Aromatic CC Research Articles

Effect of pyridine extraction on the pyrolysis of a perhydrous coal based on in-situ FTIR analysis

Pyridine extraction of coal can separate the small molecules from macromolecule skeleton and subsequently impacts the thermal behavior of coal. A perhydrous bituminous coal with a high content of volatile matters was extracted by pyridine under microwave irradiation with an extraction yield of 24.6% on the dry, ash free basis (daf). The thermal behavior of the raw coal, its extract and residue was investigated by thermogravimetric analysis and in-situ Fourier Transform Infrared Spectroscopy (FTIR) based on the evolution of weight loss and functional groups, respectively. Though pyridine extraction had only slight effect on TG curve of the perhydrous coal, it greatly influenced the evolution of functional groups during pyrolysis. Aromatic CH and CO was the most susceptible to pyridine extraction because the absence of extractable moieties reduced the production of radicals and the reactions between small molecules and macromolecules during pyrolysis. The interactions between extractable small molecules and non-extractable macromolecules could retard the decomposition of aromatic CC and hydroxyls. The evolution of aliphatic groups and CO was slightly impacted due to the occurrence of the abundant aliphatic side groups and bridge bonds in macromolecule structures.

Effect of acetone–butanol–ethanol addition to diesel on the soot reactivity

The ability of acetone–butanol–ethanol (ABE) to reduce pollutant emissions has been validated in recent studies. In this study, the effect of addition of ABE (up to 30% by volume) to diesel on the soot oxidation reactivity was investigated to further evaluate the feasibility of increasing the particulate filter regeneration rate. The oxidation activities of soot samples were compared using the average activation energies calculated from the thermal gravimetric curves. It was found that the average activation energies of the ABE-diesel-blends-derived soot are lower than that of diesel-derived soot. The variations in the physical and chemical properties of the soot samples were investigated to determine the parameters that improve the soot oxidation reactivity. Several experimental diagnostic techniques, such as Fourier transform infrared spectroscopy, elemental analysis, X-ray diffraction, and high-resolution transmission electron microscopy, were used to investigate the changes in the functional groups, atomic O/C and H/C ratios, nanocrystallite parameters, and soot nanostructures. With increasing concentration of ABE in diesel, the size of the primary particles, nanocrystallite length, and amount of aromatic CC functional groups in the soot decrease, while the nanocrystallites tortuosity, amount of oxygenated functional groups, and atomic O/C and H/C ratios increase. The changes of these parameters prove the higher reactivity of ABE-diesel-blends-derived soot.

Extraneous dissolved organic matter enhanced adsorption of dibutyl phthalate in soils: Insights from kinetics and isotherms

The widespread use of plastic film, especially in agricultural practices, has resulted in phthalic acid esters (PAEs) pollution, which poses risks for greenhouse soils. Application of composted manure is a common agricultural practice that adds extraneous dissolved organic matter (DOM) to the soil, however, the effect of extraneous DOM on the behavior of PAEs in agricultural soil is not clear. Dibutyl phthalate (DBP) was used as a model compound to investigate the effect and mechanism of extraneous DOM on the adsorption kinetics and isotherms of PAEs in two types of soils, through batch experiments and characterization of extraneous DOM and soils using fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The equilibrium adsorption amount of DBP in black soil was higher than in red soil regardless of the presence of extraneous DOM, due to the higher organic matter content of black soil. Hydrophobic partition played a dominant role in the DBP adsorption process of soils with and without extraneous DOM. The addition of DOM enhanced the adsorption capacity of DBP through partition in the two soils, especially at high DBP concentrations. Additions of a lower concentration of DOM better enhanced the adsorption effect than the higher concentrated DOM, due to an increase in water solubility of DBP resulted from excessive extraneous DOM in aqueous phase. Differences in mineral composition of soils led to diverse adsorption mechanisms of DBP as affected by additions of extraneous DOM. The FTIR spectra indicated that the intra-molecular and intermolecular hydrogen bond interactions of carboxylic acids, aromatic CC and CO in amides were involved in DBP adsorption in soils. Therefore, addition of DOM may increase adsorption of DBP in soils and thus influence its bioavailability and transformation in soils.

