Abstract:
This invention is a metal fuel cell that consumes zinc, oxygen and water. The chemistry of this fuel cell fundamental differs from other previously described metal air fuel cells because water is consumed and zinc and hydroxide anions are adsorbed by the natural carbon compounds of coal, charcoal and biochar. The adsorption of these ions is possible because of the accessible micropore structure of the natural carbon substances. The absorption limits the rate of fuel cell waste thereby decreasing the rate of increase of the cells internal resistance and this chemistry accounts for the fuel cell&#39;s longevity. The cell is inexpensive to make and renewable and rechargeable. Development of this cell could have profound effects on environmental, economic and social problems related to global energy.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/861,521 filed Aug. 2, 2013 the contents of all of which are herein incorporated by reference in their entireties into the present patent application. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    Numerous metal/air fuel cells have been described and are in use. Most of these fuel cells are composed of a metal anode, graphite cathode and a basic electrolyte such as solutions of potassium hydroxide, manganese dioxide and ammonium chloride. The metal is oxidized at the anode and oxygen is reduced at the cathode. In these cells, metal and hydroxide ions are formed that bond to each other to form the metal hydroxide that then dissociates to form the metal oxide and water. These cells contain a corrosive electrolyte and the efficiency and longevity of the cell is limited by corrosion and the formation of the metal oxide as an end product. Water is not consumed. 
         [0004]    This invention is a novel, inexpensive, renewable, rechargeable zinc/natural carbon/graphite/air fuel cell that utilizes water, oxygen and zinc as fuels. The cell can use water or salt solutions as an electrolyte. Because of the adsorptive properties of selected natural carbon substances defined as coal, charcoal or biochar, the cell produces minimal waste from metal oxides and electrolyte side reactions as found in traditional metal fuel cells or batteries, and as such, the internal ionic resistance of the cell remains stable for prolonged periods of discharge. The chemistry of this zinc/natural carbon/graphite/air fuel cell is fundamentally different than other metal fuels cells presently in use or that have been described. The charcoal and bituminous coal version of the cell can be recharged and the cell can be easily constructed with relatively inexpensive materials. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The zinc/natural carbon/graphite/air fuel cell can produce an electric current without a corrosive electrolyte and operates near neutral pH with minimal formation of zincate ion, zinc oxide and zinc hydroxide. This unique chemistry is possible because the natural carbon avidly adsorbs both zinc and hydroxide ions. The adsorption of zinc and hydroxide ions creates minimal waste in the form of oxides. This provides longevity to the cell because the internal ionic resistance of the cell does not increase as long as the waste products are buffered by the natural carbon substance. The adsorption of both zinc and hydroxide facilitates ionic movement within the cell. Furthermore, waste from corrosive electrolytes that may contribute to increases in internal resistance are not present and other impurities that could affect the cells internal resistance are buffered by the natural carbon substance. 
         [0006]    Data is presented that the longevity of this fuel cell is related to the stability of the internal resistance of the cells and more specifically the ionic component of this resistance. Production of chemical waste increases ionic resistance by uncoupling or inhibiting redox reactions in the fuel cells. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    A clear understanding of the key features of the invention summarized above may be had by reference to the appended drawings, which illustrates the method and system of the invention, although it will be understood that such drawings depict preferred embodiments of the invention and, therefore, are not to be considered as limiting its scope with regard to other embodiments which the invention is capable of contemplating. Accordingly: 
           [0008]      FIG. 1  is an illustration of the method and system of this invention showing a simplified end-view diagram of a zinc/natural carbon/graphite air fuel cell. Container is labeled  1 . Zinc anode is labeled  2 . Natural carbon is labeled  3 . Graphite is labeled  4 . L represents the length of the fuel cell. 
