The present disclosure relates generally to the technical field of material sciences. More specifically, the disclosure provides an electrode material derived from biochar of Aegle marmelos. The disclosure also provides a method of production of the electrode material from Aegle marmelos.
BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art. [0003] Biochars/activated carbons are regarded as a central component of the electrode materials for various electrochemical applications and devices e.g., microbial fuel cell, waste water treatment adsorption column, heavy metal/impurity removal. The waste water treatment capability of biochar-based electrodes is not only governed by the microstructure and morphology of the use material, but the compatibility between the electrode and the type of impurities and other components in the waste water is also important. Such study takes into account the optimization of the biochar's texture and its surface chemistry. Biochar is seen as the most prominent material for waste water treatment, energy harvesting and impurity removal. Biochar based electrodes exhibited several advantages including long lifespan, good conductivity and acceptable environmental aspects. Different suggestions have been made in literature to provide novel sources for biochar and to provide methods to enhance the performance of biochar.
[0004] CN105469999B provides a method of preparing carbon-based supercapacitor electrode material from bamboo powder based raw material. The bamboo powder is carbonized in two stages; in 1st stage, it is carbonized at temperature 200°C-300°C for l-3h and, in 2nd stage, it is carbonized at temperature 700°C-900°C for l-3h. US10090117B1 provides a method of making a porous nano-carbon electrode from jackfruit peel waste. The raw material is

placed in a muffle furnace at 400°C for 4 hours under vacuum condition. The obtained pre-carbonized material is activated by using H3PO4, stirred and filtered. The filtered solution is dried at 80°C for 24 hours and carbonized at different temperatures 600°C, 700°C, 800°C, and 900°C; followed by washing and drying in oven at 80°C for 24 hours. CN104803383B is a kind of method that utilizes camphor tree leaf to prepare activated carbon for ultracapacitor. The fine raw material is impregnated 12-24 hours in acidic liquid and carbonized at 500°C-550°C for lh under inert atmosphere. The obtained carbonized material is stirred with 1-3M HCL solution on magnetic stirring with 40°C. Then the solution is washed with deionized water till neutral (pH=7) and dried in the oven. CN108715447A discloses an activated carbon obtained from a kind of camphor tree mixed with chemical activator (KOH, NaOH) in the mass ratio 4:1 and the high-energy ball milling with rotating speed 1000r/min~8000r/min. The obtained material is placed at 500~1400°C with heating rate 2~20°C/min for 0.5~5h under inert atmosphere. The carbonized material is washed with water and 2M of HCL solution to get neutral solution and dried in vacuum for 8h. Finally, camphor tree based mesoporous activated carbon is prepared and which is preferred to synthesize electrochemical storage device. Despite many methods and sources being known, there is still a need to look for alternatives for preparation of electrode materials with high performance.
[0005] The inventors of the present disclosure provide a low cost and high performance electrode material derived from Aegle marmelos or Bael and method of its production.
OBJECTS OF THE INVENTION
[0006] An object of the present disclosure is to provide an electrode material
manufactured from biochar obtained from Aegle marmelos.
[0007] An object of the present disclosure is to provide an electrode material that
has high performance, high strength and is economic.
[0008] Another object of the present disclosure is to provide a method of
production of electrode material from Aegle marmelos.

