Desulfurization of Vulcanized Rubber Particles Using Biological and Couple Microwave-Chemical Methods

Valdés, Cecilia T.; Hernández, Camila; Morales-Vera, Rodrigo; Andler, Rodrigo

doi:10.3389/fenvs.2021.633165

Cited by 8 publications

(5 citation statements)

References 53 publications

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“…Their absorptions decrease in intensity for mixtures B, C, and D (the order being C < B < D) with an increase in the irradiation dose due to the decomposition of the vulcanization accelerators [ 59 ]. The strong absorption bands located between 1085 and 1080 cm −1 that are not found in the non-irradiated samples may be due to the vibrations of the S-O bonds formed as a result of the oxidative degradation reactions [ 13 ]. The oxidative degradation processes that take place at the irradiation dose of 450 kGy lead to the increase in these absorption bands in the order B < D < C < A.…”

Section: Resultsmentioning

confidence: 99%

“…In their case as well, with an increase in the irradiated dose, the absorptions are intensified in the order B < C < D < A as a result of the oxidative degradation. In the regions 920–975 cm −1 and 895–870 cm −1 , absorptions are recorded for the non-irradiated samples due to the presence of vinyl terminal groups (-CH=CH2) and double olefinic bond that binds the simple vinyl groups (C=CH 2 ) formed during vulcanization [ 13 , 63 ]. With an increase in the irradiation dose, these absorptions also increase due to the splitting/degradation reactions.…”

Section: Resultsmentioning

confidence: 99%

“…Biodegradation is carried out in the presence of specific microorganisms, and photodegradation is carried out by means of solar UV radiation and UV irradiation [ 12 ]; both methods are non-polluting but long-lasting. The use of microwaves is also described as a devulcanization treatment [ 13 , 14 ]. Therefore, all degradation methods require an input of external energy of a chemical, thermal, photochemical, or biological nature.…”

Section: Introductionmentioning

confidence: 99%

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Degradation by Electron Beam Irradiation of Some Elastomeric Composites Sulphur Vulcanized

et al. 2023

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Composites based on natural rubber and plasticized starch obtained by the conventional method of sulfur cross-linking using four types of vulcanization accelerators (Diphenyl guanidine, 2-Mercaptobenzothiazole, N-Cyclohexyl-2-benzothiazole sulfenamide, and Tetramethylthiuram disulfide) were irradiated with an electron beam in the dose range of 150 and 450 kGy for the purpose of degradation. The vulcanization accelerators were used in different percentages and combinations, resulting in four mixtures with different potential during the cross-linking process (synergistic, activator, or additive). The resulting composites were investigated before and after irradiation in order to establish a connection between the type of accelerator mixture, irradiation dose, and composite properties (gel fraction, cross-linking degree, water absorption, mass loss in water and toluene, mechanical properties, and structural and morphological properties). The results showed that the mixtures became sensitive at the irradiation dose of 300 kGy and at the irradiation dose of 450 kGy, and the consequences of the degradation processes were discussed.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Degradation by Electron Beam Irradiation of Some Elastomeric Composites Sulphur Vulcanized

et al. 2023

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“…However, there are few studies on the production process of desulfurized crumb rubber powder modified asphalt and the road performance of modified asphalt mixture. At present, the commonly used rubber desulfurization activation methods include heat treatment based on the thermal environment, a chemical method using chemical adjuvants, and a mechanochemical method using chemical adjuvants combined with mechanical force to accelerate the chemical reaction [ 27 , 35 , 36 ]. The mechanochemical method can effectively play the role of desulfurization activation of additives through rubber broken to increase the surface roughness and activity of rubber powder.…”

Section: Introductionmentioning

confidence: 99%

Effect of Desulfurization Process Variables on the Properties of Crumb Rubber Modified Asphalt

