Dodecylbenzenesulfonate Research Articles

Role of anionic surfactant addition in improving thermoelectric properties of PEDOT:PSS free-standing films

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has recently gained interest as a potential candidate for small-scale thermoelectric conversion because of the facile doping, solution processability, and flexibility. However, the practical applications of PEDOT:PSS are limited by its comparatively low figure of merit (ZT) compared with inorganic thermoelectric materials. Herein, to further improve the thermoelectric properties of PEDOT:PSS, we investigated the role of the addition of surfactants, sodium dodecyl sulfate, sodium dodecyl benzenesulfonate (SDBS) or Triton X-100, to the PEDOT:PSS free-standing films on their thermoelectric properties. We showed that the addition of the surfactant improved the film crystallinity, significantly improving the electrical conductivity. The highest conductivity was obtained for anionic surfactant SDBS at a 0.94 wt% concentration. Moreover, the inclusion of the surfactant reduced the thermal conductivity while maintaining a relatively constant Seebeck coefficient, consequently improving the ZT value. Furthermore, a flexible thermoelectric device crafted from the as-fabricated PEDOT:PSS/SDBS sheets was developed to explore the potential applications of wearable electronics using low-grade thermal energy. Overall, we indicate the significance of surfactants in enhancing the thermoelectric properties of free-standing PEDOT:PSS films in this study.

Study on the Tribological Properties of Acid-Doped Polypyrrole (PPY) as Conductive Grease Additive

This study investigated the acid doping of polypyrrole (PPY) using as dopants three solutions: hydrochloric acid (HCl), dodecylbenzene sulfonic acid (DBSA), and 1-butyl-3-methylimidazolium tetrafluoroborate (LB104). Four conductive lubricating greases were prepared with these dopants based on composite lithium-based grease (LCG). The research aimed to explore the physicochemical properties and tribological performance of conductive lubricating greases. Experimental results indicate that acid-doped PPY conductive lubricating greases exhibit lower resistivity and higher dropping points. Moreover, these lubricating greases can form stable boundary lubricating films, demonstrating excellent antifriction and antiwear properties. Among these, the additive with LB104-doped PPY shows superior antifriction and antiwear performance, as well as conductivity, suggesting broad prospects for application in the field of conductive lubrication.

Formation and survival of clay-mediated protocell membranes composed of single-chain amphiphiles in aqueous solutions

Protocell compartments composed of simple amphiphilic molecules could have survived on the clay mineral surfaces which can serve well as plausible sites for prebiotic chemistry on the early Earth. Herein we chose four common single-chain amphiphiles (SCAs), including the anionic surfactant sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonate (SDBS), the cationic surfactant dodecyltrimethylammonium bromide (DTAB) and the zwitterionic lauryl sulfobetaine (LSB)), as model constituents of early membranes to establish a tentative model for protocell compartment. Positively charged Mg2Al-/Mg2Fe-layered double hydroxides (LDHs) and FeS2 are viewed as models of clay minerals. We demonstrate by comprehensively experimental study that unconventional vesicles can be easily promoted in a SCA aqueous micellar solution in the presence of model particles. Morphology evolutions are traced by collecting samples from mixtures of LDHs and SCA aqueous solutions and then recording at different incubation times via negative-staining or cryo-transmission electron microscopy (NS-TEM or cryo-TEM) and dynamic light scattering (DLS). Additionally, the stability of SCA bilayer membranes under possible prebiotic environment are tentatively studied. This work not only offers a robust yet versatile approach for the fabrication of novel vesicles but also provides new insights into the origin of cellular life.

