polidocanol and naphthalene

The removal efficiency of polycyclic aromatic hydrocarbons (PAHs) by ozonation using a rotating packed bed (RPB) in the surfactant-containing solution is studied. As an ozonation process starts, the ozone-containing gas is introduced and transferred into to the solution. The target PAHs in the solution would be then eliminated via both the gas stripping and ozonation decomposition. The RPB, which provides high gravitational force by adjusting the rotational speed, is employed as a novel ozone contactor. The naphthalene (NAP) and Brij 30 are chosen as the model pollutant and surfactant. Note that the experiments with different concentrations of NAP, Brij 30, and inlet gas ozone are performed for the further investigation. The residual NAP, effluent dissolved oxygen and ozone, and off-gas ozone concentrations are simultaneously monitored. As a result, the removal of NAP in the RPB is remarkably efficient compared with the convectional contactors because of its greater mass transfer coefficient. Moreover, the removal efficiency of NAP is found significantly dependent on the concentrations of NAP, Brij 30, and inlet gas ozone. It takes about several minutes to reach the steady state under the conditions of this study. In addition, it suggests employing RPBs as ozone contacting devices for the high removal efficiency of NAP. Consequently, the present study is useful for the practicable understanding of application of RPBs for the ozonation of PAHs in surfactant-containing solution.

Topics: Environmental Pollutants; Environmental Pollution; Environmental Restoration and Remediation; Naphthalenes; Ozone; Polidocanol; Polyethylene Glycols

The principal objective of this study was to quantify the bioavailability of micelle-solubilized naphthalene to naphthalene-degrading microorganisms comprising a mixed population isolated from contaminated waste and soils. Two nonionic surfactants were used, an alkylethoxylate, Brij 30 (C12E4), and an alkylphenol ethoxylate, Triton X-100 (C8PE9.5). Batch experiments were used to evaluate the effects of aqueous, micellized nonionic surfactants on the microbial mineralization of naphthalene and salicylic acid, an intermediate compound formed in the pathway of microbial degradation of naphthalene. The extent of solubilization and biodegradation under aerobic conditions was monitored by radiotracer and spectrophotometric techniques. Experimental results showed that surfactant concentrations above the critical micelle concentration were not toxic to the naphthalene-degrading bacteria and that the presence of surfactant micelles did not inhibit mineralization of naphthalene. Naphthalene solubilized by micelles of Brij 30 or Triton X-100 in liquid media was bioavailable and degradable by the mixed culture of bacteria.

Topics: Bacteria; Biodegradation, Environmental; Micelles; Naphthalenes; Octoxynol; Polidocanol; Polyethylene Glycols