research and development (Aerogel)

Pollution Elimination of Sea Water with Aerogels Aerogels are a type of three-dimensional mesoporous nanostructures that are about 50 to 99% by volume air and are known as the lightest solid, the best type of heat and sound insulation. The company-made samples are mostly composed of silica mesh, the surface of which is modified with methyl and ethyl groups (due to reduced surface tension of fluid exit and resistance in wet environments). The reason for the low thermal conductivity in these materials is the presence of capillary cavities with an average diameter of 21 nm, which has a specific surface area of about 750 square meters per gram. These nanometer cavities trap air and thus minimize energy transfer in the form of convection and conduction within the cavities. The highest rate of radiant heat transfer is due to the low rate of radiant heat transfer at normal temperatures. Also, the density of this structure is about 8 kg per cubic meter. Membranes made of modified aerogels in the water-oil separation process act in such a way that the organic functional groups on the surface of this nanostructure cause resistance to water passage (super-hydrophobic property with a contact angle of 157 degrees), while These organic groups are super-oil-friendly and selectively prevent oil from passing through and prevent water from passing through. Unlike conventional methods such as API, in which the separation is performed only in the common season, in this method, the separation efficiency reaches its maximum about 99% in one step through the membrane.
During the production of the bottles, the preforms are placed in a stretching blower that warms them in a formable state in seconds. They are stretched longitudinally with a rod, and at the same time air is blown at high pressure, pushing the plastic to the bottle-shaped metal mould wall. After the cooling, the shaping process is carried out. When the bottles are recycled, the chain structure of the PET is broken. The primary goal is to reverse the process, to improve the mechanical and physical properties of the recycled substance. Various natural and synthetic raw materials were examined as to how effective they can be applied as chain extenders.
Oil spill cleaning using engineered nanomaterials is more effective than conventional techniques; Because they lead to a better and more distinct response to conventional chemicals. The excellent performance of nanomaterials can be attributed to the increased surface area as well as higher reactivity and on-site usability. It is necessary to optimize the capture of oil impurities by magnetic nanoparticles and further removal by magnet. Despite their potential toxicity, nanomaterials have been shown to have great potential for innovative solutions to clean up oil spills through their unique structures, excellent properties, and outstanding performance. As future work in this area, materials based on ternary systems (nanosorbents, nZVI, strong oxidants, eg organic and inorganic peroxides, aerogels, oxidizers, magnetic nanoparticles) appear to be promising. Silica aerogels have been synthesized using the drying method at ambient pressure as well as sodium silicate solution as a precursor. Silica aerogel production includes three general stages of hydrogel production, aging and drying of wet gel. In this study, inexpensive materials have been used to synthesize silica aerogels. Silica aerogels produced were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), specific surface area (BET) measurement, contact angle measurement and density determination by pycnometer. The results of FTIR showed the presence of methyl groups on the surface of silica aerogel which confirmed the hydrophobicity of silica aerogel and the desired surface modification. Based on BET analysis, the specific surface area of the sample was 822.47 m2/g. In addition, the pore volume and the mean pore size distribution were 3.76 cm3/g and 17.7nm, respectively. The SEM image showed that the pore size distributions were uniform and less than 100nm. Naphthalene was used as an organic pollutant in the effluent to investigate the adsorption performance of silica aerogel. The adsorption of naphthalene by silica aerogel is the first in this study. Among cyclic hydrocarbons, naphthalene has the highest solubility in aqueous medium. Removal of naphthalene from water has been done by various methods, and the adsorption process has received much attention due to its low cost, safety and simplicity of operating conditions [21]. The main purpose of this study was to investigate the effect of operational variables such as contact time, adsorbent concentration, solution pH and the interaction of these variables in the adsorption of naphthalene from water by silica aerogel. In the next step, to obtain the predicted model and optimal operating conditions, the surface response method (central hybrid design) was used. Based on the results obtained in the analysis of variance table, a quadratic nonlinear model was obtained to predict the removal amount of naphthalene. The variables of time, adsorbent amount, time and adsorbent interaction as well as time and pH interaction were identified as important. The accuracy of the model was confirmed by statistical variables such as characterization coefficient (0.903), adjusted characterization coefficient (0.877) and accuracy adequacy (19.23). In the kinetic study, the quasi-quadratic kinetic model showed good compatibility with the experimental results. Adsorption isotherms were obtained in the range of 10 mg/L to 34 mg/L and the results were well consistent with the Freundlich model. The problem of oil spills is always a serious problem for the environment, especially for oil-rich countries. To solve this problem, several methods have been used that the use of suitable adsorbents has been very much considered by researchers. Therefore, it is very important to provide an environmentally friendly, low-cost, high-adsorption capacity that is operationally simple. PVA-PAN fiber airborne adsorbent was prepared and its application to recover leaked oil in seawater was investigated. In order to investigate the factors affecting the structure and properties of airgel adsorbents, experiments were designed and factors such as fiber percentage, length and percentage of PVA were investigated to determine the effect of each on the density and amount of airgel adsorbent oil adsorption. Among these, the most effective factor on the properties of aerogel adsorbent was the percentage of PVA, which changed the percentage of oil absorption to a considerable amount. After performing these experiments, the optimal conditions including 3% by weight of PAN fibers, 5 mm of PAN fiber length and 1% by weight of PVA were determined and the adsorbent made in these conditions showed the ability to absorb about 1294% of oil.