Catalytic effects of ion-exchangeable K+ and Ca2+ on rice husk pyrolysis behavior and its gas–liquid–solid product properties

The effects of ion-exchangeable K+ and Ca2+ on rice husk pyrolysis, with a focus on the yields and properties of the gas–liquid–solid products, and their pyrolysis kinetic characteristics, were investigated by thermogravimetry/Fourier-transform infrared spectroscopy and a laboratory-scale fixed-bed reactor. The results indicated that the pyrolysis gas and char yields increased, and the tar yield decreased, with increasing concentrations of K+/Ca2+ in the rice husks. Compared with that of 340 °C for H-form rice husks, the maximum weight loss temperature decreased by more than 25 °C for the 2.0 wt% K-loaded sample, and increased to 360 °C for the 0.2 wt% Ca-loaded one. K+ (2.0 wt%) lowered the first-order activation energy by 18 kJ/mol, and Ca2+ (<0.1 wt%) was more reactive in pyrolysis. The K+/Ca2+ ratio affected the amounts of pyrolysis gases, but not the species, and their presence increased the amount of aromatic CC structures and surface CO groups in the biochar. Catalysis with K+/Ca2+ transformed heavy pyrolysis tar compounds into small-molecule ones.

Facile hydrothermal synthesis of CdFe2O4-reduced graphene oxide nanocomposites and their third-order nonlinear optical properties under CW excitation

Third-order nonlinear optical response of cadmium ferrite loaded upon various content of reduced graphene oxide was studied by single beam Z-scan technique using Nd: YAG laser (532nm, 50mW). In XRD disappearance of characteristic peak of graphene oxide (10.7°, (100)) and appearance of peaks of reduced graphene oxide (23.3°, (002)) along with cadmium ferrite (34.2°, (311)) confirms the trimming of CdFe2O4 upon rGO. Further the successful trimming of rGO with CdFe2O4 was further evidenced by FTIR and high-resolution C 1s XPS. FESEM and TEM image of GO show folded sheets of graphene layers due to strong oxidation and reduction process. And pure CdFe2O4 grow themselves as nanorods which upon trimming on the surface of graphene sheets suffered a morphological change with respect to the content of graphene oxide (rods to platelets). Absorption spectra of decorated composites possess, absorption peaks at 230nm (π-π* transition in aromatic CC), 292nm (n-π* transition in CO bonds) and 425nm (cadmium ferrite). Z-scan results showed that both pure and decorated samples showed saturable absorption and self-defocusing behavior along with optical limiting action. Also the nonlinear refraction was found to be more dominant than nonlinear absorption due to strong contribution arising from thermal components. Upon trimming, the nonlinear refractive index (10−8cm2/W), nonlinear absorption coefficient (10−3cm/W) and third-order nonlinear optical susceptibility (10−6esu) were found to be increasing with increase in graphene content. Variation in the distribution and morphology of CdFe2O4 has resulted in the tunability of third-order NLO coefficients and limiting threshold (9.3–30.4mW). Nanoplatelet CdFe2O4–40wt% rGO displays good optical power handling capability of laser beam at the experimental wavelength, indicating the possible photonics device application such as optical power limiters.

Heterogeneity of peat decomposition under rice cultivation on the Pacific coast, Japan

Peat decomposition has micro-scale heterogeneity because the rate of decomposition differs between micro-local conditions related to pore distribution, botanical composition, and differences in plant parts. Therefore, the heterogeneity of peat decomposition degree in micro-scale can be a good indicator for further understanding of peat decomposition process. However, previous studies using “bulk analysis” have denoted peat heterogeneity as merely chemical structural diversity, and did not examine the heterogeneity of peat constituents at a microscopic level. This study aimed to obtain peat heterogeneity in the micro-scale as a new indicator of peat decomposition and conducted “heterogeneity analysis” as follows: (1) analyzing a decomposition index of individual peat micro-fragments using spectral data from Fourier transform infrared (FTIR) micro-spectroscopy and principal component analysis (PCA) for specific absorption intensities, and (2) determining the distribution of peat decomposition index as an indicator of the heterogeneity of peaty soils. Twelve peaty horizons were sampled from three sites on coastal or alluvial plains. These horizons were buried under mineral soils used for rice cultivation. We applied PCA to 775 infrared (IR) spectra obtained from observed peat micro-fragments and calculated the micro-fragment decomposition degree (MDD) which was the first principal component score explained by a decrease in CH single bonds and a relative increase in polymerized aromatic CC double bonds. The distribution range of MDD demonstrated that heterogeneity of decomposition degree tends to be large in mid-decomposed peat. Moreover, the bimodal distribution pattern of MDD represented heterogeneous state formed by mineral inter-bedding in peat. Therefore, “heterogeneity analysis” could effectively represent the intrinsic heterogeneity of peat decomposition degree without losing the microscopic diversity.

Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates

The speciation of iron (Fe) in organic matter (OM)-rich environments under in situ variable redox conditions is largely unresolved. Peatlands provide a natural setting to study Fe–OM interactions. Utilizing chemical, spectroscopic and theoretical modeling approaches, we report the chemical forms, oxidation states and local coordination environment of naturally occurring Fe in the vertically redox-stratified Manning peatlands of western New York. In addition, we report dominant carbon, sulfur and nitrogen species that can potentially stabilize the various Fe species present in these peatlands. Our results provide clear direct and indirect evidence for the co-occurrence of ferrous (Fe2+) and ferric (Fe3+) iron species in peats under both oxic and anoxic conditions. Iron is mostly present within the operationally defined organic and amorphous (i.e., short range ordered, SRO) fractions; ferric iron primarily as magnetically isolated paramagnetic Fe3+ in Fe(III)-organic complexes, but also in mineral forms such as ferrihydrite; ferrous iron in tetrahedral coordination in Fe(II)-organic complexes with minor contribution from pyrite. All of the Fe species identified stabilize Fe(III) and/or Fe(II) in anoxic and oxic peats. Fundamental differences are also observed in the relative proportion of C, S and N functionalities of OM in oxic and anoxic peats. Aromatic CC, ester, phenol and anomeric C (ROCOR), as well as thiol, sulfide and heterocyclic N functionalities are more prevalent in anoxic peats. Collectively, our experimental evidence suggests iron forms coordination complexes with O-, S- and N-containing functional groups of OM. We posit the co-occurrence of organic and mineral forms of Fe(II) and Fe(III) in both oxic and anoxic peat layers results from dynamic complexation and hydrolysis-precipitation reactions that occur under variable redox conditions. Our findings aid in understanding the crucial role OM plays in determining Fe species in soils and sediments.

Effect of extracellular polymeric substance components on the sorption behavior of 2,2′,4,4′-tetrabromodiphenyl ether to soils: Kinetics and isotherms

Microbial extracellular polymeric substances (EPS) and persistent organic pollutants (POPs) commonly exist in the soil environment. Currently, there is a knowledge gap regarding the effect of EPS on the fate of POPs in soil. In the present study, 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) was used as a model compound to investigate the effects of bovine serum albumin (BSA) and sodium alginate (SA) - mimicking the main components of EPS - on sorption of POPs to soils, through batch experiments. Irrespective of the concentration of BSA: the addition of BSA did enhance the sorption capacity of BDE-47 to soils, due to generation of more sorption sites. For SA, it increased the sorption capacity of BDE-47 at low BDE-47 concentrations, while the presence of SA negatively affected sorption of BDE-47 at high BDE-47 concentrations. The partition effect dominates the sorption of BDE-47 to soils, but after adding either BSA or SA, the sorption of BDE-47 to soils is dominated by surface sorption. Film diffusion and intra-particle diffusion were also involved in the sorption process with and without BSA or SA, with the latter being the rate-limiting step. The heterogeneous surface and nonlinear sorption behavior of BDE-47 to soils increased in the presence of either BSA or SA. The FTIR spectra indicated that the aromatic CC, H-bonds and OH groups may be involved in the sorption process. Therefore, BSA enhanced the retention of BDE-47 to soil, while SA's influence on BDE-47 sorption to soil depended on the concentration of BDE-47.

