Protocol encompassing ultrasound/Fe3O4 nanoparticles/persulfate for the removal of tetracycline antibiotics from aqueous environments

Clean Technologies and Environmental Policy - The presence of residual antibiotics in the environment is one of the major global concerns, and it is imperative to control their discharge in water...     

Wound dressing application of castor oil- and CAPA-based polyurethane membranes

Polymer Bulletin - The objective of this study was to investigate and compare the effects of two different types of polyols on properties of synthesized polyurethanes (PUs), to develop biomedical...     

Simulating Unsaturated Zone of Soil for Estimating the Recharge Rate and Flow Exchange Between a River and an Aquifer

Coupling surface water and groundwater models dynamically based on a simultaneous simulation of saturated and unsaturated zones of soil is a useful method for determining the recharge rate and flow exchange between a river and an aquifer as well as simultaneous operation of water resources systems. Thus, the main objectives of this study are to investigate the effects of surface water and groundwater interactions through their systematic simulation and to create a dynamic coupling between surface water and groundwater resources of the area by relevant mathematical models. Accordingly, hydrologic soil moisture method and MODFLOW model were employed to simulate the unsaturated and saturated zones, respectively. The results revealed that simultaneous simulation of the saturated and unsaturated zones of the soil can illustrate the interaction between surface water and groundwater at any spatial and temporal intervals well through using complete hydroclimatological balance components in the form of a coupled model. The application of this method in the Loor-Andimeshk Plain, located in the southwest of Iran, showed that aquifer recharge through the plain area from November to March is due to precipitation. On the other hand, in the warm months (June to September), the plain is merely fed through irrigation water penetration. As the level of river water in both Dez and Balarood rivers is higher than the Loor-Andimeshk aquifer level, hence the exchange occurs as a leakage from the river to the aquifer. The highest and lowest values of average exchangeable water in Balarood River occur in March and April and in Dez River are from June to September.

     

An Improved Estimation of the Angstrom–Prescott Radiation Coefficients for the FAO56 Penman–Monteith Evapotranspiration Method

The FAO56 Penman–Monteith (FAO56-PM) method is known as the standard method for estimating reference evapotranspiration (ET₀) in a variety of climate types. Global solar radiation (R_s) is one of the essential inputs of this model, which is usually estimated from the Angstrom–Prescott (AP) method. The major drawback of the FAO56 pre-defined AP coefficients application is that the AP coefficients might need local calibration, to estimate ET₀ accurately. The aim of this study is to compare the effect of the FAO56 pre-defined AP coefficients (i.e. a and b) and the locally calibrated ones, on estimating daily ET₀ in 15 sites over Iran. Using long-term (1980–2007) experimental global solar radiation data (R_s), new locally calibrated (a) and (b) coefficients are suggested and new ET₀ values are determined accordingly. It was found that the range of the calibrated AP coefficients (a, b) are climate dependent and locally different from those of recommended by the FAO56-PM method. Estimated ET₀ at daily scale, improved up to 72.7 % when the calibrated AP coefficients were applied instead of FAO56 pre-defined AP coefficients. Based on the results, applying the FAO56 pre-defined AP coefficients (i.e. a?=?0.25 and b?=?0.50) in northern subtropical-humid and southern hot climates caused larger ET₀ errors. By contrast, the least ET₀ errors were found in cool arid and cool semi-arid inland climates, locating about 1,330 above sea level. The correlations between the calibrated AP coefficients and geographical factors are also discussed in this research.     

Photocatalytic properties of TiO2 sol-gel modified nanocomposite films

TiO₂ nanocomposite films with different concentrations of TiO₂ MT-150A nanoparticles were immobilized on glass substrates using a dip coating process. The crystalline structure and surface chemical state of nanocomposite film properties were examined by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The specific surface area and morphology of TiO₂ MT-150A nanoparticles were evaluated by the BET method and Field Emission Scanning Electron Microscopy (FE-SEM). The photocatalytic activities of films were evaluated by the methyl orange decoloring rate. XPS measurements showed that the oxygen amount (%) was related to the film composition. The composite film with 10 g/L MT-150A loading yielded the highest amount of surface oxygen (26.82%) and TiO₂ rutile showed the lowest amount of surface oxygen (13.67%) in the form of surface hydroxyl groups. The remaining oxygen was identified as lattice oxygen. In addition, the nanocomposite film with 10 g/L MT-150A loading yielded the highest photocatalytic activity.     

