The effect of binders and agricultural by-products on physical and chemical properties of granular activated carbons

Four binders (coal tar, sugarcane molasses, sugar beet molasses, corn syrup) were mixed with three agricultural by-products (rice hulls, rice straw, sugarcane bagasse) in different combinations and these mixtures transformed into granular activated carbons (GACs). GACs were evaluated for the physical properties of burn-off/yield, surface area, bulk density and hardness and the chemical properties of pH and ash. These properties, except for burn-off/yield, were compared to the same properties of two commercial reference carbons made from bituminous coal with coal tar binder. The results show that GACs made with corn syrup as binder exhibited surface areas, bulk densities, hardness, pH and ash values closest to the reference carbons. The presence of a specific by-product appeared less important than the presence of a specific binder in determining the physical and chemical characteristics of the GACs.