Papers by Keyword: Regeneration

Abstract: Iron oxide (Fe₂O₃) desulfurization sorbent was prepared from FeSO₄ and NH₄HCO₃ by precipitation method, and its regeneration behavior under different atmosphere was studied by using Thermos gravimetric analyzer. It is found that the regeneration of Fe₂O₃ desulfurization sorbent is the best in the synergy of SO₂-O₂ atmosphere. When the concentration of O₂ or SO₂ in the synergy of SO₂-O₂ atmosphere was increased, the regeneration time can be reduced, which is beneficial to the regeneration of iron oxide desulfurization sorbent. The regeneration of Fe₂O₃ desulfurization sorbent in the synergy of SO₂-O₂ atmosphere can not only prevent sorbent sintering in single O₂ atmosphere but also improve the rate of regeneration in single SO₂ atmosphere.

Abstract: The influences of the regeneration temperature and SO₂volume fraction on regeneration kinetics behavior of Fe₂O₃ sorbent as a high-temperature desulfurization sorbent were researched by TGA (Thermos gravimetric analyzer) in this work. The main regeneration product of iron oxide desulfurization sorbent was Fe₂O₃ and sulfur in SO₂ atmosphere which has an important practical significance for pollution control of H₂Sandrecycleofsulfur. The results indicate that Fe₂O₃ desulfurization sorbent was completely regenerated at temperature of 725-775 °C and the higher regeneration temperature and volume fraction of SO₂ is benefit to improve regeneration reaction rate. The regeneration reaction of Fe₂O₃ sorbent in SO₂ atmosphere can be first order reaction obtained by the equivalent grain model, and the controlling process of regeneration reaction is change from the chemical reaction control to the diffusion control in the whole regeneration process. The chemical reaction apparent activation energy and the corresponding frequency factor of chemical reaction are 145.31 kJ/mol and 0.0063 m/s, respectively. And that of diffusion are 50.73 kJ/mol and 4.38×10^-3 m²/s, respectively.

Abstract: The effects of temperature and concentration of sulfur dioxide on regeneration behavior of manganese oxide sorbent were studied in a fixed-bed reactor. The sorbents were characterized by X-ray diffraction and X-ray photoelectron spectroscopy. Subsequently, the regeneration mechanism was inferred and the yield of export elemental sulfur was calculated. The study shows that, the major regeneration products are Mn₃O₄, MnSO₄ and a small amount of elemental sulfur under SO₂ atmosphere.The sulfate can be converted to Mn₃O₄ and Mn₂O₃ at 800 °C under N₂ atmosphere. The elemental sulfur productivity increases with the increase of temperature and concentration of sulfur dioxide.The regeneration conversion attains maximum value (68%) at 800 °C under the atmosphere of 1.68% SO₂, and the productivity of elemental sulfur reaches to maximum value (29%) under the conditions.

Abstract: Collagen is one of the most used biomaterials for bone defects repair, proving good results in tissue reconstruction research, and also its features recommend it as a very attractive drug delivery scaffold for local treatment of the affected osseous tissue. The inflammatory response is a common reaction that occurs in bone disease, the topical administration of anti-inflammatory drugs (NSAIDs) representing a reliable strategy to overcome this issue. The purpose of this paper was the physical-chemical and biopharmaceutical evaluation of some spongious matrices consisting of collagen as release support and niflumic acid as drug NSAID model, usable in bone tissue regeneration. Type I fibrillar collagen gel (2.4% w/w, 3.5 pH) was extracted from calf hide by the technology currently used in Collagen Department of Division Leather and Footwear Research Institute. The collagen sponges were obtained by freeze-drying of gels adjusted at 1% and 7.3 pH, with different dextran (0; 10 and 20%) and MgO (0; 30 and 60%) concentrations (reported to dry collagen), with 0.5% and without niflumic acid (NA) (reported to gel) and the same amount of glutaraldehyde (0.5% reported to collagen dry substance). The sponges were evaluated through water absorption, FT-IR spectroscopy and optical microscopy. In vitro NA release from the designed sponges was carried out using a sandwich device adapted to a dissolution equipment. Power law kinetic model was applied to explain drug release from the tested formulations. The NA release from collagen sponges showed a non-Fickian transport mechanism. The addition in different concentrations of dextran and MgO leads to more compact structures and improves stability of collagenic matrices. Our results showed that the designed support could be adequate for treating the inflammation associated with a bone defect in orthopedic surgery.

