Low cost carbon electrodes to produce salinity gradient energy using reverse electrodialysis membranes: Effect of feed flow velocities and addition of Mg2+

In this research , we investigate the effect of feed flow velocity in both monovalent (Na+) and divalent (Mg2+) salt water solutions to harvest the electrical energy from the reverse electro dialysis (RED) membranes module. The synthetic sea water solution uses 0.5 M concentration of salt and the synthetic river water salt concentration of 0.017 M were used. The carbon electrode was used, due to its low cost, higher melting point, and insoluble in water. Variation of feed flow velocities (sea water and synthetic river water) of 8 cm2/s, 14 cm2/s, 19 cm2/s were used, in addition to compare electrical energy produced from the used of monovalent and divalent ions. The best result was obtained by using the velocity of feed solution 19 cm2/s with the electricty value of 8.033 mV, 0.002 Ω/cm2 and power density of 1,141 mW/m2, while the influence of the addition of Mg2 + ion in the feed solution resulted the electricty value of 4.47 mV, 0.003 Ω/cm2 and power density of 0.15 mW/m2. Albeit the results, some more configuration is needed and worth to be investigated in the future.

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Harvesting Natural Salinity Gradient Energy for Hydrogen Production Through Reverse Electrodialysis Power Generation

Journal of Electrochemical Energy Conversion and Storage ◽

10.1115/1.4035835 ◽

2017 ◽

Vol 14 (2) ◽

Cited By ~ 6

Author(s):

Mohammadreza Nazemi ◽

Jiankai Zhang ◽

Marta C. Hatzell

Keyword(s):

Energy Efficiency ◽

Power Density ◽

External Load ◽

Salinity Gradient ◽

Electrical Power ◽

Ionic Current ◽

Electrical Energy ◽

Hydrogen Energy ◽

Mixing Processes ◽

Reverse Electrodialysis

There is an enormous potential for energy generation from the mixing of sea and river water at global estuaries. Here, we model a novel approach to convert this source of energy directly into hydrogen and electricity using reverse electrodialysis (RED). RED relies on converting ionic current to electric current using multiple membranes and redox-based electrodes. A thermodynamic model for RED is created to evaluate the electricity and hydrogen which can be extracted from natural mixing processes. With equal volume of high and low concentration solutions (1 L), the maximum energy extracted per volume of solution mixed occurred when the number of membranes is reduced, with the lowest number tested here being five membrane pairs. At this operating point, 0.32 kWh/m3 is extracted as electrical energy and 0.95 kWh/m3 as hydrogen energy. This corresponded to an electrical energy conversion efficiency of 15%, a hydrogen energy efficiency of 35%, and therefore, a total mixing energy efficiency of nearly 50%. As the number of membrane pairs increases from 5 to 20, the hydrogen power density decreases from 13.6 W/m2 to 2.4 W/m2 at optimum external load. In contrast, the electrical power density increases from 0.84 W/m2 to 2.2 W/m2. Optimum operation of RED depends significantly on the external load (external device). A small load will increase hydrogen energy while decreasing electrical energy. This trade-off is critical in order to optimally operate an RED cell for both hydrogen and electricity generation.

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Feasibility of Pressure-Retarded Osmosis for Electricity Generation at Low Temperatures

Membranes ◽

10.3390/membranes11080556 ◽

2021 ◽

Vol 11 (8) ◽

pp. 556

Author(s):

Elham Abbasi-Garravand ◽

Catherine N. Mulligan

Keyword(s):

Power Density ◽

Membrane Fouling ◽

Low Temperatures ◽

Sea Water ◽

Salinity Gradient ◽

Operating Conditions ◽

Pressure Retarded Osmosis ◽

Water Transportation ◽

Gradient Energy ◽

Temperature Impact

A membrane-based technique for production of pressure-retarded osmosis (PRO) is salinity gradient energy. This sustainable energy is formed by combining salt and fresh waters. The membrane of the PRO process has a significant effect on controlling the salinity gradient energy or osmotic energy generation. Membrane fouling and operating conditions such as temperature have an extreme influence on the efficiency of the PRO processes because of their roles in salt and water transportation through the PRO membranes. In this study, the temperature impact on the power density and the fouling of two industrial semi-permeable membranes in the PRO system was investigated using river and synthetic sea water. Based on the findings, the power densities were 17.1 and 14.2 W/m2 at 5 °C for flat sheet and hollow fiber membranes, respectively. This is the first time that research indicates that power density at low temperature is feasible for generating electricity using PRO processes. These results can be promising for regions with high PRO potential that experience low temperatures most of the year.

