Carbon Yield Research Articles

Preparation and characterization of lignin-derived carbon aerogels.

Lignin is considered a valuable renewable resource for building new chemicals and materials, particularly resins and polymers. The aromatic nature of lignin suggests a synthetic route for synthesizing organic aerogels (AGs) similar to the aqueous polycondensation of resorcinol with formaldehyde (FA). The structure and reactivity of lignin largely depend on the severity of the isolation method used, which challenges the development of new organic and carbon materials. Resorcinol aerogels are considered a source of porous carbon material, while lignin-based aerogels also possess great potential for the development of carbon materials, having a high carbon yield with a high specific surface area and microporosity. In the present study, the birch hydrolysis lignin and organosolv lignin extracted from pine were used to prepare AGs with formaldehyde, with the addition of 5-methylresorcinol in the range of 75%-25%, yielding monolithic mesoporous aerogels with a relatively high specific surface area of up to 343.4m2/g. The obtained lignin-based AGs were further used as raw materials for the preparation of porous carbon aerogels (CAs) under well-controlled pyrolysis conditions with the morphology, especially porosity and the specific surface area, being dependent on the origin of lignin and its content in the starting material.

Reaction Kinetics and Mechanism for the Synthesis of Glycerol Carbonate from Glycerol and Urea Using ZnSO4 as a Catalyst

A series of Zn salts were used as catalysts for the reaction of glycerol and urea to produce glycerol carbonate and it was found that ZnSO4 showed the highest catalytic activity. Furthermore, the effects of reaction parameters on the glycerol conversion and glycerol carbonate yield were studied in detail. The results indicated that the glycerol conversion and glycerol carbonate yield were increased with the reaction temperature, reaction time, and catalyst amount while the optimal reaction conditions were 140 °C, 240 min, catalyst amount of 5 wt% (based on the glycerol weight), and urea-to-glycerol molar ratio of 1.1:1. During the reaction, the ZnSO4 catalyst is transformed into Zn(NH3)2SO4 at the initial stage of the reaction and then further transformed into Zn(C3H6O3). Zn(C3H6O3) and (NH4)2SO4 may be the true active species for the activation of urea and glycerol, respectively. The reaction mechanism is proposed in this article. Based on the experimental results, a reaction kinetics model considering the change in volume of the reaction system was also established, and the model parameters were obtained by fitting the experimental data. The statistical results showed that the established kinetics model is accurate.

A dual-ionic hyper-crosslinked polymer for efficient CO2 fixation and conversion

It is of great significance for reducing carbon emissions and protecting the environment to convert carbon dioxide (CO2) into high-value chemicals. The cycloaddition of CO2 with epoxides to prepare cyclic carbonates is a very attractive and potential approach. However, due to the inherent chemical inertness of CO2, the development of highly efficient, metal-free, solvent-free, and co-catalyst-free heterogeneous catalysts is crucial. Herein, a dual-ionic system hyper-cross-linked polymer (HIP-COOH-TMG) was synthesized by a post-synthetic strategy. HIP-COOH-TMG with multiple active sites was characterized by FT-IR, XPS and other characterizations. HIP-COOH-TMG exhibited the excellent catalytic activity than HIP-COOH for the CO2 cycloaddition, the yield and selectivity of chloropropene carbonate (CC) reached 99 % within 8 h at 110 °C under 1 MPa CO2 pressure. In addition, HIP-COOH-TMG is easily separated from the product, has good recyclability and structural stability, and exhibits high activity towards a series of epoxides. Finally, density functional theory (DFT) calculations reveal the synergistic catalytic mechanism of hydrogen bond donors (HBDs) groups = NH2+ sites and N sites activation of HIP-COOH-TMG, providing a reference for the design of metal-free, co-catalyst-free, and solvent-free heterogeneous catalysts.

Improving maize carbon and nitrogen metabolic pathways and yield with nitrogen application rate and nitrogen forms.