Deciphering the roles of nitrogen source in sharping synchronous metabolic pathways of linear alkylbenzene sulfonate and nitrogen in a membrane biofilm for treating greywater

Nitrogen (N) source is an important factor affecting biological wastewater treatment. Although the oxygen-based membrane biofilm showed excellent greywater treatment performance, how N source impacts the synchronous removal of organics and N is still unclear. In this work, how N species (urea, nitrate and ammonia) affect synchronous metabolic pathways of organics and N were evaluated during greywater treatment in the membrane biofilm. Urea and ammonia achieved efficient chemical oxygen demand (>97.5%) and linear alkylbenzene sulfonate (LAS, >98.5%) removal, but nitrate enabled the maximum total N removal (80.8 ± 2.6%). The nitrate-added system had poor LAS removal ratio and high residual LAS, promoting the accumulation of effluent protein-like organics and fulvic acid matter. N source significantly induced bacterial community succession, and the increasing of corresponded functional flora can promote the transformation and utilization of microbial-mediated N. The nitrate system was more conducive to the accumulation of denitrification related microorganisms and enzymes, enabling the efficient N removal. Combining with high amount of ammonia monooxygenase that contributing to LAS and N co-metabolism, LAS mineralization related microbes and functional enzymes were generously accumulated in the urea and ammonia systems, which achieved the high efficiency of organics and LAS removal.

Study on preparation and properties of antifreeze compound road dust suppressant

Open-pit mine pavement dust dries and breaks easily. As such, a composite pavement dust suppressant with good wettability, moisturizing, coagulation, and antifreezing properties in winter was investigated. Monomer screening and orthogonal experiments were conducted, using evaporation rate, permeability rate, viscosity, and freezing point as evaluation indexes. Consequently, a dust suppressant solution is a mixture of glycerol (GLY), sodium dodecylbenzene sulfonate (SDBS), polyacrylamide (PAM), compound propylene glycol (PG), and potassium acetate (PA). The characteristics of the dust suppressant and its interaction mechanism with road dust were measured and analyzed. The results showed that the optimal ratio of the antifreeze-type composite dust suppressant is 3%GLY, 0.30%SDBS, 0.07% PAM, and 50%PG + 10%PA; the contact angle is 27.62°, which can effectively wet coal dust. Moreover, it easily forms hydrogen bonds with water molecules to release free -OH, which increases the oxygen-containing functional groups in the dust. The maximum viscosity is 25.4 mPa·s, and the hydrophobic groups adsorbed on the surface of the dust can condense and agglomerate the dust to form large particles, and effectively inhibit the occurrence of dust. It freezes at − 34.2 ℃, resists a temperature of − 30 ℃ without freezing, and improves dust suppression efficiency and antifreezing effect in cold areas.

Inhibition Rates of Disinfectants on Bacterial Isolated from Student Dormitory

Background: Although most of human life is spent inside, where bacteria are always present on things, little is known about the microbial variety of indoor habitats. Objectives: The major objective of this study was to determine the rate and types of bacterial contaminants in female and male student dormitory of Al-Kufa university campus, and to explore the inhibitory effect of certain disinfectants. This study was conducted for the period from October 2022 to Jun 2023. A total of 400 bacteriological swabs were collected aseptically from different sites of male and female student dormitory of Al-Kufa university. Swabs were streaked as soon as possible on blood agar and MaConkey agar plates and incubated overnight. Identification of bacterial species was based on standard bacteriological criteria. The inhibitory effect of 40% and 60% concentrations of three commercially available disinfectants; dettol (chloroxylenol), Al-Emlaq (Alkyl benzene sulfonate), and the house bleach (sodium hypochlorite) were explored by agar diffusion method. Data were statistically analyzed. Results: The results revealed that the overall bacterial contamination rate in student’s dormitories of Al-Kufa university campus was 78%. Male dormitory unit had significantly higher contamination rate compared to female dormitory unit (57.5% vs 42.5%). Bacillus spp. Was the most predominant contaminant in both male and female units. Al-Emlaq super gel (Alkyl benzene sulfonate) was found as the most effective disinfectant against the majority of bacterial isolates. Conclusion: Authorized and public awareness toward bacterial contamination in student's dormitories is recommended. The selection of an effective disinfectant should be based on its active ingredient and concentration.