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APLIKASI MEMBRAN SILIKA-PEKTIN UNTUK DESALINASI AIR PAYAU

Jukung (Jurnal Teknik Lingkungan) ◽

10.20527/jukung.v6i1.8233 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Muthia Elma ◽

Mahmud Mahmud ◽

Akhbar Akhbar ◽

Lilis Suryani ◽

Fitri Ria Mustalifah ◽

...

Keyword(s):

River Water ◽

Calcination Temperature ◽

Thermal Processing ◽

Sea Water ◽

Salt Water ◽

Salt Content ◽

Rapid Thermal Processing ◽

Synthesis Process ◽

Banana Peel ◽

Feed Water

Di Indonesia khususnya Kalimantan Selatan, sumber air yang digunakan kebanyakan adalah air sungai. Namun saat kemarau seperti bulan juli-agustus, air sungai banyak yang telah tekontaminasi air laut yang menyebabkan air menjadi asin akibat intrusi air laut. Salah satu teknologi yang dapat digunakan untuk memisahkan garam terlarut yang ada adalah dengan menggunakan teknologi membran dengan proses desalinasi. Membran yang digunakan adalah membran silika. Namun silika memiliki hidrostabilitas yang rendah sehingga perlu disisipkan dengan karbon yang terbuat dari pektin limbah kulit pisang agar memperkuat struktur pori maupun hidrostabilitas membran itu sendiri agar menambah kekuatan membran untuk menyaring kandungan garam yang ada pada air rawa asin. Tujuan dari penelitian ini adalah mengetahui kinerja dari membran silika-pektin pisang dengan proses sintesis membran 4 layer (Konsentrasi pektin 0,1% dengan suhu kalsinasi 300 oC dan 400 oC dengan teknik RTP (Rapid Thermal Processing) menggunakan metode pervaporasi (PV) serta air laut artifisial sebagai air umpan (NaCl 0,3 wt%) dengan suhu ruang (25 0 C). Diperoleh hasil penelitian konsentrasi pektin 0,1 % dengan suhu kalsinasi 300 oC dan 400 oC adalah berturut-turut 5,45 dan 13,70 Kgm-2h-1. Sementara itu, nilai rejeksi kedua membran ini berturut-turut 91,94 % dan 92,08. Jadi, kinerja kedua membran silika pektin tersebut yang paling baik adalah pada suhu kalsinasi 400oC untuk deslinasi air asin. Kata kunci : Air asin, desalinasi, membran silika-pektin, pervaporasi. In Indonesia, especially South Kalimantan, the source of water used is mostly river water. But during the dry season like July-August, many river water has contaminated sea water which causes the water to become salty due to sea water intrusion. One technology that can be used to separate existing dissolved salts is to use membrane technology with the desalination process. The membrane used is the silica membrane. However, silica has low hydrostability so it needs to be inserted with carbon made from pectin from banana peel waste in order to strengthen the pore structure and membrane hydrostability itself in order to increase the strength of the membrane to filter out the salt content in salt marsh water. The purpose of this study was to determine the performance of the banana silica-pectin membrane with a 4 layer membrane synthesis process (pectin concentration of 0.1% with calcination temperature of 300 oC and 400 oC with RTP (Rapid Thermal Processing) technique using pervaporation (PV) method and water artificial sea as feed water (NaCl 0.3 wt%) with room temperature (25 oC) .The results of the study were 0.1% pectin concentration with calcination temperature of 300 oC and 400 oC were respectively 5.45 and 13.70 Kgm-2h-1. Meanwhile, the rejection values of the two membranes were 91.94% and 92.08, respectively, so the best performance of the two pectin silica membranes was at calcination temperature of 400oC for saltwater deslination. Keywords: Desalination, pervaporation, salt water, silica-pectin membrane.

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Harvesting Natural Salinity Gradient Energy for Hydrogen Production Through Reverse Electrodialysis (RED) Power Generation

ASME 2016 Power Conference ◽

10.1115/power2016-59565 ◽

2016 ◽

Author(s):

Mohammadreza Nazemi ◽

Jiankai Zhang ◽

Marta Hatzell

Keyword(s):

