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Mo L.,Nanjing University of Technology | Mo L.,Jiangsu National Synergetic Innovation Center for Advanced Materials | Zhang F.,Nanjing University of Technology | Deng M.,Nanjing University of Technology | And 2 more authors.
Cement and Concrete Research | Year: 2016

Calcium carbonate binders were prepared via carbonating the paste specimens cast with steel slag alone or the steel slag blends incorporating 20% of Portland cement (PC) under CO2 curing (0.1 MPa gas pressure) for up to 14 d. The carbonate products, mechanical strengths, and microstructures were quantitatively investigated. Results showed that, after accelerated carbonation, the compressive strengths of both steel slag pastes and slag-PC pastes were increased remarkably, being 44.1 and 72.0 MPa respectively after 14 d of CO2 curing. The longer carbonation duration, the greater quantity of calcium carbonates formed and hence the higher compressive strength gained. The mechanical strength augments were mainly attributed to the formation of calcium carbonate, which caused microstructure densification associated with reducing pore size and pore volume in the carbonated pastes. In addition, the aggregated calcium carbonates exhibited good micromechanical properties with a mean nanoindentation modulus of 38.9 GPa and a mean hardness of 1.79 GPa. © 2016 Elsevier Ltd

Yang J.,Key Laboratory of Mesoscopic Chemistry | Zhou Y.,Key Laboratory of Mesoscopic Chemistry | Yang J.Y.,Key Laboratory of Mesoscopic Chemistry | Lin W.G.,Key Laboratory of Mesoscopic Chemistry | And 4 more authors.
Journal of Physical Chemistry C | Year: 2010

The activity of zeolite MCM-22 in trapping nitrosamines, a class of well-known carcinogenic environmental pollutants, is reported in this article for the first time. MCM-22 possesses a set of unique porous structures and morphologies, making it possible to trap both volatile nitrosamines and bulky tobacco specific nitrosamines. Liquid adsorption and instantaneous gaseous adsorption methods have been employed to study the impact of morphology on MCM-22's ability in adsorbing nitrosamines in both gaseous and liquid media. As-synthesized MCM-22 was subjected to different treatments to induce morphological changes. SEM revealed a special rose-like appearance. The effects of these morphological modifications on MCM-22's adsorption capacities was studied and compared to NaY and NaZSM-5. The results obtained seem to suggest that enhanced collision probability between adsorbate and adsorbent may have an important role to play for MCM-22. Furthermore, the treatments created mesopores in MCM-22 that enhance mass transport within its hierarchical structure. © 2010 American Chemical Society.

Yan N.,State Key Laboratory of Materials Oriented Chemical Engineering | Wang Y.,State Key Laboratory of Materials Oriented Chemical Engineering
Journal of Polymer Science, Part B: Polymer Physics | Year: 2016

Swelling of block copolymers by selective solvents has emerged as an extremely simple and efficient process to produce nanoporous materials with well-controlled porosities. However, the role of the swelling agents in this pore-making process remains to be elucidated. Here we investigate the evolution of morphology, thickness, and surface chemistry of thin films of polystyrene-block-poly (2-vinyl pyridine) (PS-b-P2VP) soaked in a series of alcohols with changing carbon atoms and hydroxyl groups in their molecules. It is found that, in addition to a strong affinity to the dispersed P2VP microdomains, the swelling agents should also have a moderate swelling effect to PS to allow appropriate plastic deformation of the PS matrix. Monohydric alcohols with longer aliphatic chains exhibit stronger ability to induce the pore formation and a remarkable increase in film thickness is associated with the pore formation. High-carbon alcohols including n-propanol, n-butanol, and n-hexanol produce cylindrical micelles upon prolonged exposure for their strong affinity toward the PS matrix. In contrast, methanol and polyhydric alcohols including glycol and glycerol show very limited effect to swell the copolymer films as their affinity to the PS matrix is low; however, they also evidently induce the surface segregation of P2VP blocks. © 2016 Wiley Periodicals, Inc.

Feng X.,State Key Laboratory of Materials Oriented Chemical Engineering | Feng X.,Nanjing University of Technology | Chen F.,State Key Laboratory of Materials Oriented Chemical Engineering | Chen F.,Nanjing University of Technology | And 9 more authors.
Bioresource Technology | Year: 2011

Propionic acid production by Propionibacterium freudenreichii from molasses and waste propionibacterium cells was studied in plant fibrous-bed bioreactor (PFB). With non-treated molasses as carbon source, 12.69±0.40gl-1 of propionic acid was attained at 120h in free-cell fermentation, whereas the PFB fermentation yielded 41.22±2.06gl-1 at 120h and faster cells growth was observed. In order to optimize the fermentation outcomes, fed-batch fermentation was performed with hydrolyzed molasses in PFB, giving 91.89±4.59gl-1 of propionic acid at 254h. Further studies were carried out using hydrolyzed waste propionibacterium cells as substitute nitrogen source, resulting in a propionic acid concentration of 79.81±3.99gl-1 at 302h. The present study suggests that the low-cost molasses and waste propionibacterium cells can be utilized for the green and economical production of propionic acid by P. freudenreichii. © 2011 Elsevier Ltd.

Chen J.,State Key Laboratory of Materials Oriented Chemical Engineering | Chen J.,Nanjing University of Technology | Zhang W.,State Key Laboratory of Materials Oriented Chemical Engineering | Zhang W.,Nanjing University of Technology | And 4 more authors.
Bioresource Technology | Year: 2014

A screw extrude steam explosion (SESE) apparatus was designed and introduced to pretreat corn stover continuously for its following enzymatic hydrolysis. SESE parameters temperature (100, 120, 150. °C) and residence time (1, 2, 3. min) were investigated. The enzymatic hydrolysis of corn stover pretreated by SESE and steam explosion (SE) process was carried out and analyzed systematically. A serial of analysis methods were established, and the corn stover before/after the pretreatment were characterized by scanning electron microscope (SEM), X-ray Diffraction (XRD) and Thermal Gravity/Derivative Thermal Gravity Analysis (TG/DTG). After treated by SESE pretreatment at the optimum condition (150. °C, 2. min), the pretreated corn stover exhibited highest enzymatic hydrolysis yield (89%), and rare fermentation inhibitors formed. Characterization results indicated that the highest yield could be attributed to the effective removal of lignin/hemicellulose and destruction of cellulose structure by SESE pretreatment. © 2014 Elsevier Ltd.

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