Description:FIELD OF INVENTION
[001] The present invention relates to a hybrid system for continuous production of hydrogen from wastewater during day time and night time. BACKGROUND [002] With the world's increasing industrialization, the urgent need of the hour is to address the significant waste disposal problem. Utilizing waste sources with biodegradable organics is important in green "carbon-neutral" hydrogen production. Pursuing sustainable technologies in green energy and remediation has become a major concern in recent years, owing to unprecedented human population growth and its negative environmental consequences. Many efforts have been made around the world to advance hydrogen technologies. [003] India intends to achieve carbon neutrality by 2070. However, there is a need for practical solutions and direct resources in the right direction to make this a reality and to have a green environment. The Indian government established the National Hydrogen Mission to produce cost-effective, large-scale hydrogen. Suitable integrated decentralized systems are needed for sustainable hydrogen production in this era. The coupling of technologies has many potential benefits; more understanding of energy generation and consumption in the coupled system is required with the assistance of experts from various fields. However, bringing new technologies to the pilot or industrial scale remains difficult.
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[004] Thus, in light of the foregoing examination, there is a long-felt need to develop advanced hydrogen technologies that are cost-effective and produce hydrogen throughout the day and night. BRIEF DESCRIPTION OF THE DRAWINGS
[005] This invention is illustrated in the accompanying drawings, throughout which, like reference letters indicate corresponding parts in the various figures.
[006] The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[007] FIG. 1 illustrates a block diagram of a hybrid system that continuously produces hydrogen during the day time and night time.
[008] FIG. 2 illustrates an integrated system that simultaneously generate self-sustainable hydrogen, electricity generation and bioremediation, in accordance with an embodiment of the invention. SUMMARY OF THE INVENTION
[009] The present invention discloses a hybrid system for continuous production of hydrogen from wastewater in day time and night time. The hybrid system comprises a methanogenic controlled Acidogenic Anaerobic Wastewater Digestive (AAWWD) module and a switchable Microbial Electrolysis Cell (MEC) and/or a Microbial Fuel Cell (MFC) comprising molybdenum nitrides carbon dots/bio-derived carbon electrodes and a Proton Exchange Membrane (PEM).
[0010] In various embodiments, the AAWWD is integrated with MFC to form an AAWWD-MFC unit. The AAWWD-MFC unit is configured to produce
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biohydrogen by electrolysis of treated wastewater during night time. In various embodiments, the electrodes are stackable.
[0011] In various embodiments, the AAWWD is integrated with MEC to form an AAWWD-MEC unit. The AAWWD-MEC unit is configured to produce biohydrogen by electrolysis of treated wastewater during day time with additional power from the MFC anode in the night time and a solar-based power system in the day time. In various embodiments, the electrodes are stackable.
[0012] In various embodiments, the metal nitrides composite with carbon dots/bio-derived carbon is a cathode material. The bio-derived carbon is obtained from sapota peel, tamarind fruit shells or any other organic or inorganic material. The bio-derived carbon is a porous carbon nanosheet. In various embodiments, the wastewater comprises laboratory wastewater or sewage water or both. The sewage water is treated in a hollow fibre Membrane-assisted Membrane Bioreactor (MBR) system. In various embodiments, the electrodes are stackable.
