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Transesterification is a mild process to prepare cellulose acetate (CA) as compared with the traditional method. In this study, CA fibers were produced from six cellulose raw materials based on a simple and rapid transesterification method. The properties of the CA solutions and the obtained CA fibers were investigated in detail. Results showed that all of the cellulose raw materials were esterified within 15 min, and spinning dopes could be obtained by concentrating the CA solutions via vacuum distillation. The XRD, FT-IR, 1 H, 13 C and HSQC NMR analysis confirmed the successful synthesis of CA. The degree of substitution (DS) of the obtained CA was significantly affected by the degree of polymerization (DP) of cellulose raw materials, which further influenced the viscosity of CA solutions as well as the structural, thermal and mechanical properties of the CA fibers. [ABSTRACT FROM AUTHOR]

To investigate the combined effects of materials and solvents on the preparation, structural and mechanical properties of regenerated cellulose fibers, four cellulosic materials (microcrystalline cellulose, cotton linter pulp, bamboo pulp and bleached softwood sulfite dissolving pulp) and six non-derivative solvents (NaOH/urea aqueous solution, N , N -dimethylacetamide/lithium chloride, N -methyl-morpholine- N -oxide, 1-butyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate) were used to prepare fibers with wet spinning method. The results showed that the dissolvability of solvent was the determining factor in cellulose dissolution, and the dissolving time was influenced by the raw materials’ properties, such as molecular weight, exposed area and hemicellulose content. The crystallinity and elongation at break of the fibers were almost fixed and not affected by the materials and solvents. However, the tensile strength of the fibers was directly proportional to the molecular weight of the raw materials, and varied with the type of solvents through cellulose degradation. [ABSTRACT FROM AUTHOR]

This study focused on the effect of cellulose crystal type on the dissolution of cellulose in aqueous NaOH/urea. Cellulose I, II, III I , and IV I were prepared and characterized. Subsequently, the solubility of these cellulose samples in aqueous NaOH/urea was tested and the mechanism was determined by a combination of 1 H NMR spectroscopy and differential scanning calorimetry (DSC). The results indicated that, compared with the degree of polymerization (DP) and crystallinity index of cellulose, the cellulose crystal type had greater impact on cellulose dissolution. Specially, the solubility of the cellulose I, II, and III was progressively decreased, probably due to different hydrogen bond network and packing energy in it. The ability of cellulose I, II, III, and IV to form hydrogen bonds with sodium hydroxides was nearly the same, while gradually increased when cellulose preparations were associated with urea. Moreover, all the cellulose solutions showed good thermal stability. [ABSTRACT FROM AUTHOR]

• An efficient GPU parallel optimal point searching approach is proposed. • Branch and bound is used in the proposed approach. • Interval arithmetic is employed to delimit the subsets after branching. • The proposed method can be works on PC with a GPU-capable graphics card. Response surface-based simulation optimization method is widely used in the design of complex products for its low-cost in optimization target valuation. However, when design variables increase, it often takes considerable time for high-dimensional response surface to search the optimal point, which falls easily into the local optimum due to the large search space. To solve these problems, a GPU (Graphic Processing Unit) parallel optimization based on branch and bound is proposed in this paper, of which the main algorithm flow can be described as the following steps: the optimization space is branched to subsets and mapped to different GPU threads; the Chebyshev response surface is constructed within the threads; the compact convex hull of the subsets are obtained through the interval operation, and the optimization space is reduced on a large scale by pruning; all subsets that may contain optimal design points are efficiently obtained by repeating spatial subdivision and demarcation; finally, all the reserved subsets are mapped to different GPU threads, and all global optimization design points are obtained through sequential quadratic programming and comparative analysis. [ABSTRACT FROM AUTHOR]

High-value application of lignin from different biorefinery processes is an important issue facing us at the present time, and the detailed characterization of obtained lignin, chemical and morphological, is the basic requirement. In this study, lignin fractions isolated from poplar under the acidic biorefinery conditions were comparatively studied by elemental, thermal, and morphological methods. The data revealed that the balance between the cleavage of substantial alkyl–aryl ethers/esters and recondensation reactions was extensively existed in a large severity range, and the random collision of the individual layered globules was clearly observed. As the temperature reached 200 °C, recondensation reactions among monolignols predominated and significantly increased the degree of unsaturation. The aggregation state of lignin biomacromolecule was almost completely altered, closely relating to the synergetic effect from the difference on the chemical components and, more importantly, the softening-solidification process in the high-temperature biorefinery technique. These results facilitated the further understanding of interfacial properties of lignin, which will advance the development of lignin application on industrial scale. [ABSTRACT FROM AUTHOR]

A plasma–catalyst reactor was used for the adsorption of elemental mercury at low temperatures. SiO 2 , TiO 2 and SiO 2 or TiO 2 supported transition metal oxide catalysts were packed in the plasma discharge zone for adsorption enhancement. The results indicated that non-thermal plasma could induce the adsorption of elemental mercury effectively by catalysts. TiO 2 displays much higher adsorption efficiency than SiO 2 does. The adsorption efficiency is greatly improved by loading transition metal oxides on TiO 2 . Mn/TiO 2 is the most efficient catalyst, and ~ 99% of Hg 0 adsorption efficiency can be obtained under a SED of 2.3 ± 0.3 J L − 1 . The interaction between the plasma and catalyst was also investigated. The chemical properties of the catalyst, such as the active sites and electron transfer capacity, are key factors that affect adsorption efficiency. The mercury adsorption in plasma–catalyst reactor results primarily from the interaction between weakly adsorbed mercury and activated oxygen on catalyst surface induced by plasma. In addition, the effect of the O 2 concentration and HCl on mercury adsorption efficiency was investigated. The adsorption efficiency has a logarithmic correlation with O 2 concentration in the gas flow. [ABSTRACT FROM AUTHOR]

