scholarly journals Design of Experiment for the Optimization of Pesticide Removal from Wastewater by Photo-Electrochemical Oxidation with TiO2 Nanotubes

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 512 ◽  
Author(s):  
Annalisa Vacca ◽  
Laura Mais ◽  
Michele Mascia ◽  
Elisabetta Maria Usai ◽  
Simonetta Palmas
Keyword(s):  
Design Of Experiment ◽  
Flow Reactor ◽  
Removal Rate ◽  
Cell Voltage ◽  
Objective Functions ◽  
Reaction Products ◽  
Initial Concentration ◽  
Simulated Solar Light ◽  
Pesticide Removal ◽  
Density Flow

The Design of Experiment (DoE) technique has been used to investigate the photo-electrochemical removal of diuron (DRN) from wastewater. The process is carried out in a photo-electrochemical flow reactor, in which titania nanotubular electrode is irradiated with a simulated solar light. Different operative conditions have been investigated, in a planned 23 full factorial design in which imposed current density, flow rate and initial concentration have been varied at two levels. The removal process of DRN was investigated in terms of specific removal rate (K) and cell voltage (E), which were assumed as objective functions: the results show that the applied current has a paramount effect on both of the objective functions. From the analyses of the intermediates, it appears that the investigated parameters may exert different effects on the distribution of the reaction products: the initial concentration of diuron and the electrode potential seem to play a more important role, in this case.

Hydrogenolysis of glucose and fructose in glycol solutions over CuO-MgO-ZrO2 catalyst

2020 ◽  
pp. 48-55
Author(s):  
M.E. Sharanda ◽  
◽  
E.A. Bondarenko ◽  
Keyword(s):  
Ethylene Glycol ◽  
Propylene Glycol ◽  
Flow Reactor ◽  
General Trend ◽  
Raw Materials ◽  
Reaction Products ◽  
Renewable Raw Materials ◽  
High Partial Pressure ◽  
Zro2 Catalyst ◽  
Phase Process

Ethylene glycol and propylene glycol are important representatives of polyols. On an industrial scale, they are obtained from petrochemical raw materials. Within a decade, significant efforts were made for the producing of polyols from biologically renewable raw materials - carbohydrates. The general trend for carbohydrate hydrogenolysis includes application of liquid-phase process with the use of modified metal-oxide catalysts, at 120-120 ° C and pressure of 3MPa or above. So high pressure is used for the reason to increase hydrogen solubility, and also due to the high partial pressure of low boiling solvents. We supposed that usage of high boiling solvents could allow hydrogenolysis to be performed at the lower pressure. Ethylene glycol and propylene glycol are of particular interest as such kind of solvent since they are both the main products of glucose hydrogenolysis. In this work, the process of hydrogenolysis of glucose and fructose over Cu / MgO-ZrO2 catalyst have been studied at temperature range of 160-200 °C and a pressure of 0.1-0.3 MPa in a flow reactor. The solvents were simultaneously the target products of the reaction - ethylene glycol and / or propylene glycol. Gas chromatography and 13C NMR were used for the reaction products identification. It was found that the solubility of glucose in propylene glycol is 21 % by weight, and in ethylene glycol 62% by weight. It was pointed out that the process of hydrogenolysis can take place at a pressure close to atmospheric. Under these conditions, the conversion of hexoses reaches 96-100 %. The reaction products are preferably propylene glycol and ethylene glycol. The total selectivity for C3-2 polyols is 90-94 %, that is higher than in the hydrogenolysis of glucose in aqueous solution.

