Characterization of biomass and biochar by LDI-FTICRMS – Effect of the laser wavelength and biomass material

The pyrolysis of the lignocellulosic biomass is a promising process to produce biofuels or green chemicals. Specific analytical methods have to be developed in order to better understand the composition of biomass and of its pyrolysis products and therefore to optimize the design of pyrolysis processes. For this purpose, different biomasses (Douglas and Miscanthus) and one biochar were analyzed by laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (LDI FT-ICR MS). This method allowed the biomass and biochar to be analyzed without any sample preparation and with a spatial resolution of about 100 μm. The influence of LDI conditions (laser wavelength and laser irradiance) and the nature of the biomass and biochar on the obtained mass spectrum were investigated. The nature and origin of the observed ions highly depended on LDI conditions. In the softest laser–biomass interaction conditions (low laser irradiance), the detected ions were related to the nature of the investigated biomass. Indeed, the main part of the detected species came from the different biomass subunits and was produced by photolysis of covalent bonds. When more severe laser irradiation conditions were used, the obtained mass spectra gathered the ions relative to (i) the chemical components of the investigated samples, (ii) the recombination products of these species in the gas phase after their ejection from the sample surface, and (iii) the compounds produced by laser pyrolysis of the sample. This was expected to be useful to mimic thermal pyrolysis.

Open image in new window

Graphical Abstract

     

Elucidating dominant factors of PO43–, Cd2+ and nitrobenzene removal by biochar: A comparative investigation based on distinguishable biochars

Biochars produced from crab shell (CSB), oak sawdust (OB), Jerusalem artichoke tuber (JAB) and sorghum grain (SB) displayed distinguishable adsorption-related characteristics, such as specific surface area (SSA), ash content and acidic oxygen-containing functional groups (AFGs), which linked to the biochar adsorption mechanisms of most pollutants. Herein, PO₄^3–, Cd²⁺, and nitrobenzene (NB) were employed for adsorption by these biochars to elucidate the dominant factors for the adsorption. Adsorption performance of the three pollutants onto these four biochars varied considerably, as exemplified by the excellent adsorption of PO₄^3– and Cd²⁺ onto CSB (225.3 and 116.0 mg/g, respectively) as compared with onto the other three biochars (4.2–37.1 mg/g for PO₄^3– and 9.7–41.0 mg/g for Cd²⁺). OB displayed the best adsorption of NB (72.0 mg/g), followed by SB (39.5 mg/g), JAB (31.1 mg/g), and CSB (23.6 mg/g). The kinetics and isotherm adsorption assessments couple with material characterization suggested that the sorption of selected pollutants on biochars was attributed to the multiple mechanisms involved, including coprecipitation, chemical bonds, cation exchange, physical absorption, and complexation. Further path analysis suggested that AFGs and ash content in biochars were more important than SSA with regards to pollutant removal, especially, with ash playing a crucial role in the removal of Cd²⁺ and PO₄^3–, and AFGs being mainly responsible for NB adsorption. These findings might offer guidance on the preparation or modification of biochar with a targeted function for pollutant removal through an understanding the dominant factors.     

Simple synthesis and separation of the diastereomers of α-thio analogs of ribo- and deoxyribo- di- and triphosphates

Nucleoside 5′-0-(1-thiodi-) and triphosphates can be obtained in yields of up to 45% directly from the nucleosides. Their diastereomers can be separated by preparative reversed phase chromatography.     

Molecular characterization of Ulex europaeus biochar obtained from laboratory heat treatment experiments – A pyrolysis–GC/MS study

Gorse species (Ulex sp.) are ubiquitous in the shrublands of NW Spain and have the potential to become key players in an integral biofuel/biochar program in NW Spain. Here we present molecular characterization (using pyrolysis–GC/MS) of a biochar “thermosequence” obtained by laboratory heating of Ulex europaeus wood in a muffle furnace between 200 and 600 °C (T_CHAR). Low temperature chars (T_CHAR ≤ 350 °C) produced significant amounts of pyrolysis products of which the precursor biopolymer could be recognized, while high-temperature chars (T_CHAR ≥ 400 °C) produced mainly phenols and monocyclic and polycyclic aromatic hydrocarbons, which are not specific for any biopolymer. Carbohydrate could hardly be recognized at T_CHAR ≥ 350 °C. The thermal rearrangement of polyphenols, mainly lignin, was reflected in more detail (1) C₃-side chain shortening and probably depolymerization (T_CHAR 200–350 °C), (2) demethoxylation of syringyl and probably also some guaiacyl lignin (T_CHAR 300–400 °C), (3) elimination of virtually all remaining methoxyl groups (T_CHAR 350–400 °C), through dehydroxylation and demethoxylation, (4) almost complete dehydroxylation of lignin and other biopolymers (T_CHAR 400–500 °C), (5) progressive condensation into polyaromatic structures (T_CHAR 300–500 °C) and (6) partial elimination of alkyl bridges between (poly)aromatic moieties (T_CHAR 450–500 °C). These results were supported by Fourier transform infrared spectroscopy (FTIR) of the same samples. We conclude that pyrolysis–GC/MS can be used as a rapid molecular screening method of gorse-derived biochar. Molecular properties elucidation is an essential part of predicting the stability and agronomical behavior of gorse-derived biochar after future implementation in soils.     

