2.3.2 Attrition
The attrition of activated carbon samples was determined using a wet attrition test [46]. One gram of activated carbon sample (40 mesh size) was added to 100 ml of acetate buffer (0.07 M sodium acetate and 0.03 M acetic acid (pH 4.8) in a 250 ml Erlenmeyer flask. The solution was stirred for 24 h at 25°C on magnetic stirrer (model. REMI, 2MLH) at 200 rpm using ½ inch stir bars. The samples were then poured onto a 40 mesh screen, and the retained carbon was washed with 250 ml of de-ionized water. After washing, the carbon was transferred to a pre-weighed silica crucible and dried at 90°C in a vacuum oven for 4 hrs. The samples were removed and allowed to cool in desiccators and weighed. The percentage of attrition was calculated using the formula:
Weight of carbon retained by sieve (g) ×100 / Initial sampleweight (g)