Kinetics of the catalytic hydrodesulphurization reaction system; hydrogenolysis of thiophene

1980 ◽  
Vol 45 (10) ◽  
pp. 2728-2741 ◽  
Author(s):  
Pavel Fott ◽  
Petr Schneider
Keyword(s):  
Atmospheric Pressure ◽  
Active Sites ◽  
Flow Reactor ◽  
Kinetic Equations ◽  
Reaction System ◽  
Reaction Products ◽  
Molybdenum Catalyst ◽  
Cobalt Molybdenum Catalyst ◽  
Kinetics Of ◽  
Reaction Schemes

Kinetics have been studied of the reaction system taking place during the reaction of thiophene on the cobalt-molybdenum catalyst in a gradientless circulation flow reactor at 360 °C and atmospheric pressure. Butane has been found present in a small amount in the reaction products even at very low conversion. In view of this, consecutive and parallel-consecutive (triangular) reaction schemes have been proposed. In the former scheme the appearance of butane is accounted for by rate of desorption of butene being comparable with the rate of its hydrogenation. According to the latter scheme part of the butane originates from thiophene via a different route than through hydrogenation of butene. Analysis of the kinetic data has revealed that the reaction of thiophene should be considered to take place on other active sites than that of butene. Kinetic equations derived on this assumption for the consecutive and the triangular reaction schemes correlate experimental data with acceptable accuracy.

scholarly journals Nitrogen-Doped Graphene Iron-Based Particle Electrode Outperforms Activated Carbon in Three-Dimensional Electrochemical Water Treatment Systems

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3121
Author(s):  
Hosna Ghanbarlou ◽  
Nikoline Loklindt Pedersen ◽  
Morten Enggrob Simonsen ◽  
Jens Muff
Keyword(s):  
Activated Carbon ◽  
Three Dimensional ◽  
Cell Voltage ◽  
Reduction Reaction ◽  
Process Data ◽  
Nitrogen Doped ◽  
Pesticide Removal ◽  
Optimal Value ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

The synergy between electrochemical oxidation and adsorption on particle electrodes was investigated in three-dimensional (3D) systems for p-nitrosodimethylaniline (RNO) decolorization and pesticide removal. A comparison was made between granular activated carbon (GAC) and a novel synthesized nitrogen-doped graphene-based particle electrode (NCPE). Experiments on RNO decolorization show that the synergy parameter of the 3D-NCPE system was improved 3000 times compared to the studied 3D-GAC system. This was due to the specific nanostructure and composition of the NCPE material. Nitrogen-doped graphene triggered an oxygen reduction reaction, producing hydrogen peroxide that simultaneously catalyzed on iron sites of the NCPEs to hydroxyl radicals following the electro-Fenton (EF) process. Data showed that in the experimental setup used for the study, the applied cell voltage required for the optimal value of the synergy parameter could be lowered to 5V in the 3D-NCPEs process, which is significantly better than the 15–20 V needed for synergy to be found in the 3D-GAC process. Compared to previous studies with 3D-GAC, the removal of pesticides 2,6 dichlorobenzamide (BAM), 2-methyl-4-chlorophenoxyaceticacid (MCPA), and methylchlorophenoxypropionic acid (MCPP) was also enhanced in the 3D-NCPE system.

scholarly journals Evaluation of removal efficiency of residual diclofenac in aqueous solution by nanocomposite tungsten-carbon using design of experiment

2017 ◽  
Vol 76 (6) ◽  
pp. 1466-1473 ◽  
Author(s):  
M. H. Salmani ◽  
M. Mokhtari ◽  
Z. Raeisi ◽  
M. H. Ehrampoush ◽  
H. A. Sadeghian
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Design Of Experiment ◽  
High Efficiency ◽  
Carbon Powder ◽  
Batch Adsorption ◽  
Effective Parameters ◽  
Initial Concentration ◽  
Carbon Nanocomposite ◽  
Maximum Removal

Wastewater containing pharmaceutical residual components must be treated before being discharged to the environment. This study was conducted to investigate the efficiency of tungsten-carbon nanocomposite in diclofenac removal using design of experiment (DOE). The 27 batch adsorption experiments were done by choosing three effective parameters (pH, adsorbent dose, and initial concentration) at three levels. The nanocomposite was prepared by tungsten oxide and activated carbon powder in a ratio of 1 to 4 mass. The remaining concentration of diclofenac was measured by a spectrometer with adding reagents of 2, 2′-bipyridine, and ferric chloride. Analysis of variance (ANOVA) was applied to determine the main and interaction effects. The equilibrium time for removal process was determined as 30 min. It was observed that the pH had the lowest influence on the removal efficiency of diclofenac. Nanocomposite gave a high removal at low concentration of 5.0 mg/L. The maximum removal for an initial concentration of 5.0 mg/L was 88.0% at contact time of 30 min. The results of ANOVA showed that adsorbent mass was among the most effective variables. Using DOE as an efficient method revealed that tungsten-carbon nanocomposite has high efficiency in the removal of residual diclofenac from the aqueous solution.

