Upcycling of the Used Cigarette Butt Filters through Pyrolysis Process: Detailed Kinetic Mechanism with Bio-Char Characterization.

Thermo-chemical conversion via the pyrolysis of cigarette butt (CB) filters was successfully valorized and upcycled in the pre-carbonization and carbonization stages. The pre-carbonization stage (devolatilization) of the precursor material (cellulose acetate filter, r-CAcF) was analyzed by micro-scale experiments under non-isothermal conditions using TG-DTG-DTA and DSC techniques. The results of a detailed kinetic study showed that the decomposition of r-CAcF takes place via complex mechanisms, including consecutive reaction steps and two single-step reactions. Consecutive stages include the α-transition referred to as a cellulose polymorphic transformation (cellulose I → II) through crystallization mechanism changes, where a more thermodynamically ordered system was obtained. It was found that the transformation rate of cellulose I → II ('cellulose regeneration') is strongly affected by the presence of alkali metals and the deacetylation process. Two single-step reactions showed significant overlapping behavior, which involves a nucleation-controlled scission mechanism (producing levoglucosan, gaseous products, and abundant radicals) and hydrolytic decomposition of cellulose by catalytic cleavage of glycosidic bonds with the presence of an acidic catalyst. A macro-scale experiment showed that the operating temperature and heating rate had the most notable effects on the total surface area of the manufactured carbon. A substantial degree of mesoporosity with a median pore radius of 3.1695 nm was identified. The presence of macroporosity on the carbon surface and acidic surface functional groups was observed.

Foam glasses made from green bottle glass and sugar beet factory lime as a foaming agent.

Great waste production alongside limited natural resources represents huge environmental and economic problems worldwide. Sustainable waste management and industrial production can reduce pollution and gain some economic benefits. Eco-friendly thermal insulators such as foam glasses can be produced using secondary raw materials in open-loop recycling. Foam glasses were successfully produced using green bottle glass and sugar beet factory lime (SBFL), CaCO3-rich waste as a novel foaming agent. Glass powder was mixed with different amounts of SBFL, uniaxially pressed at 20 MPa, and sintered at different temperatures. The influence of sintering temperature and the addition of a foaming agent was examined. Obtained samples were mechanically, thermally, and microstructurally characterized. Results showed that samples sintered at 800 °C have the best properties. Obtained foam glasses can be used in a variety of industries where thermal insulation, non-flammability, and non-toxic materials are required.

Thermal characteristics and combustion reactivity of coronavirus face masks using TG-DTG-MS analysis.

The presented paper deals with the influence of the heating rate on combustion characteristics (reactivity and reactivity evaluation, ignition index (D i), burnout index (D f), the combustion performance index (S), and the combustion stability index (R W)) of the protective coronavirus face masks. Two types of commonly used face masks in different state (new and exploited) were investigated by TG-DTG analysis in an air atmosphere, directly coupled with mass spectrometry (MS). Based on the experimental results, the impact of ultimate and proximate analysis data on the evolved gas analysis (EGA) was discussed. Also, the derived values from thermo-analytical (TA) data were compared with the literature reports, related to individual constitutive face mask materials. According to the performed research, it was established that different maximal reaction rate values at various heating rates indicate the complex nature of coronavirus face mask thermo-oxidative degradation, which is stimulated with carbon oxidation reactions and volatile matter (VM) release. By detailed analysis of obtained TG-DTG profiles, it was established that process takes place through the multiple-step reaction pathways, due to many vigorous radical reactions, causes by polymers degradation. The performed research was done to evaluate the possible utilization of coronavirus waste to energy production and sustainable pandemic environmental risk reduction.

Model-free and model-based analysis of thermo-oxidative response of wolfberries: A new developed mechanistic scheme.

Thermally accelerated oxidative degradation of wolfberry pulp was kinetically monitored using model-free and model-based approaches. Kinetic calculations were performed based on simultaneous thermal analysis measurements in an air at four different heating rates. From kinetic analysis, new developed mechanistic scheme which is responsible for wolfberries anti-oxidative behavior was proposed. It was found that thermo-oxidative process proceeds through multiplestep mechanism including sum of two independent reaction sets, via consecutive and competitive steps. It was established that rutoside degradation pathway to flavonol through hydrolysis reaction is rate-determining step of considered process. Furthermore, it was found that key flavonol compound degraded by competitive reactions mechanism forming such kinetic branches, which lead to compounds responsible for wolfberries antioxidant activity. It was established that flavonol oxidative cleavage reaction and oxidative polymerization are main chemical routes which are very important in a complex antioxidant mechanism for scavenging free radicals in wolfberries oxidative stress response.

Comparative pyrolysis kinetics of various biomasses based on model-free and DAEM approaches improved with numerical optimization procedure.

The pyrolysis process of various types of biomass (agricultural and wood by-products) in non-isothermal conditions using simultaneous thermal analyses (STA) was investigated. Devolatilization kinetics was implemented through combined application of model-free methods and DAEM (distributed activation energy model) using Gaussian distribution functions of activation energies. Results obtained were used in the curve prediction of the rate of mass loss against temperature at various heating rates by numerical optimization. The possible calculation of biomass samples behavior under pyrolytic conditions as the summation of their pseudo-components, hemicelluloses, cellulose, and lignin is also explored. The differences between experimental and calculated data are less than 3.20% offering a quality test of applicability of proposed model on the kinetic studies of a wide range of biomass samples. It seems that the most physically realistic model is the decomposition of biomass in three reactions, depending on the composition of the biomass regarding hemicelluloses, cellulose, and lignin. Kinetic model applied here may serve as a starting point to build more complex models capable of describing the thermal behavior of plant materials during thermochemical processing.