Reduced fertilizer efficiency caused by excessive use of nitrogen (N) fertilizer is a major problem in agriculture and a hot topic of research. Most studies have focused on the effect of N application rate on N efficiency, whereas there are limited studies on changing the N form to improve N yield and efficiency. Here, the effects of different N application rates and nitrate-to-ammonium N ratios on post-anthesis carbon (C) and N metabolism and maize yield under shallow-buried drip irrigation were investigated. Two rates of N application (210 kg·ha-1 (NA1) and 300 kg·ha-1 (NA2)) and three nitrate-to-ammonium N ratios (2:1 (NF1), 3:1 (NF2), and 4:1 (NF3)) were utilized. Post-anthesis photosynthetic characteristics, activities of key enzymes in photosynthetic C and N metabolism, nonstructural carbohydrate content, post-anthesis N accumulation and transportation, yield, and N-use efficiency were determined. At both N application rates, NF2 treatment enhanced photosynthetic activity in the ear-leaf at silking stage and promoted key enzyme activities of C and N metabolic pathways, compared with NF1 and NF3. Furthermore, NF2 significantly increased nonstructural carbohydrate accumulation (4.00-64.71%), post-anthesis N accumulation and transportation (11.00-38.00%), and grain yield (2.60-13.08%). No significant differences between NA1 and NA2 were observed under NF2 in most of the measured variables; however, NA1 had higher N-use efficiency. Thus, the optimal treatment under shallow-buried drip irrigation was a N application rate of 210 kg ha-1 and a nitrate-to-ammonium N ratio of 3:1. These findings provide theoretical guidance on appropriate N applications for high-yield maize production.

Balancing act: influence of Cu content in NiCu/C catalysts for methane decomposition.

Thermal catalytic decomposition of methane is an innovative pathway to produce CO2-free hydrogen from natural gas. We investigated the role of Cu content in carbon-supported bimetallic NiCu catalysts. A graphitic carbon material was used as a model support, and we combined operando methane decomposition experiments in a thermogravimetric analyzer with in situ electron microscopy measurements. The carbon yield was maximum with around 30% Cu in the nanoparticles. Adding more Cu drastically lowered the carbon solubility in the metal nanoparticles, which lowered the initial reaction rate and overall carbon yield. In situ TEM measurements showed that the addition of Cu to the catalysts strongly influenced the metal nanoparticle shape and size during carbon growth, and the growth mode. NiCu particles were larger, remained spherical and facilitated steady CNF growth. In contrast, pure Ni nanoparticles fluctuated in shape, sometimes fragmented, and showed stuttering CNF growth. This was ascribed to fluctuating coverage of part of the Ni nanoparticle surface with amorphous carbon, which increased the chance of total encapsulation and hence deactivation of the individual Ni nanoparticles. This supports a picture where balancing the carbon supply, transport, and nucleation of amorphous and crystalline carbon is crucial. Our results also highlight the importance of combining statistically relevant measurements with microscopic information on individual nanoparticles to understand overall catalytic trends from the combined behavior of individual catalyst nanoparticles.

Aspen HYSYS’ Simulation of Ammonia Synthesis from Stranded Gas

Companies have been finding ways stranded gas can economically be used or marketed rather than flaring it. The issue of gas flaring is being frowned upon by many regulatory bodies; hence most oil and gas operators are advised to find a better alternative. A high rate of gas flaring threatens our environment as it reduces the oxygen content in the atmosphere resulting in health issues and waste of our natural resources. However, this paper aims to simulate ammonia production from stranded gas (gas flare stream). A simulation approach was adopted using Aspen HYSYS V10 (Version 10). Three basic processes were employed during the simulation: steam reforming, carbon capturing and ammonia synthesis. The data used for the simulation were obtained from a marginal field operator in the Niger Delta region of Nigeria. Upon simulation, it was observed that the gas stream flowing at a rate of 484.13MMscf/day, with a pressure of 568.9 psig, yielded high ammonia gas of0.810829276 mole fraction at a low temperature of 30oC and pressure of 298.62 bar. High purity of hydrogen and 0% yield of carbon (IV) oxide were obtained by passing the syngas through carbon capture unit which made of absorber and desorber of packed column and MEAmine solvent for removal of CO2. In a nutshell, the result obtained from the simulation proved to be environmentally friendly as little to no greenhouse gases were expended.

