Thermogravimetric Fourier Transform Infrared Research Articles

Study on pyrolysis behavior of agricultural and forestry wastes using thermogravimetric‐Fourier transform infrared spectrometer (TG‐FTIR)

AbstractTo investigate the effective utilization of agricultural and forestry wastes for mitigating the shortage of primary energy and environmental pollution, the pyrolysis behavior of corn straw (CS), wheat straw (WS), and poplar sawdust (PS) was studied using thermogravimetric–Fourier transform infrared (TG‐FTIR) analysis. The activation energies and pyrolysis mechanism functions of different biomass types were calculated. The results showed that the functional group structures of the gaseous products generated from the pyrolysis of different biomass types were similar, mainly including OH, aliphatic CH, CO, aromatic ring skeleton, aromatic CH, and CO groups. These functional group structures mainly existed in oxygen‐containing compounds such as phenols, ketones, aldehydes, acids, esters, alcohols, and ethers. The pyrolysis process of agricultural and forestry wastes exhibited certain differences, with the PS undergoing thermal decomposition more easily, while the thermal decomposition mechanism functions of the two agricultural wastes (CS and WS) were similar. PS had a later initial release time for volatile matter, and the oxygen compounds produced by its pyrolysis were the highest, followed by WS and CS.

The influence of ammonium polyphosphate on the smoke toxicity of wood materials

As one of the most widely used flame retardants, the influence of ammonium polyphosphate (APP) on the smoke toxicity of wood materials is still unclear. Three kinds of wood materials were prepared, including wood, plywood, and flame-retardant plywood (FR-plywood), and their smoke compositions were characterized by thermogravimetric-Fourier-transform infrared (TG-FTIR) spectrometry and a cone calorimeter coupled with solvent absorption (CONE-SA). The results showed that compared with plywood, the CO, HCN and nitrogen oxide (NOx) emissions of FR-plywood with APP increased by about 1.7 times, 6 times, and 1.1 times at a heat flux of 50 kW m−2, respectively. And fractional effective dose (FED) model was established. According to this model, the lethal concentration to produce death in 50% of test animals (LC50) of the FR-plywood was 3.3 times lower than that of plywood.

Pyrolytic kinetics, reaction mechanisms and gas emissions of waste automotive paint sludge via TG-FTIR and Py-GC/MS

The present study experimentally quantified the pyrolysis behaviors of waste solvent-based automotive paint sludge (OAPS) and water-based automotive paint sludge (WAPS) at four different heating rates using thermogravimetric-Fourier transform infrared (TG-FTIR) spectrometry and pyrolysis-gas chromatography-mass (Py-GC/MS) spectrometry analyses. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods combined with the master-plots method were employed to investigate the pyrolysis kinetics and reaction mechanisms of waste automotive paint sludge. Three reaction stages and three reaction peaks in stage 2 were distinguished for both OAPS and WAPS degradation. The average activation energy (Ea) estimates for OAPS (FWO: 179.09 kJ/mol; KAS: 168.28 kJ/mol) were slightly higher than WAPS (FWO: 175.90 kJ/mol; KAS: 164.80 kJ/mol) according to FWO and KAS methods. The main pyrolysis reaction mechanisms of both OAPS and WAPS closely matched with the order-based model corresponding to 3rd and 2nd order random nucleation on an individual particle. The evolved gas species of CH4, CO2, phenols, NH3, H2O, and CO from OAPS and WAPS pyrolysis were identified by TG-FTIR. According to Py-GC/MS, hydrocarbons (47.2%) and O-components (42.7%) were relatively large after OAPS and WAPS pyrolysis, respectively. Melamine was the most abundant N-component product after pyrolysis of OAPS (5.8%) and WAPS (4.8%).

Multi-products oriented co-pyrolysis of papers, plastics, and textiles in MSW and the synergistic effects

