticles coated with graphite exhibits superior soft magnetic property. The much earlier degradation suggested that there was a strong mutual effect between AMT and PTFE. The much lower residual mass implied that the intervention of a chemical reaction was responsible for the effect in nitrogen. Actually, Raman spectra revealed that the adducted PTFE was degraded into a graphite structure at this atmosphere, and the presence of the graphite layer led to the reduction of AMT into shuttle-shaped MoO 2 nanoparticles at 837 K to a complete extent. Controlled sintering measurements in air indicated that the AMT in the presence of PTFE produced a-MoO 3 nanoparticles, instead of MoO 2 . Further, our results indicated that the MoO 3 nanoparticles obtained had a positive response to the heterogeneous catalytic oxidation of thiophene in the presence of hydrogen peroxide. We believe that the present work is not only of relevance for applications in the degradation of polymer materials, but also will attract the attention of many groups studying the preparation and magnetic properties of transition metal oxide nanoparticles and their practical application in heterogeneous catalytic reactions.

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Section: Introductionmentioning

confidence: 99%

Molybdenum oxide nanoparticles: preparation, characterization, and application in heterogeneous catalysis

et al. 2011

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“…[555] Continuous depolymerization was demonstrated for filled PTFE. [556,557] As polyolefins are inert, their back-to-monomer recycling is challenging. State-of-the-art thermal cracking of polyolefins produces complex mixtures of low-molecular-weight alkanes and alkenes together with aromatics that require separate refining, to convert pyrolysis oil into olefin monomers.…”

Section: Back-to-monomer Molecular Recyclingmentioning

confidence: 99%

Closing the Carbon Loop in the Circular Plastics Economy

Schirmeister

Mülhaupt

2022

Macromol. Rapid Commun.

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Today, plastics are ubiquitous in everyday life, problem solvers of modern technologies, and crucial for sustainable development. Yet the surge in global demand for plastics of the growing world population has triggered a tidal wave of plastic debris in the environment. Moving from a linear to a zero‐waste and carbon‐neutral circular plastic economy is vital for the future of the planet. Taming the plastic waste flood requires closing the carbon loop through plastic reuse, mechanical and molecular recycling, carbon capture, and use of the greenhouse gas carbon dioxide. In the quest for eco‐friendly products, plastics do not need to be reinvented but tuned for reuse and recycling. Their full potential must be exploited regarding energy, resource, and eco‐efficiency, waste prevention, circular economy, climate change mitigation, and lowering environmental pollution. Biodegradation holds promise for composting and bio‐feedstock recovery, but it is neither the Holy Grail of circular plastics economy nor a panacea for plastic littering. As an alternative to mechanical downcycling, molecular recycling enables both closed‐loop recovery of virgin plastics and open‐loop valorization, producing hydrogen, fuels, refinery feeds, lubricants, chemicals, and carbonaceous materials. Closing the carbon loop does not create a Perpetuum Mobile and requires renewable energy to achieve sustainability.

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“…Likewise with NRe, if NRe ≥ 2000 it will cause the flow to become turbulent so that the previously formed flocs will break and it becomes difficult to settle in the settling zone of the sedimentation unit. According to Van der Walt (2008), flow conditions must be considered to obtain an effective settling velocity. The settling of solid particles and their removal efficiency depends on the flow conditions.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Cone Area Variations on the Continuous Discharges Flow (CDF) Method Sedimentation Unit as a New Method for Raw Water Turbidity Removal

Ridwan,

Afrianita,

Putri

et al. 2023

J. Ilmu Lingk.

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The Sedimentation Unit Continuous Discharges Flow (CDF) method is a modification by adding a continuous and controlled discharge flow as a net force acting on the particles to increase the efficiency of turbidity removal by applying the principle of a leaky tank at the bottom of the settling zone. The production capacity of the sedimentation unit using the CDF method is reduced due to the CDF flow of 6% of the flow rate so it needs to be recirculated. This study aims to maintain the production flow rate of the system and increase the efficiency of turbidity removal by recirculating the CDF flow. The research reactor consisted of a coagulation unit, flocculation unit, and sedimentation method using 6% CDF with a flow rate of 240 L/hour and 360 L/hour, and variations in the recirculation flow of 6% CDF to the flocculation unit were 0%, 25%, 50%, 75%, and 100 %. The sedimentation detention time at a flow rate of 240 L/hour and 360 L/hour was 90 minutes and 60 minutes, respectively. Research on a laboratory scale with raw water turbidity of 25,536 NTU. The results showed that the greater the CDF flow recirculation value, the higher the turbidity removal efficiency. Rank Spearman analysis, the correlation value of the CDF flow recirculation value to the efficiency of removal of turbidity is 0.980 and the significance value is 0.00 which means strong and significant. The highest turbidity removal efficiency was achieved at the 100% CDF flow recirculation value, ie at 240 L/hour flow rate was 87.21% with final turbidity 3.267 NTU, while at 360 L/hour flow rate was 82.50% with final turbidity 4,528 NTU. Uprating the flow rate in the experiment was able to produce a final turbidity value that met the drinking water quality standard, which was 5 NTU

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The continuous depolymerization of filled polytetrafluoroethylene with a continuous process

Cited by 8 publications

References 9 publications

Molybdenum oxide nanoparticles: preparation, characterization, and application in heterogeneous catalysis

Molybdenum oxide nanoparticles: preparation, characterization, and application in heterogeneous catalysis

Closing the Carbon Loop in the Circular Plastics Economy

The Effect of Cone Area Variations on the Continuous Discharges Flow (CDF) Method Sedimentation Unit as a New Method for Raw Water Turbidity Removal

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