Removal of linear alkylbenzene sulfonate by electrocoagulation/flotation using a cylindrical vertical reactor

This study proposes a vertical electrocoagulation/flotation reactor model and evaluates its efficiency through hydraulic tests and the removal of linear alkylbenzene sulfonate (LAS), a common wastewater surfactant. Residence time distribution assays and computational fluid dynamics verified the fluid flow pattern. Response surface methodology (RSM) was used to assess the impact of pH, electric current, and sodium chloride concentration on LAS removal. Ecotoxicity tests using Artemia salina detected no toxic byproducts from electrocoagulation/flotation (ECF). Adsorption kinetics and isotherms were used to evaluate the removal behavior of LAS, which showed the highest efficiencies with an electric current of 1.5 A, a pH of 5.73, and a NaCl concentration of 4652.4 mg/L. The electric current and pH were the most influential variables. The ecotoxicity assay indicated no toxic byproduct generation, even at high chloride concentrations, and increased LAS biodegradability posttreatment. Adsorption kinetics followed a pseudo-first-order model at 20 mg/L and a pseudo-second-order model at 240 mg/L. The Freundlich isotherm indicated a high affinity between the LAS and aluminum hydroxide flakes, achieving nearly 90 % removal in 30 min at an energy cost of 5.25 Wh.

Depth dewatering of kaolinite cake by SDBS/PEI synergy and a mesoscopic mechanism study

The objective of this study was to elucidate the synergistic dewatering mechanism of mixed sodium dodecylbenzene sulfonate (SDBS) and polyethyleneimine (PEI) on kaolinite filter cakes and to test the dewatering effectiveness of a custom-built pressure dewatering device. The dewatering experiments showed that while the reagent dose was reduced by 50%, the dewatering rate decreased to 19.78%, surpassing the optimal dose of a single reagent. During the natural compression stage of the filter cake, the deformation reached its maximum under the same pressure difference. During the transitional period, the closure of the filter cake pores occurred at a slower rate, facilitating better moisture drainage. Under strong compression, the ultimate deformation reached its maximum. PEI acted as a bridging agent for kaolin flocculation and served as a medium for SDBS on the kaolin surface. A small amount of PEI reduced the electrostatic repulsion of SDBS, increasing its adsorption capacity. PEI adsorbed on the kaolin surface through electrostatic and hydrogen bonding, while SDBS could adsorb onto the PEI reagent layer through electrostatic and polar interactions, exposing its alkyl chains on the surface and thereby facilitating flocculation and generating a hydrophobic reagent layer. This study could provide a new method and insights for the efficient pressurized dewatering of kaolin.

Thermodynamic and surface active investigations of aqueous solution of sodium dodecylbenzene sulfonate in presence of builders: sequestration of Ca2+ ions and interaction with H2O2

Abstract The current investigation examines the micellization process of sodium dodecylbenzene sulfonate in aqueous media with builders at temperatures ranging from 298.15 K to 313.15 K. Using conductometry and tensiometry analyses, the study examines changes in micellar properties in different surfactant solutions, focusing primarily on CMC. Additionally, the variation of CMC with temperature was used to determine the thermodynamic parameters of micellization such as ∆ G m ° , Δ H m ° , ${{\increment}G}_{\mathrm{m}}^{{}^{\circ}},{\Delta }{H}_{\mathrm{m}}^{{}^{\circ}}\text{,}$ and ∆ S m ° ${{\increment}S}_{\mathrm{m}}^{{}^{\circ}}$ . This approach provides valuable insights into the behavior of the surfactant and the different intermolecular interactions involved in the system. The different surface active parameters π CMC, A min, and Γ max were elucidated using tensiometry via the Wilhelmy plate technique. Moreover, the capacity of the builder to sequester calcium ions was studied using a well-established titration method, offering valuable insights into their effectiveness. Their efficiency under oxidative conditions, particularly in preventing the interaction between copper ions and hydrogen peroxide, was evaluated. This article provides a comprehensive analysis of different builders when used with the anionic surfactant, sodium dodecylbenzene sulfonate. Their combination provides improved efficiency in protecting metals from corrosion, extracting heavy metals from polluted soils, and in personal care products such as shampoos and soaps.