[0009] Yet another object of the present disclosure is to provide an electrode comprising an electrode material derived from biochar of Aegle marmelos. [0010] Still another object of the present disclosure is to provide a microbial fuel cell comprising the electrode material derived from biochar.
SUMMARY OF THE INVENTION
[0011] This summary is provided to introduce a selection of concepts in a
simplified form that are further described below in Detailed Description section.
This summary is not intended to identify key features or essential features of the
claimed subject matter, nor is it intended to be used as an aid in determining the
scope of the claimed subject matter.
[0012] Aspects of the present disclosure relate to an electrode material that is
derived from biochar of Aegle marmelos or Bael and methods of its production.
[0013] In an aspect, the present disclosure provides an electrode material derived
from biochar of Aegle marmelos.
[0014] In an embodiment, the present disclosure provides an electrode material
derived from biochar of Aegle marmelos, wherein the material may have
conductivity in a range from about 10"3 S/cm to about 10"4 S/cm.
[0015] In an embodiment, the biochar is derived from a part or extract of Aegle
marmelos. In an embodiment, the part or extract may be obtained from the group
comprising of root, leaves, shoot, fruits, rhizome, seed, stem, barks, flower, sap,
bud or combinations thereof of Aegle marmelos, preferably the stem of Aegle
marmelos.
[0016] In an embodiment, the present disclosure provides an electrode material
derived from biochar of Aegle marmelos for microbial fuel cell.
[0017] In an aspect, the present disclosure provides an electrode comprising the
electrode material derived from biochar of Aegle marmelos and one or more
additive(s).
[0018] In an embodiment, the additive may be selected from, but is not limited to,
dopants such as nitrogen; carbon black; solvent; or binders such as acetylene
black, polyvinyl alcohol or polyvinylidenedifluoride.

[0019] In an embodiment, the electrode material is deposited on a metal conductor
backing.
[0020] In an aspect, the present disclosure provides a microbial fuel cell
comprising one or more electrodes, at least one of the electrodes comprises an
electrode material derived from biochar of Aegle marmelos; and an organic or
inorganic electrolyte.
[0021] In an aspect, the present disclosure provides a method of production of
electrode material from Aegle marmelos.
[0022] In an embodiment, the present disclosure provides a method of production
of electrode material from Aegle marmelos, wherein the method comprises the
steps of: (a) washing the Aegle marmelos to remove dirt and drying at about 70°C
for 48h; (b) powdering the clean and dry Aegle marmelos and oven drying at
about 80°C to give a precursor; and (c) heat treatment in a gasifier at about
1000°C to give biochar for electrode material.
[0023] Other aspects of the invention will be set forth in the description which
follows, and in part will be apparent from the description, or may be learnt by the
practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The following drawings form part of the present specification and are
included to further illustrate aspects of the present disclosure. The disclosure may
be better understood by reference to the drawings in combination with the detailed
description of the specific embodiments presented herein.
[0025] Figure 1 provides a representative image of stem of Aegle marmelos or
Bael.
[0026] Figure 2 provides the X-ray diffraction pattern of biochar obtained from
stem of Aegle marmelos or Bael as per an embodiment of the present disclosure.
[0027] Figure 3 provides the scanning electron microscopy graph of biochar
obtained from stem of Aegle marmelos or Bael as per an embodiment of the
present disclosure.

[0028] Figure 4 provides the frequency polygon for diameter (nm) of biochar obtained from stem of Aegle marmelos or Bael as per an embodiment of the present disclosure.
[0029] Figure 5A provides the polarization plots for microbial fuel cell (MFC) (power density and D.C. voltage as a function of current density) comprising different anodes: anode without biochar to anode comprising biochar (0.25-1.0 mg/cm2) or electrodes as per an embodiment of the present disclosure. The power density and voltage data points are presented as solid and open symbols, respectively. Fixed quantity of catalyst (0.5 mg/cm2 MnCh-NPs) was loaded to graphite dust impregnated cathode support for comparison.
[0030] Figure 5B provides the half-cell polarization plots for MFC (anode and cathode half-cell voltage as a function of current density) comprising different anodes: anode without biochar to anode comprising biochar (0.25-1.0 mg/cm2) or electrodes as per an embodiment of the present disclosure. The anode half and cathode half voltage data points are presented as solid and open symbols, respectively. Fixed quantity of catalyst (0.5 mg/cm2 MnCh-NPs) was loaded to graphite dust impregnated cathode support for comparison.
[0031] Figure 6 provides the impedence plot of a microbial fuel cell comprising an electrode comprising electrode material derived from varying amounts of biochar obtained from stem of Aegle marmelos as per an embodiment of the present disclosure.
[0032] Figure 7 provides a graph for coulombic efficiency of a microbial fuel cell comprising an electrode comprising electrode material derived from varying amounts of biochar obtained from stem of Aegle marmelos as per an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0033] The following is a detailed description of embodiments of the disclosure. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all

modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0034] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. [0035] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0036] In some embodiments, numbers have been used for quantifying weights, percentages, ratios, and so forth, to describe and claim certain embodiments of the invention and are to be understood as being modified in some instances by the term "about." Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0037] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0038] As used in the description herein and throughout the claims that follow, the meaning of "a," "an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise. [0039] Unless the context requires otherwise, throughout the specification which follow, the word "comprise" and variations thereof, such as, "comprises" and "comprising" are to be construed in an open, inclusive sense that is as "including, but not limited to."
[0040] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. [0041] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention. [0042] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified.

