Pyrolysis Treatment Research Articles

Pyrolysis kinetic behaviour and TG-FTIR-GC–MS analysis of Coronavirus Face Masks

In the times of Covid-19, face masks are considered to be the main source of protection against the virus that reduces its spread. These masks are classified as single-use medical products with a very short service life, estimated at few days, hence millions of contaminated masks are generated daily in the form of hazardous materials, what requires to develop a safe method to dispose of them, especially since some of them are loaded with viruses. 3-ply face masks (3PFM) represent the major fraction of this waste and are composed mainly from polypropylene and melt blown filter with high content of volatile substances (96.6 wt.%), what makes pyrolysis treatment an emerging technology that could be used to dispose of face masks and convert them into energy products. In this context, this work aims to study pyrolysis kinetic behaviour and TG-FTIR-GC–MS analysis of 3PFM. The research started with analysis of 3PFM using elemental analysis, proximate analysis, and compositional analyses. Afterwards, TG-FTIR system was used to study the thermal and chemical decomposition of 3PFM analyzed at different heating rates: 5, 10, 15, 20, 25, and 30 °C/min. The GC/MS system was used to observe the synthesized volatile products at the maximum decomposition temperatures. After that, isoconversional methods, the advanced nonlinear integral isoconversional method, and the iterative linear integral isoconversional method were used to determine the activation energies of mask pyrolysis, while the distributed activation energy model and the independent parallel reactions kinetic model were used to fit TGA and DTG curves with deviations below <1. The TGA-DTG results showed that 3PFM can decompose in three different periods with a total weight loss of 95 % and maximum decomposition in the range 405−510 °C, while the FTIR spectra and GC–MS analysis exhibited that – CH (aromatic and aliphatic) and 2,4-Dimethyl-1-heptene (28–43 % based on heating rate) represented the major compounds in the released volatile components. Finally, Vyazovkin and the iterative linear integral isoconversional methods gave activation energies almost similar to that obtained by the KAS isoconversional method.

Preparation and Characterization of Carbon Xerogel Based Composites for Electrochemical Sensing and Photocatalytic Degradation.

In order to obtain a multifunctional nanocomposite material-for electrochemical sensors and photocatalytic applications, structures based on Bi, Fe and TiO₂ were grown inside carbon xerogel supports (BiFeCX and BiFeCX-TiO₂). First, a wet polymer containing Bi and Fe salts was obtained by following a modified resorcinol-formaldehyde based sol-gel route, followed by drying in ambient conditions, and pyrolysis under inert atmosphere. Then, through TiCl₄ hydrolysis, TiO₂ nanoparticles were deposited on the BiFeCX xerogel leading to BiFeCX-TiO₂. The morphological and structural characterization of the investigated nanocomposites consisted in X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and N₂ adsorption measurements, revealing porous carbon structures with embedded nanoparticles and the particularities driven by the pyrolysis and TiCl₄ treatment. The new modified electrodes based on BiFeCX or BiFeCX-TiO₂ nanocomposite materials, kept in a chitosan matrix (Chi) and deposited on a glassy carbon (GC) electrode surface (GC/Chi-BiFeCX or GC/Chi-BiFeCX-TiO₂), were obtained and investigated for Pb(II) voltammetric detection and H₂O₂ amperometric detection. Moreover, the BiFeCX-TiO₂ nanocomposite was tested for the photocatalytic degradation of methyl orange. The great potential of BiFeCX nanocomposite material for developing electrochemical sensors, or BiFeCX-TiO₂ for sensors application and photocatalytic application was demonstrated.