Development of biochar/HDPE composites and characterization of the effects of carbon loadings on the electromagnetic shielding properties

The aim of this research is to develop high carbon-yielding biochar from pinewood, coffee husk, sugarcane bagasse, and maize cob and to characterize the biochar/HDPE composites for electromagnetic (EM) shielding application. During the biochar/HDPE composites fabrication, slow pyrolysis and compression molding manufacturing were used. The enhanced properties characterizations were conducted by using thermogravimetric analysis (TGA), scanning electron microscopy (SEM), differential thermal analysis (DTA), Fourier transform spectrometry (FTIR), Brunauer-Emmet-Teller (BET) analysis, digital multi-meter, and proximity analysis. The results of biochar pyrolysis showed the maximum carbon yield of 74.6 %, 68.9 %, 68.4 %, and 40 % for pine wood, maize cob, sugarcane bagasse, and coffee husk respectively. The BET analysis showed the maximum specific surface area (734.5 m2/g), pore volume (0.2364 cm3/g), and pore radius (9.897 Å) from the pine wood biochar. The biochar loading analysis results showed that the 30 % and 40 % pine wood biochar significantly enhanced the electrical conductivity, thermal conductivity, thermal stability, crystallinity, and EM shielding effectiveness (SE) of the biochar/HDPE composites. In particular, the biochar/HDPE composite with 30 wt% pine wood biochar showed the highest thermal conductivity of 2.219 W/mK, and the 40 wt% pine wood biochar/HDPE composite achieved the highest electrical conductivity of 4.67 × 10−7 S/cm and EM SE of 44.03 dB at 2.1 GHz.

Halide-free CO2 cycloaddition onto styrene oxide catalysed by first row transition-metal derivatives of polyoxotungstates.

Quaternary ammonium salts of metal derivatives of polyoxometalates [XW11O39M(H2O)]n- (X = P, Si; M = Cr, Mn, Co, Ni, Zn) were successfully tested instead of quaternary ammonium halides as catalysts in the cycloaddition of CO2 to styrene oxide. Remarkably, they gave very satisfactory yields of styrene carbonate at moderate temperature (80 °C).

Hydrophobic diamine-functionalized ionic liquid for effective transformation of CO2: a bridge to achieve separation and recycling processes in homogeneous systems

The ionic liquid [MAMIm][PF6] promotes the reaction of CO2 and halohydrins under mild conditions with a high yield of cyclic carbonates, and can be readily recycled by simple washing.

Activation of uranyl peroxides by ionizing radiation prior to uranyl carbonate formation.

The solid form of the uranyl peroxide cage (UPC) cluster LiU28 (Li28[(UO2)28(O2)42]) was irradiated by 5 MeV He2+ ions to achieve doses up to 42 MGy. An intermediate compound formed that reacts with atmospheric CO2 to form uranyl carbonates. The role of water in the UPC to uranyl carbonate transformation was studied by flowing either dry or hydrated Ar over samples during He2+ irradiation, and by storing samples in dry and humid environments before and after irradiation. Raman, infrared, and X-ray photoelectron spectroscopies and electrospray ionization mass spectrometry were used to characterize solid Li-U28 salts before and after He2+ irradiation. The highest yield of uranyl carbonates occurred when hydrated Ar gas was flowed across the sample during He2+ irradiation. Electron paramagnetic resonance spectroscopy provided evidence of hydroxyl and superoxide radicals in both unirradiated and γ-irradiated Li-U28.

