sodium-dodecyl-sulfate and phenanthrene

Batch experiments were conducted to investigate the performance of nonionic-anionic mixed surfactants and their recovery through activated carbon. The solubilization capabilities of mixed surfactants toward phenanthrene (PHE) were reduced by addition of anionic surfactant to the mixed systems. Results showed that sorption of Triton X-100 (TX100) onto soil decreased with increasing mass fraction of sodium dodecyl sulfate (SDS) in the mixed surfactant solutions. Soil contaminated with PHE at 200 mg/kg was washed with different surfactant concentrations at various mass ratios of nonionic-anionic mixed surfactant. Experiments with low-concentrations of mixed surfactants revealed that removal efficiencies for PHE-contaminated soil close to the individual higher nonionic surfactant concentration can be achieved. Overall performance considering both soil washing and surfactant recovery steps is apposite when an TX100:SDS mass ratio of 8:2 at 3 g/L is used.

Topics: Adsorption; Anions; Charcoal; Environmental Pollution; Environmental Restoration and Remediation; Kinetics; Micelles; Octoxynol; Phenanthrenes; Sodium Dodecyl Sulfate; Soil; Soil Pollutants; Solubility; Surface-Active Agents; Thermodynamics

In this work, a pilot plant with two rows of three electrodes in semipermeable electrolyte wells was used to study the electrokinetic treatment of a natural soil polluted with phenanthrene (PHE). The electrokinetic pilot plant was an open system, i.e., there was direct contact between the soil and air. To increase the solubility of phenanthrene, thereby enhancing its transport through the soil, an aqueous solution of the anionic surfactant dodecyl sulfate was used as a flushing fluid. The results show that at the pilot scale considered, gravity and evaporation fluxes are more relevant than electrokinetic fluxes. Contrary to observations at the laboratory scale, desorption of PHE promoted by electric heating appears to be a significant removal mechanism at the pilot scale. In addition, PHE is dragged by the electroosmotic flow in the cathodic wells and by electrophoresis after interaction of the surfactant with phenanthrene in the anodic wells. In spite of the long treatment time (corresponding to an energy consumption over 500kWhm(-3)), the average removal attained was only 25%.

Topics: Adsorption; Electrochemical Techniques; Electrodes; Environmental Restoration and Remediation; Hot Temperature; Kinetics; Phenanthrenes; Sodium Dodecyl Sulfate; Soil Pollutants; Surface-Active Agents

With the increasing production and use of graphene oxide, the environmental implications of this new carbonaceous nanomaterial have received much attention. In this study, we found that the presence of low concentrations of graphene oxide nanoparticles (GONPs) significantly enhanced the transport of 1-naphthol in a saturated soil, but affected the transport of phenanthrene to a much smaller extent. The much stronger transport-enhancement effect on 1-naphthol was due to the significant desorption hysteresis (both thermodynamically irreversible adsorption and slow desorption kinetics) of GONP-adsorbed 1-naphthol, likely stemmed from the specific polar interactions (e.g., H-bonding) between 1-naphthol and GONPs. Increasing ionic strength or the presence of Cu(II) ion (a complexing cation) generally increased the transport-enhancement capability of GONPs, mainly by increasing the aggregation of GONPs and thus, sequestering adsorbed contaminant molecules. Interestingly, modifying GONPs with Suwannee River humic acid or sodium dodecyl sulfate had little or essentially no effect on the transport-enhancement capability of GONPs, in contrast with the previously reported profound effects of humic acids and surfactants on the transport-enhancement capability of C60 nanoparticles. Overall, the findings indicate that GONPs in the aquatic environment may serve as an effective carrier for certain organic compounds that can interact with GONPs through strong polar interactions.