Interactions and influence of α-cyclodextrin on the aggregation and interfacial properties of mixtures of nonionic and zwitterionic surfactants

The interactions of α-cyclodextrin (α-CD) with the nonionic surfactant decanoyl-N-methyl-glucamide (Mega-10) and the zwitterionic surfactant dimethyldodecylammoniopropanesulfonate (DPS) in their mixed system have been studied using interfacial tension, fluorescence, and nuclear magnetic resonance measurements. From the plots of interfacial tension vs. log of total surfactant concentration, we have obtained values of the surface excess of surfactant, the critical micellar concentration (cmc), the standard free energy of micelle formation, and association constant of surfactant/α-CD inclusion complexes (assuming a 1:1 stoichiometry). A comparison of the K _a values obtained for the interaction between α-CD and DPS and Mega-10, respectively, shows that DPS interacts stronger with α-CD than Mega-10. The experimental mixed cmc was analyzed by the pseudophase separation model and regular solution theory for the evaluation of ideality or nonideality of the mixed micelle formation. The interaction parameters in the mixed micelle and the micelle composition at different mole fractions of DPS were also computed. The fluorescence anisotropy (r) values of rhodamine B decreases with the increase of α-CD concentrations.     

Synthesis and Spectroscopic Characteriration of Transition MetalComplexes of Maleionitriledithiolene and 1,10-Phenanthroline

Thedithiolenesanddiiminesandtheirmetalcomplexesareanimportantresearchfieldintheorganicandcoordinationchemistry'-'.Metalcomplexesofadithioleneandadiiminehaveexcellentelectronicfullctionsduetotheintramolecularchargetransferfromaligandtootherligand(LL'C...     

Synthesis and study of the cyclization pathways and reactivities of α-diazoimidolates

The reaction of unsymmetrical N,N-disubstituted malonamides with benzenesulfonyl azide in the presence of sodium ethoxide gives individual sodium 1,2,3-triazol-5-olates or mixtures of their isomers, from the relative amounts of which the effect of substituents in the amido groups on the cyclization pathways and reactivities of -diazoimidolates was ascertained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1521–1527, November, 1991.     

Synthesis and Characterization of ABBA Block Copolymer of Glycolide and ε-Caprolactone

A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ε-caprolactone(CL, B) and glycolide(A) by means of step polymerization in the presence of ethylene glycol as an initiator and stannous octanoate as a catalyst at 110 ℃ for 48 h. The molecular length of the PCL pre-polymer(BB) could be adjusted by controlling the molar ratio of the ethylene glycol initiator to ε-caprolactone monomer. The structure and the composition of the block copolymer were determined by the weight ratio of the monomer glycolide(A) to PCL pre-polymer(BB). The block copolymers were characterized by 1H NMR, GPC, DSC and X-ray. The results confirm the successful synthesis of an ABBA block copolymer.     

Spectral and Electrochemical Investigation of Intercalations of Adrenaline and CT－DNA

A strong interaction between double stranded calf-thymus DNA (ds-DNA) and adrenaline in solution, but no interaction between single stranded calf-thymus DNA (ss-DNA) and adrenaline was observed by the use of UV-visible spectroscopy and voltammetric techniques. It is suggested that the interaction leads to an intercalation of adrenaline molecules into the groove of ds-DNA and the formation of ds-DNA (adrenallne)n complex. The binding site size of the interaction of adrenaline with CT-DNA in nucleotide phosphate [ NP] has been determined as 25. The interaction of different concentration adrenaline with DNA modified GCE shows that the DNA modified GCE can be a good tool to detect lower concentration adrenaline.     

Fluorometric Investigation of the Acid-Base and Complexation Behaviour of Tetracycline and Oxytetracycline

The widely used antibiotics tetracyclines have been effectively used for ailing heart attack, ulcer cure and gene therapy. The actual mechanism of their activity has been proposed to link with the complexes with many metal ions.However, the sites at which complex formation takes place are not well established. In the present work, the deprotonation sequence of tetracycline (TC) and oxytetracycline (OTC), and their specific group used to bind europium ion were investigated by examining the character of fluorescence of TC and OTC as well as that of their complexes.It was concluded that the site of complexation is coordinated with the deprotonation sequence changing with the acidity/basicity of the solution. And it was inferred that five hydrogens in TC and OTC could be dissociated. The deprotonation sequence is as follows: C(3) hydroxy, C(10) phenol, C(4) dimethylamine, C(12) hydroxy and C(12a) hydroxy. The corresponding complexation site changed with pH increase in solution as follows: C(2) acylamino and C(3) hydroxy moiety, C(10)-C(11) ketophenol moiety, C(4) dimethylamine and C(3) hydroxy moiety,C(11)-C(12)β-diketone moiety, C(12) hydroxy and C(12a) hydroxy moiety, and C(12) hydroxy and C(1) ketonemoiety respectively.     