Simultaneous sulfamethoxazole degradation with electricity generation by microbial fuel cells using Ni-MOF-74 as cathode catalysts and quantification of antibiotic resistance genes

Antibiotic wastewater presents serious challenges in water treatment. Metal-organic frameworks (MOFs) have received significant attention as promising precursors and sacrificial templates in the preparation of porous carbon-supported catalysts. Herein, we investigated the sulfamethoxazole (SMX) degradation and electrochemical performance of microbial fuel cells (MFCs) that applied as-prepared Ni-MOF-74 and Ni–N–C (Ni-MOF-74 underwent pyrolysis treatment at different temperatures) as air-cathode catalyst. Firstly, the electrocatalytic activity towards oxygen reduction reaction (ORR) of the catalyst was investigated by rotating disk electrode. The results showed that electron transfer number for Ni-MOF-74 was 2.12, while that of 800Ni–N–C was 3.44, which was close to four-electron reduction. Applying Ni-MOF-74 in MFCs, a maximum power density of 446 mW/m2 was obtained, which was close to that of 800Ni–N–C. Besides, using Ni-MOF-74 as cathode catalyst, a chemical oxygen demand removal rate of about 84% was obtained, and the degradation rate of 10 mg/L SMX was 61%. The degradation rate decreased with increasing antibiotic concentration, but the average degradation efficiency increased stepwise. Additionally, the relative abundance of resistant gene sul1 in the reactors of the new catalytic material was about 62% lower than that of sul1 in the control (Pt/C) reactors, and the relative abundance of sul2 was about 73% lower. Moreover, cost assessments related to the catalyst performance are presented. The findings of this study demonstrated that Ni-MOF-74 could be considered as a two-electron transfer ORR catalyst, and offers a promising technique for preparation of Ni–N–C for use as four-electron transfer ORR catalysts. In comparison, Ni-MOF-74 could be a promising ORR catalyst of MFCs for antibiotic degradation.

Effects ofAdding Hydrotalcite with Different Compositional Ratios in the Pyrolysis Treatment of Brominated Plastics

In recent years, chemical recycling technologies related to the pyrolysis of plastics into fuels have received increasing attention under the circular economy agenda with respect to resource depletion. Herein, a method is presented to reduce halogen compounds in the product oil derived from the pyrolysis of polystyrene with tetrabromobisphenol A. Analysis was undertaken to identify the bromine compounds present in the residue after the pyrolysis treatment. Pyrolysis was conducted in the presence of hydrotalcites as a function of the Mg and Al additive composition ratio (type 1; KW-1000 and type 2; K W-2000). The bromine compounds identified in the oil after pyrolysis at 400 °C were determined as 2-bromophenol, 4- bromophenol, 2,4-dibromophenol, 1- bromomethylbenzene, 2- bromomethylbenzene, and 3,6-dibromo-2,5-xylidine. In the absence of hydrotalcite, bromine compounds were still detected in the product oil, residue and gas, whereas the addition of KW-2000 reduced the concentration of bromine compounds in the product oil. The reduced concentration of the bromine compounds in the product oil is suggested to be related to the trapping of bromine by the added hydrotalcite during the pyrolysis of the plastic.

Catalytic Pyrolysis Kinetic Behavior and TG-FTIR-GC-MS Analysis of Metallized Food Packaging Plastics with Different Concentrations of ZSM-5 Zeolite Catalyst.

Recently, the pyrolysis process has been adapted as a sustainable strategy to convert metallized food packaging plastics waste (MFPW) into energy products (paraffin wax, biogas, and carbon black particles) and to recover aluminum. Usually, catalysts are used in pyrolysis treatment to refine pyrolysis products and to increase their yield. In order to study the effect of a catalyst on the formulated volatile products, this work aims to study the pyrolysis behavior of MFPW in presence of catalyst, using TG-FTIR-GC–MS system. The pyrolysis experiments were conducted with ZSM-5 Zeolite catalyst with different concentrations (10, 30, and 50 wt.%) at different heating rates (5, 10, 15, 20, 25, and 30 °C/min). In addition, TG-FTIR system and GC-MS unit were used to observe and analyze the thermal and chemical degradation of the obtained volatile compounds at maximum decomposition peaks. In addition, the kinetic results of catalytic pyrolysis of ZSM-5/MFPW samples matched when model-free methods, a distributed activation energy model (DAEM), and an independent parallel reaction kinetic model (IPR) were used. The TGA-DTG results showed that addition of a catalyst did not have a significant effect on the features of the TGA-DTG curves with similar weight loss of 87–90 wt.% (without taking the weight of the catalyst into account). Meanwhile, FTIR results manifested strong presence of methane and high-intensity functional group of carboxylic acid residues, especially at high concentration of ZSM-5 and high heating rates. Likewise, GC-MS measurements showed that Benzene, Toluene, Hexane, p-Xylene, etc. compounds (main flammable liquid compounds in petroleum oil) generated catalysts exceeding 50%. Finally, pyrolysis kinetics showed that the whole activation energies of catalytic pyrolysis process of MFPW were estimated at 289 kJ/mol and 110, 350, and 174 kJ/mol for ZSM-5/MFPW samples (10, 30, and 50 wt.%, respectively), whereas DAEM and IPR approaches succeeded to simulate TGA and DTG profiles with deviations below <1.