scholarly journals Preparation of isocyanates by carbamates thermolysis on the example of butyl isocyanate

2019 ◽  
Vol 58 (4) ◽  
pp. 40-47
Author(s):  
Ratmir R. Dashkin ◽  
◽  
Dmitry A. Gordeev ◽  
Khusrav Kh. Gafurov ◽  
Sergey N. Mantrov ◽  
...  
Keyword(s):  
Gas Phase ◽  
High Performance ◽  
Gas Flow ◽  
Flow Reactor ◽  
Packed Column ◽  
Biologically Active ◽  
Dibutyltin Dilaurate ◽  
Reaction Products ◽  
Uv Detector ◽  
Laboratory Setup

Butyl isocyanate is widely distributed as a precursor for the production of a number of biologically active substances: fungicides, preservatives, insecticides, personal care products, etc. Nowadays, there are a number of methods for the preparation of isocyanates, which can be divided into liquid phase and gas phase. One of the perspective methods for the production of isocyanates is the thermolysis of carbamate and/or the actions of various reaction activating agents, accompanied by the elimination of alcohol, but this process is reversible, which greatly complicates its use in industry. The paper presents the results of studies of non-catalytic thermal decomposition of N-alkylcarbamates with the formation of alkylisocyanates on the example of butylisocyanate in the gas phase, flow reactor in a wide temperature range (200 to 450 °C). In addition, a series of experiments was carried out using a catalyst, dibutyltin dilaurate, in order to reduce the thermolysis temperature and increase the yield of the final product. To implement the isocyanate production process, an experimental laboratory setup, consisting of a gas flow meter (argon) regulator, a packed column (for heating) and a sorption solution tank, was developed and tested. The thermolysis of N-n-butylcarbamate was carried out in two variations: the preparation of an individual n-butylisocyanate and the passage of reaction products through a sorption solution linking the n-butyl isocyanate to N-n-butyl-N '-(1-phenylethyl)urea, which allows to estimate the yield of the target n-butylisocyanate without additional losses. The analysis of the obtained substances was carried out by high performance liquid chromatography with a UV detector (target product) and a mass detector (analysis of by-products). According to the results of research, a modification of the laboratory facility was proposed, as well as n-butylisocyanate was obtained with a yield of 49% on the basis of a new technique.

Nanoparticle Fe3O4 magnetized activated carbon from Armeniaca sibirica shell for the adsorption of Hg(II) ions

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6100-6120
Author(s):  
Yinan Hao ◽  
Yanfei Pan ◽  
Qingwei Du ◽  
Xudong Li ◽  
Ximing Wang
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Initial Concentration

Armeniaca sibirica shell activated carbon (ASSAC) magnetized by nanoparticle Fe3O4 prepared from Armeniaca sibirica shell was investigated to determine its adsorption for Hg2+ from wastewater. Fe3O4/ASSAC was characterized using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and BET (Brunauer–Emmett–Teller). Optimum adsorption parameters were determined based on the initial concentration of Hg2+, reaction time, reaction temperature, and pH value in adsorption studies. The experiment results demonstrated that the specific surface area of ASSAC decreased after magnetization; however the adsorption capacity and removal rate of Hg2+ increased 0.656 mg/g and 0.630%, respectively. When the initial concentration of Hg2+ solution was 250 mg/L and the pH value was 2, the adsorption time was 180 min and the temperature was 30 °C, and with the Fe3O4/ASSAC at 0.05 g, the adsorption reaching 97.1 mg/g, and the removal efficiency was 99.6%. The adsorption capacity of Fe3O4/ASSAC to Hg2+ was in accord with Freundlich isotherm models, and a pseudo-second-order kinetic equation was used to fit the adsorption best. The Gibbs free energy ΔGo < 0，enthalpy change ΔHo < 0, and entropy change ΔSo < 0 which manifested the adsorption was a spontaneous and exothermic process.