Ionic liquid post-modified carboxylate-rich MOFs for efficient catalytic CO2 cycloaddition under solvent-free conditions.

The synthesis of cyclic carbonates through cycloaddition reactions between epoxides and carbon dioxide (CO2) is an important industrial process. Metal-Organic Frameworks (MOFs) have functional and ordered pore structures, making them attractive catalysts for converting gas molecules into valuable products. One approach to enhance the catalytic activity of MOFs in CO2 cycloaddition reactions is to create open metal sites within MOFs. In this study, the amino-functionalized rare earth Gd-MOF (Gd-TPTC-NH2) and its ionic liquid composite catalysts (Gd-TPTC-NH-[BMIM]Br) were synthesized using 2'-amino-[1,1':4',1''-terphenyl]-3,3'',5,5''-tetracarboxylic acid (H4TPTC-NH2) as the ligand. The catalytic performance of these two catalysts was observed in the cycloaddition reaction of CO2 and epoxides. Under the optimized reaction conditions, Gd-TPTC-NH-[BMIM]Br can effectively catalyze the cycloaddition reaction of a variety of epoxide substrates with good to excellent yields of cyclic carbonate products. Comparatively, epichlorohydrin and epibromohydrin, which possess halogen substituents, promote higher yields of cyclic carbonates due to the electron-withdrawing nature of Cl and Br substituents. Additionally, the Gd-TPTC-NH-[BMIM]Br catalyst demonstrated good recyclability and reproducibility, maintaining its catalytic activity without any changes in its structure or properties after five reuse cycles.

Long Term Effect of Integrated Nutrient Management on Soil Organic Carbon Status and Yield of Sunflower in Alfisols

Permanent manurial experiment was started from the year 1909 at Tamil Nadu Agricultural University, Coimbatore, in order to assess the impact of continuous addition of organic and mineral fertilizers on crop yield and soil quality. Conducting a long-term experiment at fixed site with continuous cropping will help to monitor the changes in soil quality and crop yields sustainability and also guide in developing strategies for fertilizer management while minimizing the environmental degradation. From the results revealed that the application of 100% NPK + Farmyard manure (FYM) @ 12.5 t ha-1 (INM) increased the seed yield (1879 kg ha-1) and straw yield of sunflower crop (3916 kg ha-1) when compared to control. Highest carbon build up was observed in the application of 100% NPK + Farmyard manure (FYM) @ 12.5 t ha-1 (INM) 9.8 g kg-1when compared to control (5.4 g kg-1).The present hypothesis showed that, the application of chemical fertilizer along with FYM @ 12.5 t ha-1 had positively impact on yield sustainability and soil health.

Effect of different sources of biochar incubated with FYM on soil carbon pools and yield of fodder maize

Effect of different sources of biochar incubated with FYM on soil carbon pools and yield of fodder maize

Fabrication of Strong Basic Sites on Cr3+ Doped Reductive Support and Its Catalytic Application for Transesterification

Solid strong base catalysts have attracted much attention for their excellent catalytic performance and environmental friendliness due to heterogeneous properties. However, this kind of catalyst usually needs a higher temperature to be activated. Therefore, it is still a challenge to obtain high-activity catalysts at lower fabrication temperatures. In this paper, a reductive catalyst support containing low-valence metal centers (Cr3+) was prepared. Through the redox reaction between the Cr3+ and KNO3, the basic sites can be produced at lower temperatures on the reductive support (Cr-MeIM). Thermogravimetry-mass (TG-MS) spectrometer results showed that the base precursor began to be transformed into basic sites at about a low temperature of 180°C. The solid base catalyst was applied into transesterification between ethylene carbonate (EC) and methanol. By using 0.05 g of catalyst for 3 h at 70°C, we obtained a dimethyl carbonate (DMC) yield of up to 60.9%, which means that the catalyst has high activity.