New strategy of S,N co-doping of conductive-copolymer-derived carbon nanotubes to effectively improve the dispersion of PtCu nanocrystals for boosting the electrocatalytic oxidation of methanol

Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance. However, the guidelines for designing hybrid materials with advantageous structures and the fundamental understanding of their electrocatalytic mechanisms remain unclear. Herein, superfine Pt and PtCu nanoparticles supported by novel S,N-co-doped multi-walled CNT (MWCNTs) were prepared through the innovative pyrolysis of a poly(3,4-ethylenedioxythiophene)/polyaniline copolymer as a source of S and N. The uniform wrapping of the copolymer around the MWCNTs provides a high density of evenly distributed defects on the surface after the pyrolysis treatment, facilitating the uniform distribution of ultrafine Pt and PtCu nanoparticles. Remarkably, the Pt1Cu2/SN-MWCNTs show an obviously larger electroactive surface area and higher mass activity, stability, and CO poisoning resistance in methanol oxidation compared to Pt/SN-MWCNTs, Pt/S-MWCNTs, Pt/N-MWCNTs, and commercial Pt/C. Density functional theory studies confirm that the co-doping of S and N considerably deforms the CNTs and polarizes the adjacent C atoms. Consequently, both the adsorption of Pt1Cu2 onto the SN-MWCNTs and the subsequent adsorption of methanol are enhanced; in addition, the catalytic activity of Pt1Cu2/SN-MWCNTs for methanol oxidation is thermodynamically and kinetically more favorable than that of its CNT and N-CNT counterparts. This work provides a novel method to fabricate high-performance fuel cell electrocatalysts with highly dispersed and stable Pt-based nanoparticles on a carbon substrate.

Influence of DVB as linker molecule on the micropore formation in polymer-derived SiCN ceramics

In this work, the formation of transient microporosity during the polymer-to-ceramic conversion in polymer-derived ceramics was studied using a commercially available poly(vinyl)silazane precursor which was modified with divinylbenzene (DVB) as linker molecule during crosslinking. After pyrolysis treatments between 400 and 700 °C, the resulting materials not only showed distinct changes in elemental composition and structural features upon introduction of the linker molecule, but also a shift in micropore size, e.g. shifting from 0.84 nm to 0.70 nm after pyrolysis at 600 °C. Due to hindrance of transamination reactions in the low-temperature region, the nitrogen content in linker-containing samples was significantly higher, leading to a different composition of micropore-forming entities and, in case of the system studied, to smaller pores. These findings are a first step towards the clarification of the mechanisms leading to the pore formation in PDCs during pyrolytic conversion, which is essential for their use in prospective applications.