scholarly journals Volatility and lifetime against OH heterogeneous reaction of ambient Isoprene Epoxydiols-Derived Secondary Organic Aerosol (IEPOX-SOA)

2016 ◽  
Author(s):  
Weiwei Hu ◽  
Brett B. Palm ◽  
Douglas A. Day ◽  
Pedro Campuzano-Jost ◽  
Jordan E. Krechmer ◽  
...  
Keyword(s):  
Flow Reactor ◽  
Secondary Organic Aerosol ◽  
Heterogeneous Reaction ◽  
Ambient Air ◽  
Organic Aerosol ◽  
Amazon Forest ◽  
Reaction Products ◽  
Ambient Conditions ◽  
Forested Areas ◽  
Humidity Dependence

Abstract. Isoprene epoxydiols-derived secondary organic aerosol (IEPOX-SOA) can contribute substantially to organic aerosol (OA) concentrations in forested areas under low NO conditions, hence significantly influencing the regional and global OA budgets, accounting for example for 16–36 % of the submicron OA in the SE US summer. Particle evaporation measurements from a thermodenuder show that the volatility of ambient IEPOX-SOA is lower than that of bulk OA and also much lower than that of known monomer IEPOX-SOA tracer species, indicating that IEPOX-SOA likely exists mostly as oligomers in the aerosol phase. The OH aging process of ambient IEPOX-SOA was investigated with an oxidation flow reactor (OFR). New IEPOX-SOA formation in the reactor was negligible, as the OFR cannot accelerate processes such as aerosol uptake and reactions that do not scale with OH. Simulation results indicate that adding ~ 100 µg m−3 of pure H2SO4 to the ambient air allows to efficiently form IEPOX-SOA in the reactor. The heterogeneous reaction rate coefficient of ambient IEPOX-SOA with OH radical (kOH) was estimated as 4.0 ± 2.0 × 10−13 cm3 molec−1 s−1, which is equivalent to more than a 2-week lifetime. A similar kOH was found for measurements of OH oxidation of ambient Amazon forest air in an OFR. At higher OH exposures in the reactor (> 1 × 1012 molec. cm−3 s), the mass loss of IEPOX-SOA due to heterogeneous reaction was mainly due to revolatilization of fragmented reaction products. We report for the first time OH reactive uptake coefficients (γOH = 0.59 ± 0.33 in SE US and γOH = 0.68 ± 0.38 in Amazon) for SOA under ambient conditions. A relative humidity dependence of kOH and γOH was observed, consistent with surface area-limited OH uptake. No decrease of kOH was observed as OH concentrations increased. These observation of physicochemical properties of IEPOX-SOA can help to constrain OA impact on air quality and climate.

scholarly journals Oxidative Dehydrogenation of Propane over Vanadium-Containing Faujasite Zeolite

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1961 ◽  
Author(s):  
Małgorzata Smoliło ◽  
Katarzyna Samson ◽  
Ting Zhou ◽  
Dorota Duraczyńska ◽  
Małgorzata Ruggiero-Mikołajczyk ◽  
...  
Keyword(s):  
Oxidative Dehydrogenation ◽  
Gas Flow ◽  
Flow Reactor ◽  
Fixed Bed ◽  
Oxidative Dehydrogenation Of Propane ◽  
Reaction Products ◽  
Promising Alternative ◽  
Vis Spectroscopy ◽  
Gas Flow Reactor ◽  
Faujasite Zeolite