Plastics, papers, and textiles are the main dry waste components of municipal solid waste (MSW). Product-oriented pyrolysis of these wastes under proper blend ratio could be important not only for improving the quality of char, oil, or gas from MSW pyrolysis, but also for enhancing the recycle of plastics from MSW. In this study, the pyrolysis characteristics of papers (ivory board, coated duplex board with grey back, kraft paper and offset printing paper), plastics (polypropylene and polyethylene), and textiles (cotton and polyester) were studied using thermogravimetric-Fourier transform infrared (TG-FTIR) analysis, gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) to obtain the optimum blend ratios for the desired products (gas, oil, volatile and char). The synergistic effects amongst different components during pyrolysis were investigated. Results showed that the co-pyrolysis of papers, plastics, and textiles under equal blend ratio promoted the production of aromatics, alkenes, water, alcohol, and phenol in volatile, but inhibited the production of CO2, CO, alkanes, and carbonyls. The optimum mass blend ratios were found to be paper: plastic: textile = 25 wt%: 50 wt%: 25 wt% and 12 wt%: 50 wt%: 38 wt%, respectively for obtaining the highest energy share in volatile and gas. While for producing char with higher surface area, higher paper ratio and lower plastics ratio is preferred. When the plastics percentage in mixture was increased from 12.5 wt% to 25 wt%, the oxygenates percentage in pyrolysis oil was reduced from 82 area% to 19 area%, further increase in plastics percentage, or, alterations of papers and textiles percentages did not show significant influence on oil composition, indicating that plastics can be recycled, without lowering the calorific values of pyrolysis oil or MSW for incineration, when their blend ratio in MSW exceeds 25 wt%.

Catalytic Fast Pyrolysis of Soybean Straw Biomass for Glycolaldehyde-Rich Bio-oil Production and Subsequent Extraction.

In this study, soybean straw (SS) as a promising source of glycolaldehyde-rich bio-oil production and extraction was investigated. Proximate and ultimate analysis of SS was performed to examine the feasibility and suitability of SS for thermochemical conversion design. The effect of the co-catalyst (CaCl2 + ash) on glycolaldehyde concentration (%) was examined. Thermogravimetric-Fourier-transform infrared (TG-FTIR) analysis was applied to optimize the pyrolysis temperature and biomass-to-catalyst ratio for glycolaldehyde-rich bio-oil production. By TG-FTIR analysis, the highest glycolaldehyde concentration of 8.57% was obtained at 500 °C without the catalyst, while 12.76 and 13.56% were obtained with the catalyst at 500 °C for a 1:6 ratio of SS-to-CaCl2 and a 1:4 ratio of SS-to-ash, respectively. Meanwhile, the highest glycolaldehyde concentrations (%) determined by gas chromatography–mass spectrometry (GC–MS) analysis for bio-oils produced at 500 °C (without the catalyst), a 1:6 ratio of SS-to-CaCl2, and a 1:4 ratio of SS-to-ash were found to be 11.3, 17.1, and 16.8%, respectively. These outcomes were fully consistent with the TG-FTIR results. Moreover, the effect of temperature on product distribution was investigated, and the highest bio-oil yield was achieved at 500 °C as 56.1%. This research work aims to develop an environment-friendly extraction technique involving aqueous-based imitation for glycolaldehyde extraction with 23.6% yield. Meanwhile, proton nuclear magnetic resonance (1H NMR) analysis was used to confirm the purity of the extracted glycolaldehyde, which was found as 91%.

Synergistic effects of mixing waste activated carbon and coal in co-slurrying and CO2 co-gasification

As a raw material, applications of waste activated carbon (WAC) in synergy with coal powder to prepare coal water slurry (CWS) and perform high-temperature gasification is a novel strategy for disposing WAC. Combining BET surface analysis, contact angle measurement, and thermogravimetric-Fourier transform infrared (TG-FTIR) methods, the physico-chemical properties and CO2 gasification behaviors of coal-waste activated carbon-slurry (CWACS) were evaluated. Compared to coal, WAC exhibited an excellent adsorption capacity and a stronger surface wettability. When the WAC mixing ratio was increased from 0 to 15%, the CWS solid concentration decreased from 62.28% to 59.44%. CWACS exhibited a shear-thinning flow behavior, and the higher the WAC mixing ratio, the more obvious the pseudoplastic characteristics. Moreover, WAC enhanced the storage stability of the CWS. Under the catalysis of Na, Ca, and Fe among others, the CO2 gasification reaction of CWACS coke moved forward to the low-temperature stage. The high fixed carbon content of WAC, as well as its unique tar adsorption and catalytic cracking effects, increased the CO gas component in the synthesis gas.

Synthesis of Novel Arginine-Based Flame Retardant and Its Application in Lyocell Fabric.