[0013] In various embodiments, an integrated system that simultaneously generates self-sustainable hydrogen, electricity generation and bioremediation is disclosed. The system comprises a treatment plant configured to receive wastewater from a wastewater tank and treat the wastewater with bio hydrogen under a methanogenic controlled condition, a hybrid system configured to continuously produce hydrogen, comprising a methanogenic controlled Acidogenic Anaerobic Wastewater Digestive (AAWWD) module and a switchable Microbial Electrolysis Cell (MEC) and/or a Microbial Fuel Cell (MFC) comprising molybdenum nitrides carbon dots/bio-derived carbon electrodes and a Proton Exchange Membrane (PEM). The system further comprises of MBR system configured to receive treated water from the hybrid system and provides aerobic treatment to the received treated
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water and an alkaline electrolyser configured to receive the treated output water from the membrane bioreactor system and generate hydrogen using solar-based electrolysis in day time and MFC based in night time. DETAILED DESCRIPTION
[0014] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and/or detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0015] The present invention discloses a hybrid system for continuous production of hydrogen from wastewater in day time and night time. The system includes a methanogenic controlled Acidogenic Anaerobic Waste Water Digestive (AAWWD) module and a switchable Microbial Electrolysis Cell (MEC) and/or a Microbial Fuel Cell (MFC) comprising molybdenum nitrides carbon dots/bio-derived carbon electrodes and a Proton Exchange Membrane (PEM). Further, the present invention discloses an integrated system that integrates the most promising technologies for achieving self-sustainable hydrogen, electricity generation and bioremediation. The system further comprises a Membrane Bioreactor (MBR) configured to receive treated wastewater from the hybrid system and provides aerobic treatment to the received treated water and an alkaline electrolyser configured to receive the treated output water from the membrane bioreactor system
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and generate hydrogen using solar-based electrolysis in day time and MFC based in night time.
[0016] FIG 1 discloses the hybrid system 100 for continuous production of hydrogen from wastewater in day time and night time. The hybrid system 100 includes methanogenic controlled Acidogenic Anaerobic WasteWater Digestive (AAWWD) module 110 and a switchable MEC 120 for hydrogen production (Day time) and MFC 130 based treated water electrolysis (Night time) (AAWWD-MEC/MFC) with indigenous PEM 126 with high-performance hollow fibre membrane-assisted membrane bio reactor (MBR) system for sewage water treatment (STP) and for self-sustained hydrogen generation using solar based treated water electrolysis and electricity generation by bioremediating the wastewater.
[0017] In various embodiments, the MEC 120 and the MFC 130 assembly is a switchable system that includes an anode chamber 122, a cathode chamber 124 and a PEM 126 placed between the anode chamber 122 and the cathode chamber 124. The MFC/MEC is a stackable and switchable structure. MFCs employ bacteria as catalysts to produce electricity by oxidizing organic and inorganic materials to convert the chemical energy of the fuel into electrical energy which is used for the treated wastewater electrolysis-based hydrogen production in night time where the solar based power generation fails. The MECs unit is configured to produce biohydrogen by electrolysis of treated wastewater during day time with additional power from the solar-based power system.
[0018]
The cathode chamber 124 consists of a cathode that is formed of metal nitrides MnMo3N, (M = Ni, n = 2; M = Co and Fe, n = 3) composite with carbon dots/bio-derived carbon. The electrode materials are bifunctional, biocompatible,
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conductive, porous, and eas
ily prepared with low cost, recyclable and scalable, and have high specific surface area, mechanical strength and corrosion resistance.
[0019] In various embodiments, the bio-derived carbon is a porous carbon nanosheet. The bio-derived carbon is obtained from sapota peel, tamarind fruit shells or any other organic or inorganic material. The bio-derived carbon nanosheets have low-volume pores, improve the surface area of the material and facilitate the high-speed channels for the quick access and leaving of electrolyte ions. The coupling of metal catalyst with carbon-based compounds induced the electrical conductivity, permits electron transfer, and promotes the mass transfer among the reactants and products.
[0020]
Metal molybdenum nitrides with carbon materials composites has better outgoing performances, which was attributed primarily to C-N bonds. Transition metal nitrides, with their unique properties such as high catalytic activity, low cost, and resistance to corrosion, drive support for MFC to attain higher outputs. The altered nature of carbon cloth, changing it from hydrophobicity to superhydrophilicity when using conducting catalysts like TiN, gives bacteria more adhesion to the electrode.
[0021] In addition, the material is also suitable for solar hydrogen production. The carbon quantum dot is properly incorporated into an electron conductive matrix to lower the over potential and improve the electrode's stability. This supports reaction absorption and charge transport between reactant species and the catalyst's surface, resulting in improved H2.
[0022]
Further, the quantum dots are chemically combined with heteroatom doping hybrids exhibiting high HER activity and moderate absorption due to degenerative
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behaviour
, which facilitated the dynamics of the overall water splitting. Besides, carbon quantum dots help to achieve good dispersion without aggregation of active material while being exposed to active sites.
