Catalytic adsorbents obtained from municipal sludges, industrial sludges, compost and tobacco waste and process for their production

Abstract

Industrial waste derived adsorbents were obtained by pyrolysis of sewage sludge, metal sludge, waste oil sludge and tobacco waste in some combination. The materials were used as media to remove hydrogen sulfide at room temperature in the presence of moisture. The initial and exhausted adsorbents after the breakthrough tests were characterized using sorption of nitrogen, thermal analysis, XRD, ICP, and surface pH measurements. Mixing tobacco and sludges result in a strong synergy enhancing the catalytic properties of adsorbents. During pyrolysis new mineral phases are formed as a result of solid state reaction between the components of the sludges. High temperature of pyrolysis is beneficial for the adsorbents due to the enhanced activation of carbonaceous phase and chemical stabilization of inorganic phase. Samples obtained at low temperature are sensitive to water, which deactivates their catalytic centers.

1 . An adsorbent derived from one of compost or compost materials and sludge comprising:
 a) 20-30% porous carbon with incorporated organic nitrogen species; and   b) 70-80% inorganic matter,   wherein the sludge is at least one of industrial or municipal sludge.   
   
   
       2 . The adsorbent of  claim 1 , wherein the inorganic matter includes highly dispersed catalytic oxides. 
   
   
       3 . The adsorbent of  claim 2 , wherein the catalytic oxides are one or more of copper oxide, zinc oxide, iron oxide, calcium oxide, silica and alumina. 
   
   
       4 . The adsorbent of  claim 1 , wherein the nitrogen species comprises amine or pyridine groups. 
   
   
       5 . The adsorbent of  claim 1 , wherein the surface area of the adsorbent is 100-500 m 2 /g. 
   
   
       6 . The adsorbent of  claim 5 , wherein the surface area of the adsorbent is 100-200 m 2 /g. 
   
   
       7 . The adsorbent of  claim 1 , wherein the adsorbent contains micropores and the volume of the micropores is at least 0.03 cm 3 /g. 
   
   
       8 . The adsorbent of  claim 1 , wherein the pH of the adsorbent is greater than 10. 
   
   
       9 . The adsorbent of  claim 1 , wherein the pH of the adsorbent is between 7 and 10. 
   
   
       10 . The adsorbent of  claim 1 , wherein the pH of the adsorbent is between 4 and 7. 
   
   
       11 . A method of making an adsorbent which comprises the steps of:
 a) composting compost materials;   b) thermally drying dewatered sewage sludge to form granulated organic fertilizer;   c) mixing the organic fertilizer and the compost; and   d) pyrolyzing the mixture at temperatures between 600° C. and 1000° C.   
   
   
       12 . The method of  claim 11 , wherein the heating rate is between 5 and 10° C./minute and the hold time is between 60 and 90 minutes. 
   
   
       13 . The method of  claim 11 , wherein the temperature of pyrolysis is between 800 and 1000° C. 
   
   
       14 . The method of  claim 13 , wherein the temperature of pyrolysis is between 900 and 1000° C. 
   
   
       15 . The method of  claim 11 , wherein the temperature of pyrolysis is between 600 and 900° C. and the adsorbent is further treated with 15-20% HCl. 
   
   
       16 . The method of  claim 15 , wherein the temperature of pyrolysis is between 800 and 900° C. 
   
   
       17 . The method of  claim 11 , further comprising the step of treating the mixture with between about 5 and about 30 wt % mineral oil, and wherein the mineral oil is selected from light mineral oil, heavy mineral oil, natural mineral oil, synthetic mineral oil, spent motor oil, and combinations thereof. 
   
   
       18 - 28 . (canceled) 
   
   
       29 . A method for producing an adsorbent, comprising the steps of:
 combining a first sludge and at least one of a second sludge and a compost material to form a mixture;   thermally drying the mixture;   pyrolyzing the mixture at a temperature between about 600° C. and 1,100° C.; and   forming at least one of wurtzite, ferroan, chalcocite, spinel, feroxyhite, bornite, hibonite, zincite, ankerite, pyrope, perrohotite, chalocopyrite, triolite, fersilicite, sapphirine, maghemite, cohenite, lawsonite, smithsonite, sphalerite, goethite, huntite, anorthite, diaspore, vaterite, lepidirocite, bayerite, moghemite, pyrohotite, hematite, and almandine during the pyrolyzing step.   
   
   
       30 . The method of  claim 29 , wherein the compost material is at least one of tobacco waste, waste paper and wood char, or a combination thereof:
 wherein the first sludge is a municipal sludge or an industrial sludge, and   wherein the second sludge is a municipal sludge or an industrial sludge and different from the first sludge.