Lyocell fabrics are widely applied in textiles, however, its high flammability increases the risk of fire. Therefore, to resolve the issue, a novel biomass-based flame retardant with phosphorus and nitrogen elements was designed and synthesized by the reaction of arginine with phosphoric acid and urea. It was then grafted onto the lyocell fabric by a dip-dry-cure technique to prepare durable flame-retardant lyocell fabric (FR-lyocell). X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated that the flame retardant was successfully introduced into the lyocell sample. Thermogravimetric (TG) and Raman analyses confirmed that the modified lyocell fabric featured excellent thermal stability and significantly increased char residue. Vertical combustion results indicated that FR-lyocell before and after washing formed a complete and dense char layer. Thermogravimetric Fourier-transform infrared (TG-FTIR) analysis suggested that incombustible substances (such as H2O and CO2) were produced and played a significant fire retarding role in the gas phase. The cone calorimeter test corroborated that the peak of heat release rate (PHRR) and total heat release (THR) declined by 89.4% and 56.4%, respectively. These results indicated that the flame retardancy of the lyocell fabric was observably ameliorated.

Simulation methods of cotton pyrolysis based on ReaxFF and the influence of volatile removal ratio on volatile evolution and char formation

To understand the influence of volatile removal ratio from the system on pyrolysis characteristics of cotton, a simulation model was proposed by performing both non-isothermal and isothermal simulations using ReaxFF molecular dynamics. Thermogravimetric-Fourier transform infrared (TG-FTIR) was used to study the overall evolution behaviors of volatile from cotton pyrolysis as a reference to simulation results. In non-isothermal simulations, volatile was remained inside the simulation unit during the entire process, while in isothermal simulations a portion of volatile was removed from the simulation unit before starting next simulation at a higher temperature. Results showed that although the non-isothermal simulation method can predict a TG curve similar to the one obtained from the experiment and can reveal the initial evolution behaviors of the volatile, but the atomic contents of chars were unpractical. In isothermal simulations, 100, 80, 60 and 30 % volatile removal ratios (VRR) were employed to resemble the different extent of secondary reactions that volatiles undergo in practical pyrolysis. It was found that contents of aldehydes and C–H were mostly influenced by VRR; and simulations with higher VRR produced chars with lower O and H contents, being close to the practical chars. Simulations with 80, 100 % of VRR had a higher probability to match the reality.

Mechanical properties of waste cotton and their changes during early pyrolysis

Waste cotton is a textile material with high mechanical properties. Understanding the mechanical properties of waste cotton and their changes at an early pyrolysis stage is important for its thermochemical recovery. In this study, a universal testing machine equipped with a heating furnace was adopted to study the mechanical properties of a cotton towel in the temperature range of 25–250 °C under N2 atmosphere. The devolatilization behaviors of the cotton towel in the same temperature range were investigated using thermogravimetric-Fourier transform infrared (TG-FTIR) analysis. A reactive force field molecular dynamics (ReaxFF MD) model was employed to reveal the tensile deformation mechanism. Results showed that the cotton yarn tensile displacement increased with increasing temperature within 25–250 °C. Cotton degradation was onset at 150 °C, while at 200 °C, initiation of rapid CO2 emission was observed; sharp reductions in the mechanical strength observed at approximately 150 °C and 200 °C were mainly due to the degradation of hemicellulose and amorphous cellulose, respectively. CO2 was the primary volatile compound and its concentration correlated well with the mechanical strength. The ReaxFF MD simulation results indicated that the breaking strength of the cotton yarn depended mainly on the mechanical strength of the amorphous cellulose; the non-bonded interactions contributed more to the mechanical strength of the amorphous cellulose than the bonded interactions. The correlations between the mechanical strengths of the yarn bundle and towel, as well as the number of yarns they contained, have been proposed.

Product Characteristics and Interaction Mechanism in Low-Rank Coal and Coking Coal Co-Pyrolysis Process

The co-pyrolysis characteristics and the interaction with a kind of low-rank coal from SunJiaCha mining area (SJC) and coking coal (Chinese pinyin for coking coal is Jiaomei, JM) from HuangLing were investigated using thermogravimetric Fourier transform infrared (TG-FTIR) analysis and gas chromatography-mass spectrometry (GC-MS). The results revealed a significant synergistic effect of the SJC+JM co-pyrolysis process The addition of JM increased the number of colloids and provided the conditions for the interaction reaction among the pyrolysis products. SJC and JM were used as hydrogen donors, the [H] and free radical fragments from pyrolysis facilitated the hydrogenation reaction. In addition, the composition and structure of the gas were changed due to the synergistic effect, which also substantially decreased the light component in tar substantially.

