Low-Temperature Thermal Degradation of Disinfected COVID-19 Non-Woven Polypropylene—Based Isolation Gown Wastes into Carbonaceous Char

Yields of carbonaceous char with a high surface area were enhanced by decreasing the temperature to improve the conversion of hazardous plastic polypropylene (PP), the major component in abundantly used isolation gowns. This study applied pyrolysis with different low pyrolytic temperatures to convert disinfected PP-based isolation gown waste (PP-IG) into an optimised amount of char yields. A batch reactor with a horizontal furnace was used to mediate the thermal decomposition of PP-IG. Enhanced surface area and porosity value of PP-IG derived char were obtained via an optimised slow pyrolysis approach. The results showed that the amount of yielded char was inversely proportional to the temperature. This process relied heavily on the process parameters, especially pyrolytic temperature. Additionally, as the heating rate decreased, as well as longer isothermal residence time, the char yields were increased. Optimised temperature for maximum char yields was recorded. The enhanced SBET values for the char and its pore volume were collected, ~24 m2 g−1 and ~0.08 cm3 g−1, respectively. The char obtained at higher temperatures display higher volatilisation and carbonisation. These findings are beneficial for the utilisation of this pyrolysis model in plastic waste management and conversion of PP-IG waste into char for further activated carbon and fuel briquettes applications, with the enhanced char yields, amidst the COVID-19 pandemic.

Study the Fuel characteristics of Ethanol and Waste Engine Oil Pyrolytic oil blends

This study shows the application of pyrolytic oil derived from Waste Engine oil (WEOPO) as an alternative fuel by blending with Ethanol. For this, the effect of blending of ethanol at 5 %, 10 %, 15 %, 20 %, 25 %, and 30 % on the compositions and fuel properties were analyzed. The utmost blending was established based on the higher heating value. The pyrolytic oil used for this study was produced at 550 °C which was the optimum pyrolytic temperature. A comparison study of the blended oil was done with commercially available gasoline to observe the similarities in their fuel properties and composition. The study confirmed that ethanol can be blended with WEOPO at 20% by volume to obtain a fuel of a higher heating value of about 44.24 MJ/kg that can be used as fuel. Since, WEOPO contains 65.80% of C4-C12 (gasoline range) hydrocarbon compounds and the rest 31.48 % C11–C15, 11.84 % C15-C19, and 6.94 % >C19 compounds it can be used as a future fuel.

Adsorption of Lead(II), Manganese(II), and Copper(II) onto biochar in landfill leachate: implication of non-linear regression analysis

The feasibility of using wood-derived biochar (BC) to remove Pb, Mn, and Cu from landfill leachate was investigated and modeled in this study. The effect of contact time, biochar dosage and particle size on adsorption of the heavy metals onto BC was examined. BC was used in two form i.e. pulverized (PWB) and crushed (CWB) to evaluate the effect of BC particle size on adsorption characteristics. Biochar was produced under the pyrolytic temperature of 740 °C. The kinetics of Pb, Mn, and Cu adsorption onto PWB and CWB were assessed using the pseudo second-order and Elovich models, where both applied models could well describe the adsorption kinetics. Equilibrium adsorption capacity of the heavy metals onto BC in leachate system was evaluated using the Langmuir, non-linearized Freundlich, linearized Freundlich, and Temkin isotherms and found to have the following order for PWB: Non-linearized Freundlich>Temkin>Langmuir>Linearized Freundlich. The Langmuir and linearized Freundlich models could not adequately represent adsorption of the heavy metals onto biochar, especially for CWB. Using the non-linearized Freundlich isotherm significantly reduced adsorption prediction error. The adsorption affinity of PWB for Pb, Mn, and Cu was greater than CWB in all treatments. Wood-derived biochar is suggested to be used for the removal of heavy metals from landfill leachate as an economical adsorbent.

Changes in availability of Ca, K, Mg, P and S in sewage sludge as affected by pyrolysis temperature

Pyrolysis is a promising technology for sewage sludge (SS) treatment providing several improvements of SS properties for soil application. However, information on the influence of pyrolytic temperature on the availability of nutrients in resulting biochar (BC) is limited. In this study, anaerobically stabilised SS was pyrolysed in a laboratory fixed-bed reactor at 220, 320, 420, 520, and 620 °C for 30 min in the N₂ atmosphere. Pyrolysis resulted in a higher total content of all studied nutrients in BCs. Aromaticity and hydrophobicity of BCs increased with increasing temperatures while solubility decreased. Relative availability (% from total content) of nutrients in BCs was in order: Ca > Mg ~ K > S > P. Pyrolysis at 220 °C produced acidic BC with a higher content of acetic acid-extractable nutrients compared to non-pyrolysed control. An increment in pH and a significant drop in the content of available Ca, Mg, K and S were found at temperature 320 °C. Pyrolysis at 320 °C increased the content of available P by 28 % compared to non-pyrolysed SS. At the temperature of 420 °C and higher, available contents of all studied nutrients were lower than in non-pyrolysed SS.

Eugenol Polysiloxane-Polycarbonate/Graphene Nanocomposite: Enhanced in Thermostability and Barrier Property

Graphene (GR) was used to blend with eugenol polysiloxane-polycarbonate (Si-PC) copolymer to prepare a Si-PC/GR nanocomposite via a solution blending method and the impact of graphene on the properties of Si-PC/GR nanocomposite was investigated. The morphology and structure of the Si-PC/GR nanocomposite were characterized. Combining morphology and property analysis, the result showed that when the graphene dispersed uniformly in the Si-PC matrix, the mechanical properties, thermostability and barrier property of Si-PC/GR nanocomposite were enhanced. Compared with Si-PC copolymer, the pyrolytic temperature of Si-PC/2.5%GR nanocomposite at 5% weight loss was 434.3 °C, which was 20.6 °C higher than Si-PC copolymer; and the oxygen barrier value of Si-PC/1.5%GR nanocomposite decreased to 160.2 cm3/m2 24 h 0.1 MPa, which was 53.2 less than pure Si-PC. The mechanical properties of Si-PC/GR nanocomposite were enhanced with an appropriate additive amount of graphene. The hydrophobicity also had been enhanced at the meantime.

Reinforcing 3D print methacrylate resin/cellulose nanocrystal composites: Effect of cellulose nanocrystal modification

Cellulose nanocrystals (CNCs) were modified with methyl methacrylate (MMA) to improve the properties of the resulting three-dimensional (3D) stereolithography printed CNC/methacrylate (MA) resin composites. The dispersibility of the MMA-modified CNCs (MMA-CNCs) was substantially improved, as evidenced by the limited precipitation in the MA solution. Thermal gravimetry and differential scanning calorimetry measurements showed that the pyrolytic temperature of the MMA-CNC was 110 °C higher than that of the CNCs; the pyrolytic temperature and glass transition temperature of the resulting MMA-CNC/MA composites were higher than those of the CNC/MA. The tensile strength and modulus of the MMA-CNC/MA composites were improved by up to 38.3 MPa and 3.07 GPa, respectively, compared to those of the CNC/MA composites. These results demonstrated that the modification of CNC with MMA is a feasible approach to substantially improve the mechanical properties and thermal stability of the resulting MA-based composites.