scholarly journals Optimal Hydrogen Production Coupled with Pollutant Removal from Biodiesel Wastewater Using a Thermally Treated TiO2 Photocatalyst (P25): Influence of the Operating Conditions

Nanomaterials ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 96 ◽  
Author(s):  
Pimsuda Pansa-Ngat ◽  
Trin Jedsukontorn ◽  
Mali Hunsom
Keyword(s):  
Hydrogen Production ◽  
Pollutant Removal ◽  
Operating Conditions ◽  
Tio2 Photocatalyst ◽  
Biodiesel Wastewater ◽  
Thermally Treated

scholarly journals Performance of Iron-Functionalized Activated Carbon Catalysts (Fe/AC-f) on CWPO Wastewater Treatment

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 337
Author(s):  
Sara Mesa Medina ◽  
Ana Rey ◽  
Carlos Durán-Valle ◽  
Ana Bahamonde ◽  
Marisol Faraldos
Keyword(s):  
Wastewater Treatment ◽  
Activated Carbon ◽  
Landfill Leachate ◽  
Surface Composition ◽  
Treatment Plant ◽  
Reaction Medium ◽  
Pollutant Removal ◽  
Operating Conditions ◽  
Water Matrix ◽  
The Stability

Two commercial activated carbon were functionalized with nitric acid, sulfuric acid, and ethylenediamine to induce the modification of their surface functional groups and facilitate the stability of corresponding AC-supported iron catalysts (Fe/AC-f). Synthetized Fe/AC-f catalysts were characterized to determine bulk and surface composition (elemental analysis, emission spectroscopy, XPS), textural (N2 isotherms), and structural characteristics (XRD). All the Fe/AC-f catalysts were evaluated in the degradation of phenol in ultrapure water matrix by catalytic wet peroxide oxidation (CWPO). Complete pollutant removal at short reaction times (30–60 min) and high TOC reduction (XTOC = 80 % at ≤ 120 min) were always achieved at the conditions tested (500 mg·L−1 catalyst loading, 100 mg·L−1 phenol concentration, stoichiometric H2O2 dose, pH 3, 50 °C and 200 rpm), improving the results found with bare activated carbon supports. The lability of the interactions of iron with functionalized carbon support jeopardizes the stability of some catalysts. This fact could be associated to modifications of the induced surface chemistry after functionalization as a consequence of the iron immobilization procedure. The reusability was demonstrated by four consecutive CWPO cycles where the activity decreased from 1st to 3rd, to become recovered in the 4th run. Fe/AC-f catalysts were applied to treat two real water matrices: the effluent of a wastewater treatment plant with a membrane biological reactor (WWTP-MBR) and a landfill leachate, opening the opportunity to extend the use of these Fe/AC-f catalysts for complex wastewater matrices remediation. The degradation of phenol spiked WWTP-MBR effluent by CWPO using Fe/AC-f catalysts revealed pH of the reaction medium as a critical parameter to obtain complete elimination of the pollutant, only reached at pH 3. On the contrary, significant TOC removal, naturally found in complex landfill leachate, was obtained at natural pH 9 and half stoichiometric H2O2 dose. This highlights the importance of the water matrix in the optimization of the CWPO operating conditions.

Tailoring hierarchical porous TiO2 based ternary rGO/NiO/TiO2 photocatalyst for efficient hydrogen production and degradation of Rhodamine B

2021 ◽  
Vol 1235 ◽  
pp. 130222
Author(s):  
Kadavath Santhosh ◽  
Saddam SK ◽  
Sadhana Chouti ◽  
Spandana Gonuguntla ◽  
Sai Prasad Ega ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Rhodamine B ◽  
Tio2 Photocatalyst ◽  
Porous Tio2 ◽  
Hierarchical Porous

scholarly journals Removal of organic pollutants from produced water by batch adsorption treatment

2021 ◽  
Author(s):  
Eman Hashim Khader ◽  
Thamer Jassim Mohammed ◽  
Nourollah Mirghaffari ◽  
Ali Dawood Salman ◽  
Tatjána Juzsakova ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Produced Water ◽  
Oxygen Demand ◽  
Powdered Activated Carbon ◽  
Pollutant Removal ◽  
Operating Conditions ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Zeolite X

AbstractThis paper studied the adsorption of chemical oxygen demand (COD), oil and turbidity of the produced water (PW) which accompanies the production and reconnaissance of oil after treating utilizing powdered activated carbon (PAC), clinoptilolite natural zeolite (CNZ) and synthetic zeolite type X (XSZ). Moreover, the paper deals with the comparison of pollutant removal over different adsorbents. Adsorption was executed in a batch adsorption system. The effects of adsorbent dosage, time, pH, oil concentration and temperature were studied in order to find the best operating conditions. The adsorption isotherm models of Langmuir, Freundlich and Temkin were investigated. Using pseudo-first-order and pseudo-second-order kinetic models, the kinetics of oil sorption and the shift in COD content on PAC and CNZ were investigated. At a PAC adsorbent dose of 0.25 g/100 mL, maximum oil removal efficiencies (99.57, 95.87 and 99.84 percent), COD and total petroleum hydrocarbon (TPH) were identified. Moreover, when zeolite X was used at a concentration of 0.25 g/100 mL, the highest turbidity removal efficiency (99.97%) was achieved. It is not dissimilar to what you would get with PAC (99.65 percent). In comparison with zeolites, the findings showed that adsorption over PAC is the most powerful method for removing organic contaminants from PW. In addition, recycling of the consumed adsorbents was carried out in this study to see whether the adsorbents could be reused. Chemical and thermal treatment will effectively regenerate and reuse powdered activated carbon and zeolites that have been eaten. Graphic abstract