Biochar Generated from Agro-Industry Sugarcane Residue by Low Temperature Pyrolysis Utilized as an Adsorption Agent for the Removal of Thiamethoxam Pesticide in Wastewater

Biochar produced from different raw materials by pyrolysis have been utilized as an alternative material for organic compound adsorption. This study aims to evaluate the use of biochar generated from sugar cane filter cake, after pyrolysis treatment at 380 °C, in the adsorption process of thiamethoxam pesticide in wastewater. The biochar was studied based on moisture, volatile matter, ash content, surface area and porosity, using elemental analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The results showed that the use of biochar as an adsorbent for organic compounds is promising, due to its surface area (19.8 m2 g−1), mesoporosity, and functional groups, such as hydroxyl, present on the biochar surface. The Langmuir and Freundlich isothermal models were used for the adsorption study. The pseudo-first- and pseudo-second-order models were used in the kinetic study of the adsorption process. The results indicated that the adsorption process was well described by the Langmuir isotherm and pseudo-second-order models. Finally, the rate of thiamethoxam removal by biochar was approximately 70% over a period of 60 min, and biochar is, therefore, suitable for the decontamination of wastewater with thiamethoxam.

Mn, N, P-tridoped bamboo-like carbon nanotubes decorated with ultrafine Co2P/FeCo nanoparticles as bifunctional oxygen electrocatalyst for long-term rechargeable Zn-air battery

Rational synthesis of cost-effectiveness, ultra-stable and high-efficiency bifunctional oxygen catalysts are pivotal for Zn-air batteries. Herein, fine Co2P/FeCo nanoparticles (NPs) anchored on Mn, N, P-codoped bamboo-like carbon nanotubes (Co2P/FeCo/MnNP-BCNTs) are constructed in the coexistence of melamine, poly(4-vinylpyridine) and adenosine-5′-diphosphate disodium salt (ADP) by convenient pyrolysis and follow-up acid treatment. The as-prepared catalyst exhibits the higher onset potential (Eonset = 0.97 V vs. RHE) and half-wave potential (E1/2 = 0.88 V vs. RHE) for oxygen reduction reaction (ORR), coupled with excellent oxygen evolution reaction (OER) with the lower overpotential of 324 mV at 10 mA cm−2. Notably, the home-made Zn-air battery delivers the greater peak power density of 220 mW cm−2, together with the outstanding cycling stability. The excellent performances of Co2P/FeCo/MnNP-BCNTs catalyst are mainly attributed to the highly conductive carbon nanotubes and the synergistic effects between carbon nanotubes and Co2P/FeCo NPs. This work offers a novel strategy to explore advanced bifunctional oxygen catalysts for high-efficiency metal-air batteries.

Nanostructured tubular carbon materials doped with cobalt as electrocatalyst for efficient oxygen reduction reaction

The development of non-precious metal catalysts with high efficiency and superior reaction durability for oxygen reduction reaction (ORR) is of great importance for construction of next-generation fuel cells. Herein, we report the preparation of in-situ nitrogen-doped carbon nanotube electrocatalysts (PPy-NCNTs) which were prepared by the pyrolysis of one-dimensional nanotube-like polypyrrole conjugated polymers precursor (PPy-Tubes) synthesized by oxidative polymerization and self-assembly method. The as-prepared PPy-NCNTs show good ORR performance, e.g., its half-wave potential reaches 0.826 V. In order to further improve the ORR performance of PPy-NCNTs, we prepared the Co-N co-doped carbon nanotube materials (Co-N-PPy-NCNTs) with different Co contents by adding cobalt nitrate into the polymerization solution during synthesis of PPy nanotube followed by a pyrolysis treatment. Comparatively, the Co-N-PPy-NCNTs have better ORR performance than that of PPy-NCNTs with a half-wave potential of 0.830 V, a biased 4e− reaction pathway, and better stability and methanol tolerance (high than Pt/C catalysts in the methanol tolerance test and the durability test). Taking advantages of its simple and cost-efficient preparation, high ORR performance and superior stability and methanol tolerance, the Co-N-PPy-NCNTs should be a kind of ideal candidate as an alternative to the precious metal platinum-based catalysts for fuel cells.

Magnetic biochars have lower adsorption but higher separation effectiveness for Cd2+ from aqueous solution compared to nonmagnetic biochars.