[0023] The anode chamber has a graphite electrode. In various embodiments, the graphite electrodes may be the same or may have different composition and characteristics. In various embodiments the electrodes are stacked. In various embodiments, a Proton Exchange Membrane (PEM) connects the anode chamber and the cathode chamber. The PEM is made of low-cost, high-quality polymeric PEM developed from POC to POV stage as a flat sheet membrane of thickness 5 microns with good stability for alkaline electrolyzer.
[0024] In various embodiments, solar based electrolysis was performed along with the MEC power during day time in the cathode and additional biohydrogen production by the potential microbes in the anode and AAWWD-MFC based treated water electrolysis with PEM produced biohydrogen in the night time.
[0025] FIG. 2 discloses the integrated system 200 that integrates multiple technologies to produce self-sustainable hydrogen, electricity generation and bioremediation simultaneously. The system as illustrated in FIG. 2 has 4 phases. In phase 1, i.e., anaerobic treatment phase the system includes a wastewater or sewage water collection tank and a treatment tank. Sewage wastewater is pumped from the wastewater collection tank into the treatment tank. In the treatment tank the sewage water or wastewater is treated under a methanogenic controlled condition for biohydrogen production. The treated water is then pumped to the second phase.
[0026] In various embodiments, phase 2 consist of the hybrid system 100 that includes the methanogenic controlled Acidogenic Anaerobic WasteWater
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Digestive (AAWWD) module and the switchable Microbial Electrolysis Cell (MEC) and/or a Microbial Fuel Cell (MFC). During day time solar powered AAWWD-MEC produces biohydrogen using potential biohydrogen producing microbes and in the night time where solar based power generation fails, AAWWD-MFC based treated water electrolysis with PEM produced biohydrogen. In various embodiments, phase 3 consist of a membrane bio reactor (MBR) system for sewage water treatment (STP). The treated wastewater from the phase 2 is received at the MBR for further aerobic treatment. The MBR is High-performance hollow fibre membrane-assisted membrane bioreactor (MBR). The well-established (TRL9) and proved system of high-performance hollow fibre membrane-assisted membrane bioreactor (MBR) system for sewage water treatment (STP) was achieved. The membrane will have a high mechanical strength reinforced PVDF hollow fiber membrane with asymmetric structure and a pore size of 0.05 microns for sewage filtration. Claim that the antifouling property was less for the post treated membrane.
[0027] In various embodiments, phase 4 consist of an alkaline electrolyser that receives the treated output water from phase 3 and generates hydrogen. After hydrogen generation, the same water is used for either toilet flushing or gardening or washing purpose. The fabricated electrolyzer will work at 2 V and delivered a current of 0.4 A/cm2. Thus, the total energy intake for the system is 50 KW to produce one kg of green hydrogen.
[0028] The advantages of the system include, but are not limited to (i) Highly stable metal nitrides composite with carbon dots and bio-derived carbon for (electro chemical) EC, (photo electro chemical) PEC, (photo catalytic) PC and biochemical cell, (ii) Low-cost and high-quality polymer membranes (PEM) production, (iii)
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Less energy consumption with more hydrogen production, (iv) Treated water as source for electrolysis (v) Lower production costs compared to conventional electrolysis.
[0029] Examples:
[0030] Example. 1: Development of the integrated system, characterization and analysis
[0031]
The integrated system was developed in the following order for simultaneous wastewater treatment, biohydrogen production and electricity production such as:
[0032] (i) Highly stable metal nitrides MnMo3N, (M = Ni, n = 2; M = Co and Fe, n = 3)/carbon dots and bio-derived carbon stackable electrodes in the AAWWD-MFC/MEC systems was developed for application in the proposed system.
[0033] (ii) Low-cost and high-quality polymer membranes were produced from the proof of concept (POC) stage to the proof of value stage (POV) that enables overall cost reduction in the Proton Exchange Membrane (PEM) application. Development of the highly stable ternary metal nitrides composite with carbon dots/bio-derived carbon for application in the following systems.
