College of Engineering and Technology

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Browsing College of Engineering and Technology by Subject "activated carbons"

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    Evaluation of agro-waste derived activated carbons in the remediation of petroleum hydrocarbon contaminated wastewater.
    (University of Dar es Salaam, 2008) Raymond, Prosper
    The removal of dissolved petroleum hydrocarbons is one of the final steps in the treatment of wastewaters from a variety of industries like oil refineries, petrochemical works and metal finishing plants. This study was aimed at investigating the removal of dissolved petroleum hydrocarbons from industrial wastewater by using activated carbons produced from agro-wastes. Agro-wastes such as cashew nut shells, coconut shells, coffee husks, peaches stones, palm fruit shells, maize cobs, and non agro-waste bituminous coal and polymers produced by wood boring beetles were used in the preparation of the carbons. All these materials were carbonized followed by physical activation at 900 °C using CO2 gas. The prepared activated carbons were characterized by nitrogen physisorption and FT-1R techniques. The BET surface areas were found to range from 70 to 800 m2g- 1 and were mainly mesoporous. Analysis of wastewater discharged into a river adjacent to the BP Depot at Kurasini, Dar es Salaam showed significant levels of contamination, with concentrations of Total Petroleum Hydrocarbons (TPH) ranging from 115 to 13079 µg/l. Experiments to evaluate the effectiveness of agro-waste based carbons in removing TPH revealed that indeed activated carbon is an excellent means for stripping-off of TPH contaminant from wastewater. Its adsorption efficiency depends on the type of source material, amount of activated carbons used and retention time. Coffee husks and bituminous coal based activated carbons showed the lowest efficiency whereas polymers produced by wood boring beetles, cashew nut shells and maize cobs based carbons showed the best results.