Topics: Adsorption; Cations; Copper; Graphite; Humic Substances; Kinetics; Nanoparticles; Naphthols; Osmolar Concentration; Phenanthrenes; Rivers; Sodium Dodecyl Sulfate; Soil; Soil Pollutants; Surface-Active Agents

In situ Fenton oxidation has been recently used to oxidize sorbed organic contaminants in soil. The objective of present contribution was to study the role of sodium dodecyl sulfate (SDS) as anionic surfactant and sol with iron oxyhydroxide/SDS for Fenton oxidation of sorbed phenanthrene in sand. The most effective experimental condition for phenanthrene oxidation was the Fenton-like reaction system with 0.35% H2O2, 30 mM SDS, and 4 mM FeCl2. The Fenton-like reactions under these experimental conditions resulted in the production and sustenance of a stable sol with iron oxyhydroxide/SDS composites over 24 h. The formation of iron oxyhydroxide/SDS composites resulted in stabilization of H2O2, and then the Fenton-like reactions were sustained over 24 h. Furthermore, the sol of iron oxyhydroxide/SDS composites gave suitable sites to sustain oxidations of dissolved phenanthrene over a prolonged reaction span, which is required for in situ chemical oxidation.

Topics: Ferric Compounds; Hydrogen Peroxide; Oxidation-Reduction; Phenanthrenes; Silicon Dioxide; Sodium Dodecyl Sulfate; Soil Pollutants

Carbon nanotubes (CNTs) can exist in the form of colloidal suspension in aquatic environments, particularly in the presence of natural organic matter or surfactants, and may significantly affect the fate and transport of organic contaminants. In the present study, the authors examined the adsorption of phenanthrene, 2-naphthol, and 1-naphthylamine to three colloidal CNTs, including a stable suspension of oxidized multiwalled carbon nanotubes (O-MWNT), a humic acid (HA)-modified colloidal O-MWNT, and a sodium dodecyl sulfate (SDS)-modified colloidal O-MWNT. All three colloidal O-MWNTs exhibit strong adsorption affinities to the three test compounds (with K(OC) values orders of magnitude greater than those of natural organic matter), likely resulting from strong nonhydrophobic interactions such as π-π electron donor-acceptor interactions and Lewis acid-base interactions. When thoroughly mixed, HA (at ∼310 mg HA/g CNT) and SDS (at ∼750 mg SDS/g CNT) significantly affected the aggregation properties of O-MWNT, causing individually dispersed tubes to form a loosely entangled network. The effects of HA or SDS modification on adsorption are twofold. Adsorption of HA/SDS significantly reduces surface areas of O-MWNT; however, the entangled network allows adsorbate molecules to interact simultaneously with multiple tubes. An important implication is that humic substances and surfactant-like materials not only facilitate the formation of colloidal carbon nanoparticles but also affect how these colloidal carbon nanoparticles adsorb organic contaminants.

Topics: 1-Naphthylamine; Adsorption; Humic Substances; Models, Chemical; Nanotubes, Carbon; Naphthols; Phenanthrenes; Sodium Dodecyl Sulfate; Surface-Active Agents; Water Pollutants, Chemical

In the present study surfactant addition with the help of either a mechanical dispersion or a thermal treatment was applied in order to increase the solubility and the bioavailability of phenanthrene in aqueous media, and therefore to promote its biodegradation. Among four tested surfactants (Tween 80, Brij 30, sodium dodecyl sulphate and rhamnolipids), Brij 30 (0.5 gL(-1)) showed the best results allowing us to attain about 20 mgL(-1) of soluble phenanthrene. An additional thermal treatment at 60°C for 24h, 200 rpm permitted to increase the solubility of phenanthrene in the presence of Brij 30 (0.5 gL(-1)) to about 30 mgL(-1). Higher dispersions of phenanthrene particles as well as the reduction of their size were obtained using Ultra-Turrax and French press. The biodegradation of phenanthrene by Pseudomonas putida was then investigated. The reduction of size of phenanthrene particles by mechanical dispersion did not influence its biodegradation, suggesting that P. putida consumed only soluble phenanthrene. The addition of Brij 30 (0.5 gL(-1)) permitted to obtain more phenanthrene metabolized. The use of Brij 30 coupled with a transitory heating of phenanthrene-containing medium at 60°C led to an even more complete biodegradation. This might be a promising way to enhance biodegradation of PAHs.