           [0009]      FIG. 2  is an illustration of the preferred embodiment of the invention. Connectors are labeled  1 . Zinc anode is labeled  2 . Natural carbon is labeled  3 . Graphite is labeled  4 . Plates of zinc and graphite offer an advantage over the construction shown in  FIG. 1  because the cells can be inexpensively stacked with increased contact surfaces to increase total power. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0010]    In a container, when a natural carbon substance such as bituminous coal, charcoal or biochar with a favorable micropore structure is placed between or in the surrounds of a zinc anode and graphite cathode in the presence of water and oxygen, a fuel cell is produce. The chemistry of this type of fuel cell has not been previously described. The large surface area of the micropore structure of the natural carbon adsorbs zinc and hydroxide ions with known ionic radii of 88 pm and 110 pm, respectively, and there is minimal formation of zincate ions, zinc oxide and zinc hydroxide which are waste. In previously described fuel cells, this waste production increases the internal ionic resistance of the fuel cell because the oxidation and reduction reactions are inhibited or inactivated according to Le Chatelier&#39;s principle. Unique to this cell, the adsorption of ions by the natural carbon substance produces a renewable, rechargeable inexpensive fuel cell with profound longevity limited by the depletion of the primary fuels zinc, water and oxygen and/or the depletion of the adsorptive capacity of the natural carbon substance. 
         [0011]    Renewability of Cell 
         [0012]    Zinc, unlike iron and aluminum, can be smelted from the oxide using concentrated solar power and is thus renewable. (Epstein M, Alde G, Santen S, Steinfeld A, Wieckert C.  J Sol Energ - T Asme . February 2008; 130(1); Guillot E, Epstein M, Wieckert C, et al.  SolarEngineering  2005. 2006:721-727; Wieckert C, Frommherz U, Kraupl S, et al.  J Sol Energ - T Asme . May 2007; 129(2):190-196 and Steinfeld A.  International journal of hydrogen energy.  2002; 27:611-619). Although bituminous coal is available and plentiful, eventually stores will be depleted and/or mining will become extraordinarily expensive. Charcoal or biochar can be made by man, is thus, renewable and the carbon dioxide produced is part of the natural carbon cycle. (Woolf D, Amonette J E, Street-Perrott F A Lehmann J, Joseph S.  Nat Commun.  2010; 1:56). Graphite is not consumed in this fuel cell. 
         [0013]    Natural Carbons 
         [0014]    The natural carbon component of this fuel cell has favorable accessible micropores in sufficient quantity to adsorb zinc and hydroxide ions. (Chen X, Chen G, Chen L, et al.  Bioresour Technol . October 2011; 102(19):8877-8884). Charcoals, biochar and bituminous coal, unlike anthracite or some activated charcoals, contain favorable accessible micropores. 
         [0015]    Water 
         [0016]    Distilled water, deep well water, fresh water, brackish water, sea water or saline can be used in this fuel cell. Addition of salt to the cell decreases the internal resistance and increases the rate of oxidation of zinc at the anode increasing the power output of the cell, but at the expense of longevity. Additional ions may compete for adsorption with zinc and hydroxide ions. 
         [0017]    Rechargeablility 
         [0018]    Both wet and dry zinc/charcoal/graphite fuel cells and wet zinc/bituminous coal/graphite cells are rechargeable. 
         [0019]    Effects of Connecting Multiple Fuel Cells 
         [0020]    This fuel cell can be connected in series to increase voltage or in parallel to increase amperage. Series and parallel cells can be connected for optimum power. 
         [0021]    Environmental Considerations 
         [0022]    The zinc/natural carbon/graphite air fuel cell converts chemical energy directly into electrical energy and is not subject to the inefficiencies of heat engines described by Carnot (steam production and rotation of turbines) and does not produce harmful greenhouse gases. The carbon dioxide produced by production of charcoal and biochar is part of the earth&#39;s natural carbon cycle, unlike the combustion of fossil fuels. 
         [0023]    Benefits to Society 
         [0024]    More than 1 billion people on our planet live without access to electricity. With available and affordable electricity comes a significant improvement in standard of living such as clean water from deep wells, agricultural technologies, and worldwide access to education and commerce via the internet. For those of us who are fortunate to have what appears to be an endless supply of electricity, we should learn from the mistakes of prior failed civilizations such as Easter Island, Mayan and Chacoan societies because they deforested their sources of energy. (Visalli D. Energy and ecology: why societies really succeed and fail. 2009. http://www.resilience.org/stories/2009-02-01/energy-and-ecology-why-societies-really-succeed-and-fail). Fossil fuels—the primary source of electrical energy in countries such as China, India, and the United States—are not renewable, but charcoal production if properly managed can be renewable. The zinc/natural carbon/graphite air fuel cell may fulfill many of the requirements of a renewable solution to global energy concerns. 
         [0025]    Chemistry and thermodynamics of the zinc/natural carbon/graphite air fuel cell 
         [0000]      (anode) Zn (s)           Zn +2 +2 e   −  E 0 =0.77 V
 
