Use of chitosan for removal of bisphenol A and bisphenol derivatives through tyrosinase‐catalyzed quinone oxidation

Abstract

In this study, the availability of chitosan was systematically investigated for removal of bisphenol A (BPA, 2,2-bis(hydroxyphenyl)propane) through the tyrosinase-catalyzed quinone oxidation and subsequent quinone adsorption on chitosan beads. In particular, the process parameters, such as the hydrogen peroxide (H 2 O 2 )-to-BPA ratio, pH value, temperature, and tyrosinase dose, were discussed in detail for the enzymatic quinone oxidation. Tyrosinase-catalyzed quinone oxidation of BPA was effectively enhanced by adding H 2 O 2 and the optimum conditions for BPA at 0.3 mM were determined to be pH 7.0 and 40 C in the presence of H 2 O 2 at 0.3 mM ([H 2 O 2 ]/[BPA] ¼ 1.0). Removal of BPA from aqueous solutions was accomplished by adsorption of enzymatically generated quinone derivatives on chitosan beads. The use of chitosan in the form of beads was found to be more effective because heterogeneous removal of BPA with chitosan beads was much faster than homogeneous removal of BPA with chitosan solutions, and the removal efficiency was enhanced by increasing the amount of chitosan beads dispersed in the BPA solutions and BPA was completely removed by quinone adsorption in the presence of chitosan beads more than 0.10 cm 3 /cm 3 . In addition, a variety of bisphenol derivatives were completely or effectively removed by the procedure constructed in this study, although the enzyme dose or the amount of chitosan beads was further increased as necessary for some of the bisphenol derivatives used.

Environmental Applications of Chitosan and Its Derivatives

“…Because chitosan is positively-charged at low pH values, it may be an effective coagulant for anionic organic contaminants such as dyes, tannins and humic acids. Recently, toxic organic chemicals (e.g., phenol and bisphenol A (BPA)) have been remediated by using chitosan incorporated with enzymes (Suzuki et al 2010), clay (Fan et al 2007) and Cu(II) hydroxide nanoparticles (Jaiswal et al 2012). …”

“…Chitosan and its derivatives have been used as a sorbent for BPA and its enzymatic oxidation by-products (i.e., quinones). Chitosan is more effective in the bead form than in solution or in powder form, when used to sorb quinones from treated wastewater (Kimura et al 2012;Suzuki et al 2010). Sorption of BPA and trichlorophenol (TCP) from wastewater has been investigated using magnetic chitosan-fly ash composite (Pan et al 2011).…”

Removal of bisphenol derivatives through quinone oxidation by polyphenol oxidase and subsequent quinone adsorption on chitosan in the heterogeneous system

“…In addition, chitosan powders with different average diameters were used in place of the chitosan beads for the removal of bisphenol derivatives. [37,38] Quantitative assay of bisphenol derivatives…”

“…The initial concentration of the other bisphenol derivatives was adjusted to 0.30 mM. [37] The solutions were continually stirred during the enzymatic reaction and the absorbance at the wavelengths shown in Table 1 was measured at the predetermined time intervals on a Shimadzu UV-visible recording spectrophotometer UV-260. Alternatively, a given amount of chitosan beads, which were stored in a buffer beforehand, were added to solutions of each bisphenol derivative with a bullet, and then the enzymatic reaction was initiated by addition of PPO.…”

“…BPA and its derivatives were successfully removed from aqueous medium through enzymatic quinone oxidation and non-enzymatic quinone adsorption on chitosan beads. [37] However, in the aforementioned enzymatic procedures, H 2 O 2 was required to treat BPA and its derivatives and unreacted H 2 O 2 was left in the reaction medium after treatment.…”