Power Density ◽

Current Density ◽

Salinity Gradient ◽

Electrical Energy ◽

Hydrogen Energy ◽

External Resistance ◽

Membrane Area ◽

Reverse Electrodialysis ◽

Gradient Energy

There is an enormous potential for energy generation from the mixing of sea and river water at global estuaries. If technologies are developed which are capable of converting this energy into a usable form (electricity or fuels), salinity gradient energy may be able to dramatically increase the worlds supply of renewable energy. Here we present a novel approach to convert this source of energy directly into hydrogen and electricity using Reverse Electrodialysis (RED). RED relies on converting ionic current to electric current using multiple membranes and redox based electrodes. A thermodynamic model for RED is created to evaluate the electricity and hydrogen which can be extracted from natural mixing processes. With equal volumes of HC and LC solutions (0.001m3), the maximum energy extracted is found to occur with 5 number of membrane pairs. At this operating point, 0.4 kWh/m3 can be extracted as electrical energy and 0.95 kWh/m3 of energy is extracted as hydrogen energy. The electrical energy conversion efficiency approaches 15%, whereas the hydrogen energy efficiency is 35%. Overall, the maximum system conversion of Gibbs free energy to electrical and hydrogen energy approaches 50%. The results show that as the number of membrane pairs increases from 5 to 20, the hydrogen power density decreases from 13.2 W/m2 to 3.7 W/m2. Likewise, the power density from electrical energy decreases from 1 W/m2 to 0.3 W/m2. This is because of increase in the total membrane area as increasing the number of membrane pairs. The stack voltage increased from 1.5V to 6V as the number of membrane pairs is increased from 5 to 20. This corresponds to an increase in internal resistance from 600 Ω.cm2 to 2400 Ω.cm2. Long term trade-off between improving the system voltage, while decreasing the system resistance will be crucial for improved long term RED performance. Furthermore, optimum operation of RED, depends on proper selection of external resistance. A small external resistance will increase hydrogen energy and decrease electrical energy, particularly using a small number of membrane pairs. With the fixed small external resistance, as increasing the number of membrane pairs, the difference between internal and external resistance increases. Therefore, the load potential and current density do not increase considerably. For the cases analyzed with 8.29 Ω.cm2 external resistance, the maximum current density increases from 11.1 mA/cm2 to 12.4 mA/cm2 as the number of membrane pairs increases from 5 to 20. Likewise, the load potential rises from 92 mV to 102 mV.

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THE PERFORMANCE OF A SINGLE SLOP SOLAR DISTILLER WHEN USING A TWO REFLECTOR

MINAR International Journal of Applied Sciences and Technology ◽

10.47832/2717-8234.3-3.2 ◽

2021 ◽

Vol 03 (03) ◽

pp. 10-17

Author(s):

Yaseen. H. MAHMOOD ◽

Abeer Ibrahim ASHAWI

Keyword(s):

Drinking Water ◽

Solar Energy ◽

River Water ◽

Salt Water ◽

Low Cost ◽

Safe Drinking Water ◽

Solar Distillation ◽

The Impact

The lack of safe drinking water is a major problem in many areas. Most of which located within the range of high solar sun and the enormous potential of solar energy can be exploited to turn salt water into drinking water. The most economical and easy way to achieve this goal is to use solar distillation. Two low-cost "Single Slope" solar distillers were designed to examine the impact of adding concentrates and reflectors on daily yield and efficiency and then compare the results. Results obtained from practical experiments have shown that solar distillers with internal and external reflectors made of mirrors have increased in efficiency by 6% and 12% when one liter and two liters of river water are added, respectively, from the distiller under the effect of the parabola concentrator. The daily yield was also (60 and 240) ml higher for the solar distiller, which contained both internal and external reflectors.

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THE OBITSDI RIVER WATER SCHEME AND IT'S SALINITY PROBLEMS

Coastal Engineering Proceedings ◽

10.9753/icce.v10.80 ◽

1966 ◽

Vol 1 (10) ◽

pp. 80

Author(s):

Yasuo Miyake ◽

Tsutomu Kishi ◽

Junichi Takahashi ◽

Tatsuya Ikeda

Keyword(s):

River Water ◽

Sea Water ◽

Saline Water ◽

Salt Water ◽

Wind Effect ◽

Approximate Theory ◽

Field Observations ◽

Reservoir Water ◽

The Earth ◽

Earth Embankment

In this paper, the authors describe the salinity problems and their solutions which were encountered in the Obitsui River Water Scheme. The salinity problems in this water scheme are caused by differnt origins; The one is seepage of the sea water through the earth embankment, and the other is the diffusion of the saline water from the reservoir bed. Laboratory experiments and field observations were performed to confirm the detailed design of the reservoir. It was found that the salinity concentration of the reservoir water could be controlled less than 500ppm m weight, when the earth embankment of 1,000m width was released. The another way of salinity control studied by the authors was the recharging channel. At the present stage of studies, the recharging channel is considered to be favourable. Finally, the wind effect on the mterfacial mixing of the salt and fresh water in a reservoir was studied. An approximate theory to calculate the mixing rate of the salt water was derived from the field observations.

