Pre-formed activated carbon matting derived from the pyrolysis of biomass natural fibre textile waste

Low grade biomass fibre produced as a by-product from the flax and hemp industry was manufactured into a non-woven, pre-formed matting material via entanglement, layering and needling. The advantage of such a structure is that textile technology is used to form a self supporting fibre matrix, utilising the ease with which fibre can be worked. The non-woven matting was then pyrolysed and gasified with steam to produce activated carbon. The influence of pyrolysis process conditions on the production of chars and activated carbon from the pre-formed, non-woven textile matting were investigated.     

Method development for the analysis of particle phase substituted methoxy phenols and aromatic acids from biomass burning using capillary electrophoresis/electrospray ionization mass spectrometry (CE/ESI-MS)

A method is developed for the determination of substituted methoxy phenols and aromatic acids in biomass burning aerosol using capillary electrophoresis (CE) coupled to an electrospray ionization mass spectrometer. Background electrolytes (BGEs) containing ammonium acetate, ammonium hydroxide and 10% (v/v) methanol at pH 9.1 and ammonium hydroxide at pH 11 are investigated for their suitability. A good linearity is found for all analytes in the range of 1-50 microM for the ammonium acetate based BGE and 1-40 microM for the ammonium hydroxide BGE. The detection limit ranged from 0.1 to 1.0 microM for the ammonium acetate based BGE and 0.3 to 0.7 microM for the ammonium hydroxide BGE. The relative standard deviation (R.S.D.) is typically less than 0.5% (ammonium acetate based BGE) and 4.2% (ammonium hydroxide BGE) for the migration time and 3-9% (ammonium acetate based BGE) and 2.5-8% (ammonium hydroxide BGE) for the peak area (n = 5). The analytical time was less than 10 min for both methods. The proposed methods are fast, sensitive and quantitative and can be applied to the analysis of complex biomass burning aerosol samples without complex pre-treatment. The results from the analysis of real biomass burning samples demonstrate the suitability of the proposed methods to the analysis of low concentration water soluble organic carbon (WSOC) in biomass burning samples. The fast analytical time and high sensitivity of the proposed methods enables the analysis of a large number of size segregated impactor samples from biomass burning aerosols.     

重金属生物吸附的研究进展

本文综述了重金属生物吸附的机理、影响生物吸附的物理化学因素和生理条件、生物吸附动力学、生物吸附过程的数学模型化、生物细胞的固定化和从生物量上回收被吸附的重金属等方面的研究进展。     

Spatially and temporally resolved IR-DFWM measurement of HCN released from gasification of biomass pellets

For the first time, to the best of the authors’ knowledge, nonintrusive quantitative measurement of hydrogen cyanide (HCN) released during the devolatilization phase of straw pellets gasification is demonstrated with high spatial and temporal resolution. Mid-infrared degenerate four-wave mixing (IR-DFWM) measurements of HCN were performed by probing the interference-free P(20) line in the v₁ vibrational band at around 3?µm and the IR-DFWM signal was detected with an upconversion-based detector, providing discrimination of thermal noise and increased sensitivity. A novel single-pellet setup consisting of a multi-jet burner was used to provide hot flue gas environments with an even and well-defined temperature distribution, for single straw pellet gasification at atmospheric pressure. The environments had temperatures of 1380?K, 1540?K and 1630?K with a constant oxygen concentration of 0.5?vol%. In order to quantify the amount of HCN released during the devolatilization of straw pellets, calibration measurements were performed in well-defined HCN gas flows. Selected hot water lines were probed with IR-DFWM in the interrogated volume to obtain the instantaneous temperature, which were used to correct the temperature effect. HCN concentrations up to 1500?ppm were detected during the devolatilization stage, and the results indicate a strong temperature dependence of the HCN release.     

Recent application of biochar on the catalytic biorefinery and environmental processes

Lignocellulosic biomass is an abundant and environment-friendly source for renewable energy production. The value and application of biochar, which is obtained from the thermochemical conversion of biomass, is increasing rapidly because of its high carbon content and porosity. The property of biochar, such as surface area, porosity, and number of functional groups, can be improved by controlling the conditions of biomass conversion, biochar activation, and functionalization methods. The production and activation of biochar as well as its potential use for soil remediation, pollutant adsorption, and biorefinery have been reviewed extensively over recent decades. This paper provides a conceptual approach for biochar production and activation together with its application as a catalyst for biorefineries and the removal of environmental contaminants.     