Magnetic biochars were prepared by chemical co-precipitation of Fe3+/Fe2+ onto rice straw (M-RSB) and sewage sludge (M-SSB), followed by pyrolysis treatment, which was also used to prepare the corresponding nonmagnetic biochars (RSB and SSB). The comparison of adsorption characteristics between magnetic and nonmagnetic biochars was investigated as a function of pH, contact time, and initial Cd2+ concentration. The adsorption of nonmagnetic biochars was better described by pseudo-second-order kinetic model, and the adsorption of RSB and SSB was better described by Langmuir and Freundlich models, respectively. Magnetization of the biochars did not change the applicability of their respective adsorption models, but reduced their adsorption capabilities. The maximum capacities were 42.48 and 4.64mg/g for M-RSB and M-SSB, respectively, underperforming their nonmagnetic counterparts of 58.65 and 7.22mg/g for RSB and SSB. Such a reduction was fundamentally caused by the decreases in the importance of cation-exchange and Cπ-coordination after magnetization, but the Fe-oxides contributed to the precipitation-dependent adsorption capacity for Cd2+ on magnetic biochars. The qualitative and quantitative characterization of adsorption mechanisms were further analyzed, in which the contribution proportions of cation-exchange after magnetization were reduced by 31.9% and 12.1% for M-RSB and M-SSB, respectively, whereas that of Cπ-coordination were reduced by 3.4% and 31.1% for M-RSB and M-SSB, respectively. These reductions suggest that for adsorbing Cd2+ the choice of conventional biochar was more relevant than whether the biochar was magnetized. However, magnetic biochars are easily separated from treated solutions, depending largely on initial pH. Their easy of separation suggests that magnetic biochars hold promise as more sustainable alternatives for the remediation of moderately Cd-contaminated environments, such as surface water and agriculture soil, and that magnetic biochars should be studied further.

A review on cleaner approach for effective separation of toxic pollutants from wastewater using carbon Sphere’s as adsorbent: Preparation, activation and applications

Carbon Spheres are known to be an outstanding carbonaceous source and has shown remarkable adsorption capacity in recent years. Owing to its simplicity and availability in nature this material has drawn attention among the researchers because of its physical and chemical property and its application in various fields. Carbon spheres with a kept pore size appropriation and morphology can be integrated by different strategies as talked about in this audit. A variety of techniques has been utilized to produce carbon spheres which include chemical vapor deposition, arc discharge, laser ablation, pyrolysis and hydrothermal treatment. Among these different techniques available for synthesizing these spheres hydrothermal method is widely adopted because of the mild and favorable conditions that exists when compared with the other methods available for synthesizing the spheres. The hydrothermal treatment of Carbon spheres has as of late got a lot of consideration because of its ease, moderate response conditions, simple procedure and natural agreeableness. Hydrothermal method is most commonly employed when spheres of micro or nano size is to be obtained on a larger scale. The major significance of hydrothermal method is the high productivity that can be accomplished at mellow temperature inside a fixed autoclave where there is no compelling reason to utilize any perilous solvents. In this review, various methods for synthesizing carbon spheres, activation techniques, morphological structures of the carbon spheres synthesized by different methods and their applications in the expulsion of pollutant has been reviewed in detail. • Porous carbon spheres were prepared by using various techniques has been scrutinized in this review. • Carbon spheres were activated with KOH, ZnCl 2 , H 3 PO 4 to produce Activated Carbon Spheres (ACS) has been discussed in brief. • Morphological structure of the ACS synthesized using various routes have been highlighted in this review. • The removal of various contaminants from aqueous solution by ACS has been reported in detail. • The application of ACS in various other fields has also been scrutinized in this review.