Mechanistic links between magnetic nanoparticles and recovery potential and enhanced capacity for crystal violet of nanoparticles-coated kaolin

Kaolin has potential in wastewaters treatment due to its advantage of nontoxicity to aquatic flora and fauna. However, its adsorption capacity needs significant improvement, in addition, the re-collection of adsorbents after application can reduce the risk of desorption of pollutants. Therefore, nanoparticle-modified kaolin (NMK) was prepared by coating kaolin with Fe3O4 nanoparticles to enhance the adsorption capacity of kaolin for crystal violet (CV) in this study. Fe3O4 nanoparticles improved the adsorption capacity of kaolin by at least an order of magnitude, with a maximum capacity of 247.68 ± 4.56 mg CV/g NMK with the initial CV concentration of 800 mg/L; additionally, nanoparticles endowed NMK a magnetization of 21.20 emu/g, indicating that NMK has a magnetic re-collection potential. Spectroscopic analysis demonstrates that the epoxy groups in kaolin are likely the link to the nanoparticles, and the aromatic CC and CO groups of NMK could be responsible for CV adsorption. The enhanced adsorption capacity mechanism of NMK is attributed to nanoparticles decreased zeta potential and changed porous surface characteristics of virgin kaolin. The results suggest that some materials can become more effective in environmental applications via modification by nanoparticles.

Equilibrium, kinetics and thermodynamics of cadmium ions (Cd2 +) removal from aqueous solution using earthworm manure-derived carbon materials

Carbon materials (CMs) derived from earthworm manure via slow pyrolysis at 400–600°C were employed as adsorbents for the removal of cadmium ions (Cd2+) from aqueous solution. The influences of adsorption conditions (including initial concentrations, contact time, ambient temperature, solution pH, ionic strength and adsorbent dosage) on the removal of Cd2+ using the developed CMs were investigated in addition to the potential mechanism studies in the adsorption process. The increase of initial concentration promoted the adsorption capacity and confined the removal rate of Cd2+. Adsorption was vigorously commenced within the initial contact time of 1h, accounting for 63.81–76.52% to the total adsorption amount. It is found that the adsorption performance was not significantly influenced by the solution pH between 3.5 and 5.5 and the ionic strength between 0 and 0.01molNaNO3/L. Overall, the optimum initial concentration, contact time, ambient temperature, solution pH, ionic strength and adsorbent dosage were 80mg/L, 24h, 25°C, 5.5, 0molNaNO3/L and 2g/L, respectively, in terms of single factor test. The maximum adsorption capacity of the CM prepared from 400, 500 and 600°C were 32.468, 19.646 and 14.599mg/g, respectively. The uptake of Cd2+ by the CMs was subjected to the spontaneous and endothermic processes. Alkali and alkaline earth metallic, especially for Ca2+ and Mg2+, can accelerate the adsorption through ion exchange interactions. Complexation and precipitation driven by surface functional groups involving oxygen-containing groups and aromatic CC, and salt minerals (phosphates, carbonates or silicates) may also make important contributions to the adsorption process.

Evaluation of Effective Microorganisms on home scale organic waste composting

Home composting can be an effective way to reduce the volume of municipal solid waste. The aim of this study is to evaluate the effect of Effective Microorganism™ (EM) for the home scale co-composting of food waste, rice bran and dried leaves. A general consensus is lacking regarding the efficiency of inoculation composting. Home scale composting was carried out with and without EM (control) to identify the roles of EM. The composting parameters for both trials showed a similar trend of changes during the decomposition. As assayed by Fourier Transform Infrared Spectroscopy (FTIR), the functional group of humic acid was initially dominated by aliphatic structure but was dominated by the aromatic in the final compost. The EM compost has a sharper peak of aromatic CC bond presenting a better degree of humification. Compost with EM achieved a slightly higher temperature at the early stage, with foul odour suppressed, enhanced humification process and a greater fat reduction (73%). No significant difference was found for the final composts inoculated with and without EM. The properties included pH (∼7), electric conductivity (∼2), carbon-to-nitrogen ratio (C: N < 14), colour (dark brown), odour (earthy smell), germination index (>100%), humic acid content (4.5–4.8%) and pathogen content (no Salmonella, <1000 Most Probable Number/g E. coli). All samples were well matured within 2 months. The potassium and phosphate contents in both cases were similar however the EM compost has a higher nitrogen content (+1.5%). The overall results suggested the positive effect provided by EM notably in odour control and humification.