Investigations on Cunninghamia Lanceolate Cedar Wood Pyrolysis by Thermogravimetric-Fourier Transform Infrared Analysis and a Modified Discrete Distributed Activation Energy Model Kinetic Method

Pyrolysis of Cunninghamia lanceolate cedar wood was studied by thermogravimetric-Fourier transform infrared (TG-FTIR) analysis and a modified discrete distributed activation energy model (DAEM) kin...

Improvement in Reactivity and Pollutant Emission by Cofiring of Coal and Pretreated Biomass

A fuel pretreatment technique is one of the most effective ways of using biomass fuel to solve problems including disadvantages of low calorific value, slagging, and fouling. Biomass fuel can gain a high calorific value and lower ash content by torrefaction and ash removal technology, respectively. In this study, a thermogravimetric analysis for deriving combustion parameters and the combustion characteristic factor (S) and an evolved gas analysis for investigating emission characteristics were studied by using a thermogravimetric Fourier transform infrared (TG-FTIR) system with coal, biomass, pretreated biomass, and their blends (10, 20, and 30%) to evaluate the combustibility and environmental performance. In the thermogravimetric analysis, coal and ashless biomass blends showed the greatest combustion performance and were confirmed to have a higher S index. Gas emissions (CO2, CO, NO, and SO2) were also investigated during the combustion process (O2, 21%; N2, 79%) to compare coal and biomass blends wit...

A novel flame retardant with reactive ammonium phosphate groups and polymerizing ability for preparing durable flame retardant and stiff cotton fabric

A novel flame-retardant ammonium salt of cholamine (methylenephosphonic acid) ethylene-organic phosphate acid (ACMPEP) with reactive -PO(ONH4)2 and OH groups was synthesized and characterized using nuclear magnetic resonance spectroscopy. The flame retardant not only could be grafted onto cotton fibers through POC covalent bonds, but also react with each other to form poly-ACMPEP. The results showed that the finished cotton fabrics have excellent flame retardance, good stiffness and durability. The limiting oxygen index (LOI) value of 30% ACMPEP-treated cotton was 42.0%, and after 50 laundering cycles, the LOI value still had 30.0%. Thermogravimetric analysis (TGA) results showed that the decomposition temperature of treated cotton fibers in N2 and air was 253 °C and 247 °C, lower than that of the control cotton fibers. Additionally, thermogravimetric-Fourier transform infrared (TG-FTIR) spectroscopy analysis indicated that the treated cotton fibers only released little combustible volatile during the thermal pyrolysis process. The cone calorimetry results showed that the heat release rate (HRR) and the total heat release (THR) of treated cottons were much lower than those of control cottons. The bending length increased 44.8% for the cotton fabric treated with 30% ACMPEP. The scanning electron microscopy (SEM) and the X-ray diffraction suggested that the finishing process only slightly affected the cotton fiber structure. The FTIR spectroscopy analysis confirmed the cross-linking reaction between ACMPEP molecules and cellulose. The tensile strengths of the finished cotton fabrics decreased a little. Together, the results suggested that the ACMPEP-treated cotton fabrics have excellent flame retardance and durability.

Low temperature oxidation of crude oil: Reaction progress and catalytic mechanism of metallic salts

Low Temperature Oxidation (LTO) reaction between crude oil and oxygen is a main reaction during the air flooding progress. The oxygen consumption rate and the reaction progress are both major factors affecting the air flooding result. Static oxidation experiments and Thermogravimetric-Fourier Transform infrared (TG-FTIR) tests have been conducted to research the LTO reaction progress, the catalytic universality of metallic salts on the oxygen consumption capacity of crude oil, and the catalytic reaction mechanism. The results show that in the progress of the low temperature oxidation of crude oil, oxygen reacts with crude oil to produce H2O, CO2 and oxygenated hydrocarbons such as carboxylic acid, alcohol, and phenol. In the early stages, the reaction products were mainly oxygenated hydrocarbons, while CO2 was a main product in the latter stages of the reaction. In the LTO reaction, the oxygen addition and the bond scission reactions existed simultaneously, but the oxygen addition reaction was dominant at the beginning of the reaction. As the reaction progresses, the bond scission reaction is gradually enhanced. From this research, it has been noted that the metallic catalyst precursor can effectively promote the LTO reaction through both the oxygen addition and bond scission reactions. The chain initiation reaction and chain propagation reaction are the main factors limiting the oxidation of crude oil. The metallic catalyst precursor can increase the formation rate of organic peroxides and promote the oxidation reaction of crude oil. The injection of the metallic catalyst precursor during air flooding can improve the safety and widen the application of air flooding technology. The catalytic effect on the oxidation of crude oils has good universality.