Simultaneous Biodegradation of Linear Alkylbenzensulfonate in Anaerobic Reactors, in Two Stages

Simultaneous Biodegradation of Linear Alkylbenzensulfonate in Anaerobic Reactors, in Two Stages

Synergism mechanism of the combined NaOL-SDBS collector at solid-liquid interface and its response to flotation separation of ilmenite from pyroxene

Recovering ilmenite efficiently through froth flotation is challenging. In this research, a novel binary system of sodium oleate (NaOL) and sodium dodecyl benzene sulfonate (SDBS) was applied to promote the flotation performance of ilmenite. Using a total dosage of 90 mg/L combined NaOL-SDBS (4:1) collector, the highest flotation recovery rate of ilmenite was 91.55% at pH 5.0. Furthermore, the artificially mixed ore tests produced a concentrate with a TiO2 grade of 43.55% and a TiO2 recovery of 84.07%, confirming the promising separation performance of the combined collector. Results indicated positive synergism between NaOL and SDBS in ilmenite flotation. The synergism of the binary collector at the solid-liquid interface was identified by the analyses of adsorption amount, contact angle, surface tension, atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). Insights into the synergistic effect between NaOL and SDBS on the ilmenite flotation were mainly attributed to a significant decrease in the surface tension of solid-liquid interface, and the strong adhesion forces of co-adsorption between the combined NaOL-SDBS collector and the mineral surface.

Alleviation of RO membrane fouling in wastewater reclamation plants using an enhanced acid-base chemical cleaning method

Membrane fouling has always been a critical constraint in the operation of the reverse osmosis (RO) process, and chemical cleaning is essential for mitigating membrane fouling and ensuring smooth operation of the membrane system. This paper presents an optimized chemical cleaning method for the efficient cleaning of RO membranes in full-scale applications. Compared to the regular cleaning method (cleaning with 0.1 % NaOH + 1 % ethylenediaminetetraacetic acid + 0.025 % sodium dodecyl benzene sulfonate followed by 0.2 % HCl), the optimized cleaning method improves the cleaning efficiency by adding sodium chloride to the alkaline cleaning solution and citric acid to the acid cleaning solution. Notably, the membrane flux recovery rate with the optimized cleaning method is 45.74 %, and it improves the cleaning efficiency by 1.65 times compared to the regular cleaning method. Additionally, the optimized cleaning method removes 30.46 % of total foulants (organic and inorganic), which is 2.11 times higher than the regular cleaning method. The removal of inorganic ions such as Fe, Ca, and Mg is significantly improved with the optimized cleaning method. For organic matter removal, the optimized cleaning method effectively removes more polysaccharides, proteins, and microbial metabolites by disrupting the complex structures of organic matter. Furthermore, it also changes the microbial community structure on the RO membrane surface by eliminating microorganisms that cannot withstand strong acids, bases, and high salt environments. However, Mycobacterium can adapt to these harsh conditions, showing a relative abundance of up to 84.13 % after cleaning. Overall, our results provide a new chemical cleaning method for RO membranes in full-scale applications. This method effectively removes membrane foulants and enhances the understanding of the removal characteristics of foulants on RO membrane surfaces by chemical cleaning.

Chitosan-Surfactant Composite Nanocoatings on Glass and Zinc Surfaces Prepared from Aqueous Solutions.

