System and method for producing activated carbon material from cow dung

A method for producing activated carbon material from cow dung, comprising:

• a) drying cow dung at a temperature of about 110° C. for about 12 hours, followed by washing with distilled water and subsequent drying at about 110° C. for about 12 hours;
• b) attrition milling the dried cow dung at a temperature of about 70° C.;
• c) sieving the milled cow dung through a sieve with a mesh size of about 400 μm;
• d) drying the sieved cow dung at a temperature of about 110° C. for about 5 hours;
• c) carbonizing the dried and sieved cow dung at a temperature of about 700° C. for about 120 minutes in a nitrogen (N2) environment;
• f) chemically activating 75 grams carbonized material by soaking in 1.2 litre of an aqueous sodium hydroxide (NaOH) solution for about 5 hours;
• g) pyrolyzing the chemically activated material at a temperature of about 600-800° C. for about 150 minutes in an N2 environment;
• h) washing 75 grams pyrolyzed material with about 500 mL hydrochloric acid (HCl) solution;
• i) drying the washed material at a temperature of about 110° C. overnight;
• and
• j) crushing the dried material to obtain activated carbon material, wherein the attrition milling in step (b) breaks down the dried cow dung into smaller particles, wherein during the drying step of cow dung in step (a), the drying is carried out in a programmable convection-IR hybrid chamber equipped with dual spectral IR emitters operating in the range of 2-10 μm, wherein the chamber includes a capacitive moisture sensor and a Fourier-transform infrared (FTIR) reflectance probe that continuously monitor the internal moisture desorption kinetics, and wherein a thermal model-based PID control loop regulates emitter power levels to maintain an exponential desorption curve, such that drying is halted only when the rate of moisture removal stabilizes below 0.05% per minute over a rolling 10-minute interval, and wherein prior to step (a), the cow dung is subjected to a microbial pre-treatment process involving aerobic fermentation with lignin-degrading microbial consortia, maintained in a controlled bioreactor at 37° C. and 60% relative humidity for 72 hours, wherein the pre-treatment breaks down lignocellulosic compounds and reduces bound nitrogen and sulfur content;
• and wherein the sieving in step (c) comprises a two-pass fluidized-bed air classifier integrated with an electrostatic pre-separation unit, wherein said classifier generates a low-turbulence laminar airflow directed at an angle of 25 degrees to horizontally suspended cow dung particles, allowing separation of fragments based on aerodynamic drag coefficients, and wherein the classifier includes a programmable material rejection gate that routes oversized biofibers to a secondary micronization loop without manual intervention.