[0043] The description that follows, and the embodiments described therein, is provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.
[0044] It should also be appreciated that the present disclosure can be implemented in numerous ways, including as a system, a method or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as processes. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention. [0045] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments. [0046] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed. [0047] Aspects of the present disclosure relate to carbon-based electrode materials obtained from a biomass-based, economic source.
[0048] In an embodiment, the present disclosure provides an electrode material derived from biochar of Aegle marmelos.
[0049] Wood apple is commonly named Bael in Hindi with its scientific name Aegle marmelos. This tree is a native tree of India and its leaves are pinnate. Its edible fruit is commonly found all over India and its plants can survive for a longer time without water. This fruit has an excellent health benefit and has a great religious value in India. The trees require subtropical climatic conditions with sandy loam soil for its favorable yield. Leaves of wood apple have properties of methanol which helps in lowering the cholesterol level, and blood sugar. It has a good nutritive value of moisture, protein, iron, phosphorous, carbohydrates and fats. This plant has a lot of scope in research prospective as a medicine for various

therapeutic benefits and skin ailments. The leaves of wood apple are rich in
nutrients like vitamin C, vitamin A, riboflavin, calcium, potassium and Bi, B6 and
B12 which helps in overall development of the body, it also helps in making hair
strong and healthy. The fruits have flavonoids with anti-oxidant property. The
bark of wood apple has Coumarins which consists of Marmesin, psoralen,
xanthotoxin, scopoletin, osthol, alkaloids, steroids, terpenoids, flavones, amino
acids protein, lipid tannins and phenols.
[0050] In an embodiment, the biochar is derived from a part or extract of Aegle
marmelos. In an embodiment, the part or extract may be obtained from the group
comprising of root, leaves, shoot, fruits, rhizome, seed, stem, barks, flower, sap,
bud or combinations thereof of Aegle marmelos. In a preferred embodiment, the
part may be obtained from stem of Aegle marmelos (refer Figure 1), more
preferably stem waste of Aegle marmelos may be used to produce the electrode
material.
[0051] The electrode material obtained has high surface area and macroporosity.
In some embodiments, the material has high porosity. In some embodiments, the
electrode material may comprise interconnected pores.
[0052] In some embodiments, the electrode material may have a size range of
about 4.8mm3 to about 8.0 mm3. In some embodiments, the material may have a
% crystallinty of about 1.16%. In some embodiments, the material shows X-ray
diffraction peaks at 29 at 22° (220), 43.8°(310) and 78.8° (322).
[0053] In an embodiment, the electrode material has a desirable morphology, is
low cost, has superior performance parameters and high strength. The source of
the electrode material is natural, eco-friendly and economical.
[0054] In an embodiment, the electrode material provides good conductivity,
good adsorption and has long term stability. In some embodiments, the electrode
material is a semi-conductor powder. In some embodiments, the conductivity may
range from about 10"3 S/cm to about 10"4 S/cm. Preferably, this conductivity may
be recorded at lOOKHz.

