Papers by Keyword: Characterization

Abstract: In the present work, ZIF-8/6FDA-durene mixed matrix membranes (MMMs) were synthesized and characterized. ZIF-8 nanocrystals, which were used as the inorganic filler, were synthesized using rapid room-temperature synthesis method whereas 6FDA-durene polyimide was synthesized by polycondensation method followed by chemical imidization. Pure and 6FDA-durene membranes loaded with 5 wt%, 10 wt% and 15 wt% of ZIF-8 were fabricated. The structural properties and morphology of the resultant membranes were characterized by using X-ray Diffraction (XRD) and Field emission scanning electron microscope (FESEM) . The EDX images showed that ZIF-8 particles agglomerated in the polymer matrix. However, no phase separation was observed for all resultant MMMs.

Abstract: In the present work, the lengthy synthesis duration of zeolite-T was successfully reduced by inducing the ultrasonic pre-treatment method prior to hydrothermal growth. The effect of ultrasonic pre-treatment durations on the formation of zeolite-T was investigated. The structure and morphology of the resultant samples were characterized by FTIR, XRD and FESEM. As verified by FTIR, samples produced using synthesis durations of 5, 4, 3 and 2 days with ultrasonic pre-treatment durations of 60 min and 90 min, respectively, demonstrated zeolite-T structure. One day synthesis duration was not sufficient for the formation of zeolite-T. From the results obtained by XRD and FESEM, it was found that samples underwent 60 min ultrasonic pre-treatment produced zeolite-T with higher crystallinity, while no significant changes on the morphology of the resultant zeolite-T synthesized using ultrasonic pre-treatment durations of 60 min and 90 min.

Abstract: Material characterization is a crucial step to ensure the characteristics and properties of the samples are comparable to the standard adsorbent and suitable for CO₂ adsorption. The objective of this work is to characterize natural calcium based materials for CO₂ adsorption which are obtained from waste cockle shells. Characterization analyses are conducted by using XRD, BET and FESEM. Material characterization indicates that raw cockle shell is made up of aragonite and needle-like structure. It is also shown that CaCO₃ can be decomposed to CaO through high temperature calcination process. Through physisorption analysis, the samples are classified as mesoporous materials and it is shown that calcined cockle shell is better than raw cockle shell in term of surface area and pore volume. The results proved that calcium based materials could be successfully employed as sorbent for CO₂ separation.

Abstract: In the present study, polyethersulfone (PES) dope solution were prepared from mixtures of two solvents containing dimethylformamide (DMF) as core solvent, and acetone as co-solvent (CS), deionized water was used as coagulant bath. The amount of PES was kept at 20 wt% and the weight ratios of acetone were varied 20-24 wt.% to DMF and the dope solutions were prepared under closed heating system Results revealed the complete miscibility of PES with the fixed mixture of acetone and DMF under atmospheric pressure. The relationships between degree of adsorption, relative water absorption, were investigated. The results revealed that the interaction of DMF and acetone is strongest when their mole ratio is unity, which exhibit the phenomenon of true cosolvency for PES membrane. Keywords: polyethersulfone, solvent mixture, characterization.

Abstract: Papers with Ca (NO₃) ₂ • 4H₂O and (NH₄) ₂HPO₄ as raw material, prepared by ionic liquids assisted nanoHAP, resulting hexagonal nanoHAP are crystal grain size are 10-20nm level, are smaller nanometer range ; specific surface area, the findings show that ionic liquids have the technology to promote the significance of the preparation method can provide a reference for large-scale preparation of biomedical nanomaterials.

Abstract: Gossypol (GP) is a kind of poorly water-soluble polyphenolic compounds. In this study, freeze dried gossypol nanosuspensions (GP-NS) were prepared by high-pressure homogenization and Freeze-drying technique. Bovine serum albumin (BSA) and D-alpha-tocopheryl polyethylene glycol succinate (TPGS) were used as stabilizing agents for the nanosuspensions while mannitol were used as lyophilized protecting medium. The physicochemical characteristics of the GP-NS were investigated when it was found that the mean particle size and zeta potential of the GP-NS were 217±23 nm and-21.4±2.7 mV, respectively, and the saturation solubility was 586.48±23.03 μg.mL^-1. Differential scanning calorimetry and X-Ray Diffraction indicated that GP was in a crystalline state in nanosuspensions. GP-NS with a small particle size, and high saturation solubility, can be produced by the method described in this study.

Abstract: Proteases have diverse applications in a wide variety of industries, such as in detergent, leather, food, pharmaceutical and silk. The extracellular cold-active protease was purified from the psychrotrophic bacterium Serratia sp. WJ39 from a meat factory. The protease was cold-active with a molecular mass of 47.6 kDa estimated on SDS-PAGE. It showed an optimal activity at pH of 8 and was stable at pH 6 to 10, while its optimal temperature was 37°C and it was stable at 0-25°C, even remained 35% residual activity at 0°C. The protease was totally inhibited by PMSF which was telling that the purified enzyme was a serine protease. The properties like moderate thermostability, activity in a broad pH range and resistance to metal ions make this enzyme a suitable candidate for the possible use in food and leather industry.

Abstract: The profile of 58 species non-methane hydrocarbons (NMHCs) emissions from a typical coke production plant in northern China was studied. Source samples were taken using a dilution chamber system and were quantified by a gas chromatography/mass spectrometry (GC/MS) system. Based on the measurement of source profiles, aromatic hydrocarbons were found in highest concentration (48.5%), followed by alkanes (42.9%) and alkenes (8.6%), respectively. The emission of C₆-C₇ species took the largest proportion of the NMHCs, toluene and n-hexane were primary species, accounted for 27.4% and 25.1% of total NMHCs. The OH loss rate of NMHCs were estimated, indicated that alkenes (46.5%) played the most important role in L_OH, followed by aromatic hydrocarbons (34.3%) and alkanes (19.2%). The top 5 species in L_OH were: 1-butylene, toluene, n-hexane, trans-2-butene and cis-2-pentene.

Abstract: Rabbit is a traditional textile material and has protein content about 93%. Rabbit hair wastes are abundantly present in textile processing due to its poor spinnability. In order to recycle the waste rabbit fiber effectively, the rabbit protein was researched. The papermaking method was performed for the first time and their properties of the hybrid paper were discussed in this study. Different contents of rabbit protein were successfully prepared and mixed with pulp fibers to remade papers. Finally, performances of these papers were characterized. The results showed that the surface of the rabbit protein paper was flat, white and writing fluently. The ink absorbance of novel paper increased. Moreover mechanical properties of the rabbit protein paper were stronger than the untreated paper. The folding endurance decreased firstly and then increased.

Abstract: Detailed characterisation and recovery of galena, sphalerite, and pyrrhotite from the beneficiation plant tailing of YouXi, China, was investigated. Different characterisation techniques viz. size analysis, chemical analysis, mineral analysis by Mineral Liberation Analyser（MLA）were carried out. Based on the appreciable differences in specific gravity, floatability and magnetic susceptibility between the desired lead, zinc, sulphur minerals and the gangue minerals, the flow sheets comprising desliming, flotation and magnetic separation, was used to recover galena, sphalerite, and pyrrhotite values. A lead and zinc concentrate of Pb 16.02%, Zn 35.1% and sulphur concentrate assays 35% S and 56% Fe can be produced from the tailing.