Interaction between bacterial cell membranes and nano-TiO2 revealed by two-dimensional FTIR correlation spectroscopy using bacterial ghost as a model cell envelope

The interaction between microorganisms and nanoparticles is a crucial step towards understanding the subsequent biological effect. In this study, the interaction between TiO2 nanoparticles and bacterial cell membrane was investigated by Two-dimensional Correlation Fourier Transformation Infrared spectroscopy (2D-FTIR-COS) using bacterial ghosts (BGs), which are non-living bacterial cell envelopes devoid of cytoplasm. The synchronous map of 2D-FTIR-COS results indicated that the functionalities in proteins of BGs preferentially interacted with TiO2 nanoparticles; whereas the interaction of TiO2 nanoparticles with characteristic functionality in polysaccharides (COH) and phospholipids (PO) were very weak or insensitive. This conclusion was further corroborated by settling of TiO2 nanoparticles in the presence of pure protein, polysaccharide and phospholipid represented by bovine serum albumin (BSA), alginate and phosphatidylethanolamine (PE). Additionally, the asynchronous map of 2D-FTIR-COS indicated a sequential order of functionalities bonded to TiO2 nanoparticles with the order of: COO− > aromatic CC stretching > NH, amide II > CO, ketone. These findings contribute to deeper understanding of the interaction between TiO2 nanoparticles and bacterial cell membrane in aquatic systems.

Nonlinear mechanical behaviour of γ-graphyne through an atomistic finite element model

A non-linear finite element model for the simulation of the mechanical in-plane behaviour of γ-graphyne is presented in this paper. Different types of bonds (Single CC, Aromatic CC, Triple CC) are simulated by means of non-linear springs, which accurately take into account the different behaviour of interatomic forces in tension and compression at 0K temperature. Then, the finite element model is used to conduct six tests (two uniaxial tension–compression tests, one biaxial tension–compression test, two uniaxial shear tests, one biaxial shear test) to evaluate the non-linear mechanical behaviour of γ-graphyne. After that, a set of linear elastic properties (Young’s modulus, Poisson’s ratio, shear modulus, bulk modulus) and non-linear elastic properties (limit of proportionality stress and strain, ultimate stress and strain) is reported and compared with values reported in the literature (mostly linear elastic properties). This validation shows that the developed finite element model is able to predict accurately the linear and non-linear mechanical properties of γ-graphyne (i.e. stiffness and strength). Additionally, some remarks are drawn regarding the anisotropy of γ-graphyne and its distinct behaviour under tension and compression.

Evolution of char structure during mengdong coal pyrolysis: Influence of temperature and K2CO3

Weight loss and gas release behavior of mengdong coal (MD) during pyrolysis was investigated using thermogravimetric analyzer coupled with Fourier transform infrared spectroscopy (TGA-FTIR), and char evolution of coal chars derived at different pyrolysis temperature were analyzed with two dimensional perturbation correlation infrared spectroscopy (2D-PCIS) method to reveal the mechanism of mengdong coal pyrolysis. The MD coal showed a significant weight loss at 300–600°C during pyrolysis. Free OH groups reacted before OH-πand self-associated n-mers hydrogen bond. The demethylenation reaction sequence was aliphatic R3-CH groups and asymmetric aliphatic R-CH3>symmetric aliphatic R2-CH2>asymmetric aliphatic R2-CH2. CO2 releasing mainly resulted from the crack of CO in aryl ethers groups, CO in alcohols in coal molecular. The effect of K2CO3 on char structure was also studied. The results showed that, inherent mineral of coal presented stronger catalytic effects towards pyrolysis. K2CO3 addition influenced the reaction sequences of R3-CH, symmetric R2-CH2 and asymmetric R2-CH2 insignificantly, but could significantly change the correlation of CO, CO, CHCH3, and aromatic CC bond.