[0055] In an embodiment, the electrode material shows good energy conversion
capacity, acceptable waste water management and good impurity removal
property.
[0056] In a preferred embodiment, the present disclosure provides an electrode
material derived from biochar of Aegle marmelos for microbial fuel cell.
[0057] In another embodiment, the present disclosure provides an electrode
comprising the electrode material derived from biochar of Aegle marmelos.
[0058] In an embodiment, the electrode may further comprise one or more
additive(s); the additive may be selected from, but is not limited to, dopants such
as nitrogen; carbon black; solvent; or binders such as acetylene black, polyvinyl
alcohol or polyvinylidenedifluoride. In an embodiment, the solvent may be an
organic solvent or an inorganic solvent. In a preferred embodiment, the solvent
may be water.
[0059] In some embodiments, the electrode material of the present disclosure may
be deposited on a metal conductor backing. In some embodiments, the metal
conductor backing may be a graphite sheet.
[0060] In an embodiment, the present disclosure also provides a microbial fuel
cell. The microbial fuel cell may typically comprise two or more electrodes
separated by an organic or inorganic electrolyte. At least one of the electrodes
comprises the electrode material derived from biochar of Aegle marmelos. The
electrodes may be obtained from the electrode material of the present disclosure
by mixing the biochar with the additives, compacting or pressing into desired
shape and depositing and laminating onto a metal conductor backing.
[0061] In an embodiment, the present disclosure provides a microbial fuel cell
comprising one or more electrodes at least one of the electrodes comprising an
electrode material derived from biochar of Aegle marmelos; and an organic or
inorganic electrolyte. The microbial fuel cell shows high coulombic efficiency,
low resistance and high current density.
[0062] In an embodiment, the microbial fuel cell shows good performance
parameters with significant value of output voltage at remarkable current density.
The performance is compatible with industrial biological systems. In some

embodiments, the microbial fuel cell may show power densities of up to about 6W/m3. In some embodiments, the cell may have a maximum open circuit potential (OCP) of about 977 mV and maximum volumetric power density of about 7.15 W/m3.
[0063] In an embodiment, the present disclosure provides a method of production of electrode material from Aegle marmelos.
[0064] In an embodiment, the present disclosure provides a method of production of electrode material from Aegle marmelos, wherein the method comprises the steps of: (a) washing the Aegle marmelos to remove dirt and drying at about 70°C for 48 h; (b) powdering the clean and dry Aegle marmelos and oven drying at about 80°C to give a precursor; and (c) heat treatment in a gasifier at about 1000°C to give biochar for electrode material.
[0065] A preferred solvent for washing may be water. For specific embodiments, the Aegle marmelos stem may be collected and washed with distilled water for several times to remove moisture and dirt particles and dried at about 70°C for about 48h. The dried stem is powdered and the fine powder of cleaned stems maybe dried in an oven for 4 to 5 days at 80°C to remove any moisture content and give a precursor. The precursor may be heat treated for about an hour in a top-lit updraft (TLUD) gasifier at 1000°C maximum heat temperature for the biochar synthesis.
[0066] In an embodiment, the biochar may further be crushed to desired sizes. In some embodiments, without any additional activation, larger biochar particles maybe crushed to desired size range.
[0067] The method of the present disclosure provides a simple carbonization technique of producing high quality electrode material.
[0068] In an embodiment, the present disclosure provides use of the electrode material in electrochemical applications and devices, including but not limited to, battery, supercapacitor, microbial fuel cell application, microbial desalination cells, microbial electrolysis cells, microbial synthesis cells, energy conversion devices, energy producing devices, energy storage devices, hydrogen storage devices, water filtration apparatus, waste water treatment, waste water

management, pollutant removal, pharmaceutical devices, biomedical devices, or
impurity removal.
[0069] In some embodiments, use of the electrode material in wastewater
management helps reduce the impurities in water, specifically the chemical
oxygen demand (COD) of wastewater.
[0070] While the foregoing describes various embodiments of the disclosure,
other and further embodiments of the disclosure may be devised without departing
from the basic scope thereof. The scope of the invention is determined by the
claims that follow. The invention is not limited to the described embodiments,
versions or examples, which are included to enable a person having ordinary skill
in the art to make and use the invention when combined with information and
knowledge available to the person having ordinary skill in the art.
EXAMPLES
[0071] The present invention is further explained in the form of following
examples. However, it is to be understood that the following examples are merely
illustrative and are not to be taken as limitations upon the scope of the invention.
[0072] MATERIALS AND METHODS
[0073] The Bael (Aegle marmelos) wood waste timber was obtained from a
construction site in Noida, Uttar Pradesh, India.
[0074] Example 1: Preparation of Biochar
[0075] The Bael stem was collected and washed with distilled water several times
to remove moisture and dirt particles and dried at 70°C for 48h. This was then
powdered and the fine powder of cleaned stems of Bael was dried in oven for 4 to
5 days at 80°C to remove any residual moisture content to give a precursor. The
precursor was then heat treated for 1 hour in a top-lit updraft (TLUD) gasifier at
1000°C maximum heat temperature to give the biochar suitable as electrode
material.
[0076] Example 2: Characterization and electrode preparation from biochar
[0077] Without any additional activation, the larger biochar of Example 1 were
crushed to the size range of 4.8 to 8.0 mm3. These materials were analyzed for

