Utilization of wheat bran for producing activated carbon with high specific surface area via NaOH activation using industrial furnace

Abstract

Abstract Waste of wheat bran was used for the first time to prepare activated carbon with high specific surface area via sodium hydroxide activation. The effects of activation temperature (700–900\u202f°C) and NaOH mass ratio (1–5) on surface area were studied. Products were characterized by thermal analysis, nitrogen adsorption–desorption, X–ray diffraction, infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. One development model was used to explain the evolution of pore structure. The product synthesized at 800\u202f°C with mass ratio of 4 possessed the largest surface area of 2543\u202f±\u202f89\u202fm2/g with low ash content of 0.68\u202f±\u202f0.03\u202fwt%. For liquid adsorption of methylene blue, the maximum adsorption capacity was recorded as 887.3\u202f±\u202f24.9\u202fmg/g, higher than 663.8\u202f±\u202f14.8\u202fmg/g for commercial coconut shell carbon. Adsorption data were fitted well with the Redlich–Peterson isotherm and pseudo-second order model, closing to surface area. Cost of carbon production using industrial furnace was calculated as 3.56\u202f±\u202f0.18 $/kg (reduced 32.4% than tube furnace), with output of 1.28\u202f±\u202f0.07\u202fkg/d (improved 11.8 times). It could be demonstrated that wheat bran was an effective and sustainable raw material to obtain low cost carbon product with high surface area, indicating its potential utilization.