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Investigational Studies on Quantity of Salinity in Netravati River Estuary Sand-Coastal Karnataka

International Journal of Emerging Research in Management and Technology ◽

10.23956/ijermt.v6i6.243 ◽

2018 ◽

Vol 6 (6) ◽

pp. 46

Author(s):

Raveesha P ◽

K. E. Prakash ◽

B. T. Suresh Babu

Keyword(s):

Brackish Water ◽

Sea Water ◽

Salt Water ◽

Construction Material ◽

Salt Content ◽

River Estuary ◽

Sand Sample ◽

River Sand ◽

Natural Aggregates

The salt water mixes with fresh water and forms brackish water. The brackish water contains some quantity of salt, but not equal to sea water. Salinity determines the geographic distribution of the number of marshes found in estuary. Hence salinity is a very important environmental factor in estuary system. Sand is one major natural aggregate, required in construction industry mainly for the manufacture of concrete. The availability of good river sand is reduced due to salinity. The quality of sand available from estuarine regions is adversely affected due to this reason. It is the responsibility of engineers to check the quality of sand and its strength parameters before using it for any construction purpose. Presence of salt content in natural aggregates or manufactured aggregates is the cause for corrosion in steel. In this study the amount of salinity present in estuary sand was determined. Three different methods were used to determine the salinity in different seasonal variations. The sand sample collected nearer to the sea was found to be high in salinity in all methods. It can be concluded that care should be taken before we use estuary sand as a construction material due to the presence of salinity.

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COASTAL AND ESTUARINE SEDIMENT DYNAMICS IN THE MEZEN BAY AND ESTUARIES MEZEN AND KULOY

Materials of XXIV International Coastal Conference, devoted to the 60th anniversary of the “Sea Coasts” Working Group of RAS Council SEA COASTS – EVOLUTION, ECOLOGY, ECONOMY ◽

10.31519/conferencearticle_5b5ce39a80e646.57291683 ◽

2018 ◽

Author(s):

Н. Демиденко ◽

N. Demidenko

Keyword(s):

River Water ◽

River Discharge ◽

Sea Water ◽

Sediment Dynamics ◽

Estuarine Sediment ◽

Sea Surface ◽

Cross Sectional ◽

Sand Waves ◽

Tidal Estuaries ◽

High Concentrations

In the Mezen bay and estuaries Mezen and Kuloy can be high concentrations of mud suspension there, involving the formation at times mobile suspensions and settled mud. Within estuaries the river water is mixed with the sea water by the action of tidal motions, by waves on the sea surface and by the river discharge forcing its way to the sea. Nearly all shallow tidal estuaries, where currents exceed about 1,0m s-1 and where sand is present, have sand waves. Sand waves have a variety of cross-sectional and plan forms.

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Bamboo Waste-based Bio-composite Substance: An application for Low-cost Construction Materials

SPECTA Journal of Technology ◽

10.35718/specta.v4i1.162 ◽

2020 ◽

Vol 4 (1) ◽

pp. 41-48

Author(s):

Teodoro Astorga Amatosa ◽

Michael E. Loretero

Keyword(s):

Composite Materials ◽

Sea Water ◽

Raw Materials ◽

Low Cost ◽

Construction Materials ◽

Single Layer ◽

High Strength ◽

Green Technology ◽

Experimental Medium ◽

Natural Treatment

Bamboo is a lightweight and high-strength raw materials that encouraged researchers to investigate and explore, especially in the field of biocomposite and declared as one of the green-technology on the environment as fully accountable as eco-products. This research was to assess the technical feasibility of making single-layer experimental Medium-Density Particleboard panels from the bamboo waste of a three-year-old (Dendrocalamus asper). Waste materials were performed to produce composite materials using epoxy resin (C21H25C105) from a natural treatment by soaking with an average of pH 7.6 level of sea-water. Three different types of MDP produced, i.e., bamboo waste strip MDP (SMDP), bamboo waste chips MDP (CMDP) and bamboo waste mixed strip-chips MDP (MMDP) by following the same process. The experimental panels tested for their physical-mechanical properties according to the procedures defined by ASTM D1037-12. Conclusively, even the present study shows properties of MDP with higher and comparable to other composite materials; further research must be given better attention as potential substitute to be used as hardwood materials, especially in the production, design, and construction usage.

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