Preparation and Characterization of High Porosity and High Oil-Absorbent Block CMCS Aerogel

2014 ◽  
Vol 887-888 ◽  
pp. 669-673 ◽  
Author(s):  
Wan Tao Guo ◽  
Ling Bin Lu ◽  
Jian Jun Shi ◽  
Jia Yu Sun

Carboxymethyl chitosan aerogel was prepared by freeze-drying method with glutaraldehyde as crosslinking agent. The effect of different concentrations of crosslinking agent and solvent on the gel time and porosity was investigated. The absorption capacity of aerogel was investigated with different oils (gasoline, diesel oil, peanut oil, dimethyl silicone). The results were shown as 1) the highest porosity of the aerogel was 95.01% and the lowest density was 0.026g/cm3. 2) The optimum preparation condition was the concentration of crosslinking agent 20%, the solvent concentration 2%. Oil absorption capacity of the aerogel was up to the maximum of 28.6g/g (to dimethyl silicone), which was higher than to the other three oils. This work offered a preparation method for the high porosity, high oil-absorbing massive carboxymethyl chitosan aerogel and revealed its potential application in the treatment of oil pollution.

2014 ◽  
Vol 805 ◽  
pp. 116-121 ◽  
Author(s):  
Greyce Yane Honorato Sampaio ◽  
Ana C.B.M. Fook ◽  
Thiago Bizerra Fideles ◽  
M.E.R.R.M. Cavalcanti ◽  
Marcus Vinícius Lia Fook

Currently researchers has pointed chitosan as one of the viable alternatives for application as scaffolds in tissue regeneration, mainly due to its availability, biocompatibility, biodegradability and ability to chemical modifications, among them, the crosslinking. With the growing number of investigations of crosslinking agents from natural sources and its applicability, this work focuses on the development and microstructural characterization of chitosan scaffolds and chitosan crosslinked with genipina using the technique of freeze drying. Solutions were prepared with chitosan concentration of 2% (w / t), and genipin 0.15% (w / t) and 0.3% (w / t). These were frozen at-20 ° C and ≈ 196 ° C, and lyophilized. The effect of different concentrations of genipin and freezing rates of the solutions in the porous architecture of the scaffolds were evaluated by Scanning Electron Microscopy (SEM), Optical Digital Microscopy 2D and 3D (OM) and testing the Degree of Swelling (DS). The SEM analysis revealed the formation of a three dimensional structure with pores and / or channels interconnected, influenced by the freezing rate and addition of crosslinking agent, these variables also influence the absorption capacity of the scaffolds. It was observed by OM, the effectiveness of the crosslinking with genipin, through points of fluorescence presented.


2016 ◽  
Vol 840 ◽  
pp. 77-81
Author(s):  
Nur Syazana Suparman ◽  
Khadijah Ahmad Alwi ◽  
Mohd Al Amin Muhamad Nor

Ceramic foam are a class of high porosity materials that are used for various applications. In this study, foam ceramic porcelain powder was produced by using polymeric sponge replication method at different solid content ranging from 30 to 50 wt. %. Properties of ceramic foam was characterized for porosity and density. Ceramic foam then grafted with methyltriethoxysilane (MTMS) at different concentration ranging from 0 to 9.0% v/v to determine hydrophobic effect and oil absorption capacity. From the results, it was found that the density of ceramic foam increased while porosity was decreased with increasing solid contents. It is clearly seen that, MTMS grafting contribute to hydrophobic effect of ceramic foam which enable repelling of water. The amount of oil absorbed by ceramic was found increased by increasing concentration of MTMS for all solid contents. As conclusion, MTMS give significant effects on hyrdophobic ceramic foam and produce good absorption capacity. The lower solid content produced better oil absorption compared to higher solid content due to presence of higher porosity.


2021 ◽  
Vol 11 (9) ◽  
pp. 4012
Author(s):  
Diana Rico-García ◽  
Luis Guillermo Guerrero-Ramírez ◽  
Leonardo Ramses Cajero-Zul ◽  
Euologio Orozco-Guareño ◽  
Edgar Benjamin Figueroa-Ochoa ◽  
...  

