3.3. Physico- chemical properties
The pH, EC, bulk density and hardness of the carbon samples were recorded and presented in Table 3. All the carbon samples recorded alkaline pH values except H3PO4 treated DRFP (3.73±0.01). The untreated BEFP recorded the highest pH (10.23±0.01) followed by H3PO4 and KOH treated carbon samples (9.78±0.0 and 9.04±0.01, respectively). Interestingly the KOH treated DRFP sample recorded a neutral pH (7.3±0.03) when compared to untreated carbon (8.72±0.08). The electrical conductivity of the BEFP samples was higher than for DRFP. Untreated BEFP had very high EC values (3040±0.03 μS) followed by H3PO4 and KOH treated carbon samples (1227±2.43 μS and 1183±3.05 μS, respectively). A comparatively low EC value (353.66±3.51 μS) for H3PO4 treatedDRFP was obtained followed by untreated DRFP (321.33±1.52 μS) and KOH treated DRFP samples (189±3.86 μS), respectively. Bulk density is an important characteristic of the carbon and is invariably related to the starting material. In this study, KOH treated DRFP showed a higher bulk density (0.46 g/ml)followed by H3PO4 treated DRFP (0.45 g/ml). The H3PO4 treated BEFP, however, showed lowest bulk density (0.33 g/ml) when compared to other experimental carbons. Hardness or attrition is a measure of the mechanical strength of the carbons and it is an important parameter for understanding its relative loss during the transportation, handling and regeneration. The results indicate that BEFP have lower attrition values than the DRFP (Table 3). The hardness was high in untreated (10.30%) and H3PO4 activated (10.20%) DRFP. The H3PO4 treated BEFP sample showed the lowest attrition (1.5%) followed by untreated BEFP carbon (1.9%). The percentage of attrition observed in carbon, as the results indicate, depends upon the carbon density or starting materials of the attrition percentage is varied [60].