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ABS was the first surfactant used in detergent formulations, but because its molecular structure is branched, it is difficult to decompose biologically, making ABS a toxic compound for the environment. This study aims to remove MBAS surfactant, using a combination of phytoremediation and filtration methods to remove surfactant (MBAS) Chemical Oxygen Demand (COD) from detergent wastewater by optimizing operating factors such as pH, contact time, plant type, and filter media. Water lettuce (Pistia stratiotes) and water hyacinth (Eichhornia crassipes) were selected as plant species and silica-activated carbon was used as filter media. Water lettuce and hyacinth were grown in a 10-liter reactor with detergent wastewater samples for 6 and 12 days. Filter media are placed in the reactor in use, and aeration is done. The efficiency for reducing COD was 81.73%, and the efficiency for surfactant was 99.42% for each experiment, which was thought to be because of plant adsorption and filtering processes. The water lettuce (Pistia stratiotes) plant had the maximum adsorption capability for all the qualities evaluated, with a surfactant content in the roots of 27543.24 (mg/kg MBAS), compared to the water hyacinth plant, which only absorbed 2597.95 (mg/kg MBAS).

Water and several chemicals, including dyestuffs, surfactants, acids, and salts, are required during textile dyeing processes. Surfactants are harmful to the aquatic environment and induce several negative biological effects in exposed biota. In this context, the present study aimed to assess acute effects of five surfactants, comprising anionic and nonionic classes, and other auxiliary products used in fiber dyeing processes to aquatic organisms Vibrio fischeri (bacteria) and Daphnia similis (cladocerans). The toxicities of binary surfactant mixtures containing the anionic surfactant dodecylbenzene sulfonate + nonionic fatty alcohol ethoxylate and dodecylbenzene sulfonate + nonionic alkylene oxide were also evaluated. Nonionic surfactants were more toxic than anionic compounds for both organisms. Acute nonionic toxicity ranged from 1.3 mg/L (fatty alcohol ethoxylate surfactant) to 2.6 mg/L (ethoxylate surfactant) for V. fischeri and from 1.9 mg/L (alkylene oxide surfactant) to 12.5 mg/L (alkyl aryl ethoxylated and aromatic sulfonate surfactant) for D. similis , while the anionic dodecylbenzene sulfonate EC50s were determined as 66.2 mg/L and 19.7 mg/L, respectively. Both mixtures were very toxic for the exposed organisms: the EC50 average in the anionic + fatty alcohol ethoxylate mixture was of 1.0 mg/L ± 0.11 for V. fischeri and 4.09 mg/L ± 0.69 for D. similis . While the anionic + alkylene oxide mixture, EC50 of 3.34 mg/L for D. similis and 3.60 mg/L for V. fischeri . These toxicity data suggested that the concentration addition was the best model to explain the action that is more likely to occur for mixture for the dodecylbenzene sulfonate and alkylene oxide mixtures in both organisms. Our findings also suggest that textile wastewater surfactants may interact and produce different responses in aquatic organisms, such as synergism and antagonism. Ecotoxicological assays provide relevant information concerning hazardous pollutants, which may then be adequately treated and suitably managed to reduce toxic loads, associated to suitable management plans.

The median effective concentration (EC 50 ) is the concentration of a substance expected to produce a specific effect in 50% of the populations with a certain density under defined conditions. This parameter is expressed as an acute toxicity and is obtained via chemical toxicity testing. But, the laboratory work is time-consuming, expensive, and not eco-friendly. Therefore, to predict EC 50 for new anionic surfactants, a quantitative structure-activity relationship (QSAR) tool was studied for modeling the EC 50 of anionic surfactants on Daphnia magna based on the molecular descriptors. The best model ( R 2 = 0.901 and F = 118.077, p <0.01) included 3 variables of the number of carbons, hydrogens, and the octanol-water partition coefficient logarithm. The main contribution to the toxicity was the octanol-water partition coefficient logarithm descriptor that had a negative effect on the toxicity of surfactants. The QSAR approach exhibited good results in predicting anionic surfactants EC 50 , which allows the building of a simple, valid, and interpretable model that can be utilized as potential tools for rapidly predicting the lnEC50 of new or untested anionic surfactants to Daphnia magna .