Hydrogen Production via Catalytic Autothermal Reforming of Desulfurized Jet-A Fuel

2016 ◽  
Author(s):  
Shuyang Zhang ◽  
Xiaoxin Wang ◽  
Peiwen Li
Keyword(s):  
Energy Efficiency ◽  
Hydrogen Production ◽  
Hydrogen Storage ◽  
Coke Formation ◽  
Autothermal Reforming ◽  
Operating Conditions ◽  
Hydrogen Yield ◽  
Fuel Conversion ◽  
Optimal Operating ◽  
Reaction Equilibrium

On-board hydrogen production via catalytic autothermal reforming is beneficial to vehicles using fuel cells because it eliminates the challenges of hydrogen storage. As the primary fuel for both civilian and military air flight application, Jet-A fuel (after desulfurization) was reformed for making hydrogen-rich fuels in this study using an in-house-made Rh/NiO/K-La-Ce-Al-OX ATR catalyst under various operating conditions. Based on the preliminary thermodynamic analysis of reaction equilibrium, important parameters such as ratios of H2O/C and O2/C were selected, in the range of 1.1–2.5 and 0.5–1.0, respectively. The optimal operating conditions were experimentally obtained at the reactor’s temperature of 696.2 °C, which gave H2O/C = 2.5 and O2/C = 0.5, and the obtained fuel conversion percentage, hydrogen yield (can be large than 1 from definition), and energy efficiency were 88.66%, 143.84%, and 64.74%, respectively. In addition, a discussion of the concentration variation of CO and CO2 at different H2O/C, as well as the analysis of fuel conversion profile, leads to the finding of effective approaches for suppression of coke formation.

scholarly journals Using one filter stage of unsaturated/saturated vertical flow filters for nitrogen removal and footprint reduction of constructed wetlands

2017 ◽  
Vol 76 (1) ◽  
pp. 124-133 ◽  
Author(s):  
Ania Morvannou ◽  
Stéphane Troesch ◽  
Dirk Esser ◽  
Nicolas Forquet ◽  
Alain Petitjean ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Operating Conditions ◽  
Vertical Flow ◽  
Saturated Layer ◽  
Recirculation Rate ◽  
Total Filtration ◽  
Filtration Area ◽  
Stage System

French vertical flow constructed wetlands (VFCW) treating raw wastewater have been developed successfully over the last 30 years. Nevertheless, the two-stage VFCWs require a total filtration area of 2–2.5 m2/P.E. Therefore, implementing a one-stage system in which treatment performances reach standard requirements is of interest. Biho-Filter® is one of the solutions developed in France by Epur Nature. Biho-Filter® is a vertical flow system with an unsaturated layer at the top and a saturated layer at the bottom. The aim of this study was to assess this new configuration and to optimize its design and operating conditions. The hydraulic functioning and pollutant removal efficiency of three different Biho-Filter® plants commissioned between 2011 and 2012 were studied. Outlet concentrations of the most efficient Biho-Filter® configuration are 70 mg/L, 15 mg/L, 15 mg/L and 25 mg/L for chemical oxygen demand (COD), 5-day biological oxygen demand (BOD5), total suspended solids (TSS) and total Kjeldahl nitrogen (TKN), respectively. Up to 60% of total nitrogen is removed. Nitrification efficiency is mainly influenced by the height of the unsaturated zone and the recirculation rate. The optimum recirculation rate was found to be 100%. Denitrification in the saturated zone works at best with an influent COD/NO3-N ratio at the inflet of this zone larger than 2 and a hydraulic retention time longer than 0.75 days.

Modelling of solid oxide steam electrolyser: Impact of the operating conditions on hydrogen production

2011 ◽  
Vol 196 (4) ◽  
pp. 2080-2093 ◽  
Author(s):  
J. Laurencin ◽  
D. Kane ◽  
G. Delette ◽  
J. Deseure ◽  
F. Lefebvre-Joud
Keyword(s):  
Hydrogen Production ◽  
Operating Conditions ◽  
Solid Oxide

scholarly journals CFD Modeling and Experimental Validation of an Alkaline Water Electrolysis Cell for Hydrogen Production

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1634
Author(s):  
Jesús Rodríguez ◽  
Ernesto Amores
Keyword(s):  
Fluid Dynamics ◽  
Hydrogen Production ◽  
Current Density ◽  
Fluid Dynamic ◽  
Water Electrolysis ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
Electrolysis Cell ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water