         [0000]      (cathode) ½O 2(g) +H 2 O+2 e −         2OH −  E 0 =0.34 V
 
         [0000]      (cell) Zn (s) +½O 2(g) +H 2 O         Zn +2 +2OH −  E 0 =1.11 V
 
         [0000]    It is assumed that at neutral pH, [OH − ]=10 −7 , the concentration of zincate ions (Zn(OH) 4   2− ) is very low, and that some zinc hydroxide (Zn(OH) 2 ) is formed. Therefore: 
         [0000]      K sp  of Zn(OH) 2 =3×10 −16  
 
         [0000]      [Zn +2 ]=3×10 −2  
 
         [0000]    Nernst equation for a system not at equilibrium at 298K: 
         [0000]      E=E 0 −0.0592V/ n  log Q
 
         [0000]      E=0.95 V, n =2,OH=[10- 7 ],log Q=[Zn +2 ]/[OH − ] 2    
         [0000]      E 0 =1.32V (best experimental) 
         [0000]    Calculating ΔG 0  from enthalpy of formation, and standard entropies 
         [0000]      Zn (s) +½O 2(g) +H 2 O         Zn +2 +20H − 
 
       Reference Values of Standard Enthalpy of Formation 
       [0026]      
         [0000]    
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Zn +2   
                 −153 
                 kJ/mol 
               
               
                   
                 H 2 O 
                 −286 
                 kJ/mol 
               
               
                   
                 OH −   
                 −230 
                 kJ/mol 
               
               
                   
                 O 2   
                 0 
               
               
                   
                   
               
             
          
         
       
     
       Reference Values of Standard Entropy 
       [0027]      
         [0000]    
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 Zn (s)   
                 42 
                 J/molK 
               
               
                   
                 Zn +2   
                 −112 
                 J/molK 
               
               
                   
                 H 2 O 
                 70 
                 J/molK 
               
               
                   
                 O 2   
                 205 
                 J/molK 
               
               
                   
                 OH −   
                 −11 
                 J/molK 
               
               
                   
                   
               
             
          
         
       
     
       Standard Enthalpy Calculations 
       [0028]      ΔH 0   f products −ΔH 0   f reactants  
 
         [0000]      [Zn +2 +2OH − ]−[H 2 O]
 
         [0000]      [−153+(2)−−230]−−286
 
         [0000]      ΔH f   0 =−327 kJ/mol
 
       Standard Entropy Calculations 
       [0029]      ΔS 0   products −ΔS 0   reactants  
 
         [0000]      [Zn +2 +2OH − ]−[Zn (s +½O 2 +H 2 O]]
 
         [0000]      [−112+(2)(−11)]−[42+(0.5)205+70]
 
         [0000]      ΔS 0 =−348 J/molK
 
         [0000]      ΔS 0 =−0.348 kJ/molK
 
         [0000]      T=298K 
         [0000]      TΔS 0 =−104 kJ/mol
 
         [0000]      ΔG 0 =ΔH°−TΔS 0  
 
         [0000]      ΔG 0 =−327 kJ/mol+104 kJ/mol
 
         [0000]      ΔG 0 =−223 kJ/mol using values of ΔH 0   f  
 
         [0000]      −ΔG 0   /n F=E 0  
 
         [0000]      ΔG kJ/mol, n =2,F=96,485 C/mol,E 0 =J/C
 
         [0000]      223/(2)(96,485) 
         [0000]      E 0 =1.15 V using values of ΔH 0   f  
 