The environmental impacts caused by dyes in industrial wastewater are incalculable, due to their adverse effects on the ecosystem and human life, especially when discarded at illegal levels. The ionic micellar flocculation process to remove metals and organic compounds has proven to be an innovative and efficient alternative in the removal of pollutants from aqueous solutions. In this respect, an anionic surfactant, composed of a mixture of surfactants derived from coconut oil and animal fat, was used to remove the ionic dyes methylene blue (MB) and Acid Red 57 (AR57) from an aqueous medium. During extraction trials, the use of a soap base anionic surfactant at concentrations below the critical micelle concentration (CMC) promotes the formation of an insoluble surfactant (cationic dye-anionic monomer), acting as an ionic flocculant by monomers. On the other hand, at concentrations above the CMC, adding calcium ions to an aqueous solution allowed the formation of micellar flocs capable of removing dye, reaching maximum extraction percentages of 60% of MB and 90% of AR57. The influence of initial dye concentration, surfactant concentration, pH and the presence of electrolytes demonstrated that the interaction mechanisms between the dyes and micelles are based on electrostatic interactions and/or micellar solubilization, confirmed by determining the diameter of micellar aggregates. Solvent-assisted ionic micellar flocculation was applied to increase MB removal efficiency from 26 to 91%.

Nonionic surfactants could effectively improve the enzymatic hydrolysis efficiency of lignocellulose, while small molecule anionic and cationic surfactants usually inhibited the enzymatic hydrolysis. The results showed that the anionic surfactant sodium dodecyl sulfate (SDS) could improve the enzymatic hydrolysis efficiency of Avicel at the concentration range of 0.1–1 mM, but it did inhibit enzymatic hydrolysis at higher concentration. Cationic surfactant cetyltrimethylammonium bromide (CTAB) was used to regulate the surface charge of SDS; thereby catanionic surfactant SDS-CTAB was formed. The effect of SDS-CTAB catanionic surfactant with varied molar ratios on the enzymatic hydrolysis of pure cellulose and corn stover at various enzymatic hydrolysis environments was investigated. SDS-CTAB could increase the enzymatic hydrolysis of corn stover at high solid loading from 33.3 to 42.4%. Using SDS-CTAB could reduce about 58% of the cellulase dosage to achieve 80% of the enzymatic hydrolysis of corn stover. SDS-CTAB catanionic surfactant could regulate the surface charge of cellulase in the hydrolyzate and reduce the non-productive adsorption of cellulase on the lignin, thereby improving the enzymatic hydrolysis efficiency of lignocellulose.

The extensive application of chemically synthesized anionic surfactants would cause serious pollution of water and increase health risk to humans. However, the adverse impact of anionic surfactant on human cells has never been systematically demonstrated. In this paper, a series of fluorescent anionic surfactants containing a varying length of alkyl chain from C8 to C18 and a fixed hydrophilic head of 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) were synthesized and utilized for visualizing the interaction between surfactants and cells. The obtained molecules exhibited blue fluorescence presenting a decreasing fluorescent intensity with the increasing length of alkyl chain from C8 to C18 while showed the same sequence of HPTS-C16>HPTS-C18>HPTS-C12>HPTS-C8 on either surface activity, cellular adsorption, or cytotoxicity. In opposite, HPTS which contained no hydrophobic chain and thus exhibited no surface activity showed no cellular adsorption and cytotoxicity. It seems that the ligand of the appropriate chain length (C16) onto the hydrophilic HPTS molecules could cause the largest surface activity, the most distinguished cellular adsorption as well as the most adverse cytotoxicity. As reflected by the dynamic fluorescent visualization, the surfactant molecules of HPTS-C16 initially bound with cell membrane and entered into the intracellular lumen before finally localized at the endoplasmic reticulum (ER) and damaged it into a swollen structure. It is most likely that the structure of hydrophobic chain could determine the surface activities of surfactants and hence affect their cellular uptake and cytotoxicity. This study could help us to understand the adverse impact of anionic surfactant on human cells and its correlation with the surface activities or, in another word, the hydrophobic chain length.

Hexafluoroisopropanol (HFIP)-induced coacervation in aqueous mixed systems of catanionic surfactants of dodecyltrimethylammonium bromide (DTAB) and sodium dodecyl sulfate (SDS) was described in detail, and its application in the extraction of strongly polar sulfonamides (SAs) was investigated. With 10 % ( v / v ) HFIP inclusion, coacervation formation and two-phase separation occur in a wide range of SDS/DTAB mole ratios (88:12∼0:100 mol/mol) and total surfactant concentrations (10∼200 mmol/L). The interactions between HFIP and DTAB play an important role in coacervation formation. The HFIP-induced SDS–DTAB coacervation extraction proves to be an efficient method for the extraction and preconcentration of SAs. Both hydrophobic interaction and polar interactions (hydrogen–bond, electrostatic, and π-cation) contribute to the distribution of SAs into coacervate phase. The proposed HFIP-induced SDS–DTAB coacervation extraction combined with HPLC–UV was employed for the extraction and quantitative determination of SAs in environmental water samples. Limits of detection were 1.4∼2.5 ng mL −1 . Excellent linearity with correlation coefficients from 0.9990 to 0.9995 was obtained in the concentration of 0.01∼10 μg mL −1 . Relative recoveries were in the range of 93.4∼105.9 % for analysis of the lake, underground, and tap water samples spiked with SAs at 0.01, 1.0, and 10 μg/mL, respectively. Relative standard deviations were 0.7∼3.2 % for intraday precision and 1.3∼4.6 % for interday precision ( n  = 3). Concentration factors were 17∼49 for three water samples spiked with 0.01 μg/mL SAs. The results demonstrate that the proposed extraction method is feasible for the preconcentration and determination of trace SAs in real water samples. Graphical abstract ᅟ