their physical and electrochemical nature. Their conductivity was noted to be 2.53xl0-4S/cmatl00KHz. [0078] 2.1 X-Ray diffraction analysis:
[0079] Powder X-Ray Diffraction (XRD) is a technique to understand the internal morphology of the specimen. It helps understand a specific level of crystallinity and homogeneity of finely grounded specimen. Apart from this it gives information about the arrangement of the unit cell and its measurements, glass¬like allomorphs present, and the crystallinity of the sample. The procedure depends on impinging a light emission beam on the sample, which turns in the plane, with a 9 point comparative with the x-beam pillar, which is reflected when it experiences a precious stone plane that causes a diffraction of the shaft, and the power of the reflected radiation is counted by detector forming an angle 29 with the sample. In powder diffraction, all the symmetry-equivalent reflections have the same 'd' spacing with the result that individual intensities cannot be measured. The maximum observed are produced by specific reflections of the crystalline regions. Crystallinity changes due to the change in range of the temperature during calcination and sintering. [0080] The percentage crystallinity indices of sample are calculated using
formula:
Area of Crystalline Peak
Crvstallinitv — x 100
Area of Peaks {Amorphous + Crystalline)
[0081] The phase purity and crystallinity of the pure biochar of Example 1 were examined by XRD at room temperature (Figure 2). All the lattice parameters were estimated from the peak position of the XRD patterns. The XRD peaks were found to be less sharp indicating the amorphous nature of the material. The crystalline size was in nanometre range thus showing the creation of enormous surface area needed for MFC. The highest intensity occurred at an angle of 22° for pure sample. A peak (220) of intensity 8579 A was observed at 26 at 22° for pure biochar. Peaks were observed at 43.8° (310) and 78.8° (322) for pure biochar. More peaks of less intensity were observed at hkl values of 310 and 322 for pure

biochar. The crystallinity of pure biochar was calculated to be 1.16%. Drying produces morphological changes in the material such that it modifies the pro-crystalline structure. Crystallinity increases with drying, which is thermodynamically the most stable crystalline conformation. It was determined from FWHM for the peak (220) corresponding to 29 = 22° pure biochar by using Scherer's formula, d = 0.9X / p cos 9.
Table 1: X-Ray diffraction of the pure Bael biochar sample

Biomass C A C/A Crystallite Size % Crystallinity
Biochar of Aegle marmelos 6.3635 8.343 0.7627 41.8 urn 1.16%
[0082] 2.2 Scanning Electron Microscopy Analysis
[0083] Surface morphology of the biochar was done through SEM (Surface Electron Microscope) as shown in Figure 3. The material under investigation was polished and morphology of biochar was investigated. The size (in nm) distribution of particles has been presented in the Figure 4 which was analyzed quantitatively by fitting the histogram using a Lorentzian function. The polygon shows particle size was observed in the range of 38 to 42 micrometer (urn) for pure biochar. The mean diameter of sample was of 41.8 urn for pure biochar which indicates that distribution of the particle size was not uniform and was found to decrease with increase in the carbon concentration. [0084] 2.3 Preparation of electrodes:
[0085] The electrodes were prepared with the biochar of Example 1, as per the method described in, Biochar as a sustainable electrode material for electricity production in microbial fuel cells, T. Huggins et al, Bioresource Technology 157(2014) 114-119, contents of which are incorporated herein as reference. Example 3: Microbial Fuel Cell (MFC) Construction and Operation for wastewater treatment

