Synthetic soil and methods for producing same from waste

Abstract

The present disclosure provides efficient and cost-effective methods for producing synthetic soil and synthetic stone from waste, including inorganic waste and organic waste, through a hydrolysis—polycondensation process.

What is claimed is: 
     
         1 . A method for producing a synthetic soil from wastes, the method comprising:
 (a) hydrolyzing an organic waste composition using a hydrolyzing composition to produce a biomaterial, wherein the hydrolyzing composition has a pH ranging from about pH13 to about pH14;   (b) activating an inorganic waste composition using an alkaline activator to produce a reactive zeolite gel, wherein the alkaline activator has a pH ranging from about pH13 to about pH14; and   (c) mixing the biomaterial with the reactive zeolite gel to produce the synthetic soil.   
     
     
         2 . The method of  claim 1 , wherein the hydrolyzing composition comprises alkali-activated red mud. 
     
     
         3 . The method of  claim 1 , wherein the hydrolyzing composition comprises sodium hydroxide (NaOH), potassium hydroxide (KOH), sodium bicarbonate (NaHCO 3 ), sodium silicate (Na 2 SiO 3 ), or combinations thereof. 
     
     
         4 . The method of  claim 1 , wherein the alkaline activator comprises sodium hydroxide (NaOH), potassium hydroxide (KOH), sodium silicate (Na 2 SiO 3 ), potassium silicate (K 2 SiO 3 ), or combinations thereof. 
     
     
         5 . The method of  claim 1 , wherein the inorganic waste composition comprises fly ash (FA), ground blast furnace slag (GBFS), red mud (RM), phosphogypsum (PG), rice husk ash (RHA), or combinations thereof. 
     
     
         6 . The method of  claim 1 , wherein the inorganic waste composition comprises about 40-50 wt % fly ash (FA), about 50-60 wt % ground blast furnace slag (GBFS), and about 4-8 wt % of silicate. 
     
     
         7 . The method of  claim 6 , wherein the silicate is sodium silicate or sodium metasilicate. 
     
     
         8 . The method of  claim 1 , wherein the organic waste composition comprises municipal solid waste (MSW), animal waste, agricultural waste, green waste, mixed refuse, sewage sludge, or combinations thereof. 
     
     
         9 . The method of  claim 1 , wherein in step (c) the biomaterial and the reactive zeolite gel is mixed at a volume ratio ranging from about 5:1 to about 1:5. 
     
     
         10 . The method of  claim 9 , wherein the volume ratio of the biomaterial to the reactive zeolite gel is about 2:3. 
     
     
         11 . The method of  claim 1 , wherein in step (a) the hydrolyzing is performed at a pH ranging from about pH13 to about pH14. 
     
     
         12 . The method of  claim 1 , wherein in step (a) the hydrolyzing is performed at a temperature ranging from about 20° C. to about 25° C. or at an ambient temperature. 
     
     
         13 . The method of  claim 1 , wherein in step (a) the hydrolyzing is performed for about 8 hours to about 16 hours. 
     
     
         14 . The method of  claim 1 , wherein in step (b) the activating is performed at a pH ranging from about pH 13 to about pH 14. 
     
     
         15 . The method of  claim 1 , wherein in step (b) the activating is performed at a temperature ranging from about 20° C. to about 25° C. or at an ambient temperature. 
     
     
         16 . The method of  claim 1 , wherein in step (c) the mixing is performed for about 2 hours to about 4 hours. 
     
     
         17 . The method of  claim 1 , wherein in step (c) the mixing is performed at a temperature ranging from about 20° C. to about 25° C. or at an ambient temperature. 
     
     
         18 . A method for producing a synthetic stone from wastes, the method comprising:
 (a) activating an inorganic waste composition using an alkaline activator to produce a reactive zeolite gel, wherein the alkaline activator has a pH ranging from about pH13 to about pH14; and   (b) curing the reactive zeolite gel to produce the synthetic stone.   
     
     
         19 . A synthetic soil, comprising about 4-6 wt % feldspar, about 4-6 wt % gypsum, and about 3-5 wt % maghemite.