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In this study, an Electro-Fenton (EF) reaction was employed to treat hazardous and resistant wastewater from a pesticide factory using graphite cathode modified with industrial carbon black (N330). Carbon black nanoparticles (N330) could increase the porosity of the cathode surface and hydrogen peroxide production during the electro-Fenton reaction. In order to examine the quality of the porous surface of the modified cathode, Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM) tests were successfully applied. Moreover, the performance of the modified cathode was assessed by the Cyclic Voltammetry (CV) test. The experiments were designed using the Central Composite Designs (CCD) technique under the Response Surface Methodology (RSM). The Analysis of Variance (ANOVA) showed that the model accurately predicted the process. 78.15% of COD removal was optimally found with a current intensity of 253 mA, air flow rate of 1.56 L/min, Fe2+ catalyst dosage of 0.63 g, pH of 3, and reaction time of 126 min, while 33.78% of COD removal (with 15 mmol/l of hydrogen peroxide production) was obtained at pH of 6 (close to the original pH of wastewater) on the modified cathode.

In this study, biomass dry weight [DW (0.912 g/L)] was markedly enhanced at pH of 10 for 24 h of aeration. The maximum production of protein (14.239 mg/L) was obtained at the highest photoperiod. The highest content of PC and APC (0.129 and 0.099 mg/L, respectively) was recorded at pH of 10 for 24 h of aeration. The highest content of total chlorophyll (Ca and Cb) and carotenoids (K) (6.436, 3.421, and 2.856 mg/L) was recorded at pH of 9. The content of photosynthesis pigments (Ca, Cb, and K) was reduced by increasing pH from 9 to 10, while the high alkaline pH (10) may favor the over-production of biomass, protein, phycobiliprotein pigments (PC and APC). Moreover,  A. maxima increased the accumulation of photosynthesis pigment under strong illumination and decreased the accumulation of phycobiliprotein pigments by increasing the light irradiance time

In this study, copper nanoparticles (Cu-NPs) were synthesized through green and economic techniques. The Centaurea cyanus plant extract was used as an appropriate reducing and stabilizing agent in this process. The synthesized nanoparticles were characterized by Fourier-Transform InfraRed (FT-IR) spectroscopy, X-Ray powder Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), and N2 adsorption porosimetry analysis. The analysis showed that the average size of spherical nanoparticles was around 11.9 nm, with 74.2 m2/g and 0.36 cm3/g mane surface area and pore size, respectively. Then, Cu-NPs were studied as a low-cost adsorbent to remove Methylene Blue (MB) dye from aqueous solutions. For this purpose, Central Composite Design (CCD) under the Response Surface Methodology (RSM) was applied to design the experiments, model the data, and optimize the operating conditions. The effect of various operating parameters such as pH, MB initial concentration, adsorbent amount, and contact time on the MB removal was practiced. Analysis of variance (ANOVA) showed a good agreement between the experimental data and the predicted ones obtained from the quadratic model. The optimum conditions for MB removal (63.20 %) were found at pH of 6.6, MB initial concentration of 30 mg/L, adsorbent amount of 0.15 g, and time of 101.5 min. The results showed that the Langmuir isotherm with a maximum adoption capacity of 21.9 mg/g and pseudo-second-order kinetic models with a rate constant of 0.359 (g/mg) (1/min) can properly legitimize the experimental data.

Backscatter radiography as a technique can successfully be applied for predicting the pipeline bursting and casing failure. A valid numerical technique will allow predicting these issues without needing to access the outside of the pipelines. Furthermore, this technique has the ability to estimate the shape and depth of damages. It is normally preferred to apply non-destructive testing (NDT) methods which can monitor the status of a pipeline from the internal surface of it without needing to access both sides of it depending on various locations of pipe such as underground or submarine. In the current study, backscatter radiography as an applicable and NDT method to detect locations with potential for pipeline bursting or casing failure was carefully investigated using the Monte Carlo simulation tool. The data obtained by the simulation process showed that backscatter radiography could detect deformations, corroded areas, depositions, creation of load on the casing, lacking proper cementation, excessive pressure inside the pipelines, and other factors which may increase the risk of pipelines bursting or casing failure (in-situ and online) with an acceptable accuracy.

