Waste Activated Sludge as an Additive for Increment of Lime Sorption Capacity

Lime was physically blended with Waste Activated Sludge (W.A.S) in various proportions. These blends were hydrated, dried, ground, and sieved to size of utmost 200 μm. The sorbents were then used in fixed-bed reactor for dry desulfurization tests. It was found that the blends had higher sorption capacities than lime alone which means that W.A.S augmented lime's sorption capacity. Higher surface area and porosity of the blended sorbents compared to lime was the main cause of the improved sorption capacity, a conclusion supported by Brunauer–Emmett–Teller surface area analysis (surface area increment with sorption capacity) and scanning electron microscopy imaging (rough morphology being formed). This higher surface area and porosity was caused by pozzolanic reaction between lime and the alumina silicate constituents of W.A.S. The products of this reaction are high surface area, complex calcium alumina silicates.