Anionic Surfactant Linear Alkylbenzene Research Articles

A novel in situ method for linear alkylbenzene sulfonate quantification in environmental samples using a digital image-based method.

Surfactants from detergents, when inadequately treated in sewage treatment plants, are carried away into estuaries, resulting in the contamination of aquatic environments. It is thus necessary to develop rapid and efficient techniques that are capable of effectively monitoring these pollutants. In this context, for the first time in the literature, this study reports the development and application of a digital image-based (DIB) method for the in situ quantification of the anionic surfactant linear alkylbenzene sulfonate (LAS) in water bodies using a smartphone. The DIB method is a highly effective modern detection method based on methylene blue, which is employed as a modified alternative technique to the spectrophotometric method and commonly used in environmental studies; in the DIB method, the images of interest are obtained using a smartphone and the analyses are carried out using free software Color grab. The results obtained from the application of the DIB method showed that the method possesses high precision and accuracy, with a linear calibration curve in the range of 0.15 to 4.5 mg L-1, R2 = 0.993, a limit of detection of 6.0 μg L-1, and recovery rates ranging from 82.7% to 114%. The efficacy of the proposed method was evaluated by comparing its results with those of spectrophotometry (used as a reference method) through the analysis of environmental samples obtained from the Capibaribe River Estuary using methylene blue. No statistically significant differences were observed between the results obtained from the DIB and the spectrophotometric method. The innovative method proposed in this study is fast, economical and environmentally friendly; the technique involves the use of only a few microliters of samples and generates little waste compared to spectrophotometry. In addition, the proposed method is applicable for in situ analyses, allowing real-time monitoring of LAS in different types of aquatic environments.

New Biobased Sulfonated Anionic Surfactants Based on the Esterification of Furoic Acid and Fatty Alcohols: A Green Solution for the Replacement of Oil Derivative Surfactants with Superior Proprieties.

The surfactant market represents a key sector of the chemical industry and encompasses many diverse applications. Their sustainability in terms of feedstock used, synthetic procedure, biodegradability, and formulation are crucial parameters to assessing the environmental impact of the surfactant. The anionic surfactant linear alkyl benzene sulfonates have proven successful to date because of their high performance, low cost, and extensive studies within formulations to optimize performance, allowing usage in a large variety of applications, especially in cleaning. Due to their advantageous properties and extensive research and development, their substitution with a biobased surfactant such as sodium dodecyl sulfate has struggled to succeed. Furan surfactants have been reported as valuable candidates for the implementation of green alternatives to traditional anionic sulfonated surfactants with a perfect trade-off between performances and green credentials. However, their implementation suffers of scalability and high cost in producing the final product due to feedstock availability and low yields of the final product. Herein, we report a new class of furan surfactants, sulfonated alkyl furoates, which are derived from the esterification of furoic acid and fatty alcohols, followed by a sulfonation step. Compared to traditional surfactants, they showed more favorable behavior in basic proprieties (such as critical micelle concentration, ecotoxicity, hard water resistance, surface tension water/oil), which gives a good prospective for the introduction of a new biobased chemical with superior performances.

In Silico Analysis to Define Microbial Common Core Associated with Degradation of Anionic Surfactant Linear Alkylbenzene Sulfonate (Las)

In Silico Analysis to Define Microbial Common Core Associated with Degradation of Anionic Surfactant Linear Alkylbenzene Sulfonate (Las)

Adsorption mechanism on surfactant removal using eggshell waste and rice straw as economically biosorbent

Adsorption is an effective process to remove organic compounds, including surfactants. In this research, rice straw (JP) and eggshell waste (CT) would be tested as economically adsorbents of surfactant. This research aims to determine the effect of pH, adsorbent dose, initial concentration, and particle size on adsorption effectivity, find out kinetics, removal efficiency and desorption ability of adsorbents. Anionic surfactant Linear Alkylbenzene Sulfonate (LAS) was determined by using MBAS method. A preliminary test was conducted to examine which adsorbent is the potential to be used in the main experiment. Adsorbent selected from the preliminary test was CT2 and JP1. Surfactant removal at an acidic solution was better than in an alkaline solution. The particle size of adsorbent was not influencing much at removal of surfactant. As increasing dosage, removal efficiency increases. Removal efficiency decreases as initial concentration is increased. Isotherm D-R fitted well for both adsorption and desorption using JP; therefore Langmuir isotherm fitted well for CT. Removal efficiency of LAS adsorption was better using JP than CT adsorbent. Desorption release at CT was 9.68-20.94%, while for JP was 8.51-12.20%. Pseudo-second order and second-order models fitted data well for adsorption kinetics. Physisorption was dominant in the adsorption process.