         [0000]      E 0 =0.780-0.935 V using experimental values 
         [0000]      Theoretical limit of conversion of 1 mole of zinc into electrical energy=1.92×105 Coulombs
 
         [0030]    Discharge Properties of the Zinc/Natural Carbon/Graphite Air Fuel Cells 
         [0031]    The cells produce low current (0.6-0.8 mA) and low voltage (0.5-0.8V) with a constant 1000Ω for prolonged periods of time because the ionic component of the internal resistance of the fuel cell increases very slowly. The extraordinary slow buildup of wastes in the form of metal oxides occurs because the natural carbons adsorb the metal and hydroxide ions. Internal resistance of the cells was calculated according to: (V 100Ω −V 100Ω )/(I 1000Ω −I 100Ω ). 
         [0032]    Table 1 shows discharge characteristics of zinc/charcoal/graphite fuel cell as designed in  FIG. 1  and continuously connected to a 1000Ω resistor with periodic additions of aliquots of water. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Discharge of zinc/charcoal/graphite fuel cell 
               
             
          
           
               
                   
                   
                   
                   
                   
                 Internal 
               
               
                   
                 10Ω 
                 100Ω 
                 1000Ω 
                 10,000Ω 
                 resistance 
               
               
                 Days 
                 V/mA 
                 V/ma 
                 V/ma 
                 V/mA 
                 Ω 
               
               
                   
               
             
          
           
               
                 1 
                  0.1/11 
                 0.51/5.2 
                 0.83/.75 
                 0.93/.08  
                 72 
               
               
                 2 
                 0.06/10  
                 0.35/4.6 
                  0.68/0.72 
                 0.77/0.07 
                 85 
               
               
                 7 
                 0.05/7.4 
                 0.29/4.1 
                  0.64/0.75 
                 0.78/0.08 
                 104 
               
               
                 38 
                 0.02/2.5 
                 0.18/2.2 
                 0.56/0.6 
                 0.78/0   
                 237 
               
               
                 83 
                 0.02/3.1 
                 0.17/2.2 
                 0.51/0.6 
                 0.69/0.07 
                 212 
               
               
                   
               
             
          
         
       
     
         [0033]    Table 2 shows discharge characteristics of zinc/bituminous coal/graphite fuel cell as designed in  FIG. 1  and continuously connected to a 1000Ω resistor with periodic additions of aliquots of water and addition of 54 g of sodium chloride on day 10. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Discharge of zinc/bituminous coal/graphite fuel cell 
               
             
          
           
               
                   
                   
                   
                   
                   
                 Internal 
               
               
                   
                 10Ω 
                 100Ω 
                 1000Ω 
                 10,000Ω 
                 resistance 
               
               
                 Days 
                 V/mA 
                 V/mA 
                 V/mA 
                 V/mA 
                 Ω 
               
               
                   
               
             
          
           
               
                 1 
                 0.03/3.4 
                 0.24/2.5 
                 0.67/0.73 
                 0.93/0.09 
                 243 
               
               
                 2 
                 0.03/3.2 
                 0.22/2.6 
                 0.65/0.75 
                 0.83/0.09 
                 232 
               
               
                 7 
                  0.02/0.05 
                  0.16/0.02 
                 0.52/0.56 
                 0.72/0.02 
                 667 
               
               
                 38 
                  0.03/0.11 
                  .24/1.2 
                  0.5/0.51 
                 0.72/0   
                 377 
               
               
                 83 
                 0.005/0.2  
                 0.006/0.17 
                 0.11/0.1  
                 0.44/0.05 
                 1485 
               