Microcrystalline paraffin wax, biogas, carbon particles and aluminum recovery from metallised food packaging plastics using pyrolysis, mechanical and chemical treatments

Abstract Metallised food packaging plastics waste (MFPW) is the most complex part of plastic waste ever with poor recyclability. In order to close the circle loop of MFPWs and to increase their economic and environmental benefits according to the zero waste principle, this research aims to convert MFPWs into energy products (Microcrystalline paraffin wax and biogas) and raw materials (carbon particles and aluminum) using three combined approaches: pyrolysis, mechanical and chemical treatments. The thermal treatment using mini-pyrolysis plant (capacity of 250 g) was applied as the main treatment to convert MFPWs into three main energy products: biooil, biogas, and char mixed with aluminum flakes (Al/char) at 25 °C/min up to 500, 600, and 700 °C, while the mechanical treatment using milling process was used to break the bonds between char and Al flakes, thus liberating Al flakes after sieving process. Finally, the leaching process using hydrochloric acid was employed to extract the remaining Al particles from the milled Al/char and to recover the carbon particles simultaneously, using a density separation method. The experiments were performed on a mixture of five types of equal shares of packages (potato chips, chocolate, bakery, coffee, and biscuits). The obtained energy products and recovered materials were analyzed by GC, FTIR, ICP, and SEM-EDS. The results showed that MFPWs can be decomposed thermally into Al/char (99.4%) only up to 500 °C, while in case of 600 and 700 °C, they can be converted into microcrystalline paraffin wax (19.5%), biogas (63%), and Al/char (17.8%). Also, the mechanical and chemical treatments were succeeded by leaching >90 wt% of Al and extraction of carbon particles on a micro-scale (10–50 μm). Finally, the assessment of economic performance and greenhouse gases showed that application of the developed approach on an industrial scale can provide an economic return up to 610 $/ton of MFPWs and decrease carbon footprint by −984 kg CO2-eq/t of MFPWs.

Effect of pyrolysis on Zhaotong lignite oxidation with aqueous sodium hypochlorite

The pyrolysis treatment of lignites could remove thermal-unstable aliphatic structures but enrich aromatic structures in resulting pyrolysis residues, which would facilitate producing benzene polycarboxylic acids (BPCAs). Herein, the demineralized Zhaotong lignite (DZL) was pyrolyzed at 250–550 °C to afford the corresponding pyrolysis residues. Subsequently, DZL and its pyrolysis residues were subjected to oxidation with aqueous sodium hypochlorite. By XRD, FTIR, and element analyses, it was found that the content and polycondensation degree of aromatic structures simultaneously increased with increasing pyrolysis temperature. Furthermore, the yield and selectivity of BPCAs both increased along with raising pyrolysis temperature in resulting products from fully oxidation of DZL and its pyrolysis residues. Based on the distribution of BPCAs, peri-condensed aromatic structures were dominant in DZL and its DPRs, and obviously increased with increasing pyrolysis temperature. More interestingly, good correlation was found between the yield of BPCAs and aromaticity parameters. Meanwhile, the yield of benzenepentacrboxylic acid was well associated with polycondensation degree parameters.

Thermochemistry of sulfur during pyrolysis and hydrothermal carbonization of sewage sludges

Sulfur (S) is an abundant and redox-active element in urban wastewater systems and plays a critical role in both the wastewater and sludge treatment processes. This study comparatively characterized the transformation of S and several closely associated metals (Cu, Zn, and Fe) during pyrolysis (250 to 750 °C) and hydrothermal carbonization (HTC, 150 to 275 °C) treatments of sewage sludge. S, Fe, Zn, and Cu K-edge X-ray absorption spectroscopy was applied to quantitatively evaluate the fate of S and contribution of different S species in regulating metal speciation. During pyrolysis, aliphatic-S and sulfonate were preferentially degraded at low temperature (below 350 °C) and sulfate was thermochemically reduced at temperature above 450 °C, while metal sulfides (up to 27%) and thiophenes (up to 70%) were increasingly formed. Similar to the pyrolysis process, metal sulfides (up to 40% at temperature above 200 °C) and thiophenes were formed during HTC. The degradation of thiols and organic sulfide, as well as sulfate reduction, released sulfide and strongly affected metal speciation. For example, almost all Cu and half of Zn were transformed into Cu-Fe- or Zn-Fe-sulfides during HTC, whereas they were partially desulfidized during pyrolysis. High abundance of reduced S species (S−1 and S−2) in hydrochars may contribute to their strong reductive adsorption of Cr(VI). Results from this work reveal the thermochemical reactions driving the transformations of S and its associated metals during pyrolysis and HTC. The results provide fundamental knowledge for selecting thermochemical sludge treatment techniques for value-added applications of the products.

