Removal of Hydrophobic Organic Contaminants from Aqueous Solutions by Sorption onto Biodegradable Polyesters

Abstract

Sorption by biodegradable polyesters of several aromatic chemicals as model compounds for hydrophobic organic contaminants (HOCs) was studied. The biodegradable polyesters used were poly(butylene succinate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(ε-caprolactone), poly(butylene succinate/ terephthalate), and poly(L-lactic acid). Petrochemical plastics, low-density polyethylene and polyethylene terephtalate, were used for comparison. The target HOCs were biphenyl, bisphenol-A, dibenzofuran, diethylstilbestrol, nonyl-phenol, and chlorophenols. The treatment of the HOC solutions with each of the biodegradable polyesters resulted in the nearly complete removal of the chemicals by sorption from the aqueous phase, except for the case of poly(L-lactic acid). Low-density polyethylene adsorbed biphenyl and dibenzofuran selectively, and polyethylene terephtalate did not adsorb any of the HOCs. The adsorptive interaction between the plastics and the HOCs might be related to both the glass transition temperature of the former and the nature of the latter as defined by the Fujita's inorganicity/organicity ratio. The toxic effect of 3,5-dichlorophenol on bacte-rial growth in liquid culture was removed by the addition of a biodegradable polyester. These results provide a basis for the applicability of the biodegradable plastics as the adsorbents for the removal of HOCs from aquatic environments

Significance of Chlorinated Phenols Adsorption on Plastics and Bioplastics during Water Treatment

“…The adsorption kinetics and isotherm data presented above demonstrate significant variations in the degree to which microplastics interact with chlorinated phenols in neutral pH aqueous environments. The different polarities of the phenols studied, as demonstrated by their various pKa values, mean that under the conditions investigated some of these compounds are partially present in disassociated forms, rather than as neutral species [11,13]. The different plastics have differing monomeric compositions, with the linear aliphatic PE, and the slightly branched aliphatic PP and PLA which is an aliphatic polyester.…”

“…Recent studies have highlighted that these plastics are also frequently used as construction materials in drinking water treatment facilities, which can contribute further to the presence of these microplastics in drinking water [12]. Matsuzawa et al (2010) [13] reported that some types of biodegradable polymers can adsorb certain hydrophobic organic compounds, including chlorinated phenols. Bioplastics have attracted much attention as alternatives of conventional plastics.…”

Environmental Applications

“…Matsuzawa et al [12] studied the removal of different aromatic chemicals as model HOCs from aqueous solutions by sorption onto commercial BDPs as the sorbents, such as PLA, poly(e-caprolactone) (PCL), poly(butylene succinate) (PBS), poly(butylene adipate/terephthalate) (PBT), poly (3-hydroxybutyrate) (PHB), and poly(3-hydroxybutyrateco-3-hydroxyvalerate) (PHBV). The target HOCs used were biphenyl (BP), bisphenol A (BPA), dibenzofuran (DF), diethylstilbestrol (DES), nonylphenol (NP), phenol, and its chlorinated derivatives, 2-monochlorophenol (2-CP) and 3,5-dichlorophenol (3,5-DCP).…”

“…However, Matsuzawa et al [12] also found that HOCs adsorbed onto the BDPs were not fully extracted with organic solvents. However, Matsuzawa et al [12] also found that HOCs adsorbed onto the BDPs were not fully extracted with organic solvents.…”

“…1 Sorption of Aromatic Chemicals as Model HOCs by Biodegradable and Conventional Petrochemical Polyesters[12] …”