Nowadays, the uses of natural colors attract the attention of many researchers due to its high applications. Spirulina Maxima is a rich source of proteins and pigments. Thus, it is vital to optimize the production of biomass and pigments to choose appropriate concentration and method of adding glucose. In this paper, the impact of alternative and additive glucose in Zarrouk’s medium at various concentrations (0, 0.5, 1 and 1.5 gL-1) on biomass and pigments production like phycobilioproteins, carotenoid and chlorophyll was investigated during the 7 days of cultivation. Microalga was grown in 8 treatments (4 treatment as an additive and 4 treatment as an alternative carbon source) with 3 replications in laboratory temperature and light intensity of 24 ± 2 µmoles/m2/s (24 hours exposure-time). Maximum specific growth rate and doubling time were calculated using nonlinear modeling by Wolfram-Mathematica software. The highest cell concentration (2.39 gL-1) and specific growth rate (0.47 day-1) were obtained from additive glucose source at the highest initial concentration that was 2 times higher than when the glucose was added as an alternative source and 3.3 times higher than the control treatment. As a result, low concentrations of glucose have not caused growth in biomass and photosynthetic pigments production as well as the highest concentration of glucose. In addition, glucose concentration of 1.5 gL-1 could increase the biomass of Spirulina Maxima, the content of carotenoid and chlorophyll a, but has no positive effect on the increase of phycobilioproteins content. Compared with glucose as an alternative source, additive glucose with the highest initial concentration of glucose has shown the highest biomass growth, chlorophyll a and carotenoid production. On the other hand, high accumulation of biomass has reduced light penetration in culture medium and phycobilioproteins production during the last cultivation days. Moreover, adding glucose as an additive and alternative carbon source have not a significant effect on the production of phycobilioproteins pigment.

In the present study, the removal of lead (II) ions from aqueous solutions was investigated by powdered Henna. Henna is a herbal material that can dramatically adsorb metal ions. Adsorption experiments were carried out in a batch system at room temperature. Then, the equilibrium concentration of each sample was analyzed by atomic adsorption device. The effects of various parameters such as time, initial concentration, adsorbent amount, and pH were investigated. pH, initial concentration, and adsorbent amount showed sharp effects on the adsorption rate. The effect of time on the process was not considerable, as well. The optimum operating conditions were found at pH of 4.78, time of 49.47 min, lead (II) initial concentration of 93.5 mg/L, and adsorbent amount of 1 g led to 97.8% removal of lead (II). Furthermore, Langmuir and Freundlich adsorption isotherms were investigated for the lead (II) adsorption process on Henna. The results showed that Langmuir's isotherm model is more suitable for this process (R2=0.947).

Slaughterhouse waste contains many organic matters, suspended solid particles (SS), oil and lipid, nitrogen and phosphate and biological infiltration of these pastes for removing much organic matters has special efficiency because of high concentration of organic load and nitrogen (Merzouki et al., 2005). The aim of the present study is to examine the effect of pre-fermentation and duration of aeration on removing the pollutant from waste containing COD, ammonium and phosphate.

In this study, Chemical Oxygen Demand (COD) from a pharmaceutical wastewater (PhW) was reduced by several techniques such as electro-Fenton (EF), photo electro-Fenton (PEF) and activated sludge (AS) processes and the obtained data were compared with each other. The effects of several parameters such as pH, current density, H2O2/Fe2+ molar ratio, volume ratio of H2O2/PhW, reaction time and UVA light were studied on the COD reduction through the EF and PEF processes. The Box-Behnken Design (BBD) under Response Surface Methodology (RSM) was applied to design and then optimize these processes. The optimal conditions for 87% of COD removal through the EF process were at pH of 3.27, current density of 57 mA/cm2, H2O2/Fe2+ molar ratio of 3.5, volume ratio of H2O2/PhW of 1.34 ml/l and reaction time of 56.32 min while the optimal conditions for 91.6% of COD removal through PEF process were at pH of 3.5, current density of 57.5 mA/cm2, H2O2/Fe2+ molar ratio of 3.81, volume ratio of H2O2/PhW of 1.5 ml/l, reaction time of 10.12 min and 6 W UVA light while 77.70% of COD removal was obtained by  the AS process with residence time of 1020 min. According to the kinetic study, the second order reaction (with high R2 data) could properly model the EF and PEF processes.

microalgae use has been recently attracted for the production of biologically active drugs and pharmaceuticals.Carbon source is an essential factor for the Spirulina maxima growth. Since finding the appropriate carbon source and its concentration to achieve high levels of biomass in the shortest cultivation period is very valuable. Therefore, the effect of different carbon sources (sodium carbonate, sodium bicarbonate, glucose and molasses) with different concentrations (16, 24 and 32 gL-1) on growth and biomass production were evaluated.

Microalgae was grown in 11 treatments with 3 replications at labarotary temperature (28±3 °C) and 1350±100 Lux light intensity (24 hours exposure-time). Maximum specific growth rate and doubling time were calculated according to nonlinear modeling by Wolfram Mathematica software at 99% confidence interval.