[0034] (iii) Integrated methanogenic controlled acidogenic anaerobic wastewater digestive (AAWWD) hydrogen production system (@500Litre capacity) with switchable MEC hydrogen production (Day time) and MFC based treated water electrolysis (Night time) (AAWWD-MEC/MFC) with indigenous PEM. Solar based treated water electrolysis developed by at TRL level 6 to be used in day time where solar based power generation is feasible. AAWWD-MEC based systems for
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hydrogen production to be used in night time where solar based power generation fails.
[0035] iv) The well-established and proved system of high-performance hollow fibre membrane-assisted membrane bio reactor (MBR) system for sewage water treatment (STP).
[0036] At first, the carbon cloth (CC) was used as flexible substrate and, cleaned by using the following process. In that process, 15 × 3 cm of carbon cloth flexible substrate was cut into small pieces and cleaned through the deionized water, ethanol and methanol. For the synthesis of MnMo3O, (M = Ni, n = 2; M = Co and Fe, n = 3)/CC, equal amount of sodium molybdate and nickel, cobalt and iron nitrate was used as major precursors maintain in continuous stirring for 30 min. Subsequently, it was autoclaved at 180°C for 12 h. At room temperature, obtained CC rinsed with the help of deionized water, ethanol for several times. And, it transferred in hot air oven for drying process. Lastly, the CC annealed in nitrogen atmosphere at 300°C for 1 h (heating rate-1°C/min).
[0037] For the synthesis of MnMo3N, (M = Ni, n = 2; M = Co and Fe, n = 3)/CC, the fabricated MnMo3O, (M = Ni, n = 2; M = Co and Fe, n = 3)/CC was placed at tube furnace under NH3/Ar atmosphere for 90 min with different optimized temperatures at 5°C/min. After 24 hours, optimized MnMo3N, (M = Ni, n = 2; M = Co and Fe, n = 3)/CC was obtained and explored for further characterization. For comparison, CoNx/CC, NiNx/CC, FeNx/CC and MoNx/CC was separately prepared by using the above same optimized conditions.
[0038] For the synthesis of carbon dots, graphite rod was used as both anode and cathode. The graphite rod was immersed in ultrapure water and gives an external
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voltage of 40 V DC. After continuous stirring in certain amount of time, a dark-yellow solution was obtained. Then, centrifuge the obtain solution for certain minutes to neglect the insoluble graphite particles. At last, the resultant solution is soluble carbon dots.
[0039] For the synthesis of MnMo3N(M = Ni, n = 2; M = Co and Fe, n = 3)/CC/Carbon dots, the bimetallic nitride/CC photoelectrode were soaked into carbon dots solution for variant time such as 2, 4, 6, 8 and 10 h. Finally, the resultant bimetallic nitride/CC/Carbon dots immersed in deionized water and dried at certain temperature for 8 h. For the synthesis of porous carbon nanosheets, sapota peel was collected with the appropriate amount. To begin with, sapota peel was repeatedly washed with deionized water to remove dust and other impurities and then dried at 80ºC for 12 h.
[0040] For chemical activation, the certain amount of dried sapota peel powder was mixed with KOH in the ratio of 1:2 to 5:2. The resultant slurry was dried at 80ºC for 12 h. Following the carbonization and activation process, the sample was carbonized under nitrogen flow at different optimum temperature with desired time.
[0041] Development of green hydrogen production technology on a larger scale using indigenous polymer membrane (POC to POV).
[0042] We developed a technology at a Proof of Concept (POC) level which can produce green hydrogen without any hydrocarbon feedstock with indigenous PEM membrane (proprietary polymer membrane) alternate to Nafion PEM membrane (global market is to grow from $2.10 billion in 2021 to $22.74 billion in 2028 at a CAGR of 40.6%), using less cell cost and producing zero emissions.
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[0043] In this POC stage, the team has achieved the following items with the help of our pilot setup. Product Research PEM electrolyser, PEM Electrolyser, 3. Proof of Concept for 50 L, expand lab tests, checked product purity confirmation.
[0044] The proposed method enables a path forward to produce PEM membrane for electrolyser and fuel cell at low cost in India to achieve this goal. Designing and optimizing the fabrication process and operating condition to achieve high process efficiency and lifecycle of PEM. The feasibility of large-scale production of membrane and its validation was performed based on our prior knowledge at POC level.
