Polycyclic aromatic hydrocarbons (PAHs) are a group ofvaried organic compounds consists of two or more fused aromatic rings of carbonand hydrogen atoms (Henner et al., 1997).They are mainly produced from the insufficient burning of fossil fuels,petrochemical industries and biomass combustion.
PAHs have been become widespreadcontaminants in the environment (Jacques et al., 2008; Sartoros et al., 2005;Ye et al., 2011). In fact, PAHs are steady and persistent in the environment becauseof their lower solubility in water, low volatility and their slow biodegradability(Sartoros et al.
, 2005; Cheung et al., 2008; Nkansah et al., 2011).Although there are more than 100 different species of PAHs,United States Environmental Protection Agency (US-EPA) has classified 16 individualPAHs in the priority list due to their adverse effect towards ecosystem andhuman health (Jahin et al., 2009).
The remediation of wastewater polluted with PAHsis currently performed by physic-chemical and biological treatments (Changming2012). In fact, the biodegradation process generally needs a long time to digestsuch organic pollutants to an acceptable level of PAHs (Lamichane et al., 2016).Moreover, PAHs are not efficiently removedby traditional methods such as coagulation, sedimentation, flocculation,filtration and ozonation.
Adsorption method is a promising technique to remediatePAHs in a low cost and environmental friendly method (Bhatnagar and Sillanpaa, 2010;Oller et al., 2011; Xi and Chen, 2014). So, this last ten years, there has beenan increasing interest to find cheap and naturally available adsorbent.
Activatedcarbon produced from rice peel is observed to have higher adsorption capacitythan adsorbent based on other agricultural and industrial materials (Lamichaneet al., 2016).Activated Carbon is the most frequentlly usedmaterial for the removal of PAHs from aqueous solution (Valderrama et al.
, 2009).Activated carbon is produced from several available materials (bituminous coal,petroleum coke, shells, sewage sludge and plant derived material) (Awoyemi,2011; Kong et al., 2011; Gupta, 2015) through carbonization followed byactivation processes. Activated carbon is prepared in different forms ofpowder, granules or briquette depending on its specific application. Practically,granular activated carbon (GAC) and powder activated carbon (PAC) are the commonforms for PAHs sorption. (Paune et al.
, 1998; Ania et al., 2008; Valderrama etal., 2008). For PAHs (naphthalene, phenanthrene, pyrene) activatedcarbon produced from rice husk is observedto have higher adsorption capacity and removal efficiency than adsorbents basedon other agricultural and industrial materials (such as chitosan, chitin, sugarbagasse, coconut shells, leonardite and mesoporous organo silica) (Yakout etal., 2013). The degree of the adsorption of PAHs on activated carbon surfacedepends on many factors such as initial PAHs concentration, inwater/wastewaters, contact time, the type of used material, the Activatedcarbon dose and etcIn this paper, authors aim to study the usage ofactivated carbon, produced from agricultural wastes (corncob), as an adsorbentfor removal of different concentrations of eight individual PAHs from aqueoussolution.
First, factors affecting the adsorption of PAHs on activated carbon suchas the effects of pH, contact time and the doses of activated carbons will beexamined. Secondly, a modeling of the isotherms of adsorption will be taken byfitting the parameters of the Langmuir and Freundlich models.