ABSTRACT
The ability of biological and non-biological adsorbents to remove 2-nitrophenol (2-NP) and 2-chlorophenol (2-CP) from aqueous solutions in batch experiments at room temperature was compared. The marine seaweeds Macrocystis integrifolia Bory (S1) and Lessonia nigrescens Bory (S2) were cross-linked with CaCl(2) to enhance their mechanical properties. Natural bentonite was chemically exchanged with hexadecyltrimethylammonium bromide (B1) and bencyltriethylammonium chloride (B2) to increase their affinity towards organic compounds as well. The adsorption capacity of all of the adsorbents strongly depends on solution pH, whereas equilibrium assays showed a mixed mechanism according to the Langmuir and Freundlich isotherms. The maximum adsorption capacity of 2-NP follows the trend: S1>S2>B2>B1 within the range of 97.37 and 18.64 mg g(-1) whereas for 2-CP, it ranged between 24.18 and 9.95 mg g(-1) with the trend: S1>S2>B2 approximately B1. The importance of the octanol-water partition coefficient as the main factor on the adsorption of these compounds on two different kinds of adsorbents is discussed.
Subject(s)
Phenols/isolation & purification , Seaweed/chemistry , Water Pollutants, Chemical/isolation & purification , Adsorption , Calcium Chloride , Cetrimonium , Cetrimonium Compounds , Chlorophenols/isolation & purification , Nitrophenols/isolation & purification , Octanols , Water , Water Purification/methodsABSTRACT
Biosorption of phenol by the marine seaweeds Lessonia nigrescens Bory and Macrocystis integrifolia Bory was investigated as a function of initial solution pH, showing a higher adsorption percentage at pH 10 with values between 10% and 35%, respectively. The apparent ionization constants of the algae were determined by means of the Katchalsky's theory, obtaining values close to 3.0 for both seaweeds. From the results, a strong adsorption dependence on pH is proposed at the level of the phenol's aqueous chemistry driven purely by a polar mechanism that involves the formation of hydrogen bonds with the hydroxyl groups that are spatially arranged in the polysaccharic chains that form the seaweed structure. This study shows that both marine algae are potential biosorbents in their application for the removal of phenol and derivatives from residual waters.