Theoretical and experimental study on the fluidity performance of hard-to-fluidize carbon nanotubes-based CO2 capture sorbents

Carbon nanotubes-based materials have been identified as promising sorbents for efficient CO₂ capture in fluidized beds, suffering from insufficient contact with CO₂ for the high-level CO₂ capture capacity. This study focuses on promoting the fluidizability of hard-to-fluidize pure and synthesized silica-coated amine-functionalized carbon nanotubes. The novel synthesized sorbent presents a superior sorption capacity of about 25 times higher than pure carbon nanotubes during 5 consecutive adsorption/regeneration cycles. The low-cost fluidizable-SiO₂ nanoparticles are used as assistant material to improve the fluidity of carbon nanotubes-based sorbents. Results reveal that a minimum amount of 7.5 and 5 wt% SiO₂ nanoparticles are required to achieve an agglomerate particulate fluidization behavior for pure and synthesized carbon nanotubes, respectively. Pure carbon nanotubes + 7.5 wt% SiO₂ and synthesized carbon nanotubes + 5 wt% SiO₂ indicates an agglomerate particulate fluidization characteristic, including the high-level bed expansion ratio, low minimum fluidization velocity (1.5 and 1.6 cm·s^–1), high Richardson−Zakin index (5.2 and 5.3 > 5), and low Π value (83.2 and 84.8 < 100, respectively). Chemical modification of carbon nanotubes causes not only enhanced CO ₂ uptake capacity but also decreases the required amount of silica additive to reach a homogeneous fluidization behavior for synthesized carbon nanotubes sorbent.     

CFD simulation of impeller shape effect on quality of mixing in two-phase gas–liquid agitated vessel

Mixing efficiency in two-phase gas-liquid agitated vessel is one of the important challenges in the industrial processes. Computational fluid dynamics technique (CFD) was used to investigate the effect of four different pitched blade impellers, including 15°, 30°, 45° and 60°, on the mixing quality of gas-liquid agitated vessel. The multiphase flow behavior was modeled by Eulerian-Eulerian multiphase approach, and RNG k-ε was used to model the turbulence. The CFD results showed that a strong global vortex plays the main role on the mixing quality of the gas phase in the vessel. Based on the standard deviation criterion, it was observed that the axial distribution of the gas phase in the 30° impeller is about 55% better than the others. In addition, the results showed that the 30° impeller has a uniform radial distribution over the other impellers and the maximum gas phase holdup in the vessel. Investigation of the power consumption of the impellers showed that the 30° impeller has the highest power consumption among the other pitched blade impellers. Also, examine the effect of same power condition for pitched blade impellers showed that the 30° impeller has the best mixing quality in this condition.     

Development of a multispectral imaging system for online quality assessment of pomegranate fruit

The objective of this study was to develop a prototype multispectral imaging system for online quality assessment on pomegranate fruit. At first, a visible/near infrared spectroscopy (400–1100 nm) was tested for non-destructive determination of total soluble solids, titratable acidity, and pH. The spectral data were analyzed using the partial least square analysis. Then to establish consistent multispectral imaging system, the highest absolute values of β-coeffcients correspond to wavelengths from the best partial least square calibration model were selected and used for identifying the optimal wavelengths. Consequently, a multispectral imaging system was developed based on the effective wavelengths 700, 800, 900, and 1000 nm. The performance of the developed multispectral imaging system was evaluated by multiple linear regression models. The multiple linear regression model predict total soluble solids with r = 0.97, root mean square error of calibration = 0.21°Brix, and ratio performance deviation = 6.7 °Brix. Also, the results showed that the models had good predictive ability for pH and titratable acidity. Results showed that the developed multispectral imaging system based on the optimal wavelengths could be used for online quality assessment of pomegranate fruit.     

Antiradical activity of different parts of Walnut (Juglans regia L.) fruit as a function of genotype

The objective of this work was to analyse phenolic compounds and antiradical capacity of different parts of walnut fruit among six genotypes of Juglans regia L. Therefore, total phenolic and flavonoid content were determined and methanolic extracts of walnut genotypes were considered by the reducing power, DPPH (2,2-diphenyl-1-picrylhydrazyl), superoxide anion and nitric oxide radical scavenging. Significant differences were found in phenolic content and radical scavenging capacity of different parts of fruits and among various genotypes. High correlation coefficient (R² = 0.81) was observed between phenol content and radical scavenging activity, but this was not always true (R² = 0.01). These results demonstrated that walnut genotypes have different phenolic compounds and phenolic compounds have different radical scavenging power. The differences of phenolic compounds were confirmed by using high performance liquid chromatography (HPLC).