The identification and performance assessment of dominant bacterial species during linear alkylbenzene sulfonate (LAS)-biodegradation in a bioelectrochemical system.

The anionic surfactant linear alkylbenzene sulfonate (LAS) is a major chemical constituent of detergent formulation. Regarding the recalcitrant nature of sulfonoaromatic compounds, discharging these substances into wastewater collection systems is a real environmental issue. A study on LAS biodegradation based on bioelectrochemical treatment and in the form of developing a single-chamber microbial fuel cell with air cathode is reported in the present work. Pretreatment study showed LAS concentration of 60ppm resulted in the highest anaerobic LAS removal of 57%; so, this concentration was chosen to run the MFC. After the sustained anodic biofilm was formed, LAS degradation rate during 4days in MFC was roughly 76% higher than that in the serum bottle, which indicated the role of the bioelectrochemical process in improving anaerobic LAS removal. Additionally, through 16S rRNA gene sequencing, the dominant bacterial species in the biofilm was identified as Pseudomonas zhaodongensis NEAU-ST5-21(T) with about 98.9% phylogenetic similarity and then a pathway was proposed for LAS anaerobic biodegradation. The MFC characteristics were assessed by pH monitoring as well as scanning electron microscopy and current density evolution.

Evaluation of the Photosonolysis Process Efficacy for the Removal of Anionic Surfactant Linear Alkyl Benzene Sulfonate from Aqueous Solutions

In this study, the experiments on the sulfonate linear alkylbenzene (LAS) solution were performed using the methylene blue active substances (MBAS) method. The effectiveness of the sonochemical and photochemical reactors for LAS degradation was evaluated with an emphasis on the effect of the contact time, pH values, type of process and initial concentrations. The experiments were carried out at the initial concentrations of 0.5 mg/L, 14.00 mg/L and 21.00 mg/L, the contact time of 8, 16, and 24 minutes, pH of 3, 7, and 11, the ultrasonic frequency of 42 kHz, the acoustic power value of 160 W, an ultraviolet lamp with 150W power and the wavelength of 254 nm. This study showed that the LAS degradation was increased along with the contact time. In addition, at alkaline pH, the removal efficiency increased as well. Overall, the results obtained from this research demonstrated that by themselves, both the sonochemical and photochemical reactors may not be useful for completely reducing the complex wastewaters with high surfactant loads, but the succession of the UV/US process has a significant effect on the removal of anionic detergents. These findings demonstrated the removal efficiency under alkaline conditions and the contact time of 24 minutes was equal to 96.97 percent.

Reusability Enhancement of Taste Sensor Using Lipid Polymer Membranes by Surfactant Cleaning Treatment

The aim of our study was to enhance the reusability of a taste sensor by increasing the efficiency of the cleaning process. In this paper, we proposed a surfactant cleaning method for two types of bitterness sensor using lipid polymer membranes with high hydrophobicity. To select suitable surfactants for cleaning, the usability of four types of surfactant with different polarities and ionicities was evaluated. Among these surfactants, the anionic surfactant linear alkylbenzene sulfonate (LAS) showed no impact on the initial membrane potential and completely removed residue substances of high-concentration quinine hydrochloride adsorbed on the bitterness sensor used for hydrochloride salts. On the other hand, the amphoteric surfactant lauryl dimethylaminoacetic acid (LDA) showed no impact on the initial membrane potential and almost completely removed residue substances of high-concentration iso- $\alpha $ acid adsorbed on the bitterness sensor used for acidic bitter materials. Moreover, we found that the combined use of the conventional cleaning solution and LDA acid solution in turn greatly improved the reusability of an astringency sensor in multiple measurements of black tea.

Screening and mutagenesis of high-efficient degrading bacteria of linear alkylbenzene sulfonates.

As a widely used detergent, anionic surfactant linear alkylbenzene sulfonates (LAS) is a common toxic pollutant in wastewater. In this study, Pseudomonas sp. strain H6 was isolated from activated sludge and municipal wastewater, which had good degradation effect on LAS. The results showed that strain H6 could grow with LAS as the sole carbon source. When the concentration of LAS was less than 100mg/L, strain H6 could degrade more than 80% of the LAS within 24h. Meanwhile, the growth of strain H6 increased with the increase of LAS concentration, reaching the maximum growth at the presence of 100mg/L LAS. When the concentration of LAS was over 100mg/L, strain H6's cell growth and degradation of LAS showed a downward trend due to the strong toxicity of LAS, and the degradation rate of LAS almost tended to zero with 500mg/L LAS. Further mutagenesis analysis of strain H6 showed that positive mutation occurred under ultraviolet and nitrite mutagenesis with using ampicillin to increase the screening pressure, and the degradation rate of LAS was 44.91% higher than that of original strain.