               
                   
               
             
          
         
       
     
         [0034]    Table 3 shows weight of cells in Table 1 and 2. 
         [0000]    
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 cell weights 
               
             
          
           
               
                   
                 Zinc 
                 Natural 
                 Graphite 
                   
               
               
                   
                 (g) 
                 carbon (g) 
                 (g) 
                 Water 
               
               
                   
                   
               
             
          
           
               
                 Charcoal cell (Table 1) 
                 100 
                 350 
                 69 
                 750 ml 
               
               
                 Bituminous coal cell (Table 2) 
                 100 
                 500 
                 69 
                 750 ml 
               
               
                   
               
             
          
         
       
     
         [0035]    Experimental Data with Explanation of Tables 
         [0036]    Table 4 shows that various natural carbon substances moistened with water will produce different electrical potentials when coupled to a graphite electrode. These data lead to optimum cathode materials of the fuel cell to consist of coconut shell biochar, non-activated charcoals and bituminous coal. 
         [0000]    
       
         
               
             
               
               
             
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Electrical potentials of various natural carbon/graphite 
               
               
                 cathodes with stainless steel anode 
               
             
          
           
               
                 Cathode 
                 Millivolts 
               
               
                   
               
             
          
           
               
                 Distilled water/graphite electrode (control) 
                 266 
               
               
                 Biochar-coconut shell/graphite electrode 
                 683 
               
               
                 Bituminous coal/graphite electrode 
                 524 
               
               
                 Artist charcoal/graphite electrode 
                 500 
               
               
                 Oil sandstone/graphite electrode 
                 480 
               
               
                 Biochar-corn husk/graphite electrode 
                 466 
               
               
                 Woodstock ™ hardwood charcoal/graphite electrode 
                 434 
               
               
                 Peat/graphite electrode 
                 392 
               
               
                 Oil shale/graphite electrode 
                 334 
               
               
                 Anthracite coal/graphite electrode 
                 224 
               
               
                 Light petroleum crude/graphite electrode 
                 201 
               
               
                 Lignite/graphite electrode 
                 107 
               
               
                 Kingsford ® compressed charcoal/graphite electrode 
                 97 
               
               
                 Activated charcoal/graphite electrode 
               
               
                 Food grade 
                 30 
               
               
                 Granular 
                 &lt;10 
               
               
                 Heavy petroleum crude/graphite electrode 
                 1 
               
               
                   
               
             
          
         
       
     
         [0037]    Table 5 shows generated electrical potentials with various anodes attached to a charcoal graphite electrode. Zn is the preferred anode for the fuel cell when compared to Al, Fe, Cu, Ag and Pt and the cathode connector can be any of the listed metals. Zinc is preferred presumably because the adsorption onto the charcoal is optimal. A wet cell version of this experiment (data not entered) further confirms that zinc is the preferred metal. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Electrical potentials with anode and cathode connector 
               
               
                 separated by charcoal/graphite electrode 
               
             
          
           
               
                 Anode 
                 Cathode 
                   
               
               
                 metal 
                 connector 
                 Volts 
               
               
                   
               
             
          
           
               
                 Zn 
                 Zn 
                 .935 
               
               
                 Zn 
                 Al 
                 .900 
               
               
                 Zn 
                 Cu 
                 .935 
               
               
                 Zn 
                 Fe 
                 .930 
               
               
                 Zn 
                 Pt 
                 .920 
               
               
                 Al 
                 Zn 
                 .500 
               
               
                 Fe 
                 Zn 
                 .430 
               
               
                 Cu 
                 Zn 
                 .003 
               
               
                 Ag 
                 Zn 
                 −.150 
               
               
                 Pt 
                 Zn 
                 −.225 
               
               
                   
               
             
          
         
       
     
         [0038]    Table 6 shows that the fuel cell unlike zinc alkaline batteries and zinc air fuel cells functions near neutral pH of 7.00 because the natural carbon adsorption of hydroxide buffers the cell. 
         [0000]    
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 6 
               
