Natural organic matter adsorption from aqueous solutions using powdered activated carbon

Introduction: Due to environmental and human health concerns related to humic acid (HA), mainly leading to disinfection by-products creation, removal or reduction of this matters is a necessary for drinking water suppliers. Based on resistive economy map road and move to self-sufficiency, it is necessary to produce our need in water treatment industry. One of the main consumed material is activated carbon that mainly imported to the country. In order to qualifying the produced activated carbon in HA adsorption, the present study was conducted to determine the capacity of powdered activated carbon (PAC). Methods: A type of PAC was provided, then to finding the effective parameters in adsorption process, the tests of BET were done on samples; to determine special surface area (SSA), total pore volume (TVP) and mean pore diameter (MDP) of PAC pores. In a batch system, the experimental parameters were studied on 48 samples using the PAC which include; contact time (5-120 min), initial HA concentration (0.5-10 mg/L), initial adsorbent dose (0.5–20 g/L) and pH (3-11). Then the most conventional models for adsorption isotherm (Freundlich and Langmuir) and kinetic (pseudo first and -secondorder) were evaluated. Results: Based on BET test, the SSA was 161.53 m^2/g, TVP and MDP were 0.2016 cm^3/g and 4.9919 nm respectively. The maximum removal rate for HA was 97.65%, and the optimum conditions were as; equilibrium time of 10 min, initial HA concentration of 5 mg/L, adsorbent dose of 10 g/L and pH 7. The fittest adsorption isotherm and kinetic model were Freundlich isotherm (R^2=0.963) and pseudo-second-order kinetic model (R^2=0.999) respectively. Conclusion: The results showed that produced PAC is able to remove HA as much as 97.65% in a reasonable time and dose range. Thus we can relying on production of this carbon, so it was no need of import of similar foreign products.