Hydrophobic coatings from chitosan-surfactant composites (ca. 400 nm thick by UV-Vis spectroscopy) for possible corrosion protection were developed on glass and zinc substrates. The surfactants (sodium dodecyl sulfate, SDS or sodium dodecylbenzenesulfonate, and SDBS) were added to the chitosan by two methods: mixing the surfactants with the aqueous chitosan solutions before film deposition or impregnating the deposited chitosan films with surfactants from their aqueous solutions. For the mixed coatings, it was found that the lower surface tension of solutions (40-45 mN/m) corresponded to more hydrophobic (80-90°) coatings in every case. The hydrophobicity of the impregnated coatings was especially significant (88° for SDS and 100° for SDBS). Atomic force microscopy studies revealed a slight increase in roughness (max 1.005) for the most hydrophobic coatings. The accumulation of surfactants in the layer was only significant (0.8-1.0 sulfur atomic %) in the impregnated samples according to X-ray photoelectron spectroscopy. Polarization and electron impedance spectroscopy tests confirmed better barrier properties for these samples (40-50% pseudo-porosity instead of 94%). The degree of swelling in a water vapor atmosphere was significantly lower in the case of the impregnated coatings (ca. 25%) than that of the native ones (ca. 75%), measured by spectroscopic ellipsometry. Accordingly, good barrier layer properties require advantageous bulk properties in addition to surface hydrophobicity.

Quantification of linear alkylbenzene sulphonates in complex sludge samples: Influence of matrix effects in calibration methods

Linear Alkylbenzene Sulfonates (LAS) are among the priority organic pollutants in sludge owing to their high concentrations, due to its use as a major cleaning agent (surfactant) in laundry detergents and household cleaning products, and to the concentration limits of 2,600 mg/kg outlined in the EU directive draft for land application of sludge. In this work, a method has been optimized and validated for the accurate quantification of LAS homologues C10-C13 in different types of samples in the sludge treatment and disposal process including primary, secondary, and digested sludge, compost, and soil. The type of matrix had a significant impact on the method’s validation process, resulting in the need of the use of distinct dilution factors for each matrix. Overall, the procedure propose involves a cost-effective and user-friendly technique that combines both extraction and clean-up in a single step (ultrasound-assisted extraction and dispersive solid phase extraction). Analytical determination is conducted using liquid chromatography-tandem mass spectrometry. The method demonstrated excellent accuracy (relative recoveries exceeding 84.5 % across all types of sludge samples) and the limit of quantification enables the measurement of LAS concentrations up to 1000 times lower than the concentration limits stipulated in the EU directive draft. For an accurate quantification, three calibration approaches were tested (external calibration, standard addition, and matrix-matched calibration). Standard addition was the preferred method for quantitative analysis. It helps mitigate matrix effects that could otherwise distort the accuracy of analyte measurements, making it crucial for quality control, especially in monitoring applications where matrix effects may introduce bias into concentration calculations.

Wetting and aggregation mechanisms of coal molecules via XTG and SDBS based on molecular simulation

To study the interaction process of sodium dodecyl benzene sulfonate (SDBS) and xanthan gum (XTG) molecules in a composite dust suppressant and its influence mechanisms on the wettability and agglomeration characteristics of bituminous coal dust, Material Studio software was used to establish water–XTG binary system models, water–SDBS–XTG ternary system models, and water–SDBS–XTG–coal quaternary system models. Then, molecular dynamics simulations were performed through angular distribution, relative concentration distribution, mean squared displacement (MSD), and interaction energy to study the interaction mechanism between SDBS and XTG and the change in wettability of coal dust. Results showed that the configuration in the binary system changed after stabilization, and SDBS transformed from a disordered state into a directional arrangement with the head group oriented toward the liquid phase and the tail group oriented toward the gas phase. In the ternary system, the head group of SDBS interacted with the XTG molecules, and the XTG wound into a helical structure, reducing the viscosity of the solution. With an increase in the number of SDBS molecules, the angle of the head group of SDBS and the tail chain of SDBS increased to 113.95°. The number of H bonds in the system increased from 1676 to 1697. In the quaternary system, the rate of change of the diffusion coefficient continuously increases. The absolute value of the interaction energy increased from 5920.48 kJ/mol to 9295.35 kJ/mol. The higher the concentration of SDBS, the better the adsorption effect, and the more stable the molecular configuration. The number of H bonds and the distribution area of the overlapping region between water and coal gradually increased, indicating that the larger the area where water molecules could penetrate into the coal molecules, the better the wetting effect on coal. This study reveals the intermolecular interaction process and the mechanisms of coal dust wetting and agglomeration in a composite dust suppressant. It provides theoretical support for the application of this composite dust suppressant.