             
             
               
                   
               
               
                 Interim pH measurements of zinc/natural carbon/graphite 
               
               
                 air fuel wet cells During discharge 
               
             
          
           
               
                   
                 pH 1   
                 pH 2   
                 pH 3   
                 average pH 
               
               
                   
                   
               
             
          
           
               
                 Zinc/charcoal/graphite 
                 7.02 
                 7.11 
                 7.11 
                 7.08 
               
               
                 Zinc/bituminous coal/graphite 
                 6.82 
                 6.97 
                 6.7 
                 6.83 
               
               
                   
               
             
          
         
       
     
         [0039]    Table 7 shows the longevity of wet and dry charcoal cells connected with an LED load. The charcoal cells could be recharged after they had discharged the energy required to light the LED. Aliquots of water were periodically added for fuel and as an electrolyte. The discharge capacity and number of recharges was not determined. The bituminous coal wet cell lit an LED for 144 days also requiring periodic additions of water. The bituminous coal cells were also rechargeable. The table further shows that step up of current could be achieved with series connections of cells. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 7 
               
             
             
               
                   
               
               
                 Duration of LED light from zinc/natural carbon/graphite air fuel cells with 
               
               
                 addition of aliquots of water 
               
             
          
           
               
                   
                 Cell type 
                   
                   
                   
                   
                   
                   
               
               
                   
                 Zn/natural 
               
               
                   
                 carbon/ 
                   
                   
                   
                   
                 Duration 
               
               
                 LED 
                 graphite in 
                 Number 
                   
                 Initial 
                 Initial 
                 of light in 
               
               
                 Rating 
                 grams 
                 of cells 
                 Connection 
                 volts 
                 mA 
                 days 
                 Rechargeable 
               
               
                   
               
             
          
           
               
                 LED 1   
                 Charcoal dry 
                 4 
                 Series 
                 3.2 
                 20 
                 48 
                 yes 
               
               
                 3.2 V/20 mA 
                 7.9/10/53 
               
               
                 LED 2   
                 Charcoal wet 
                 4 
                 Series 
                 3.4 
                 20 
                 53 
                 yes 
               
               
                 3.2 V/20 mA 
                 1.4/10/3.1 
               
               
                 LED 3   
                 Bituminous 
                 4 
                 Series 
                 3.1 
                 50 
                 144 
                 yes 
               
               
                 1.7 V/20 mA 
                 coal wet 
               
               
                   
                 1.6/22.5/2.7 
               
               
                   
               
             
          
         
       
     
         [0040]    Table 8 shows that select hardwood charcoal and bituminous coal neutralize alkaline solutions presumably by the adsorption of hydroxide ions. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 8 
               
             
             
               
                   
               
               
                 Neutralization of hydroxide ions by natural carbons 
               
             
          
           
               
                   
                   
                 Grams 
                   
                   
                   
               
               
                   
                   
                 natural 
                 pH 
                 pH after 
                 Change 
               
               
                   
                 Solution 
                 carbon 
                 initial 
                 24 hours 
                 in pH 
               
               
                   
                   
               
             
          
           
               
                 Bituminous 
                 100 ml 
                 25 
                 9.84 
                 8.29 
                 −1.55 
               
               
                 coal 
                 NaOH in 
               
               
                   
                 distilled 
               
               
                   
                 water 
               
               
                 Hardwood 
                 100 ml 
                 25 
                 9.84 
                 7.93 
                 −1.91 
               
               
                 Charcoal 
                 NaOH in 
               
               
                   
                 distilled 
               
               
                   
                 water 
               
               
                   
               
             
          
         
       
     
         [0041]    Table 9 shows that select anthracite coal does not neutralize an alkaline solution presumably because the micropore structure is not advantageous and therefore select anthracite coals are not acceptable natural carbons for this fuel cell. This confirms the observations previously shown in Table 4. However some activated carbons may neutralize an alkaline solution but those tested were not good natural carbons for the fuel cells. 
         [0000]    
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 9 
               
             
             
               
                   
               
               
                 Failure of anthracite coal to neutralization an alkaline 
               
               
                 solution and neutralization by select activated charcoal. 
               