[0086] The cylindrical earthenware type MFC was utilized in this investigation. The wall of the anodic chamber was composed of an earthenware cylinder, which also acts as cationic earthenware separator, having a total capacity of 0.250 litres and a stainless-steel current collector surrounding the cathode. The cathode was constructed by coating the wall with a graphite dust around the wall. Graphite sheet of 32cm2 (4*4 cm, both sides) was used as an anode, which was impregnated with different concentrations of biochar to investigate its efficacy in terms of power output. Further, N-doped biochar was used to replace graphite dust as cathode coating materials to check its oxygen reduction reaction activity and current generation in MFC. 0.01 mg/cm2 of polyvinyl alcohol was used as binder for the coating of biochar on both the electrode surfaces.
[0087] Before each study, the synthetic wastewater was used. The wastewater was pumped into the anode chamber using a peristaltic pump. Two distinct reactors were built, one for open circuit operation and the other for closed circuit operation. Every 10 minutes, the MFC's cell voltage (Evoit) was monitored by a data collection system. External resistances were varied from 50,000 to 30 ohm and each resistor was stabilized for 30 minutes to get polarization curves. To evaluate the anode and cathode potentials, Ag/AgCl reference electrode was placed in both chambers of the fuel cell (anode and cathode), respectively. [0088] To evaluate the efficacy of biochar as an electrode for the treatment of wastewater and bioenergy production at the same time, a tubular overflow type of fuel cell was used using varying amounts of granular biochar as anode materials -1.0 mg/cm2; 0.750 mg/cm2; 0.50 mg/cm2; 0.250 mg/cm2 and zero biochar. Experiments were conducted in closed-circuit configurations to determine the wastewater efficacy of every mode of operation.
[0089] The electricity produced by the Microbial Fuel Cell was also measured in real-time throughout the closed-circuit wastewater treatment study (Figure 5A and 5B). For almost 5 days, power generation remained below the limit of 2 Wm"3 for all five reactors. A max volumetric power density of 6.7W m"3 was produced 5 days after the reactor started, and was maintained at this level of power density for the duration of the 20-day experiment. The greatest power density was generally

recorded at 6 Wm"3 on day 10. The electrode's great adsorption rate as well as the conveniently available food supply to linked biofilm, as shown with comparable adsorptive electrode materials, contributed to the ongoing power generation. The power output is equivalent to that of a litre-scale MFC operating on real wastewater, and even greater benefits may be realized by raising the surface area to volume ratio and adjusting the flow velocity even further. [0090] The power generation from MFCs was dominated by anodic overpotential as it was observed that a larger driving force with an overpotential of ±0.12 was required for the anode compared to the value of ±0.08 V required for the cathode. In the case of anode, the more rapid decrease in anodic potential from the OCP suggests poor substrate oxidation kinetics at the anode. The current density of anodic half-cell was found to follow the following order: 1.0 mg/cm2>0.750 mg/cm2>0.50 mg/cm2>0.250 mg/cm2>biochar-free anode, at all the resistance values, indicating their order of catalytic performance. Biochar promotes electroactive biofilm, thereby facilitates in improving power output of the MFC. [0091] A substantial variation in the semicircle region was observed in the electrode's impedance plot during the study (Figure 6). The Ret value of MFCs attained the following order: MFC-without biochar anode (266.4 Q) > MFC-with 0.5 mg/cm2 biochar anode (224.3Q) > MFC-with 1.0 mg/cm2 biochar anode (167.5Q). The minimum Ret value observed in anode in the presence of 1.0 mg/cm2 biochar in MFC indicated the maximum electron transport due to high substrate oxidation, which increased the anodic voltage losses and improved the current generation. The EIS results also support the results of the half-cell polarization study. The results indicate that the major reason for high internal resistance in MFCs without biochar is the lack of EAB biofilm on the anode surface. Additionally, the coulombic efficiency of the MFCs with varying amounts of biochar was studied and results of the analysis have been provided in Figure 7. It can clearly be seen that the coulombic efficieny was maximum for 1.0 mg/cm2 biochar. All the results of the effects of varying biochar supplementation on the MFCs are presented in Table 2 below.