Monolith Materials unveil plans carbon-free ammonia plant in US.

In this study, tire tread (TT) and side wall (SW) of waste tire were separately used as feedstocks for pyrolysis treatment, and the resulting chars were thoroughly characterized to exploit the potential applications. Analytic results show that the SW contained higher fixed carbon (27.55%) and carbon content (82.30%) than those of TT (15.21% and 56.56% respectively). TGA results indicated that 400–600 °C is the main decomposition temperature range for both feeds. The char yields showed a declining trend and stabilized at 500 °C, and higher char yield of TT was achieved than that of SW. Meanwhile, the chars from TT showed a high surface area (121.47 m2/g) than that of SW (44.72 m2/g), which could be a good adsorbent or an activated carbon precursor. FT-IR results showed that leading surface functional group of TT-500 was C-O/C-O-C from alcohols, ketones or ether, whereas SW-500 from phenols, alcohols and carboxylic acids. When compared with commercial products, SW-500 showed better properties than those of a carbon black (N660, 10 μm) in terms of carbon quality and ash content. This study suggested that by pyrolyzing the distinct sections of the waste tire is a promising approach to produce chars for more specific applications.

Impact of torrefaction conditions on the physicochemical properties of mustard crop residue

Abstract Torrefaction process is related to pyrolysis treatment in an inert atmosphere which is employed to improve the chemical and physical properties of biomass/solid fuels for energy generation. In present study, mustard crop residue (MCR) which is an abundantly available lignocellulosic waste was torrefied at three different temperatures (200 °C, 250 °C, and 300 °C) for three different residence time (30, 45, and 60 min). Mass yield, energy yield, high heating value, elemental composition, ash content, and volatile matter content of raw and torrefied MCR are computed. The functional behavior and combustion characteristics of raw and torrefied MCR was studied by Fourier Transform Infra-Red Spectrometry (FTIR). The mass and energy yield of torrefied MCR were found to decrease with an increase in torrefaction temperature and residence time. Elemental analysis of torrefied MCR showed an increase in weight percentage of carbon with increase in temperature and residence time of torrefaction due to release of oxygen congaing volatiles. The high heating value was found to upgrade from 16.92 MJ kg−1 for raw MCR to 21.93 MJ kg−1 of torrefied MCR at higher torrefaction temperature and time. FTIR analysis confirmed that hydroxyl group content decreased due to release of H2O, CO, and CO2. Therefore, torrefaction is found to be an effective treatment process for improving physicochemical properties of MCR.

Carbon Xerogel Nanostructures with Integrated Bi and Fe Components for Hydrogen Peroxide and Heavy Metal Detection.

Multifunctional Bi- and Fe-modified carbon xerogel composites (CXBiFe), with different Fe concentrations, were obtained by a resorcinol–formaldehyde sol–gel method, followed by drying in ambient conditions and pyrolysis treatment. The morphological and structural characterization performed by X-ray diffraction (XRD), Raman spectroscopy, N2 adsorption/desorption porosimetry, scanning electron microscopy (SEM) and scanning/transmission electron microscopy (STEM) analyses, indicates the formation of carbon-based nanocomposites with integrated Bi and Fe oxide nanoparticles. At higher Fe concentrations, Bi-Fe-O interactions lead to the formation of hybrid nanostructures and off-stoichiometric Bi2Fe4O9 mullite-like structures together with an excess of iron oxide nanoparticles. To examine the effect of the Fe content on the electrochemical performance of the CXBiFe composites, the obtained powders were initially dispersed in a chitosan solution and applied on the surface of glassy carbon electrodes. Then, the multifunctional character of the CXBiFe systems is assessed by involving the obtained modified electrodes for the detection of different analytes, such as biomarkers (hydrogen peroxide) and heavy metal ions (i.e., Pb2+). The achieved results indicate a drop in the detection limit for H2O2 as Fe content increases. Even though the current results suggest that the surface modifications of the Bi phase with Fe and O impurities lower Pb2+ detection efficiencies, Pb2+ sensing well below the admitted concentrations for drinkable water is also noticed.