Synergistic co-removal of zinc(II) and cefazolin by a Fe/amine-modified chitosan composite

A novel Fe/amine modified chitosan composite (Fe/N-CS) was facilely synthesized and showed higher affinity to both Zn(II) and cefazolin (CEF) than its precursors. Synergistic co-adsorption of them by Fe/N-CS was observed in varied conditions. The adsorption amount maximally increased by 100.1% for Zn and 68.2% for CEF in bi-solute systems. The initial adsorption rate of Zn(II) also improved with CEF. The increasing temperature facilitated coadsorption. The results of the preloading tests, FTIR/XPS characterizations and DFT calculations suggested that (1) both polyamines and Fe sites participated in the adsorption of Zn(II) and CEF, (2) Zn(II) could serve as a new efficient site for CEF, forming [amine-Zn-CEF]/[FeOH-Zn-CEF] ternary complexes, and (3) the co-presence of CEF shielded the electrostatic repulsion between protonated amines and Zn(II), contributing to the enhancement of Zn(II) adsorption. Further, the ion strength exerted positive and negative influences on the adsorption of Zn(II) and CEF, respectively. Additionally, CEF and Zn(II) were successively recovered by 0.1 mol/L NaOH followed by 2 mmol/L HCl. Fe/N-CS could be stably reused five times. The findings imply that Fe/N-CS is promising for the highly efficient co-removal of concurrent heavy metals and antibiotics.     

Clean preparation of S-thiocarbamates with in situ generated hydroxide in 2-methyltetrahydrofuran

A simple and clean protocol for the synthesis of various alkyl and (hetero)aryl S-thiocarbamates was established. The usage of in situ generated hydroxide as both an oxygen source and hydrogen source as well as biomass-derived 2-methyltetrahydrofuran as a green reaction medium, the avoidance of phosphorus-containing reductant, and the generation of harmless water and nitrogen as the side-products have given the present method atom-economy and environmental friendliness.     

Identification of Crucial Intermediates in the Formation of Humins from Cellulose-Derived Platform Chemicals Under Brønsted Acid Catalyzed Reaction Conditions

Humins are one of the undesirable products formed during the dehydration of sugars as well as the conversion of 5-hydroxymethylfurfural (HMF) to value-added products. Thus, reducing the formation of humins is an important strategy for improving the yield of the aforementioned reactions. Even after a plethora of studies, the mechanism of formation and the structure of humins are still elusive. In this regard, we have employed density functional theory-based mechanistic studies and microkinetic analysis to identify crucial intermediates formed from glucose, fructose, and HMF that can initiate the polymerization reactions resulting in humins under Brønsted acid-catalyzed reaction conditions. This study brings light into crucial elementary reaction steps that can be targeted for controlling humins formation. Moreover, this work provides a rationale for the experimentally observed aliphatic chains and HMF condensation products in the humins structure. Different possible polymerization routes that could contribute to the structure of humins are also suggested based on the results. Importantly, the findings of this work indicate that increasing the rate of isomerization of glucose to fructose and reducing the rate of reaction between HMF molecules could be an efficient strategy for reducing humins formation.     

Microalgae and bioremediation of domestic wastewater

Domestic wastewaters are produced in huge volumes and abundant with carbon, nitrogen and phosphorous, which are a promising source of nutrients for production of microalgae. Microalgae-based bioremediation of domestic wastewater offers various advantages over traditional treatment approaches because the process consumes CO₂, completely removes nitrogen and phosphorous for production of green biomass and oxygen. Moreover, the abundance of biochemical compositions (e.g., lipids, proteins, carbohydrates, bioactive compounds) of microalgae biomass is superior to terrestrial plant biomass in refining to multi-products having variety of commercial values. In this review, the most dominant microalgae used for simultaneous removal of pollutants and production of biomass and metabolites from domestic wastewater are presented. Biorefinery of microalgae biomass produced from domestic wastewater for production of multiple products is also explored. Finally, challenges and perspectives of successful microalgae-based bioremediation of domestic wastewater toward the biorefinery are briefly discussed.     

Three-dimensional surface reconstruction and in situ site-specific cutting of the teliospores of Puccinia miscanthi causing leaf rust of the biomass plant Miscanthus sinensis

The rust fungus Puccinia miscanthi on the naturally infected leaves of eulalia grass were investigated by light and electron microscopy. Many black telia were present on both the adaxial and abaxial leaf surfaces. The telia were often confluent, protruding distinctly from the leaf surface, and had numerous teliospores. Light microscopy revealed that the teliospores were club-like in shape (clavate), chestnut brown, and produced pedicels from one end. They were measured to be approximately 45 μm × 20 μm in size, and slightly constricted at the septa. Using stereo imaging, it was possible to generate images with more three-dimensionality than conventional scanning electron micrographs. Without the need for the mechanical sectioning of telia, the height of telia from the leaf epidermis could be measured at approximately 230 μm using three-dimensional surface reconstruction. Urediniospores were also found on the leaf surface, and possessed spines on the surface (echinulate). The internal features of the nonembedded teliospores could be unveiled using a focused ion beam system with a field emission scanning electron microscope, allowing for the in situ site-specific cutting of the non-embedded teliospores. These results show that three-dimensional surface reconstruction and targeted cutting are a potential alternative to mechanical sectioning of resin-embedded blocks, and have the potential to eliminate the uncertainty involved in selecting the region of interest.