Locally discarded olive oil waste was tested as a potential raw material for the preparation of activated carbons. Chemical activation by impregnation with H_3PO_4 was employed using acid solutions of varying concentration in the range 30-70% followed by thermal treatment at 500-700 deg C. The development of porosity was followed from an analysis of the nitrogen adsorption isotherms obtained at 77 K by applying standard BET and t-plot methods. Carbons with low to moderate surface areas (273-827 m~2/g) and total pore volumes (0.27-0.69 ml/g), containing essentially micropores with diameters of 8.2 A up to 12.4 A were porosity with the optimum being attained at 60% H_3PO_4. Phosphoric acid is visualized as acting both as an acid catalyst promoting bond-cleavage reactions and the formation of new crosslinks and also as a reactant which combines with organic species to form phosphate and polyphosphate bridges which connect and crosslink biopolymer fragments. The present study suggests many applications for environmental pollution control, firstly by utilizing accumulating low-cost agricultural by-products and secondly by producing a multi-purpose high-capacity adsorbent useful in the remediation of micropollutants in various water courses.
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