Biodegradation and Mineralization of Polystyrene by Plastic-Eating Mealworms: Part 1. Chemical and Physical Characterization and Isotopic Tests.

Polystyrene (PS) is generally considered to be durable and resistant to biodegradation. Mealworms (the larvae of Tenebrio molitor Linnaeus) from different sources chew and eat Styrofoam, a common PS product. The Styrofoam was efficiently degraded in the larval gut within a retention time of less than 24 h. Fed with Styrofoam as the sole diet, the larvae lived as well as those fed with a normal diet (bran) over a period of 1 month. The analysis of fecula egested from Styrofoam-feeding larvae, using gel permeation chromatography (GPC), solid-state (13)C cross-polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) spectroscopy, and thermogravimetric Fourier transform infrared (TG-FTIR) spectroscopy, substantiated that cleavage/depolymerization of long-chain PS molecules and the formation of depolymerized metabolites occurred in the larval gut. Within a 16 day test period, 47.7% of the ingested Styrofoam carbon was converted into CO2 and the residue (ca. 49.2%) was egested as fecula with a limited fraction incorporated into biomass (ca. 0.5%). Tests with α (13)C- or β (13)C-labeled PS confirmed that the (13)C-labeled PS was mineralized to (13)CO2 and incorporated into lipids. The discovery of the rapid biodegradation of PS in the larval gut reveals a new fate for plastic waste in the environment.

Effect of Chemical Structure on Pyrolysis Behavior of Alcell Mild Acidolysis Lignin

In this study, two purified mild acidolysis lignins (MAL) extracted from triploid poplar, i.e., Alcell MAL and Alkali MAL, were compared. Some properties, including elemental contents, higher heating value (HHV), functional hydroxyl group compositions, and molecular weights, were tested to characterize the structure of these two MALs. The releasing laws of gases and the distribution of products were also investigated through the use of thermogravimetric Fourier transform infrared (TG-FTIR) and pyrolysis-gas chromatography combined with mass spectrometry (Py-GC/MS). The results showed that both MALs had pyrolytic advantages, largely because of their unique chemical structures. However, although the species of volatiles from Alkali MAL were similar to those from Alcell MAL, the releasing temperature range for Alcell MAL was relatively narrow and the volatiles from it were concentrated. Among the fast pyrolytic products, phenols were the most abundant. The yield of 2,6-dimethoxy-4-(2-propenyl)phenol, which was the dominant product, was 25.66% for Alcell MAL and 20.77% for Alkali MAL, respectively. Overall, pyrolytic products from Alcell MAL were more enriched.

Quality improvement of pyrolysis oil from waste rubber by adding sawdust

This work was aimed at improving the pyrolysis oil quality of waste rubber by adding larch sawdust. Using a 1kg/h stainless pyrolysis reactor, the contents of sawdust in rubber were gradually increased from 0%, 50%, 100% and 200% (wt%) during the pyrolysis process. Using a thermo-gravimetric (TG) analyzer coupled with Fourier transform infrared (FTIR) analysis of evolving products (TG–FTIR), the weight loss characteristics of the heat under different mixtures of sawdust/rubber were observed. Using the pyrolysis–gas chromatography (GC)–mass spectrometry (Py–GC/MS), the vapors from the pyrolysis processes were collected and the compositions of the vapors were examined. During the pyrolysis process, the recovery of the pyrolysis gas and its composition were measured in-situ at a reaction temperature of 450°C and a retaining time of 1.2s. The results indicated that the efficiency of pyrolysis was increased and the residual carbon was reduced as the percentage of sawdust increased. The adding of sawdust significantly improved the pyrolysis oil quality by reducing the polycyclic aromatic hydrocarbons (PAHs) and nitrogen and sulfur compounds contents, resulting in an improvement in the combustion efficiency of the pyrolysis oil.