Abstract: The goal of this study was to create a Gephi network visualisation of the guided bone regeneration induced by tissue-engineered grafts using a histological score. Bioengineered bone grafts were obtained using CD 1 mice mesenchymal stem cells seeded on red deer antler scaffolds. Both basal and complex osteogenic media were used as osteogenic inducers of mesenchymal stem cells in the bioengineering process.Bone defects (5 mm in diameter) in the cranial bone of CD1 mice were surgically induced. Bone reconstruction was not performed in surgically induced bone defects in the control group, consisting of 30 subjects. In the study group, consisting of 60 subjects, bone reconstruction was performed using tissue engineered bone grafts. Subjects were sacrificed 2 and 4 months after surgery. Bone regeneration was assessed using a histological record.Comparative analysis of the bone regeneration process between the groups was performed using SPSS (Statistical Package for the Social Sciences) , network analysis and the visual results were performed using Gephi software.The created Gephi network indicates a more advanced bone regeneration stage for subjects in the study group sacrificed after 4 months.The Gephi networks reveal the time evolution of the bone regeneration process, the nodes size and edges complexity increasing from subjects sacrificed at 2 months to those sacrificed at 4 months.At each stage, two and four months after surgery, bone regeneration was more advanced in the study group than in the control group and it was different for the two osteogenic media. We conclude that bone regeneration in critical size defects, as in our research, cannot be obtained without bone reconstruction.

Abstract: The increasing demand for producing dimethyl ether from synthesis gas explains the renewed interest in studying the activity and stability of catalysts. In the present work, resource catalytic testing of ZSM-5 zeolites was carried out in the one-step synthesis of dimethyl ether from synthesis gas for 120 hours. Formation of condensation products was observed on zeolite surface after catalytic tests which leads to lower catalytic activity of samples. Condensation products were investigated by thermal analysis in an oxidizing atmosphere. Textural characteristics of zeolites before and after reaction were investigated. It was shown that methanol significantly contribute to formation of condensation products on the catalyst surface in the process of dimethyl ether production.

Abstract: Vehicular pollution is one of the main reasons for air pollution in many cities. According to Industrial Environment Carbon, every gallon of gasoline produces 14% total volume of carbon dioxide, this will ultimately lead to air pollution and global warming [10]. To minimize the emission level, physical adsorption [4] can be used for the removal of organic molecule from exhaust gas stream by impulse collision. So our proposed system consists of a filter matrix bed, made of activated carbon, calcium hydroxide, lithium hydroxide [8,9]. Activated carbon is the most widely used adsorbent. It can adsorb a wide range of pollutants with varying dimensions by its broad pore distribution, micro and mesophores. Calcium group can naturally adsorb carbon component and get transformed into lime. Lithium hydroxide is widely used as carbon capturing material in space craft for adsorbing carbon dioxide exhaled by astronaut as a breathing scrubber. So collectively these three carbon sequestrating material can efficiently remove the pollutant by chemisorptions [2].

Abstract: Boron-oxygen related defects formed under working conditions of a c-Si solar cell can be a showstopper for new cell concepts enabling higher conversion efficiencies. The recombination activity of these defects can be reduced to negligible values by a regeneration process under elevated temperatures and in the presence of excess charge carriers in the Si bulk. It is shown that this process also relies on the presence of H in the c-Si bulk. Regeneration kinetics can be sped up by higher temperatures, higher concentrations of excess charge carriers and higher H concentration in the c-Si bulk. But care has to be taken to avoid a destabilization reaction taking place at higher temperature, resulting in the BO-related defects being again present in the recombination-active state. A 3-state model with the corresponding reaction rates between the different defects states describes the experimental findings and can be used for predictions of an optimized regeneration process.

Abstract: Aqueous technological liquids are widely used in industrial processes. However, due to limited resources, there is an increasing pressure on their protection and reduction of water consumption by, for example, closing water circulation. It is facilitated by the development of membrane technology. The article describes a method for regenerating aqueous technological liquids used in metal surface treatment processes and cleaning a production plant. This process was conducted in batch system using a mobile microfiltration installation. The working unit was equipped with tubular ceramic membranes having a nominal pore diameter of 0.2 μm, working in a cross-flow regime. The main advantage of the apparatus is its low weight and high mobility. The installation and method of regeneration were verified during the processing of a model alkaline liquid used for cleaning a plant in the dairy industry. It was found that microfiltration can be used to remove technological impurities (coagulated proteins and fats) from the liquid. The physicochemical properties of the liquid, including alkalinity, remained stable after repeated filtration. This indicates that the purified liquid can circulate in the system and be used in accordance with its original purpose. The proposed solution enables the reduction of water consumption and chemicals used for the preparation of these liquids.

Abstract: Over the past several decades with significant technological advances there has been continuous increase in plastic manufacturing in China, which has contributed to the production of a great deal of plastics worldwide every year, and at the same time it has resulted in a large amount of plastic solid waste (PSW). It has great potential values for waste plastics to reuse as secondary materials, which may lessen pressure on resource and environment. The paper studies the status of waste plastics in recycling, reusing and reducing on management countering on the increase in the flow of waste plastics in Shanghai. In light of the methodology of life cycle, the study analyzes the environmental impacts associating with the alternatives in a ‘cradle to grave’ approve to PSW technological recycling systems. We will choose regenerating and energy recovery processes based on site investigation and literatures data in Shanghai to analyze recycling options and how various processes affect the environment. Life-cycle methodology was very suitable for evaluating the overall environmental consequences, and could be used for making decisions and planning strategies with the rapid increase of plastic solid waste generation for Shanghai.