Synthesis and Characterization of ABBA Block Copolymer of Glycolide and ε-Caprolactone

A biodegradable ABBA block copolymer was synthesized via the ring-opening co-polymerization of ε-Scaprolactone (CL, B) and glycolide (A) by means of step polymerization in the presence of ethylene glycol as an initiator and stannous octanoate as a catalyst at 110 ℃ for 48 h. The molecular length of the PCL prepolymer(BB) could be adjusted by controlling the molar ratio of the ethylene glycol initiator to ε-caprolactone monomer. The structure and the composition of the block copolymer were determined by the weight ratio of the monomer glycolide (A) to PCL pre-polymer(BB). The block copolymers were characterized by ^1H NMR, GPC, DSC and X-ray. The results confirm the successful synthesis of an ABBA block copolymer.     

U(VI) adsorption by biochar fiber–MnO2 composites

The removal of U(VI) by biochar fibers from aqueous solutions has been investigated prior and after MnO₂ surface-deposition. The removal efficiency has been studied as a function of pH, U(VI) concentration, ionic strength, temperature and contact time. The fibers morphology and surface complexes were analyzed by SEM–EDX and FTIR, respectively. Evaluation of the experimental data indicates that the composite presents extraordinary adsorption capacity (q_max = 3.8 mmol g⁻¹, 904 mg g⁻¹), which is attributed to the formation of inner-sphere surface complexes, and that the adsorption reaction is a relatively fast, endothermic and entropy-driven process.

     

Chromatographic and Computational Studies of the Physicochemical Properties of Cholinesterase Inhibitors — Alkyl- and Arylcarbamate Derivatives of N-Benzylpiperidine and N-Benzylpiperazine

JPC – Journal of Planar Chromatography – Modern TLC - This paper reports an investigation of physicochemical properties of four series of carbamates of 3-hydroxy and...     

Synthesis Characterization and Viscosity Studies of Homopolymer of Methyl Methacrylate and Copolymer of Methyl Methacrylate and Styrene

A homopolymer of methyl methacrylate (MMA) and its copolymer with styrene at different compositions were synthesized and characterized. Viscosity measurements of the synthesized homopolymer and the copolymers in toluene solutions were performed at 313 K. Different equations were used to calculate the intrinsic viscosity, viscometric constants values, and molecular weight of the synthesized polymers. The values of intrinsic viscosity and viscosity average molecular weight obtained by the two methods (single point determination and graphical extrapolation) were compared in order to verify the validity of the single point determination for the polymers. Viscometric properties derived included the specific viscosity (it determines the contribution of the solute to the viscosity of the solution), the reduced viscosity (that provides a measure of the polymer capacity for increasing the solution viscosity), and the intrinsic viscosity.     

Study of Preparation and Characteristics of Pyridoxalated Polyhemoglobin

ＳｔｕｄｙｏｆＰｒｅｐａｒａｔｉｏｎａｎｄＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＰｙｒｉｄｏｘａｌａｔｅｄ　ＰｏｌｙｈｅｍｏｇｌｏｂｉｎＬｉａｎｇＳｈｕｇｕａｎｇ；ＴｏｎｇＭｉｎｇｒｏｎｇ；ＰａｎＪｉｌｕｎａｎｄＹｕＹａｏｔｉｎｇ（Ｉｎｓｔｉｔｕｔｅｆｏ...     

Syntheses of Benzoxepinoquinolinone and Benzothiepinoquinolinone

l-Benzoxepino(3, 4-b)quinolin-l3(6H)-one and its halogen,alkyl, alkoxy derivatives Va'-d' and 1-benzothiepino(3,4-b}-quinolin- 13 ( 6H)-one Vf, and its alkyl derivatives Vg, weresynthesized through cyclization of 2-(substituted phenoxymethyl)-3-quinolinecarboxylic acids Va-d and 2-[ (un)substituted phen-ylthiomethyll-3-quinolinecarboxylic acids IVf-g in the presence ofpolyphosphoric acid.The acids IV were obtained from the corresponding ethyl-esters @ whcih were prepared through refluxing ethyl 2-bromo-methyl-3-quinolinecarboxylate(1) with substituted phenol or (un)substituted thiophenol in the presence of NaOEt.The compound Vg, was allowed to react with NBS, KaBH4, NH2OH-HCl to give compounds VII , VIII, and IX, respectively.The structures of 24 new compounds have been confirmed by elemental analysis, IR and 1H NMR.     

Design, Synthesis and Investigation of Bone Affinity of the Conjugates of 5-Fluorouracil and Hydroxybisphosphonate

Bone tumor, as a common disease, is treated by surgical resection, radiotherapy and chemotherapy. Chemotherapy is one of the most important treatment, however, a major problem of chemotherapy is lack of selectivity of cytotoxic drugs. Although many attempts have been made to increase the selectivity of therapeutic drugs for the bone diseases, such as osteoporosis, paget’s, hypercalcemia and bone metastases by conjugating them with targeting carriers1-4, there are still no bone-targeting agent…