Oxidative dehydrogenation (ODH) of light alkanes to olefins—in particular, using vanadium-based catalysts—is a promising alternative to the dehydrogenation process. Here, we investigate how the activity of the vanadium phase in ODH is related to its dispersion in porous matrices. An attempt was made to synthesize catalysts in which vanadium was deposited on a microporous faujasite zeolite (FAU) with the hierarchical (desilicated) FAU as supports. These yielded different catalysts with varying amounts and types of vanadium phase and the porosity of the support. The phase composition of the catalysts was confirmed by X-ray diffraction (XRD); low temperature nitrogen sorption experiments resulted in their surface area and pore volumes, and reducibility was measured with a temperature-programmed reduction with a hydrogen (H2-TPR) method. The character of vanadium was studied by UV-VIS spectroscopy. The obtained samples were subjected to catalytic tests in the oxidative dehydrogenation of propane in a fixed-bed gas flow reactor with a gas chromatograph to detect subtract and reaction products at a temperature range from 400–500 °C, with varying contact times. The sample containing 6 wt% of vanadium deposited on the desilicated FAU appeared the most active. The activity was ascribed to the presence of the dispersed vanadium ions in the tetragonal coordination environment and support mesoporosity.

Study on the Alage Removal by Microwave Irradiation

2010 ◽  
Vol 113-116 ◽  
pp. 87-90
Author(s):  
Qing Jie Xie
Keyword(s):  
Activated Carbon ◽  
Microwave Irradiation ◽  
Removal Efficiency ◽  
Oxidation Process ◽  
Removal Rate ◽  
Treatment Efficiency ◽  
Dynamic Reaction ◽  
Initial Concentration ◽  
First Order ◽  
Pollutants Removal

The microwave irradiation (MI) was found that it had significantly treatment efficiency for pollutants removal. It was developed to treat the alage in this paper. The granular activated carbon (GAC) was used as catalyst. The effect of the acting time, MI power, GAC amount and the initial concentration on alage removal were studied. The results showed: with the increasing of the acting time, MI power, GAC amount the alage removal rate were increased, but the effect of the initial concentration to alage removal was opposite; the optimum value of acting time, MI power and GAC amount were 5min, 450W and 3g respectively with the alage removal efficiency reached up to 100%. It also showed that with the alage removed under the MI the COD, SS were removed too. It was discovered that the oxidation process was basically in conformity with the first-order dynamic reaction(ln(C/C0)＝-0.9371t+0.6744（R2=0.9472）).

scholarly journals The effect of artificial support material existence on removal of organic and nutrient in laboratory scale using plug flow reactor (PFR)

2020 ◽  
Vol 148 ◽  
pp. 01003
Author(s):  
Sarah Aphirta ◽  
Prayatni Soewondo ◽  
Nida Maisa Zakiyya ◽  
Dyah Wulandari Putri ◽  
Barti Setiani Muntalif
Keyword(s):  
Flow Reactor ◽  
Removal Rate ◽  
Plug Flow ◽  
Sem Analysis ◽  
Absorption Capacity ◽  
Organic Substrate ◽  
Laboratory Scale ◽  
Support Material ◽  
Substrate Removal ◽  
Removal Capacity

Artificial support material was examined to determine the removal capacity of organic pollutants and nutrients on laboratory scale using PFR system. The experiment was performed using artificial water with similar characteristics to Cikapayang River in three PFRs of 10.78 L. The PFRs were made of PVC pipes filled with an inert chemical substrate as an artificial support material. The process of pollutants removal in the PFR relies on a biological layer (biofilm) grown on the surface of the material support. Three type of C:N:P ratio used in this study were 30:15:1, 75:25:2, and 180:35:3. The results showed that the maximum removal efficiency of TSS, TN, TP, and COD in the preliminary tests were 85%, 87%, 71% and 79%, respectively. Moreover, the maximum water absorption capacity result was up to 30.8%. Organic substrate removal rate compared with first order and Strover-Kincannon substrate removal models prediction. The best fit model for this experiment was Stover-Kincannon model, with the average correlation coefficient up to 90% for all of the three reactors. SEM analysis shown that the microorganisms shape is coccus with the average size of 5 µm.

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