Acrylonitrile–Butadiene–Styrene Terpolymer with Metal Hypophosphites: Flame Retardance and Mechanism Research

Three metal hypophosphites, including aluminum hypophosphite (AP), magnesium hypophosphite (MP), and calcium hypophosphite (CP), were applied to flame retard acrylonitrile–butadiene–styrene (ABS). Thermal stability of three flame-retardant ABS were evaluated, and the enhancement of thermal stability were found. Flammable properties of flame-retardant ABS were investigated by Underwriters Laboratories 94 vertical burning test (UL-94), limit oxygen index (LOI), and cone calorimetry. Results suggested that AP could endow the best flame retardance for ABS with a UL-94 V-0 rating and LOI value of 25.1%. The peak heat release rate of ABS-AP reduced to 174.8 kW/m2, and the total heat released was decreased to 40.9 MJ/m2. Thermogravimetric Fourier transform infrared (TG-FTIR), FTIR, and scanning electron microcsopy–energy-dispersive X-ray spectrometry (SEM-EDX) were used to characterize the gaseous products and condensed residue respectively. Results showed that the flame-retardant mechanism was attributed to the formation of a two-layer protective barrier consisting of an organic P–O–C char layer and an inorganic layer to insulate material from fire and oxygen in the condensed phase, and the generation of P• and PO• to capture the reactive radicals in the vapor phase.

Quantitative and kinetic TG-FTIR investigation on three kinds of biomass pyrolysis

Biomass is applied in power generation or heat production as renewable energy resources. This paper focused on the pyrolysis in thermogravimetric (TG) analyzer of three biomasses, corn cob, tree root and bagasse, which showed different characteristics on their differential thermogravimetric (DTG) curves. In pyrolysis of corn cob, tree root and bagasse, there were three, one and two obvious peaks of DTG curves, respectively. Thermogravimetric Fourier Transform Infrared (TG-FTIR) analysis showed that the maximum mass loss rate at DTG curves was mainly due to cellulose and lignin pyrolysis, and the second mass loss rate peak of corn cob and the first one of bagasse were mainly due to pyrolysis of hemicellulose; while the first mass loss rate peak of corn cob was most likely due to breaking off of OH stretching function groups and H2O generation of sucrose pyrolysis. The main typical gaseous products were CO2, CO, H2O, CH4, NH3 and acid & aldehydes (CH3COOH or furadelhyde). Quantitative FTIR analysis showed that CO produced variation and CO2 produced before 400°C fitted with DTG curves well. IR results also indicated that hemicellulose pyrolysis had higher CH3COOH generation. Distributed activated energy model (DAEM) was applied to analyze kinetics of biomass pyrolysis. Similar to their DTG curves, the activation energy (AE) of corn cob showed four high distributions, in which the distributions of about 174.7kJ/mol and 181.6kJ/mol were highest (more than 20%), followed by that of 161.1kJ/mol (18.91%) and 140.5kJ/mol (9.08%); the AE of tree root had a distinctive distribution, which was as high as 33.9% at 181.6kJ/mol; while that of bagasse had only two distributions more than 6.8%, one is 50.69% at 181.6kJ/mol, and the other is 25.43% at 167.9kJ/mol. The pseudo-reactions fitting curves showed that the pyrolysis of corn cob was more complicated than the other two, because of more obvious pseudo-reactions contributed to the DTG curve and there were more than three main components in corn cob. It indicated that pseudo-reaction at 181.6kJ/mol was mainly contributed to cellulose pyrolysis in DTG curves, and those at 161.1kJ/mol and 167.9kJ/mol were mainly contributed to hemicellulose pyrolysis, while pseudo-reaction at 174.7kJ/mol might relate to the pyrolysis of sucrose.

Catalytic Pyrolysis of Coffee Grounds Using NiCu-Impregnated Catalysts

NiCu/γ-Al2O3 catalysts with different Cu loadings were prepared using an ultrasonic-assisted impregnation method. The effect of the Cu content in the catalyst on the mass loss behavior of coffee grounds and the evolution of gaseous products during pyrolysis were investigated. The effect of two different heating rates of 10 and 60 °C/min on the catalytic pyrolysis was also studied. The mass loss and evolution of the main pyrolytic volatiles were analyzed with a thermogravimetric (TG) analyzer connected to a Fourier transform infrared (FTIR) spectrometer. The bio-oils collected from non-catalytic and catalytic pyrolyses of coffee grounds were subjected to gas chromatography–mass spectrometry (GC–MS) analysis. Gram–Schmidt curves obtained by TG–FTIR indicated that the addition of NiCu/γ-Al2O3 catalysts and the increase in the Cu content in the catalysts increased the concentrations of CO2 and CO in the produced gas evolved during coffee grounds pyrolysis. In comparison to the slow heating rate of 10 °C/min, ...