Biokinetics of the anionic surfactant linear alkylbenzene sulfonate (LAS) in the marine fish Sparus aurata: Investigation via seawater and food exposure pathways

Uptake and depuration kinetics of [14C]C12-6-linear alkylbenzene sulfonate (LAS) in the fish Sparus aurata were determined during experimental exposure via seawater or food separately under laboratory conditions. The fish concentrated LAS from seawater (using realistic contaminant concentrations) with a mean BCF value of 20 ± 2 L kg−1 reached within 3 days and following a one-compartment exponential model. High differences in BCF were noted among organs, with values ranking in the order gall bladder (1400 ± 600 L kg−1) >> digestive tract (52 ± 9 L kg−1) > liver (38 ± 4 L kg−1) > gills (16 ± 3 L kg−1) > skin (13 ± 2 L kg−1) > head (9 ± 1 L kg−1) > muscles (4 ± 1 L kg−1). After three days of exposure, 14C activity decreased in gall bladder while it remained constant in other organs. Biotransformation and elimination processes could explain this phenomenon observed in gall bladder. LAS depuration was rapid in all organs (with up to 90% elimination within 2 days) and depuration kinetics was best fitted by a two-compartment exponential-model. When fish were fed with radiolabeled food, ingested LAS was transferred to organs within the first hours following the feeding. Model best describing depuration kinetics of LAS in the whole fish indicated that the contaminant can be considered as not assimilated.

Laundry wastewater and domestic sewage pilot-scale anaerobic treatment: Microbial community resilience regarding sulfide production

In this study, the removal of anionic surfactant Linear Alkylbenzene Sulfonate (LAS) from laundry wastewater was evaluated in co-digestion with domestic sewage, using a pilot-scale Expanded Granular Sludge Bed reactor. Surfactant influent concentration was enhanced from 5 ± 3 mg LAS L−1 (stage I) to 19 ± 10 mg LAS L−1 (stage II) and 36 ± 19 mg LAS L−1 (stage III) throughout reactor operation. Sulfide levels higher than 20 mg L−1 influenced LAS removal efficiency, which decreased from 71% to 55% and 32% in stage I, II and III, respectively. Acclimation of microbial population was verified and higher relative abundance of the genera similar to Cytophaga, Bacteroides, Syntrophus and Syntrophobacter in the early stages (adaptation and stage I) was replaced by higher relative abundance of the genera Anaerophaga, Nitrosovibrio, Sulfurovum and Desulfovibrio in the last stages (stage II and III).

Modeling on Many Scales - Multiscale Modeling of Exposure to Chemicals in Products

Informing decision about chemical alternatives and related exposure to chemicals in consumer products necessitate to cover both far and near-field exposure over a range of scales and receptor populations. Building on USEtox, we present a suite of models covering a) near-field direct exposure of consumers to chemicals in products and in indoor air, and b) the far-field environmental and human exposure associated with localized chemical releases. In addition to the continent specific calculations of USEtox, a spatialized adaptation of USEtox is implemented on the multi-scale multimedia Pangea modeling platform, with 120000+ cells from 10km to global scale and using the high resolution global hydrological dataset HydroBASINS. We first apply the model to four chemicals used across Asia, selected to cover a variety of applications, volumes of production and emission, and physico-chemical and environmental fate properties: the anionic surfactant linear alkylbenzene sulphonate (LAS), the antimicrobial triclosan (TCS), the personal care preservative methyl paraben (MeP), and the emollient decamethylcyclopentasiloxane (D5). LAS emission levels and Predicted Environmental Concentrations are two to three orders of magnitude greater than for other substances. We observe a good agreement for TCS in freshwater (r=0.82, for 253 monitored values covering 12 streams), the substance with most data, whereas the model underestimate MeP sediments concentrations. Intake fraction and spatialized intakes are also determined both for the near field and spatially for environmentally mediated exposure in Australia. The direct indoor exposures are dominant, whereas we observe high spatial variation in intake fractions from 0.68 to 33 ppm for benzene emitted in ambient air, which travels over longer distances, and from 0.006 to 9.5 ppm for formaldehyde that has a more local impact. We finally discuss strengths and weaknesses of each of these complementary tools.