Low cost earthworm manure-derived carbon material for the adsorption of Cu2+ from aqueous solution: Impact of pyrolysis temperature

Earthworm manure, an emerging and abundant bio-waste from vermicomposting, was subjected to pyrolyze at 400–600°C to prepare carbon material (EMBCs) for the removal of Cu2+ from aqueous solution. The adsorption capability and inherent mechanism were thoroughly investigated. All adsorption processes of Cu2+ by EMBCs were described through Langmuir isotherm model and pseudo-second-order model. The adsorption capacity of EMBCs was declined with the pyrolysis temperature, while the binding strength between EMBCs and Cu2+ was significantly enhanced accordingly. The adsorption process of Cu2+ by EMBCs was found to be dominated by precipitation, complexation, Cπ-cations interactions. Precipitation was mainly stimulated by silicates and phosphates leading to 35.12%–40.72% adsorption of Cu2+. The contribution of complexation to Cu2+ adsorption were decreased from 46.61% to 17.12% as the pyrolysis temperature was increased form 400 to 600°C. Comparatively, the contribution of Cπ-cations interaction were increased from 18.27% to 42.16% with the increased temperature due to the abundant aromatic CC structure.

Immobilization of Cu2 + and Cd2 + by earthworm manure derived biochar in acidic circumstance

Earthworm manure, the by-product obtained from the disposing of biowastes by earthworm breeding, is largely produced and employed as a feedstock for biochar preparation through pyrolysis. For repairing acidic soil or acidic electroplating effluent, biochar physicochemical properties would suffer from some changes like an acidic washing process, which hence affected its application functions. Pristine biochar (UBC) from pyrolysis of earthworm manure at 700°C and biochar treated by HCl (WBC) were comparatively investigated regarding their physicochemical properties, adsorption capability and adsorption mechanism of Cu2+ and Cd2+ from aqueous solution to explore the immobilization characteristics of biochar in acidic environment. After HCl treatment, the soluble ash content and phenolic-OH in the WBC sample was notably decreased against the increase of the carboxyl CO, aromatic CC and Si–O–Si, compared to that of UBC. All adsorption processes can be well described by Langmuir isotherm model. The calculated maximum adsorption capacity of Cu2+ and Cd2+ adsorption on UBC were 36.56 and 29.31mg/g, respectively, which were higher than that of WBC (8.64 and 12.81mg/g, respectively), indicating that HCl treatment significantly decreased biochar adsorption ability. Mechanism analysis revealed that alkali and alkaline earth metallic, salts (carbonates, phosphates and silicates), and surface functional groups were responsible for UBC adsorption, corresponding to ion exchange, precipitation and complexation, respectively. However, ion exchange made little contributions to WBC adsorption due to the great loss of soluble ash content. WBC adsorption was mainly attributed to the abundant exposure of silicates and surface functional groups (carboxyl CO and aromatic CC).

Structure of some western Anatolia coals investigated by FTIR, Raman, 13C solid state NMR spectroscopy and X-ray diffraction

Turkey has one of the largest lignite deposits in Europe but the low calorific values of Turkish lignites dictate new and environmentally safe new utilization technologies for further utilization. Research on coal chemical structures has long been of great interest as a fundamental issue for coal chemistry. Identifying the structures of organic material in lignites is important for lignite conversions to clean liquid fuels and value-added chemicals. Therefore, investigation of chemical and degree of ordered structure present in Turkish lignites is desirable. We report structural information of two coals from the Manisa Soma region, two from the Mugla Yatagan region and one from Kutahya Seyitomer region. FTIR spectra of coal samples contained peaks due to OH and CO functional groups, aliphatic CH, CH2, CH3 and aromatic CC and aromatic-CH structures. Coals with higher fixed carbon were oxidized more after oxidation experiments, as evidenced by the higher intensity of the CO band. Coals that contained higher amounts of nonpolar alkyl and aromatic CC, C-H groups were affected more by the oxidation reactions, which formed high-intensity CO band. XRD investigation revealed crystal structures present in the lignites were arranged slightly to form turbostratic arrangement. The structure of Yatagan region coals was less ordered compared to the other samples. The XRD aromaticity (fa) of the coals ranged between 0.642 and 0.777. Investigations showed that there was a good correlation between calculated structural parameters and maturity of the coals. Raman spectra of the coals revealed that samples contained significant proportions of highly disordered amorphous carbon structures. 13C NMR aromaticities of the coal samples were found between 0.536 and 0.754. Aromaticity values obtained by XRD and NMR methods were in high correlation.