Topics: Biodegradation, Environmental; Glycolipids; Phenanthrenes; Polidocanol; Polyethylene Glycols; Polysorbates; Pseudomonas putida; Sodium Dodecyl Sulfate; Solubility; Surface-Active Agents; Temperature; Water Pollutants, Chemical

The chemical-enhanced washing of Cu2+ or/and phenanthrene (PHE) single or combined contaminated loess soil in Gansu Province was investigated with disodium ethylene diamine tetraacetate (EDTA) or/and sodium dodecyl sulfate (SDS) by the batch equilibrium experiments. The experimental results showed that EDTA or/and SDS could remove efficiently Cu2+ and/or PHE in single-contaminated or combined contaminated loess soils. The Cu2+ removal was significantly promoted by coexisting PHE with low concentration of EDTA (EDTA < 0.1 mol/L), however, the removal was slightly hindered with high concentration of EDTA (EDTA > 0.1 mol/L). As for the PHE removal by EDTA, it was founded that coexisting Cu2+ could enhance the PHE removal in the investigated ranges of the concentrations of EDTA. When concentration of EDTA was 0.01 mol/L, the removal of combined PHE was 20.94% higher than that of single PHE. The experimental results of the removal of contaminations by SDS showed that coexisting Cu2+ could suppress slightly the removal of PHE at a concentration of less than 4 000 mg/L SDS, but could assist the removal of PHE in 5 000 mg/L or higher SDS concentration. On the contrary, the influence of coexisting PHE for the removal of Cu2+ by SDS was that it facilitated Cu2+ extraction by low concentrations of SDS, however, it inhibited the removal of Cu2+ at high concentrations of SDS. The removal efficiencies of PHE and Cu2+ were improved greatly as using combined EDTA-SDS. Beside, there are some differences in the removal efficiency of the oth contaminants with the different sequence of EDTA and SDS added in the washing solution. In EDTA washing followed by SDS, SDS washing followed by EDTA and mixture of SDS-EDTA washing concurrently, the removal of Cu2+ is 91.40%, 95.10% and 96.50%, respectively, which is 28.46%, 32.16%, 33.56% higher than that of combined, 62.94%, by single EDTA. For PHE, the removal is 68.30%, 85.40%, 84.95%, respectively, which is 16.14%, 33.24%, 32. 79% higher than that of combined PHE, 52.16%, by single SDS. Thus, SDS washing followed by EDTA or mixture of SDS-EDTA washing concurrently is considered as the optimal washing sequence for PHE and Cu2+ removal.

Topics: China; Copper; Edetic Acid; Environmental Restoration and Remediation; Phenanthrenes; Sodium Dodecyl Sulfate; Soil Pollutants

A comparison of column flushing for phenanthrene-contaminated sandy soils was made by using an anionic surfactant, sodium dodecyl sulfate (SDS), a nonionic surfactant, Triton X-100 (TX100), and their mixed surfactants (SDS-TX100). The tested concentrations of surfactants were 1000, 1750, 2500 and 3250 mg x L(-1) while the mass ratios of SDS to TX100 (S:T) in the mixed surfactants were 1:1, 1:2 and 1:4. It was shown that the elution curves (phenanthrene concentration in elutant versus porous volume number) by SDS were zigzag fluctuating rather than regular patterns while those by TX100 and SDS-TX100 were regular ones in which the phenanthrene concentrations in elutant increased, achieved maximum and then decreased with the porous volume numbers of eluting solutions. Moreover, the maximum phenanthrene concentrations increased and the total porous volume numbers decreased with surfactant concentration increasing. Given the surfactant and total porous volume number, the removal efficiencies of phenanthrene were positively related to surfactant concentrations. The removal efficiencies by TX100 and SDS-TX100 depended on concentration and ratio of surfactant and were much larger than those by SDS. Given 1000, 1750 and 2500 mg x L(-1) of the surfactant concentrations respectively, the removal efficiencies by TXl00 and SDS-TX100 were more than 95% but the total porous volume numbers by SDS-TX100 were less than those by TX100. Given 3250 mg x L(-1) of the surfactant concentration, the total removal efficiencies by five surfactants (i.e., SDS, TX100, S:T = 1:1, S:T = 1:2 and S:T = 1:4) achieved their maximum values as 70.8%, 99.9%, 99.9%, 98.7% and 99.2%, respectively, but the needed porous volume numbers by TX100 were the least among those by all surfactants. The results illustrates that the factors such as type, concentration and ratio of surfactant play important roles in surfactant-enhanced flushing remediation for soils contaminated by organics.