[0045] Development of integrated systems of AAWWD-MFC/MEC with indigenous PEM; high-performance hollow fibre membrane-assisted membrane bio reactor (MBR) System for sewage water treatment (STP) and solar based treated wastewater electrolysis.
[0046] The final outcome of treated wastewater was checked for various physiochemical parameters and other biosafety parameters as per the approved standards before it is used for flushing, gardening, and other washing applications.
Table 1: The proposed benefits of investigation
Description
Revenue Generated (Rs)
Tangible benefits
Generate 25 units of electricity every day
200
Sell or reuse 10000 L of water for cleaning / washing / gardening or send to MPTC for bus washing @ Rs 60/m3
600
Bio Hydrogen generation every day 20 units
160
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Total revenue generation per day
960
Total revenue generation per year (330 days)
3,16,800
Intangible benefits
Students can purse research work
Zero liquid discharge
Patent filing
Commercialization of the system
Table 2: Single chambered MFC (SMFC) - 8 series
Reactor type
Reactor volume
Substrate/inoculum
Energy/H2 output
Single chambered MFC (SMFC) - 8 series
8L
100% STWW
748 mW/m3 (Powered up one 16W LED bulb for 4 Hours.
Single chambered MFC (SMFC)
1L
100% STWW
35.84 mW/m3
[0047] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will
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recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein. , Claims:WE CLAIM:
1. A hybrid system (100) for continuous production of hydrogen from wastewater in day time and night time comprising:
a methanogenic controlled Acidogenic Anaerobic WasteWater Digestive (AAWWD) module (110); and
a switchable Microbial Electrolysis Cell (MEC) (120) and/or a Microbial Fuel Cell (MFC) (130) comprising molybdenum nitrides carbon dots/bio-derived carbon electrodes and a Proton Exchange Membrane (PEM) (126).
2. The hybrid system as claimed in claim 1, wherein AAWWD (110) is integrated with MFC (130) to form an AAWWD-MFC unit.
3. The hybrid system as claimed in claim 1, wherein the AAWWD (110) is integrated with MEC (120) to form an AAWWD-MEC unit.
4. The hybrid system as claimed in claim 2, wherein the AAWWD-MFC unit is configured to produce biohydrogen by electrolysis of wastewater during night time.
5. The hybrid system as claimed in claim 3, wherein the AAWWD-MEC receives power from the anode along with additional power from the solar-based power system to electrolyze the treated waste water to produce green hydrogen.
6. The hybrid system as claimed in claim 1, wherein the metal nitrides composite with carbon dots/bio-derived carbon is a cathode material.
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7. The hybrid system as claimed in claim 1, wherein the bio-derived carbon is obtained from sapota peel, tamarind fruit shells or any other organic or inorganic material.
8. The hybrid system as claimed in claim 1, wherein the bio-derived carbon is a porous carbon nanosheet.
9. The hybrid system as claimed in claim 1, wherein the wastewater comprises laboratory wastewater or sewage water or both.
10. The hybrid system as claimed in claim 9, wherein the sewage water is treated in a hollow fibre Membrane-assisted Membrane Bioreactor (MBR) system.
11. The hybrid system as claimed in claim 1, wherein the electrodes are stackable.
12. An integrated system for simultaneous generation of hydrogen, electricity generation and bioremediation comprising:
a treatment plant configured to receive wastewater from a wastewater tank and treat the wastewater with bio hydrogen under a methanogenic controlled condition;
a hybrid system configured to continuously produce hydrogen, comprising:
a methanogenic controlled Acidogenic Anaerobic WasteWater Digestive (AAWWD) module; and
a switchable Microbial Electrolysis Cell (MEC) and/or a Microbial Fuel Cell (MFC) comprising molybdenum nitrides carbon dots/bio-
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derived carbon electrodes and a Proton Exchange Membrane (PEM);
a MBR system configured to receive the treated wastewater from the hybrid system and provides aerobic treatment to the received treated wastewater; and
an alkaline electrolyser configured to receive the treated wastewater from the MBR system and generate hydrogen using solar-based electrolysis in day time and MFC based in night time.