In this research a chemical modification of kraft lignin was carried out using a basic nucleophilic substitution reaction (NSA) in order to functionalize it as a novel crosslinking agent for the synthesis of active hydrogels. The chemical modification success of the synthesized crosslinker was demonstrated by using several techniques such as volumetry probes, FTIR, 1H-NMR and DSC. Thus, the obtained materials were employed during the synthesis of acrylic acid-based hydrogels, due to its high-water absorption capacity to evaluate their retention potential of heavy metal ions. Characterization of the active hydrogels were performed by FTIR and SEM, showing the specific signals corresponding to the base monomers into the polymer skeleton and the efficiency of modified kraft lignin as a novel crosslinking agent. Additionally, to demonstrate the potential use of these hydrogels in wastewater treatment, metal ions adsorption experiments were conducted, showing adsorption percentages higher than 90% and 80% for Pb2+ and Cu2+, respectively.


2006 ◽  
Vol 1 (2) ◽  
Author(s):  
P. Literathy ◽  
M. Quinn

Petroleum and its refined products are considered the most complex contaminants frequently impacting the environment in significant quantities. They have heterogeneous chemical composition and alterations occur during environmental weathering. No single analytical method exists to characterize the petroleum-related environmental contamination. For monitoring, the analytical approaches include gravimetric, spectrometric and chromatographic methods having significant differences in their selectivity, sensitivity and cost-effectiveness. Recording fluorescence fingerprints of the cyclohexane extracts of the water, suspended solids, sediment or soil samples and applying appropriate statistical evaluation (e.g. by correlating the concatenated emission spectra of the fingerprints of the samples with arbitrary standards (e.g. petroleum products)), provides a powerful, cost-effective analytical tool for characterization of the type of oil pollution and detecting the most harmful aromatic components of the petroleum contaminated matrix. For monitoring purposes, the level of the contamination can be expressed as the equivalent concentration of an appropriate characteristic standard, based on the fluorescence intensities at the relevant characteristic wavelengths. These procedures are demonstrated in the monitoring of petroleum-related pollution in the water and suspended sediment in the Danube river basin


Two medium-scale ecosystems (mesocosms) were built on the Oslofjord: one a hard-bottom intertidal system and the other a subtidal soft-sediment system. The hard-bottom mesocosm consists of four basins, two controls and two which were dosed with diesel-oil (129 μg 1 -1 a high oil (HO) dose and 29 μg 1 -1 a low oil (LO) dose). Both oil doses caused high mortality of Mytilus edulis and growth was reduced in the macroalgae Ascophyllum nodosum and Laminaria digitata . Recruitment of Littorina littorea was also affected by oil so that populations declined over time. Subtidal benthic communities have been established in the mesocosm and show variations in sediment chemistry within the range found in the field. Although recruitment of benthic macrofauna is reduced, dominant species and species structure remain closely similar to that in the field over six months. Bioturbation effects studied in the mesocosm have shown the important influence of large, rare species in structuring benthic communities, a finding which would not be possible in nature by diving or by the use ofsubmersibles. Preliminary results from a community taken from 200 m depth and established in the mesocosm suggest that it is now possible to do detailed manipulation experiments on communities simulating the whole continental shelf.


Fuel ◽  
2016 ◽  
Vol 166 ◽  
pp. 453-460 ◽  
Author(s):  
Larissa Noemi Silva ◽  
Claudia Cristina Cardoso ◽  
Vânya M.D. Pasa

2011 ◽  
Vol 415-417 ◽  
pp. 1810-1815 ◽  
Author(s):  
Jian Bing Liu ◽  
Qiang Tang ◽  
Shen Zhou Lu ◽  
Ceng Zhang ◽  
Ming Zhong Li

When the articular cartilage defect accompanies with the subchondral bone defect, using bilayer scaffolds which can integrate with surrounding host cartilage and bone tissue respectively as the tissue engineering scaffolds will be conducive to the repair of tissue defects. This paper reports a new method for preparing bilayer scaffolds. Firstly, hydroxyapatite (HA)/silk fibroin(SF) composite porous materials which have high porosity were prepared by a isostatic compaction molding method, then it was fully immersed in silk fibroin solution, and finally SF/HA bilayer scaffolds were obtained by freeze-drying. The structure of the bilayer scaffolds were investigated through scanning electron microscopy, X-ray diffraction, Fourier transform-infrared spectroscopy, electron excitation spectroscopy and electron microprobe. The results indicated that the upper layer of SF/HA bilayer scaffolds is porous SF component, the under layer is the porous HA/SF composite component and the interface of the two layer is closely connected. Furthermore, mesenchymal stem cells from mouse bone marrow were seeded into the bilayer scaffolds and the results showed that the cells had a well adhesion and growth after culturing for 3 days.


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