Cardiac biomarkers as sensitive tools to evaluate the impact of xenobiotics on amphibians: the effects of anionic surfactant linear alkylbenzene sulfonate (LAS)

Amphibian populations have been experiencing a drastic decline worldwide. Aquatic contaminants are among the main factors responsible for this decline, especially in the aquatic environment. The linear alkylbenzene sulfonate (LAS) is of particular concern, since it represents 84% of the anionic surfactants' trade. In Brazil, the maximal LAS concentration allowed in fresh waters is 0.5mgL−1, but its potential harmful effects in amphibians remain unknown. Therefore, this study aimed to analyze the effects of a sublethal concentration of LAS (0.5mgL−1) for 96h on sensitive cardiac biomarkers of bullfrog tadpoles, Lithobates catesbeianus (Shaw, 1802). For this, we measured the activity level (AL - % of animals), in situ heart rate (fH - bpm), relative ventricular mass (RVM - % of body mass), in vitro myocardial contractility and cardiac histology of the ventricles. Tadpoles' AL and fH decreased in LAS group. In contrast, the RVM increased, as a result of a hypertrophy of the myocardium, which was corroborated by the enlargement of the nuclear measures and the increase of myocytes’ diameters. These cellular effects resulted in an elevation of the in vitro contractile force of ventricle strips. Acceleration in the contraction (TPT - ms) also occurred, although no alterations in the time to relaxation (THR -ms) were observed. Therefore, it can be concluded that even when exposed to an environmentally safe concentration, this surfactant promotes several alterations in the cardiac function of bullfrog tadpoles that can impair their development, making them more susceptible to predators and less competitive in terms of reproduction success. Thus, LAS concentrations that are considered safe by Brazilian by regulatory agencies must be revised in order to minimize a drastic impact over amphibian populations. This study demonstrates the relevance of employing cardiac biomarkers at different levels (e.g., morphological, physiological and cellular) to evaluate effects of xenobiotics in tadpoles.

A global framework to model spatial ecosystems exposure to home and personal care chemicals in Asia

This paper analyzes spatially ecosystem exposure to home and personal care (HPC) chemicals, accounting for market data and environmental processes in hydrological water networks, including multi-media fate and transport. We present a global modeling framework built on ScenAT (spatial scenarios of emission), SimpleTreat (sludge treatment plants), and Pangea (spatial multi-scale multimedia fate and transport of chemicals), that we apply across Asia to four chemicals selected to cover a variety of applications, volumes of production and emission, and physico-chemical and environmental fate properties: the anionic surfactant linear alkylbenzene sulphonate (LAS), the antimicrobial triclosan (TCS), the personal care preservative methyl paraben (MeP), and the emollient decamethylcyclopentasiloxane (D5). We present maps of predicted environmental concentrations (PECs) and compare them with monitored values. LAS emission levels and PECs are two to three orders of magnitude greater than for other substances, yet the literature about monitored levels of LAS in Asia is very limited. We observe a good agreement for TCS in freshwater (Pearson r=0.82, for 253 monitored values covering 12 streams), a moderate agreement in general, and a significant model underestimation for MeP in sediments. While most differences could be explained by uncertainty in both chemical/hydrological parameters (DT50water, DT50sediments, Koc, foc, TSS) and monitoring sites (e.g. spatial/temporal design), the underestimation of MeP concentrations in sediments may involve potential natural sources. We illustrate the relevance of local evaluations for short-lived substances in fresh water (LAS, MeP), and their inadequacy for substances with longer half-lives (TCS, D5). This framework constitutes a milestone towards higher tier exposure modeling approaches for identifying areas of higher chemical concentration, and linking large-scale fate modeling with (sub) catchment-scale ecological scenarios; a major limitation in model accuracy comes from the discrepancy between streams routed on a gridded, 0.5°×0.5° global hydrological network and actual locations of streams and monitoring sites.