Zhang

Zhang²,

Chen³

et al. 2022

Polymers

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A large number of waste tires are in urgent need of effective treatment, and breaking waste tires into crumb rubber powder for modifying asphalt has been proved as a good idea to solve waste tires. Crumb rubber modified asphalt not only has good high and low temperature performance, durability, and aging resistance but can also reduce pavement noise and diseases, which has wide application prospects. In this study, crumb rubber powder was desulfurized by mechanochemical method to prepare desulfurized crumb rubber modified asphalt. During the desulfurization process of crumb rubber, the effects of desulfurization process variables including desulfurizer type, desulfurizer content, and desulfurization mixing temperature and time were considered, and then the physical properties of modified asphalt were tested. The test results showed that after mixing crumb rubber powder with desulfurizer, the viscosity of crumb rubber powder modified asphalt can be reduced. Moreover, the storage stability of crumb rubber powder modified asphalt could also be improved by mixing crumb rubber with desulfurizer. Based on the physical properties of crumb rubber powder modified asphalt, the desulfurization process of selected organic disulfide (OD) desulfurizer was optimized as follows: the OD desulfurizer content was 3%, the desulfurization mixing temperature was 160 °C, and the mixing time was 30 min. In addition, Fourier infrared spectroscopy analysis was carried out to explore the modification mechanism of desulfurized crumb rubber powder modified asphalt. There is no fracture and formation of chemical bonds, and the modification of asphalt by crumb rubber powder is mainly physical modification.

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“…They are also difficult to re-use or recycle. And the majority of them are just discarded in landfills [3][4][5]. Robust, economical, and easily scalable methods for converting rubber products or waste into by-products or composites that ideally can be reused are desperately needed.…”

Section: Introductionmentioning

confidence: 99%

Rubber Degrading Strains: Microtetraspora and Dactylosporangium

et al. 2021

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Rubber composed of highly unsaturated hydrocarbons, modified through addition of chemicals and vulcanization are widely used to date. However, the usage of rubber, faces many obstacles. These elastomeric materials are difficult to be re-used and recovered, leading to high post-consumer waste and vast environmental problems. Tyres, the major rubber waste source can take up to 80 years to naturally degrade. Experiments show that the latex clearing proteins (Lcp) found in Actinobacteria were reportedly critical for the initial oxidative cleavage of poly(cis-1,4-isoprene), the major polymeric unit of rubber. Although, more than 100 rubber degrading strains have been reported, only 8 Lcp proteins isolated from Nocardia (3), Gordonia (2), Streptomyces (1), Rhodococcus (1), and Solimonas (1) have been purified and biochemically characterized. Previous studies on rubber degrading strains and Lcp enzymes, implied that they are distinct. Following this, we aim to discover additional rubber degrading strains by randomly screening 940 Actinobacterial strains isolated from various locations in Sarawak on natural rubber (NR) latex agar. A total of 18 strains from 5 genera produced clearing zones on NR latex agar, and genes encoding Lcp were identified. We report here lcp genes from Microtetraspora sp. AC03309 (lcp1 and lcp2) and Dactylosporangium sp. AC04546 (lcp1, lcp2, lcp3), together with the predicted genes related to rubber degradation. In silico analysis suggested that Microtetraspora sp. AC03309 is a distinct species closely related to Microtetraspora glauca while Dactylosporangium sp. AC04546 is a species closely related to Dactylosporangium sucinum. Genome-based characterization allowed the establishment of the strains taxonomic position and provided insights into their metabolic potential especially in biodegradation of rubber. Morphological changes and the spectrophotometric detection of aldehyde and keto groups indicated the degradation of the original material in rubber samples incubated with the strains. This confirms the strains’ ability to utilize different rubber materials (fresh latex, NR product and vulcanized rubber) as the sole carbon source. Both strains exhibited different levels of biodegradation ability. Findings on tyre utilization capability by Dactylosporangium sp. AC04546 is of interest. The final aim is to find sustainable rubber treatment methods to treat rubber wastes.

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Desulfurization of Vulcanized Rubber Particles Using Biological and Couple Microwave-Chemical Methods

Cited by 8 publications

References 53 publications

Degradation by Electron Beam Irradiation of Some Elastomeric Composites Sulphur Vulcanized

Degradation by Electron Beam Irradiation of Some Elastomeric Composites Sulphur Vulcanized

Effect of Desulfurization Process Variables on the Properties of Crumb Rubber Modified Asphalt

Rubber Degrading Strains: Microtetraspora and Dactylosporangium

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