CO2-hierarchical activated carbon prepared from coal gasification residue: Adsorption equilibrium, isotherm, kinetic and thermodynamic studies for methylene blue removal

Mineral matter in a residue(RC G)from coal gasification(CG)was removed by two-stage acid leaching.Hierarchical activated carbon(HAC)was prepared by activating RC Gwith CO2.The performance of HAC on removing methylene blue(MB)from an aqueous solution was investigated.HAC was characterized by N2 adsorption–desorption isotherm,Fourier transform infrared spectroscopy,and scanning electron microscopy.The results show that HAC exhibits hierarchical pore structure with high specific surface area(862.76 m2·g-1)and total pore volume(0.684 cm3·g-1),and abundant organic functional groups.The adsorption equilibrium data of MB on HAC are best fitted to the Redlich-Peterson.The kinetic data show that the pseudo-first-order model is more suitable at low MB concentration,while the advantages of the pseudo-second-orderand the Elovich models are more obvious as the concentration increases.According to the thermodynamic parameters,the HAC-MB adsorption process is spontaneous and endothermic.

Characterization of nitrogen-containing aromatics in Baiyinhua lignite and its soluble portions from thermal dissolution

Soluble portions(SPs) 1-4(SP1-SP4) were afforded from sequentially dissolution and alkanolyses of Baiyinhua lignite(BL) in cyclohexane,CH3OH,CH3CH2OH,and(CH3)2CHOH at 300℃.They were analyzed with a gas chromatograph/mass spectrometer and quadrupole exactive orbitrap mass spectrometer(QEOTMS) with an atmosphere pressure chemical ionization source in positive-ion mode,while BL was characterized with an X-ray photoelectron spectrometer(XRPES).The results show that the yields of SP2 and SP3 are much higher than those of SP1 and SP4,and the total SP yield is ca.39.0%.According to the analysis with XRPES,pyrrolic nitrogen atoms are the most abundant nitrogen existing forms in BL.Thousands of nitrogen-containing aromatics(NCAs) were resolved with QEOTMS and their molecular masses are mainly in the range of 200-450 u.The main NCAs are N1O1 and N1O2 class species with double bond equivalent values of 4-18 and carbon numbers of 7-30.The nitrogen atoms appear in pyridine s,quinolines,benzoquinolines or acridine,and dibenzoquinolines or naphthoquinolines,while the oxygen atoms exist in methoxy and furan rings.

Insight into the structural features of organic species in Fushun oil shale via thermal dissolution

Fushun oil shale(FOS) was subjected to thermal dissolution(TD) under different conditions. The results show that the optimal solvent, temperature, time, and ratio of solvent to FOS are ethanol, 300 °C, 2 h, and 5 ml·g^(-1),respectively and the corresponding yield of the soluble portion(SP) is 32.2%(daf), which is much higher than the oil content of FOS(ca. 6%), suggesting that TD in ethanol is an excellent way to extract organics from FOS.According to 3 direct analyses, aliphatic moieties in FOS are the most abundant followed by C\\O-containing moieties and each cluster in FOS has 3 conjugated aromatic rings on average with fewer substituents. According to the analysis with a gas chromatograph/mass spectrometer, alkanes are predominant in all the SPs. A number of alkenes were identified in the SPs from the TD, while none of the alkenes were detected in acetone-SP obtained at room temperature, implying that the TD can destroy the π-π and intertwining interactions between alkenes and macromolecular structures in FOS. Moreover, a small amount of alkyl-substituted phenols and alkoxysubstituted phenols were detected in ethanol-SP from the TD, which could be the products from ethanolyzing the macromolecular moiety of FOS.

Isolation and purification of carbazole contained in anthracene slag by extraction combined with medium pressure liquid chromatography

Ultrasonic-assisted extraction(UAE)combined with medium pressure liquid chromatography(MPLC)was designed for carbazole separation from anthracene slag(AS).The effects of liquid/solid ratio,temperature,and extraction times on carbazole separation were investigated.When using CC14 and ethyl acetate as extraction solvents and combining with MPLC,carbazole recovery and purity are 75.1%and 95.4%,respectively.The mechanism for carbazole separation were presumed by examining intermolecular interactions such as N-H…π,π-π,and C-Cl…πinteractions.These results demonstrate that UAE/MPLC has a considerable potential as a green and promising strategy for separating and purifying carbazole and other chemicals from AS.

Mild oxidative degradation of spent auricularia auricular substrate and molecular composition of carboxylic acids in the resulting soluble portion

Spent auricularia auricular substrate(SAAS)was oxidatively degraded with aqueous hydrogen peroxide(AHPO)/acetic anhydride(AAH)to produce carboxylic acids(CAs)under mild conditions.The results show that up to 53.6%of the organic matter in SAAS was converted to the soluble species(SSs).In total 122 CAs were detected in the SSs by the analysis with a gas chromatograph/mass spectrometer,which can be classified into 29 group components,mainly being aliphatic acids and along with small amount of aromatic acids.Among the aliphatic acids,normal alkanedioic acids are the most abundant.The detected aromatic acids include benzoic acids,phthalic acids,trimellitic acids,pyromellitic acids,and their derivatives.The synergistic oxidation and the released·OH,CH3COO·,and HOO·induced by AHPO/AAH play crucial roles in oxidatively degrading SAAS.

A study on the catalytic performance of Pd/γ-Al_(2)O_(3),prepared by microwave calcination,in the direct synthesis of dimethylether

A series of Pd/γ-Al_(2)O_(3) hybrid catalysts were prepared by impregnation and subsequent calcination under microwave irradiation.The catalysts were used for direct synthesis of dimethylether(DME)from syngas.The results show that calcination under microwave irradiation improved both the activity and selectivity of the catalysts for DME synthesis.The optimum power of the microwave was determined to be 420 W.Under such optimum conditions,CO conversion,DME selectivity and time space yield of DME were 60.1%,67.0%,and 21.5 mmol$mL-1$h^(-1),respectively.Based on various characterizations such as nitrogen physisorption,X-ray diffraction,COtemperature-programmed desorption,and Fourier transform infrared spectral analysis,the promotional effect of the microwave irradiation on the catalytic property was mainly attributed to both the higher dispersion of Pd and the significant increase in the adsorption on the CO-bridge of Pd.Microwave irradiation with very high power led to the increase in CO-bridge adsorption and thereby decreased the catalytic activity,whereas the coverage by metallic Pd of the active sites on acidicγ-Al_(2)O_(3) significantly occurred under microwave irradiation with very low power,resulting in a decrease in the selectivity to DME.