Investigation of mechanism and kinetics of non-isothermal low temperature pyrolysis of perhydrous bituminous coal by in-situ FTIR

Perhydrous coal has advantages as a fuel source and raw material for hydrocarbon production over other coal with similar rank. Good understanding of thermal characterization of perhydrous coal can provide important information for control of the pollutants release and enhancement of the conversion rate of coal during its utilization. A perhydrous bituminous coal from Dingji Coal Mine, China was selected for the investigation of the non-isothermal pyrolysis process below 500°C in N2 flow by in-situ transmission FIIR. Evolutions of the main functional groups in coal, including aliphatic groups, aromatic CC and CH, carbonyl, CO and hydroxyl could be divided into several stages. The thermal characterization of each stage was discussed. The aliphatic groups and aromatic CC content decreased slightly with the volatilization of small molecules below 400°C, while the amount of aromatic CH increased with the loss of substituent groups. The conversion of CO to CO contributes to the slight increase in the CO amount below 370°C, and the decrease of hydroxyl was attributed to loss of water and the condensation and elimination of hydroxyl groups. The amount of all functional groups except for the aromatic CH declined rapidly with the cracking of CC bonds after 400°C. The kinetic characterization of pyrolysis stages for three functional groups, including aliphatic groups, CO and hydroxyl, was studied with modified integral method. Activation energy of pyrolysis stages of the three functional groups increased with rising temperature. Kinetics for the different stages of functional groups were fitted with different kinetic models. The initial loss of aliphatic groups and CO was controlled by diffusion. Then, the reaction of the three functional groups fitted on the first-order or third-order reaction models. The results obtained by in-situ FTIR revealed more detail information about thermal characterization and kinetic characterization and can be expected to lead to good understanding of pyrolysis of a perhydrous coal.

Synthesis and characterization of enzymatically cross-linked feruloyl amylopectin for curcumin encapsulation

Feruloyl amylopectin (FAP) was synthesized by the N,N′-carbonyldiimidazole (CDI) activation method, and the enzymatically cross-linked feruloyl amylopectin (CL-FAP) was prepared via catalysis of horseradish peroxidase (HRP) with the presence of hydrogen peroxide (H2O2). RP-HPLC-DAD/ESI-TOF-MS measured ferulic acid and its derivatives in FAP and CL-FAP. FAP was primarily composed of two ferulate monomers, while CL-FAP was composed of two ferulate monomers and two ferulate dehydrodimers. The ester formation in the feruloyl group was confirmed by the presence of carbonyl and aromatic CC signal near 1725 (1723) and 1510cm−1 in the FT-IR spectra. X-ray diffraction studies showed that the two modified amylopectins lost the ordered A-type crystalline structure, characteristic of maize amylopectin. The encapsulation capacity of curcumin (ECC) in 1mg/mL CL-FAP microemulsion was measured at 88.13μg/mg by HPLC.

Toluene removal from waste air stream by the catalytic ozonation process with MgO/GAC composite as catalyst

This paper investigates the catalytic potential of MgO/GAC composite for toluene elimination from waste air in the catalytic ozonation process (COP). The MgO/GAC composite was a micro-porous material with the BET surface area of 1082m2/g. Different functional groups including aromatic CC, saturated CO of anhydrates, hydroxyl groups and SH bond of thiols were identified on the surface of MgO/GAC. Effects of residence time (0.5–4s), inlet toluene concentration (100–400ppmv) and bed temperature (25–100°C) were investigated on degradation of toluene in COP. Impregnation of GAC with MgO increased the breakthrough time and removal capacity by 73.9% and 64.6%, respectively, at the optimal conditions. The catalytic potential of the GAC and MgO/GAC for toluene degradation was 11.1% and 90.6%, respectively, at the optimum condition. The highest removal capacity using MgO/GAC (297.9gtoulene/gMgO/GAC) was attained at 100°C, whereas the highest removal capacity of GAC (128.5mgtoulene/gGAC) was obtained at 25°C. Major by-products of the toluene removal in COP with GAC were Formic acid, benzaldehyde, O-nitro-p-cresol and methyl di-phenyl-methane. MgO/GAC could greatly catalyze the decomposition of toluene in COPand formic acid was the main compound desorbed from the catalyst. Accordingly, the MgO/GAC is an efficient material to catalyze the ozonation of hydrocarbon vapors.