Table 2: Effect of biochar supplementation on power generation in MFCs

Sr No. Anode Cathode Max. OCP
(mV) Max. vol. power density COD
removal
(%) Coulombic efficiency Internal resistance
(ohm)
1 Bare
graphite
sheet Mn02
NPs/ Vulcan XC (0.5 mg/cm2) 677 3.15 54.2 5.89 274
2 biochar
(0.25 mg/cm2)
+
graphite
sheet Mn02
NPs/ Vulcan XC (0.5 mg/cm2) 749 4.67 65.4 7.51 225
3 biochar
(0.50
mg/cm2)
+
graphite
sheet Mn02
NPs/ Vulcan XC (0.5 mg/cm2) 792 5.55 71.6 8.32 181
4 biochar
(0.75 mg/cm2)
+
graphite
sheet Mn02
NPs/ Vulcan XC (0.5 mg/cm2) 841 6.32 74.7 9.25 130
5 biochar
(1.0
mg/cm2)
+
graphite
sheet Mn02
NPs/ Vulcan XC (0.5 mg/cm2) 856 6.79 76 9.44 106
[0092] Nutrient Recovery during Wastewater Treatment: The elemental composition of the anode and cathode were investigated before and after each

treatment experiment to determine the potential for recovery of nutrient through sorption and holding on the surface of electrode. MFC is documented as an effective wastewater treatment with simultaneous power generation. The efficiency of MFC suggests the extent of COD removal from wastewater. High COD removal (utilizing substrate/waste) enumerates the effective function of mixed microflora in the wastewater treatment. The COD removal in MFC increased with biochar loading in anode surface and showed highest stable COD removal of 71.6% with 0.5 mg/cm2 (Table 2). 0.75 mg/cm2 and 1.0 mg/cm2 showed further increase of COD removal ability to 74.7 % and 76.0%, respectively (Table 2).
[0093] Thus, the biochar made from the waste of the lignocellulosic rich wood was tested as a granular electrode material in a cylindrical Microbial Fuel Cell that treats waste-water from industry. The electrode material was characterized using SEM images and shown to have a large surface area and macroporosity. When compared to 100 Q external resistance closed-circuit MFC operation, MFC operations employing biochar electrodes exhibited enhanced COD removal efficiency, implying that the addition of biochar on anode as electrochemical components enhance treatment of wastewater while creating electricity. High CE and enhanced COD removal were found with anode containing 1 mg/cm2 of present electrodes. The results of this study demonstrate that electrode materials of the present disclosure may be used in an MFC to cleanse wastewater while also producing electricity.
[0094] The foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention.

ADVANTAGES OF THE PRESENT INVENTION
[0095] The present disclosure provides an electrode material that is cost-effective,
ecologically beneficial and capable of use in multiple electrochemical
applications.
[0096] The present disclosure provides an electrode material with high surface
area, macroporosity, good conductivity and energy conversion capacity.
[0097] The present disclosure provides a microbial fuel cell comprising the
electrode material having high coulombic efficiency, low resistance and high
current density.

We Claim:
1. An electrode material derived from biochar of Aegle marmelos, wherein the material has conductivity in a range from 10"3 S/cm to 10"4 S/cm.
2. The electrode material as claimed in claim 1, wherein the biochar is derived from a part or extract of Aegle marmelos.
3. The electrode material as claimed in claim 2, wherein the part or extract is obtained from the group comprising of root, leaves, shoot, fruits, rhizome, seed, stem, barks, flower, sap, bud or combinations thereof of Aegle marmelos.
4. An electrode comprising the electrode material as claimed in claim 1 and one or more additive(s).
5. The electrode as claimed in claim 4, wherein the additive is selected from dopants, carbon black, solvent, or binders.
6. The electrode as claimed in claim 4, wherein the electrode material is deposited on a metal conductor backing.
7. A microbial fuel cell comprising one or more electrodes, at least one of the electrodes comprising an electrode material as claimed in claim 1; and an organic or inorganic electrolyte.
8. A method of production of electrode material from Aegle marmelos, wherein the method comprises the steps of: (a) washing the Aegle marmelos to remove dirt and drying at 70°C for 48h; (b) powdering the clean and dry Aegle marmelos and oven drying at 80°C to give a precursor; and (c) heat treatment in a gasifier at 1000°C to give biochar for electrode material.