Topics: Environmental Restoration and Remediation; Octoxynol; Phenanthrenes; Silicon Dioxide; Sodium Dodecyl Sulfate; Soil; Soil Pollutants; Surface-Active Agents

Laboratory column experiments were conducted to investigate the performance of anionic-nonionic mixed surfactant, sodium dodecyl sulfate (SDS) with Triton X-100 (TX100), in enhancing phenanthrene flushing for contaminated soil in an aim to improve the efficiency of surfactant remediation technology. The experimental results showed that the sorption of TX100 onto soil was severely restricted in the presence of SDS in batch and column experiments and decreased with the increasing mass fraction of SDS in mixed surfactant solutions; meanwhile the enhanced solubilization of phenanthrene by SDS-TX100 mixed surfactant was greater than that by individual surfactant. These results can be attributed to the formation of mixed surfactant micelles in solution. The column flushing experiments showed that the flushing efficiencies for phenanthrene-contaminated soil by SDS-TX100 mixed surfactants were greater than that by individual surfactant and increased with the increasing mass fraction of SDS in mixed surfactant solutions.

Topics: Adsorption; Octoxynol; Phenanthrenes; Sodium Dodecyl Sulfate; Soil Pollutants; Solubility; Surface-Active Agents; Waste Management

SDS and Triton X-100 added at their critical micelle concentrations (CMCs), increased phenanthrene solubility in the presence of sediments and inhibited phenanthrene biodegradation. Triton X-100 caused more inhibition than SDS. 16S rDNA analyses revealed that both surfactants changed the microbial communities of phenanthrene-degrading cultures. Further, after the surfactant additions, parts of the microbial populations were not detected and methane production decreased. Surfactant applications, necessary to achieve actual CMCs, alter microbial community structure and diminish methanogenic activity under anaerobic conditions. We propose that this change may be related to the inhibitory effects of SDS and Triton X-100 on phenanthrene biodegradation under methanogenic conditions.

Topics: Anaerobiosis; Bacteria; Biodegradation, Environmental; DNA, Ribosomal; Methane; Micelles; Octoxynol; Phenanthrenes; Phylogeny; Polymorphism, Restriction Fragment Length; Sodium Dodecyl Sulfate; Surface-Active Agents

A new approach using an anionic/nonionic mixed surfactant, sodium dodecyl sulphate (SDS) with Triton X-100 (TX100), was utilized for the desorption of phenanthrene from an artificial contaminated natural soil in an aim to improve the efficiency of surfactant remediation technology. The experimental results showed that the presence of SDS not only reduced the sorption of TX100 onto the natural soil, but also enhanced the solubilization of TX100 for phenanthrene, both of which resulted in the distribution of phenanthrene in soil-water systems decreasing with increasing mole fraction of SDS in surfactant solutions. These results can be attributed to the formation of mixed micelles in surfactant solution and the corresponding decrease in the critical micelle concentration of TX100 in mixed solution. The batch desorption experiments showed that the desorption percentage of phenanthrene from the contaminated soil with mixed solution was greater than that with single TX100 solution and appeared to be positively related to the mole fraction of SDS in surfactant solution. Thus, the anionic/nonionic mixed surfactants are more effective for the desorption of phenanthrene from the contaminated soil than a single nonionic surfactant.