Mechanisms for removal of anionic surfactant sodium dodecyl benzene sulfonate (SDBS) in wastewaters by zero-valent iron (ZVI) were systematically examined. The contributions of four removal mechanisms, i.e., reductive degradation, oxidative degradation, adsorption, and precipitation, changed significantly with solution pH were quantified and the effective removal of SDBS by ZVI was found to be attributed to the adsorption capability of iron oxides/hydroxides on ZVI surface at nearly neutral pH instead of the degradation at acidic condition. The fastest SDBS removal rate and the maximum TOC (total organic carbon) removal efficiency were obtained at pH 6.0. The maximum TOC removal at pH 6.0 was 77.8%, and the contributions of degradation, precipitation, and adsorption to TOC removal were 4.6, 14.9, and 58.3%, respectively. At pH 3.0, which is an optimal pH for oxidative degradation by the Fenton reaction, the TOC removal was only 9.8% and the contributions of degradation, precipitation, and adsorption to TOC removal were 2.3, 4.6, and 2.9%, respectively. The electrostatic attraction between dodecyl benzene sulfate anion and the iron oxide/hydroxide layer controlled the TOC removal of SDBS. The kinetic model based on the Langmuir-Hinshelwood/Eley-Rideal approach could successfully describe the experimental results for SDBS removal by ZVI with the averaged correlation coefficient of 0.994. ZVI was found to be an efficient material toward the removal of anionic surfactant at nearly neutral pH under the oxic condition.

A simple analytical method for quantitative determination of an anionic surfactant in aqueous solutions without liquid-liquid extraction is described. The method is based on the formation of a green-colored ion associate between sodium dodecylbenzenesulfonate (SDBS) and cationic dye, Brilliant Green (BG) in acidic medium. Spectral changes of the dye by addition of SDBS are studied by visible spectrophotometry at maximum wave length of 627 nm. The interactions and micellar properties of SDBS and cationic dye are also investigated using surface tension method. The pH, the molar ratio ([BG]/[SDBS]), and the shaking time of the solutions are considered as the main parameters which affect the formation of the ion pair. Determination of AS in distilled water gives a significant detection limit up to 3 × 10 −6  M. The response surface methodology (RSM) is applied to study the absorbance. A Box-Behnken is a model designed to the establishment of responses given by parameters with great probability. This model is set up by using the three main parameters at three levels. Analysis of variance shows that only two parameters affect the absorbance of the ion pair. The statistical results obtained are interesting and give us real possibility to reach optimum conditions for the formation of the ion pair. As the proposed method is free from interferences from major constituents of water, it has been successfully applied to the determination of anionic surfactant contents in wastewaters samples collected from Algiers bay.

Sodium dodecyl sulphate, (SDS) is an anionic surfactant that widely used all over the world. They will eventually end-up and accumulate in household or industrial sewage. Due to their high foaming capabilities, which can cause numerous problems in sewage treatment facilities as well as direct toxic effects on many different organisms in ecosystem; they are generally considered as serious pollutants. In this survey, two different bacteria were isolated from Tehran municipal activated sludge. Biochemical tests as well as 16S rRNA gene sequencing for identification have been applied. After experiments to optimize the pH and temperature for growth of the two bacterial isolates, the extent of SDS utilization was evaluated by HPLC method. Two bacterial isolates show which ability to rapidly and actively degrade SDS upon using it as their sole source of carbon. The identification tests have indicated the two isolates to be Acinetobacter johnsoni and Pseudomonas beteli . The Pseudomonas beteli and Acinetobacter johnsoni isolates were able to degrade 97.2% and 96.4% of the original SDS levels after 10 days of growth; respectively. Mixed culture of the two isolates did not significantly increase SDS utilization, (97.6%). In conclusion, the results of this study suggest that growth of simple bacteria such as Acinetobacter or Pseudomonas in household and industrial sewage can be costeffective method anionic surfactants elimination.