Pyrolysis characteristics and products distribution of petroleum sludges

ABSTRACT Pyrolysis can realise the harmlessness, reduction and resource utilisation of petroleum sludge in a short period. In the present work, a tank bottom sludge (SSOS) and a landing sludge (SLOS) from Shengli Oilfield were used for experimental research. Thermogravimetric testing is used to initially determine the optimal range of pyrolysis temperature. Pyrolysis experiments were performed in a tube furnace reactor. Pyrolysis products were collected and analysed separately. The char yield of SSOS and SLOS were 50% and 70%, respectively. Although there are differences in the oil content of the two types of petroleum sludge, the oil yield remained nearly the same, which were both between 7% and 8%. As the pyrolysis temperature was raised to 500°C, the yield of each product did not change greatly while their composition had obvious changes. High temperature is more conducive to the production of small molecule products. Result showed that pyrolysis treatment of petroleum sludge can effectively recover energy materials in the form of pyrolysis gas and oil. The heating value of char is lower than that of petroleum sludge, which means that char is not suitable for direct use as fuel. Pyrolysis treatment also showed good curing effect on Cr, which reached 85%. However, the solidification effect decreased as pyrolysis temperature increasing. It is necessary to pay attention to the heavy metal contained in char as soil improver. The rich surface structure of char provides evidence to produce high value-added carbon materials.

Indian mustard bioproducts dry-purification with natural adsorbents - A biorefinery for a green circular economy

Processes based on homogeneous catalysts are the most widely used for industrial production of fatty acid derivatives, despite catalyst loss in aqueous effluents during the wet-purification stage. In this work, dry-purification of the crude bioproducts; ethyl biodiesel and biolubricants, derived from Indian mustard was conducted using various natural mineral (clay) and organic (plant issue) adsorbents to evaluate operating conditions including temperature, contact time and number of treatment cycles and to define the optimal procedure. Adsorbent characterization was determined by average particle size assessed using laser granulometry, morphology and elemental chemical composition measured by scanning electron spectroscopy with microanalysis using energy dispersive X-ray spectroscopy, chemical structure determination based on Fourier Transform InfraRed spectroscopy and porosity and specific area assessed using carbon dioxide or nitrogen adsorption. The quality of the biofuel and biolubricants, before and after dry-purification on the above adsorbents, was evaluated using different methods including Karl Fischer titration, gas chromatography with a flame ionization detector and inductively coupled plasma-atomic emission spectroscopy. Montmorillonite clay and finely ground Indian mustard stems (particle size of 100–710 μm) without further pyrolysis or carbonization treatment were found to be the best adsorbents. Combined with the selected dry-purification procedure (35–45 °C, 20 min, single treatment cycle), most impurities including residual glycerides, free glycerin, water, catalysts and metals were removed from the resultant ethyl biodiesel thus meeting the basic biofuel specifications of acid value, color, density, viscosity, flash point, pour point, cloud point, cold filter plugging point, higher heating value, and oxidation stability. Further purification of biolubricants was required using bubble-washing with citric acid and vacuum distillation to obtain a product with acceptable density, viscosity and color. This work highlights the potential of a biorefinery system focused on Indian mustard contributing to a green circular economy, that would benefit both farmers and consumers in the respect of environment; farmers would gain in energy security and flexibility by biofuel, biolubricant and other bioproducts on-farm production, while ensuring healthy food security and offering job opportunities, the whole with reduced chemical and energy inputs and minimized waste effluents.