Topics: Chemical Phenomena; Chemistry, Physical; Environmental Restoration and Remediation; Octoxynol; Phenanthrenes; Sodium Dodecyl Sulfate; Soil Pollutants; Solubility; Surface-Active Agents

The effects of anionic-nonionic mixed surfactants, sodium dodecyl sulfate (SDS) mixed with Triton X-100 (TX100), on the desorption and biodegradation of phenanthrene in soil-water system were investigated in an aim to improve the efficiency of surfactant bioremediation technology. Results indicated that the presence of SDS not only increased the solubilization of TX100 for phenanthrene, but also reduced the sorption of TX100 onto soils. As a result, the desorption efficiency of phenanthrene from the contaminated soil was greatly enhanced by mixed surfactant solutions compared with that by single TX100 solution and appeared to be positively related with the mole fraction of SDS in solution. Mixed surfactants with relatively smaller ratio promoted phenanthrene biodegradation, for example, the biodegradation percentage of phenanthrene in 1:9 SDS-TX100 mixed solutions was about 165% of that in the single TX100 solution at the same TX100 concentration of 1.6 mmol/L in 24h. But the biodegradation was inhibited with larger ratio of SDS in the mixed solutions, which may be due to the preferential utilization of SDS by phenanthrene degraders. Thus, the selection of mixed surfactants should consider simultaneously the effects of SDS on desorption and biodegradation. The experimental results can be used to provide valuable information in designing the surfactant bioremediation technology for contaminated soils.

Topics: Environmental Restoration and Remediation; Phenanthrenes; Sodium Dodecyl Sulfate; Soil Pollutants; Surface-Active Agents; Water Pollutants, Chemical

Removal of hydrophobic organic contaminants (HOCs) using surfactant-enhanced electrokinetic (EK) method was studied in a model system. Kaolinite and phenanthrene were selected as a model clay soil and a representative HOC, respectively. Three different types of surfactants: APG (alkyl polyglucoside), Brij30 (polyoxyethylene-4-lauryl ether), and SDS (sodium dodecyl sulfate), were used to enhance the solubility of HOC. Characteristics of surfactants, such as surface tension, HOC solubility, and biodegradability were measured. In the case of Brij30 solution, phenanthrene solubility was higher than that of others. After 4 days, APG and Brij30 were degraded by 65% and 26% of the initial amount, respectively. However, degradation of SDS was hardly detected. Electroosmotic flow (EOF) of Brij30 solution was lower than others when the 0.1M NaCl was used as electrolyte. Addition of the acetate buffer solution increased the EOF of Brij30 solution and enhanced removal of phenanthrene. Among three different surfactants tested, APG showed the highest removal efficiency.

Topics: Electroosmosis; Glucans; Kaolin; Phenanthrenes; Polidocanol; Polyethylene Glycols; Sodium Dodecyl Sulfate; Soil; Solubility; Surface-Active Agents

The effects of mixed anionic-nonionic surfactants, sodium dodecyl sulfate (SDS) mixed with Tween80 (TW80), Triton X-100 (TX100) and Brij35 respectively on the solubility enhancement and biodegradation of phenanthrene in the aqueous phase were investigated. The efficiency of solubilization and biodegradation of phenanthrene in single-, and mixed-surfactant solutions were also compared. The critical micellar concentrations (CMCs) of mixed surfactants were sharply lower than that of sole SDS. The degree of solubility enhancements by the mixed surfactants followed the order of SDS-TW80>SDS-Brij35>SDS-TX100. Synergistic solubilization was observed in the mixed surfactant solutions, in which the molar ratios of SDS to nonionic surfactant were 1:0, 9:1, 7:3, 5:5, 3:7, 1:9 and 0:1 while the total concentration of surfactants was kept at 5.0 and 10.0 mM, respectively. SDS-Brij35 exhibited more significant degree of synergistic solubility enhancement for phenanthrene. The mixed surfactants exhibited no inhibitory effect on biodegradation of phenanthrene. Substantial amounts of the solubilized phenanthrene by mixed surfactants were completely degraded by phenanthrene-degrading microorganisms within 96 h. The results suggested that anionic-nonionic surfactants would improve the performance of remediation of PAH-contaminated soils.