Application of a spatially resolved model to contextualise monitoring data for risk assessment of down-the-drain chemicals over large scales

Many regulatory screening level exposure assessments are based on simple large scale conceptual scenarios. However, exposure, and therefore risks associated with chemicals, are characterised by high spatial variability. The Scenario assembly tool (ScenAT) is a global screening level model to enable spatially resolved local predictions of environmental concentrations of home and personal care chemicals. It uses the European Union Technical Guidance Document (TGD) equation to predict local scale freshwater concentrations (predicted environmental concentrations - PECs) of chemicals discharged via wastewater. ScenAT uses Geographic Information System (GIS) layers for the underlying socio-economic (population) and environmental parameters (per capita water use, sewage treatment plant connectivity, dilution factor). Using a probabilistic approach, we incorporate sources of uncertainty in the input data (tonnage estimation, removal in sewage treatment plants and seasonal variability in dilution factors) for two case-study chemicals: the antimicrobial triclosan (TCS) and the anionic surfactant linear alkylbenzene sulphonate (LAS). We then compare model estimates of wastewater and freshwater concentrations of TCS and LAS to UK monitoring data. Comparison showed that modeled PECs were on average higher than mean measured data for TCS and LAS by a factor 1.8 and 1.4, respectively. Considering the uncertainty associated with both model and monitoring data, the use of a probabilistic approach using the ScenAT model for screening assessment is reasonable. The combination of modelled and monitoring data enables the contextualisation of monitoring data. Spatial PECs can be used to identify areas of elevated concentration for further refined assessment.

Study of the impact of combination of ZnO nanoparticles with ultraviolet radiation (photocatalytic process) on the removal of anionic surfactant linear alkyl benzene sulfonate (LAS) from aqueous solutions using Taguchi statistical method

Surfactants or surface-active agents are molecules with hydrophilic head and hydrophobic tail. They have been widely used as active ingredient in soap and detergent formulations. Detergents are synthetic, organic materials with cleansing and dissolution properties. Among the anionic surfactants, linear alkyl benzene sulfonate (LAS) has the highest consumption and is used in high concentrations in household detergents as washing powders, dishwashing liquids, and other household cleaners. LAS can have an impact of inhibiting the biological activity in the soil, which plays an important role in soil fertility and nutrient cycles. Removing pollutants in advanced oxidation processes is mainly based on producing the hydroxyl free radicals with potential high oxidation as well as the fact that many organic compounds can be converted into minerals. In the past two decades, photocatalyzing by semiconducting materials such as zinc oxide (ZnO) has received much attention due to its high sensitivity, high stability, non-toxic nature, wide energy gap, and higher efficiency in the production of electrons. The properties of the energy gap may cause the absorption of UV portion of the spectrum by these nanoparticles. In this study, initial concentrations of LAS including 0.5, 14, and 21 mg/L, ZnO concentration of 50, 100, and 150 mg/L, pH 3, 7, and 11, duration of 8, 16, and 24 min were used. Also, the Taguchi statistical method was used. The result showed that, in the LAS concentration of 21 mg/L, duration of 24 min, pH 3, and ZnO concentration of 150 mg/L, the highest percentage of removal could be seen.

An ecosystem model of the lower Po river for use in ecological risk assessment of xenobiotics

Ecological modelling has the potential to increase the realism of chemical risk assessment for better informed risk management and decision making meeting the protection goals and requirements of the EU's chemicals- and water-related regulations. We developed a food web model of the final lowland section of the longest Italian river (Po) to assess the importance of ecological interactions in setting protective thresholds for river ecosystems exposed to chemicals discharged via wastewater. An integrated 14 compartment model was setup using AQUATOX 3.1, providing a dynamic, quantitative representation of the main functional groups in the food web. To our knowledge, this is the first time that the functioning of the Po ecosystem is quantitatively described. The model was calibrated against observations of biomass density of riverine biota, as typically available for a large lowland river in Europe. The role of ecological interactions on the response of the modelled organisms to chemical exposure was tested on realistic and hypothetical exposure scenarios for two compounds contained in home and personal care products: the anionic surfactant linear alkylbenzene sulphonate and the antimicrobial triclosan. At realistic exposure concentrations the model showed no significant effect compared to control simulations. At hypothetical higher exposure, effects resulting from complex ecosystem-scale interactions emerge. Depending on the organism's position in the food web, indirect effects due to ecological interactions can either amplify or mitigate the effect of direct toxicity. Model results indicate that organisms’ responses to chemicals in real ecosystems is poorly correlated to their direct toxicity (i.e. measured by L/ECX values) for a range of simulated exposure, including concentrations equal to the reported PNEC values. AQUATOX is a useful tool to investigate the relative importance of direct toxicity and ecological interactions, but at this stage it is difficult to use it for prospective chemical risk assessment, given the underlying model uncertainties and the practical limitations of field scale evaluations. An improvement of the quantitative monitoring of feeding preferences and abundance over time of the most representative species within each functional group would be of great help to refine the model parameterisation and calibration. Nonetheless, the development of river ecosystem model scenarios is a stepping stone towards the incorporation of ecological modelling in risk assessment. When extensively tested on different scenarios AQUATOX provides a useful platform, which can be linked to mechanistic effect models as long as this component can be evaluated in controlled settings (i.e. laboratory or mesocosm scale).