Enzyme-accelerated CO2 capture and storage (CCS) using paper and pulp residues as co-sequestrating agents.

In the present work, four CaCO3-rich solid residues from the pulp and paper industry (lime mud, green liquor sludge, electrostatic precipitator dust, and lime dregs) were assessed for their potential as co-sequestrating agents in carbon capture. Carbonic anhydrase (CA) was added to promote both CO2 hydration and residue mineral dissolution, offering an enhancement in CO2-capture yield under atmospheric (up to 4-fold) and industrial-gas mimic conditions (up to 2.2-fold). Geological CO2 storage using olivine as a reference material was employed in two stages: one involving mineral dissolution, with leaching of Mg2+ and SiO2 from olivine; and the second involving mineral carbonation, converting Mg2+ and bicarbonate to MgCO3 as a permanent storage form of CO2. The results showed an enhanced carbonation yield up to 6.9%, when CA was added in the prior CO2-capture step. The proposed route underlines the importance of the valorization of industrial residues toward achieving neutral, or even negative emissions in the case of bioenergy-based plants, without the need for energy-intensive compression and long-distance transport of the captured CO2. This is a proof of concept for an integrated strategy in which a biocatalyst is applied as a CO2-capture promoter while CO2 storage can be done near industrial sites with adequate geological characteristics.

Understanding the preparative chemistry of atomically dispersed nickel catalysts for achieving high-efficiency H2O2 electrosynthesis.

Electrochemical hydrogen peroxide (H2O2) production via two-electron oxygen reduction reaction (2e- ORR) has received increasing attention as it enables clean, sustainable, and on-site H2O2 production. Mimicking the active site structure of H2O2 production enzymes, such as nickel superoxide dismutase, is the most intuitive way to design efficient 2e- ORR electrocatalysts. However, Ni-based catalysts have thus far shown relatively low 2e- ORR activity. In this work, we present the design of high-performing, atomically dispersed Ni-based catalysts (Ni ADCs) for H2O2 production through understanding the formation chemistry of the Ni-based active sites. The use of a precoordinated precursor and pyrolysis within a confined nanospace were found to be essential for generating active Ni-N x sites in high density and increasing carbon yields, respectively. A series of model catalysts prepared from coordinating solvents having different vapor pressures gave rise to Ni ADCs with controlled ratios of Ni-N x sites and Ni nanoparticles, which revealed that the Ni-N x sites have greater 2e- ORR activity. Another set of Ni ADCs identified the important role of the degree of distortion from the square planar structure in H2O2 electrosynthesis activity. The optimized catalyst exhibited a record H2O2 electrosynthesis mass activity with excellent H2O2 selectivity.

LTA zeolites as catalysts for transesterification of glycerol with dimethyl carbonate

The objective of this study was to investigate the use of LTA-structured zeolites as catalysts for synthesizing glycerol carbonate through the transesterification of glycerol with dimethyl carbonate, under mild reaction conditions. To evaluate the catalysts, a range of characterization techniques, including XRD, AES, SEM, TPD-NH3, TPD-CO2, and FT-IR with probe molecules like pyridine and pyrrole, along with elemental analysis, were employed. The investigation focused on various forms of LTA-structured zeolites (with K, Na, and Ca cations) to assess their impact on transesterification activity, with particular attention to the type of ion utilized and their basicity. Among these zeolites, K-Na-LTA (3A) zeolites demonstrated the most promising performance, achieving glycerol conversion rates ranging from 55 % to 77 %. Moreover, increasing basicity in the 3A zeolites led to higher glycerol conversion and glycerol carbonate yield. Encouragingly, all tested samples exhibited 100 % selectivity, exclusively producing the desired glycerol carbonate. However, during catalyst recycling, the decrease in glycerol conversion was observed, likely due to the leaching of active sites from the catalyst into the reaction medium. Methanol, being a one of the products, was identified as a potential agent responsible for the removal of potassium ions, during this process.