Topics: Biodegradation, Environmental; Chromatography, High Pressure Liquid; Environmental Pollution; Micelles; Octoxynol; Phenanthrenes; Polidocanol; Polyethylene Glycols; Polysorbates; Sodium Dodecyl Sulfate; Soil Pollutants; Solubility; Surface-Active Agents

The sorption of an anionic surfactant (sodium dodecyl sulfate; SDS) and a cationic surfactant (hexadecyl trimethylammonium bromide; HDTMA) to estuarine sediment has been studied in river water and seawater. Sorption isotherms for SDS were essentially linear in both waters, suggesting a nonspecific, hydrophobic interaction between the SDS tail and particle surface. Sorption of HDTMA was considerably greater, more nonlinear, and more sensitive to water composition. These observations were attributed to a combination of both electrostatic and hydrophobic interactions between the surfactant and particle surface, the formation of admicelles, and salinity-induced structural alteration of the hydrophobic tail of the HDTMA molecule. Presence of SDS caused a reduction in the sorption of phenanthrene to estuarine sediment because of the competitive effects of the surfactant tail for hydrophobic sorption sites on the particle surface. Conversely, the presence of HDTMA caused significant enhancement in phenanthrene sequestration because of head-on sorption of surfactant molecules and a resulting, more hydrophobic particle surface. The most persistent feature of our results was an inverse dependence of unit sorption on particle concentration, and an empirical algorithm defining the effect was used to calculate the sediment-water fractionation of realistic concentrations of reactants in the estuarine water column. The results of these calculations, and the more general findings of this study, significantly improve our understanding of both the transport and fate of ionic surfactants in the estuarine environment, and the effects that these surfactants have on the partitioning of hydrophobic organic micropollutants.

Topics: Adsorption; Cetrimonium; Cetrimonium Compounds; Ecosystem; Geologic Sediments; Particle Size; Phenanthrenes; Sodium Dodecyl Sulfate; Surface-Active Agents; Water

Surfactants are known to increase the apparent aqueous solubility of polycyclic aromatic hydrocarbons and may thereby enhance their bioavailability. In this study the effects of four surfactants on the mineralization of phenanthrene by Pseudomonas aeruginosa in liquid culture and in soil-water suspensions was studied in batch reactors over a 15-week study period. In the absence of surfactant, liquid cultures mineralized approximately 50% of the phenanthrene added within seven weeks following a one-week lag period and an initial mineralization rate of 0.04 mg/d. Mineralization in soil-water suspensions proceeded without any measurable lag period. The initial mineralization rate was lower (0.006 mg/d), but mineralization continued to >70% over the fifteen week period. In general, the addition of very low concentrations of surfactant (<0.001%) to liquid cultures did not impact mineralization significantly. At higher surfactant concentrations (>CMC) all surfactants were seen to be inhibitory. In soil-water systems, the rate of phenanthrene mineralization was decreased even at surfactant doses that did not produce significant solubilization. In summary, none of the surfactants enhanced the mineralization of phenanthrene by P. aeruginosa in liquid culture or in soil-water suspensions. In order to rank surfactant toxicity, microbial toxicity tests were performed measuring the light output of bioluminescent bacteria as affected by the presence of surfactants. Additional toxicity testing indicated that the presence of solubilized phenanthrene increased the toxicity of the surfactant by a 100-fold suggesting that the toxicity of solubilized substrate needs also to be considered in the application of surfactant-amended remediation.

Topics: Biodegradation, Environmental; Citrus; Emulsions; Minerals; Organic Chemicals; Phenanthrenes; Pseudomonas aeruginosa; Sodium Dodecyl Sulfate; Soil; Soil Microbiology; Surface-Active Agents