             
          
           
               
                   
                   
                 Grams 
                   
                 pH after 24 
                   
               
               
                   
                   
                 natural 
                 pH 
                 hours mean of 
                 Change 
               
               
                   
                 Solution 
                 carbon 
                 initial 
                 3 readings 
                 in pH 
               
               
                   
                   
               
             
          
           
               
                 Anthracite 
                 10 ml 
                 2.5 
                 9.79 
                 9.83 
                 +0.04 
               
               
                 coal 
                 NaOH in 
               
               
                   
                 distilled 
               
               
                   
                 water 
               
               
                 Activated 
                 10 ml 
                 2.5 
                 9.79 
                 7.67 
                 −2.12 
               
               
                 granular 
                 NaOH in 
               
               
                 charcoal 
                 distilled 
               
               
                   
                 water 
               
               
                   
               
             
          
         
       
     
         [0042]    Table 10 shows that the internal resistance of the fuel cell can be decreased by the addition of graphite to charcoal without a change in the chemistry of the cell. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 10 
               
             
             
               
                   
               
               
                 Graphite powder decreases internal resistance 
               
             
          
           
               
                   
                   
                 50 g charcoal and 2 g 
               
               
                   
                 50 g charcoal 
                 graphite powder 
               
               
                   
                   
               
             
          
           
               
                   
                 mA 
                 0.53 
                 0.69 
               
               
                   
                 V 
                 0.49 
                 0.78 
               
               
                   
                   
               
             
          
         
       
     
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       [0000]    
       
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         Woolf D, Amonette J E, Street-Perrott F A, Lehmann J, Joseph S. Sustainable biochar to mitigate global climate change. Nat Commun. 2010; 1:56. 
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         [0065]    Materials
   Activated charcoal (Norit A Supra USP certified food grade)—Charcoal House®, Crawford, Nebr., USA   Activated charcoal (granular)—Black Diamond® Media, MARINELAND®, Cincinnati, Ohio, USA   Anthracite coal—ONATA, Toronto, Ontario, Canada   Bituminous coal—ONATA, Toronto, Ontario, Canada   Bituminous coal—Bridgers Coal and Farm Supply Inc., Wendell, N.C., USA   Compressed artist charcoal—PRO ART® Square Charcoal Sticks, Lansing, Mich., USA   Graphite (sawed)—½″×12″×6″ Oversized IG8SAW½×½×6, Small Parts and Bearings, Queensland, Australia   Graphite (pencil)—PRO ART®, Lansing, Mich., USA   Heavy crude oil—ONATA, Toronto, Ontario, Canada   Kingsford® original charcoal briquets—Oakland, Calif., USA   LED 1 —Ultra High Brightness 10 mm Blue, FW supply: 3.2V FW current: 20 mA, #276-0006, RadioShack, Fort Worth Tex., USA   LED 2 —Yellow LED, 3.0V 20 mA, #276-0021, RadioShack, Fort Worth Tex., USA   LED 3 —Wide-Angle Red LED, FW supply: 1.7V 20 mA, #276-0309, RadioShack, Fort Worth Tex., USA   Light crude oil—ONATA, Toronto, Ontario, Canada   Lignite—ONATA, Toronto, Ontario, Canada   Multimeter—IDEAL 61-340, Sycamore, Ill., USA   Oil sandstone—ONATA, Toronto, Ontario, Canada   Oil shale—ONATA, Toronto, Ontario, Canada   Peat—ONATA, Toronto, Ontario, Canada   pH meter—BECKMAN Φ 10 pH meter, Fullerton, Calif., USA   Woodstock™ hardwood charcoal—Providence, R.I., USA   Zinc sheet—0.020″×12″×12″Rotometals, Inc., St. San Leandro, Calif., USA