The highest biomass concentration (gL-1) at the highest carbon source concentration in the first 5 days belonged to molasses (3.083), glucose (2.094), sodium carbonate (0.869) and sodium bicarbonate (0.835). Biomass production of treatments except glucose in medium was increased by increasing concentration from 16 to 32 gL-1. Although molasses has reached on highest biomass production during the first 5 days of cultivation, but the greatest effect on increasing specific growth rate belongs to the glucose sample.

As a result, the carbon source and its concentration had a significant effect on the growth and biomass production. Glucose has been selected as an effective carbon source for growth with a concentration of 24gL-1. Moreover, the highest concentration of treatments had shown the least effect on specific growth rate.

The conventional liquids have some limitations regarding the thermal properties. The nanoparticles addition is one of the techniques which can modify them. In this research, heat transfer coefficient (h) and pressure loss (Δp) of various nanofluids containing Al2O3, SiO2 and MgO nanoparticles dispersed in water in an annular tube with constant wall temperature were numerically considered. According to the literature, five different nanofluid volume concentrations (1%, 2%, 3%, 4% and 5%) were chosen and used. Two models involving the mixture and VOF were applied and their data were compared. The average convective heat transfer coefficient and pressure loss enhanced with volume fraction and Reynolds number (Re) increment (3000

In this research study, methanol synthesis catalysts were manufactured with various mole ratios of metal carbonates (zinc, copper and aluminum carbonate) and ammonium hydrogen carbonate via a green solid-state method that employed a ball mill apparatus. Some parameters for the catalyst preparation, such as Al mole percent, Cu/Zn mole ratio, rotations milling speeds and aging time, were optimized to obtain the maximum catalyst activity. The prepared catalysts were compared with the best quality industrial catalyst under the same temperature and pressure condition in a titanium tabular fixed bed reactor. This novel method has many advantages in comparison to the conventional method. The main advantage of the solid-state method is that the methanol synthesis catalyst can be produced without using solvent. Furthermore, this new method reduces operating costs due to the elimination of the filtration and washing steps. Methanol synthesis catalytic activity was maximized at an optimized mole ratio of Cu/Zn of 1.9234 and an Al mole percent of 8 at the maximum grinding speed (450 rpm) during an aging time of 30 min, which showed higher activity (240 gCH3OH/kg cat.h) in comparison with an industrial catalyst sample (218 gCH3OH/kg cat.h). The production of a green catalyst, which requires less water and results in higher catalyst activity, can be widely used for methanol synthesis catalytic applications.

Having accurate values of the parameters which mainly govern the industrial processes in hand is the key aspect to handle the process and optimize it. To deal with this challenge, some mathematical models have been developed and modified to be epidemic. This Study aims to present the simulation of gas-solid flow in fluidized bed dryer. Numerical solution of two-dimensional, axis-symmetrical cylindrical model for both phases is the very base on which this study is conducted. Some of the versatile parameters like inlet gas velocity and temperature, diameter and density of particles during drying process went under magnification and also challenges of heat transfer along the bed are investigated and discussed in detail. Solid temperatures in the center and on the surface which are greatly affected by time as well as results of the study are shown. At the end, model outputs are compared with experimental data which shows reasonable agreement and good match.

A micro reactor or a micro structured reactor or a micro channel reactor is a device in which chemical reactions take place in a channel with typical lateral dimensions less than 1 mm. Process Intensification (PI) is currently one of the most significant methods in chemical engineering and process technology. There is some lack of the literature for the Process Intensification Systems (PIS) and the miniaturized systems which has created some problems for the researchers. In this article, PIS and micro reactors were identified and discussed. Furthermore, their potentials and defects were mentioned. Some published literature and patents were applied for this purpose. A complete reconsideration on these micro reactors and their control was achieved.

The paper describes the effect of temperature, ammonia concentration and feed flow rate on nitrifying treatment of wastewater usage Computational Fluid Dynamics (CFD) for two phase bubbly flow in a split cylindrical airlift reactor with a 0.085 m initiator diameter and 0.505 m height. Superficial gas velocity was used as the operational parameter, air was used as the dispersed phase, and wastewater containing ammonia was used as continuous phase. Temperature enhancement in a constant O and NH concentrations, resulted the 2 4 + increase of reactions rate also NO had an increase of about 3 times as much. By the feed flow rate increase, 2 - O consumption increase and the rate of NO production increase more than NO but decrease the reactions 2 2 3 - - efficiency decrease in a constant time. NH concentration enhancement leads to the increase of O 4 2 + consumption and better reactions efficiency at higher NH concentration, NO concentration increases more. 4 2 + - Modeling results are compared with the experimental data. The CFD modeling results show suitable agreement with the experimental data.