Pulp and paper are gradually transforming from a traditional industry into a new green strategic industry. In parallel, cellulose-derived transparent paper is gaining ground for the development of advanced functional materials for light management with eco-friendly, high performance, and multifunctionality. This review focuses on methods and processes for the preparation of cellulose-derived transparent papers, highlighting the characterization of raw materials linked to responses to different properties, such as optical and mechanical properties. The applications in electronic devices, energy conversion and storage, and eco-friendly packaging are also highlighted with the objective to showcase the untapped potential of cellulose-derived transparent paper, challenging the prevailing notion that paper is merely a daily life product. Finally, the challenges and propose future directions for the development of cellulose-derived transparent paper are identified. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of active transition-metal oxide (TMO) catalysts for the abatement of volatile organic compounds (VOCs) remains a great challenge. Controllable synthesis of TMOs with specific morphology and suitable composition is a promising way for acquiring efficient oxidation catalysts. Herein, a series of hierarchical Co 3 O 4 /CoNi-layered double oxides (CoNi-LDO) nanocages covered by interlaced nanosheets were synthesized using a cobalt metal-organic framework (Co-MOF)-based strategy. The textural properties, morphology, surface chemical state, and reducibility of the CoNi-LDO catalysts were systematically characterized by various techniques. The catalytic activity toward toluene oxidation and the stability performance was investigated. Results demonstrated that the morphology, composition, and textual properties can be controlled by tuning the post-synthetic etching reaction conditions. Benefiting from the structural and compositional merits, as well as the superior low-temperature reducibility, the CoNi-LDO-1 catalyst (Ni/Co molar ratio was 0.39) with core-shell structure exhibited excellent activity toward toluene oxidation. Our work offers a new strategy for the design of high-performance oxidation catalysts for the abatement of VOCs. [Display omitted] • Co 3 O 4 /CoNi-layered double oxides nanocages with varying Ni/Co ratios were prepared. • The CoNi-LDO-1 catalyst showed the superior activity toward toluene oxidation. • The catalytic activity was critically dependent on the composition and structure. [ABSTRACT FROM AUTHOR]

Abstract: A series of non-stoichiometric Fe–Ti spinel (Fe3−x Ti x )1−δ O4 were synthesized using a co-precipitation method and then developed as environmental-friendly and low cost catalysts for the selective catalytic reduction (SCR) of NO with NH3. As Ti was incorporated into γ-Fe2O3, the SCR reaction over (Fe3−x Ti x )1−δ O4 through the Langmuir–Hinshelwood mechanism was restrained. Therefore, the SCR activity of (Fe3−x Ti x )1−δ O4 (x ≠0) was less than that of γ-Fe2O3 at 150–250°C. However, the SCR reaction over (Fe3−x Ti x )1−δ O4 through the Eley–Rideal mechanism was promoted due to the incorporation of Ti. The SCR activity of (Fe3−x Ti x )1−δ O4 (x ≠0) was mainly related to the oxidative ability of Fe3+ cation on the surface, the concentration of NH3 adsorbed on the surface and the concentration of reducible Fe3+ cation on the surface. Although the oxidative ability of Fe3+ cation on the surface decreased due to the incorporation of Ti into γ-Fe2O3, the concentration of NH3 adsorbed on the surface and the concentration of reducible Fe3+ cation on the surface both increased. As a result, (Fe2Ti)0.8O4 showed excellent activity, selectivity, and H2O/SO2 durability for the SCR reaction at 300–400°C. [Copyright &y& Elsevier]

This work reported a novel hierarchical flower-like Co 3 O 4 was synthesized by the imidazolate-induced hydrothermal and subsequent thermolysis method. The catalyst exhibited superior catalytic activity for toluene oxidation, which was associated with hierarchical flower-like morphology, reactive exposed planes, abundant adsorbed oxygen species at surface and better low-temperature reducibility. [Display omitted] • The flower-like Co 3 O 4 is synthesized via the imidazolate-induced strategy. • ZIF-67 is proved to be the transient phase in the formation of flower-like Co(OH) 2. • Excellent toluene oxidation activity and stability are obtained over the Co 3 O 4 -H. • The surface adsorbed oxygen species play a crucial role in the oxidation reaction. Cobalt oxide (Co 3 O 4) materials with specific structure have shown great potential as highly efficient catalysts in the oxidation reactions. In this work, a novel hierarchical flower-like Co 3 O 4 was synthesized by the imidazolate-induced hydrothermal and subsequent thermolysis method. The effect of reaction parameters as well as the phase evolution of the flower-like structure was investigated in detail. For comparison, a rod-like Co 3 O 4 was also prepared with urea under similar conditions. The morphology-dependent effect of Co 3 O 4 towards toluene oxidation was studied. Moreover, the physicochemical properties of Co 3 O 4 were analyzed by various characterization techniques. The flower-like Co 3 O 4 catalyst presented a higher catalytic activity for toluene oxidation than the rod-like Co 3 O 4 , which was associated with hierarchical flower-like morphology, reactive exposed planes, abundant adsorbed oxygen species at surface and better low-temperature reducibility. [ABSTRACT FROM AUTHOR]