Although alkaline water electrolysis (AWE) is the most widespread technology for hydrogen production by electrolysis, its electrochemical and fluid dynamic optimization has rarely been addressed simultaneously using Computational Fluid Dynamics (CFD) simulation. In this regard, a two-dimensional (2D) CFD model of an AWE cell has been developed using COMSOL® software and then experimentally validated. The model involves transport equations for both liquid and gas phases as well as equations for the electric current conservation. This multiphysics approach allows the model to simultaneously analyze the fluid dynamic and electrochemical phenomena involved in an electrolysis cell. The electrical response was evaluated in terms of polarization curve (voltage vs. current density) at different operating conditions: temperature, electrolyte conductivity, and electrode-diaphragm distance. For all cases, the model fits very well with the experimental data with an error of less than 1% for the polarization curves. Moreover, the model successfully simulates the changes on gas profiles along the cell, according to current density, electrolyte flow rate, and electrode-diaphragm distance. The combination of electrochemical and fluid dynamics studies provides comprehensive information and makes the model a promising tool for electrolysis cell design.

Thermodynamic Investigation of Acetic Acid Steam Reforming for Hydrogen Production

2012 ◽  
Vol 550-553 ◽  
pp. 2801-2804
Author(s):  
Peng Fu ◽  
Sen Meng An ◽  
Wei Ming Yi ◽  
Xue Yuan Bai
Keyword(s):  
Carbon Monoxide ◽  
Acetic Acid ◽  
Hydrogen Production ◽  
Steam Reforming ◽  
Operating Conditions ◽  
Negative Effects ◽  
Minimization Method ◽  
Gibbs Free Energy Minimization ◽  
Methane Selectivity ◽  
Increasing Temperature

The thermodynamics of acetic acid steam reforming (AASR) for hydrogen production were simulated using a Gibbs free energy minimization method to study the influences of pressure, temperature and water to acetic acid molar feed ratios (WAFR) on the AASR. On the basis of the equilibrium calculations, the optimal operating conditions obtained were 700-800 oC, 1bar and WAFR = 6-10. At these conditions, the yield and selectivity of hydrogen were maximized and the formation of methane and coke was almost inhibited. Higher pressures had negative effects on the yields and selectivities of hydrogen and carbon monoxide. With increasing temperature from 300 to 1000 oC, the selectivity for hydrogen and carbon monoxide increased significantly along with a reduction in methane selectivity. Increase in the WAFR led to the increase in hydrogen selectivity and the decrease in carbon monoxide selectivity.

Research on Low Concentration Municipal Wastewater Removal Rate with Chemical-Biological Flocculation and Suspended Medium Process

2012 ◽  
Vol 599 ◽  
pp. 387-390
Author(s):  
Xing Yu Bian ◽  
Xing Sheng Kang ◽  
Yi Li ◽  
Yu Lin Sun ◽  
Min Kong ◽  
...  
Keyword(s):  
Municipal Wastewater ◽  
Removal Rate ◽  
Pilot Scale ◽  
Pollutant Removal ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Optimal Operating ◽  
Operational Parameter ◽  
Low Concentration ◽  
Scale Test

In this paper, chemical and biological flocculation and suspended medium process was applied to treat low concentration municipal wastewater in a pilot scale test in order to find the optimum operational parameter. The results showed that: system on pollutant removal mainly on chemical and biological flocculation reaction pool, Under the optimal operating condition, CODCr, TP and SS removal efficiencies reached 75.5％, 76％and 90.5％ respectively, and the CODCr, TP, SS concentrations of effluent meet the National Wastewater Integrated Discharge Standard. The optimum operating conditions according to the local actual situation, running for more than half a year, for the optimization of control parameters for the contrast obtained.

scholarly journals 3D CFD Electrochemical and Heat Transfer Model of an Internally Manifolded Solid Oxide Electrolysis Cell

2011 ◽  
Author(s):  
Grant L. Hawkes ◽  
James E. O’Brien ◽  
Greg G. Tao
Keyword(s):  
Heat Transfer ◽  
Hydrogen Production ◽  
Current Density ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Electrolysis Cell ◽  
Transfer Model ◽  
Gas Composition ◽  
Solid Oxide Electrolysis ◽  
Solid Oxide Electrolysis Cell

A three-dimensional computational fluid dynamics (CFD) and electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in an internally manifolded planar solid oxide electrolysis cell (SOEC) stack. This design is being evaluated experimentally at the Idaho National Laboratory (INL) for hydrogen production from nuclear power and process heat. Mass, momentum, energy, and species conservation are numerically solved by means of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, operating potential, steam-electrode gas composition, oxygen-electrode gas composition, current density and hydrogen production over a range of stack operating conditions. Results will be presented for a five-cell stack configuration that simulates the geometry of five-cell stack tests performed at the INL and at Materials and System Research, Inc. (MSRI). Results will also be presented for a single cell that simulates conditions in the middle of a large stack. Flow enters the stack from the bottom, distributes through the inlet plenum, flows across the cells, gathers in the outlet plenum and flows downward making an upside-down “U” shaped flow pattern. Flow and concentration variations exist downstream of the inlet holes. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

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