Study on the interaction of alkaline protease with main surfactants in detergent

The effects of surfactants on protease with and without stabilizer boric acid were investigated in this paper. From the structural features of surfactants, we discussed the possible mechanism between surfactants and protease. Surfactants studied were anionic surfactants having varying hydrophilic group and nonionic surfactants having varying hydrophobic types and chain length. The results showed that anionic surfactant linear alkyl benzene sulfonate (LAS) has the biggest influence on protease, due to benzene ring in its structure; nonionic surfactant fatty alcohol polyoxyethylene (AEO) with more ethylene oxide shows bigger impact on protease; carbon chain length in alkyl polyglucosides (APGs) has less influence on protease. Understanding the reaction mechanism of surfactants and protease is essential for many industry uses. Especially the results provide references for the application of protease in laundry formulation.

Food web modeling of a river ecosystem for risk assessment of down-the-drain chemicals: A case study with AQUATOX

Conventional approaches to estimating protective ecotoxicological thresholds of chemicals, i.e. predicted no-effect concentrations (PNEC), for an entire ecosystem are based on the use of assessment factors to extrapolate from single-species toxicity data derived in the laboratory to community-level effects on ecosystems. Aquatic food web models may be a useful tool to improve the ecological realism of chemical risk assessment because they enable a more insightful evaluation of the fate and effects of chemicals in dynamic trophic networks. A case study was developed in AQUATOX to simulate the effects of the anionic surfactant linear alkylbenzene sulfonate and the antimicrobial triclosan on a lowland riverine ecosystem. The model was built for a section of the River Thames (UK), for which detailed ecological surveys were available, allowing for a quantification of energy flows through the whole ecosystem. A control scenario was successfully calibrated for a simulation period of one year, and tested for stability over six years. Then, the model ecosystem was perturbed with varying inputs of the two chemicals. Simulations showed that both chemicals rapidly approach steady-state, with internal concentrations in line with the input bioconcentration factors throughout the year. At realistic environmental concentrations, both chemicals have insignificant effects on biomass trends. At hypothetical higher concentrations, direct and indirect effects of chemicals on the ecosystem dynamics emerged from the simulations. Indirect effects due to competition for food sources and predation can lead to responses in biomass density of the same magnitude as those caused by direct toxicity. Indirect effects can both exacerbate or compensate for direct toxicity. Uncertainties in key model assumptions are high as the validation of perturbed simulations remains extremely challenging. Nevertheless, the study is a step towards the development of realistic ecological scenarios and their potential use in prospective risk assessment of down-the-drain chemicals.

Methanogenic potential of an anaerobic sludge in the presence of anionic and nonionic surfactants

The methanogenic potential of an anaerobic sludge in the presence of nonionic surfactant Alcohol Ethoxylate (AE) (GENAPOL® C-100) and anionic surfactant Linear Alkylbenzene Sulfonate (LAS) from laundry wastewater was evaluated in anaerobic batch reactors. For this purpose yeast extract, sucrose, sodium bicarbonate, salt solution plus AE (7.2 ± 0.9 mg L−1 – 123.4 ± 34 mg L−1) or LAS (16.3 ± 2.5 mg L−1 – 75.4 ± 7.5 mg L−1) were used as synthetic substrate. The reactors were kept under agitation of 130 rpm at 30 ± 1 °C for 28 days. The highest concentrations of AE and LAS provided higher methane yields. The highest surfactant degradation observed was for the AE (99%), compared to LAS (71.10% ± 11.3). The presence of other compounds in the laundry wastewater may have impaired this degradation, but favored higher COD removal efficiencies (86.2% ± 2.8). High concentrations of AE influenced COD removal efficiency resulting in less COD removal. Although higher concentrations of surfactants have favored higher methane production, lower similarity indices were observed for both Domains (Archaea and Bacteria).

Assessment of Soil Microbial Toxicity on Acute Exposure of the Anionic Surfactant Linear Alkylbenzene Sulphonate

Assessment of Soil Microbial Toxicity on Acute Exposure of the Anionic Surfactant Linear Alkylbenzene Sulphonate