Degradation of sodium dodecylbenzene sulfonate (SDBS) and high efficiency treatment of real grey water by TiO2-loaded stainless steel mesh under VUV irradiation

Reusing treated greywater indoors in buildings is an advanced strategy to increase the utilization of limited water resources, but currently there is a lack of feasible technologies for efficiently purifying greywater indoors. In this study, we construct the heterogeneous TiO2-stainless steel mesh (SSM) interface with photocatalytic degradation of sodium dodecylbenzene sulfonate (SDBS) by under vacuum ultraviolet (VUV) irradiation. At the initial SDBS of 10 mg/L, the degradation rates of SDBS with UV/TiO2-SSM and VUV/TiO2-SSM process were 53 % and 74 % respectively within 50 min. The results of specific scavengers experiments and EPR analysis revealed that the ·OH, h+ and direct photolysis contributed to SDBS degradation and mineralization. The degradation rate of SDBS in VUV/TiO2-SSM process was higher at weak acid or weak alkali conditions, while the performance of UV/TiO2-SSM process was better at alkaline conditions. Both Cl− and HCO3− could inhibit SDBS degradation, while SO42− slightly promoted the degradation. Active oxygen species mainly degrade SDBS in two ways: by attacking the α carbon, β carbon, or branched chain carbon on the alkane chain; or by attacking the adjacent carbon on the alkane chain, resulting in the formation of three branch forms of products. The toxicity of the intermediate products shows a decreasing or stable trend. The experiment shows that UV or VUV photocatalytic TiO2-SSM has a good prospect of removing anionic surfactant in the real greywater. This study provides strategies for the development and design of indoor water reuse technologies and devices in buildings.

Kinetic of Aerobic Decomposition Process of Linear Alkylbenzene Sulfonate (LAS) in a Well-Shaped Bioreactor Using Commercial Inoculum

Linear alkylbenzene sulfonate (LAS) belongs to a class of surfactants claimed as an environmentally friendly detergent due to its biodegradability. However, the disposal of LAS waste into the waters without prior treatment causes a risk to the ecosystem. These experiments aimed to study the effects of commercial inoculum size EM-4 on the aerobic decomposition process of LAS in a well-shaped bioreactor. These experiments of LAS decomposition were carried out in a batch system aerated by 2.5 L/min for the low and high initial LAS concentrations. The effects of inoculum acclimation were also investigated for the high LAS concentration. The effects of inoculum size were explored at sizes ranging from 5 to 20% v/v, and samples were taken on a regular basis for residual LAS assessment. The first-order kinetic model gave the best fit to the rate of LAS decomposition, with the highest rate coefficient of 10.44 x 10-2 hour-1. This was achieved by using a 20% v/v inoculum for the initial low concentration of LAS, resulting in the highest decomposition efficiency of 89.4% after 24 hours of incubation. The decomposition rate was slower at the high LAS concentrations than at the low concentrations. The inoculum acclimation increased the decomposition rate for the high LAS concentrations. The results of this study show great potential for the bioremediation of LAS detergent waste using commercial inoculum in a well-shaped batch bioreactor.