Catagenetic trends in composition and structure parameters of asphaltenes

Сatagenetic transformations of asphaltenes of organic matter (OM) from recent sediments and fossil rocks were studied on rocks sampled from different sedimentary basins (Timan-Pechora, Mezen, West Siberian, Kuznetsk, Aldan-Maya and Middle Amur) of Russia. Changes in the elemental composition of asphaltenes were analyzed with the Veselovsky’s model of the formation of major groups of fossil fuels using cO parameter (cO = (O/8 – N)/(C/3)) as compared with the total carbon based on elemental analysis. Just as the Van-Krevelen diagram, the plot built in C–cO coordinates for OM of various genetic forms demonstrates a significant difference in the asphaltenes composition evolution during catagenesis. At the same time, the cO parameter has notably increased in asphaltenes of both types of OM. Structural transformations of asphaltenes during catagenesis were identified in the course of high-resolution NMR (nuclear magnetic resonance) spectroscopy. The research results comprise data on carbon distributions in the aromatic and aliphatic groups in the investigated asphaltenes of different type OM of sediments and rocks at different stages of lithogenesis. A correlation between the asphaltene composition and structural parameters depending on thermocatalytic transformations is revealed. The asphaltenes of terrestrial organic matter are distinguished by higher cO values and different carbon yields of aromatics (higher) and aliphatics (lower) throughout the catagenesis phase. The highly transformed marine OM is marked by surge condensation of aromatic rings in asphaltenes, which makes them similar to asphaltenes of the terrestrial type OM.

Production of glycerol carbonate from glycerol and carbon dioxide using metal oxide catalysts

This work is focused on a green production of glycerol carbonate through converting glycerol, as a by-product of biodiesel production, and a greenhouse gas, carbon dioxide, using metal oxide catalysts of MgO, CaO, and Al2O3. The catalysts were prepared by precipitation method and characterized by surface area and pore size, TGA, XRD, CO2-TPD, and SEM analyses. The catalysts’ performance was mostly influenced by the number of basic sites and the BET surface area of the catalysts. The catalysts’ activity results displayed that MgO showed the highest glycerol conversion of 22.7% and the highest yield of 10.6% among the investigated catalysts. The turnover number of the optimum catalyst was 14.9 μmol glycerol carbonate/μmol CO2. The effect of reaction parameters on the performance of the reaction was also investigated and the highest glycerol carbonate yield of 12.76 % was achieved at a catalyst loading of 5.5 wt% of glycerol amount, the temperature of 150 ⁰C, and pressure of 8 MPa. The physicochemical properties of catalysts were correlated with their activities and abilities for CO2 activation.

Ionic liquids bonded in mesoporous HAP serve as efficient catalysts for CO2 fixation

In this study, hydroxyapatite (HAP) with abundant surface hydroxyl and large pores was used as the ionic liquid ([DMCA]X) immobilization carrier, where the surface hydroxyl groups of HAP were used as binding sites and the n-halogen-acids were used as bonding agents. The supported ionic liquid catalysts [DMCA]X-n-HAP were characterized by XRD, TEM, TG and FTIR, proving that the ionic liquids were successfully bonded onto the surface of HAP. The utilization of hydroxyl sites on the surface of HAP was as high as 90%. The above catalysts were used to catalyze the cycloaddition reaction of CO2 and propylene oxide (PO), and the yield and selectivity of propylene carbonate (PC) were up to 98.7% and 100%, respectively. The length effect of the bonding agents on the catalyst performance was also studied, and found that n-chlorine-butyric acid was the most suitable chemical for channel structure of HAP and spatial freedom of ionic liquid. In addition, the effects of halogen anion and hydroxyl hydrogen on the performance of the reaction were also studied. Importantly, autocatalysis was discovered in the reaction. Finally, the reaction intermediates and reaction mechanism of CO2 cycloaddition were investigated by in situ-DRIFTS, revealing that ring-open of PO is rate-determining step.