Binding mechanisms and QSAR modeling of aromatic pollutant biosorption on Penicillium oxalicum biomass

Abstract

a b s t r a c tThe biosorption of eight aromatic compounds with different functional groups by Penicillium oxalicum biomass were investigated. The affinity of the biomass for the eight compounds at pH 6.0 follows the following trend: 1-naphthalenamine > naphthol > benzoic acid > p-toluidine > p-cresol > p-toluic acid > phenol > p-toluenesulfonic acid. Biomass surface was characterized, and it was found that four discrete binding sites, corresponding to carboxyl (pK a = 4.0), phosphoric (pK a = 7.0), amine (pK a = 8.8), and hydroxyl groups (pK a = 10.0), were identified on the biomass surface by using the linear programming method (LPM) for the fitting of the titration data and FTIR analysis. The carboxyl and amine groups dominate the biomass surface sites, which might have played an important role in biosorption of organic compounds. Furthermore, the compounds were divided into two groups based on the calculation of ionization degree for toluene derivatives and the comparison on the number of benzene rings for barely ionized compounds. It was found that low ionization degree and high hydrophobicity favor the biosorption for the two groups, respectively. Moreover, a R 2 adj of 0.724 between the log of Freundlich coefficient (log K f ) and log Kow indicated that the hydrophobicity plays role in the sorption of eight organic compounds. The QSAR model with one variable was developed for the first time between log K f and polar surface area (PSA) to predict the biosorption behaviors of organic compounds (R 2 adj = 0.960) except for ptoluenesulfonic acid (with pK a < 0), which also supported the electrostatic attraction and hydrophobicity mechanisms.

Decarboxylated polyethylenimine-modified bacterial biosorbent for Ru biosorption from Ru-bearing acetic acid wastewater

“…The peaks at 2925 and 2850 cm À1 indicated the aliphatic CAH stretch vibrations of the CH, CH 2 , and CH 3 groups. The peaks for amide bands were observed at 1654 cm À1 (amide I band), 1537 cm À1 (amide II band), and 1453 cm À1 (amide III band) [14]. The peaks at 1408 and 1384 cm À1 corresponded to the carboxylic acid and carboxylate ions on the biomass surface, respectively.…”

Cellulosic substrates for removal of pollutants from aqueous systems: A review. Part 4. Dissolved petrochemical compounds

“…Several studies have found correlations between adsorption capacity and decreasing water-solubility of the sorbate Girgis 1998, 2003;Nouri et al 2002b;Dąbrowski et al 2005;Wu and Yu 2006a;Aktar et al 2007a;Hamdaoui and Naffrechoux 2007a;Thuy et al 2008;Navarro et al 2009;Hansen 2010;Zhang et al 2011c). An example is shown in Fig.…”

“…As shown by Kumar and Min (2011b), fungal biomass may contain significant amounts of nitrogen in the form of amines and amides; this is attributable to the presence of protein. Various researchers have evaluated fungal material relative to the uptake of phenols and other synthetic organic compounds from solution (Young and Banks 1998;Rao and Viraraghavan 2002;Denizli et al 2005;Wu and Yu 2006b;Kumar et al 2009b;Pernyeszi et al 2009;Huang et al 2010;Kumar and Min 2011b;Zhang et al 2011c;Farkas et al 2013). Rao and Viraraghavan (2002) found the highest uptake following pretreatment of Aspergillus niger with sulfuric acid.…”

“…Ionic interactions have been proposed as having a major influence by many researchers who have studied adsorption of petrochemicals onto cellulosic materials and activated carbons (Radobic et al 1997;Nouri et al 2002a,b;Ayranci and Dyman 2006;Villacanas et al 2006;Blackburn et al 2007;Zhang et al 2011c;Fu et al 2012a). Some of the strongest evidence supporting a major role of ionic attractions and repulsions in the adsorption of petrochemical compounds to cellulose-derived substrates comes from studies of pH effects, as covered in an earlier section (see, for instance, Brandt et al 1997;Ayranci and Dyman 2006).…”

Sulfamethazine removal by means of a combined process coupling an oxidation pretreatment and activated sludge culture – preliminary results

“…Based on a review of the related literature, biosorption of organic compounds depends on various factors (molecular size, degree of ionization, solubility, charge, hydrophobicity [34]. 18.7% of sulfamethoxazole, sulfamonomethoxine and sulfadimethoxine were respectively biosorbed at pH 7, for 2.56 g.L -1 of activated sludge.…”