Effects of sodium dodecylbenzene sulfonate (SDBS), active principle of detergents, on the liver and kidney of zebrafish (Danio rerio)

ABSTRACT Sodium dodecylbenzene sulfonate (SDBS), a predominant component in detergents, requires an evaluation of its toxicological potential due to its hazardous environmental levels. Therefore, we evaluated the toxicological effects of SDBS on the liver and kidney of male D. rerio. Therefore, we evaluated the toxicological effects of SDBS on the liver and kidney of male D. rerio. The fish were divided into three groups: 0.0 (control), 0.25, and 0.5 mg/L of SDBS with exposure for up to 96 hours. After exposure, histopathological, histochemical (hepatic glycogen content), and biochemical analyses (SOD and CAT enzyme analysis) were performed on both organs. The results showed significant histopathological effects, such as circulatory disturbances and progressive and regressive alterations, leading to an altered histopathological alteration index. SOD and CAT enzymes exhibited prominent changes. Thus, it became clear that the surfactant SDBS can cause serious hepatic and renal problems in D. rerio fish, even with short-term exposure, necessitating more stringent control and regulation in the disposal of this surfactant.

Remarkable Toughening of Plastic with Monodispersed Nano-CaCO3: From Theoretical Predictions to Experimental Validation.

The structure-property relationship of poly(vinyl chloride) (PVC)/CaCO3 nanocomposites is investigated by all-atom molecular dynamics (MD) simulations. MD simulation results indicate that the dispersity of nanofillers, interfacial bonding, and chain mobility are imperative factors to improve the mechanical performance of nanocomposites, especially toughness. The tensile behavior and dissipated work of the PVC/CaCO3 model demonstrate that 12 wt % CaCO3 modified with oleate anion and dodecylbenzenesulfonate can impart high toughness to PVC due to its good dispersion, favorable interface interaction, and weak migration of PVC chains. Under the guidance of MD simulation, we experimentally prepared a transparent PVC/CaCO3 nanocomposite with good mechanical properties by in situ polymerization of monodispersed CaCO3 in vinyl chloride monomers. Interestingly, experimental tests indicate that the optimum toughness of a nanocomposite (a 368% increase in the elongation at break and 204% improvement of the impact strength) can be indeed realized by adding 12 wt % CaCO3 modified with oleic acid and dodecylbenzenesulfonic acid, which is remarkably consistent with the MD simulation prediction. In short, this work provides a proof-of-concept of using MD simulation to guide the experimental synthesis of PVC/CaCO3 nanocomposites, which can be considered as an example to develop other functional nanocomposites.

Surfactant-assisted thermal hydrolysis of sewage sludge: Biomolecule extraction and its potential for protease production

Efficient management of sewage sludge from wastewater treatment plants (WWTPs) are crucial to obtain industrial value-added products and reducing environmental impact. Thermal hydrolysis, coupled with surfactants to enhance solubilisation, offers a promising approach for sewage sludge treatment. This study assessed the impact of four surfactants: sodium dodecyl sulphate (SDS), sodium dodecylbenzenesulfonate (SDBS), cetyl trimethyl ammonium chloride (CTAC), and tetraethylammonium chloride (TAC) on thermal hydrolysis of sewage sludge. The addition of anionic surfactants (SDS and SDBS) significantly increased biomolecule production, with proteins, humic-like substances, carbohydrates, and DNA concentrations reaching 6018 ± 28 mg/L (306 mg/gVSSo), 2496 ± 103 mg/L (127 mg/gVSSo), 1822 ± 4 mg/L (93 mg/gVSSo), and 389 ± 3 mg/L (20 mg/gVSSo), respectively, after 155 min of thermal hydrolysis. Low levels of surfactants (10 and 50 mg/gVSSo) also led to a substantial increase in the readily biodegradable fraction of hydrolysed sewage sludge, reaching up to 90 %. Additionally, surfactant-assisted hydrolysed sewage sludge proved to be a favourable substrate for protease production using Bacillus licheniformis. The optimal enzymatic activity of 678 ± 14 U/mL was achieved when CTAC was added at a concentration of 10 mg/gVSSo. In summary, this study evaluated an innovative approach to enhance the solubilisation of biomolecules from sewage sludge using surfactant-assisted thermal hydrolysis. This methodology not only positively affected biodegradability but also proved to be suitable for potentially producing valuable industrial products like proteases through fermentation with B. licheniformis, thus offering a new strategy for the sustainable treatment of sewage sludge.