Benzene Sulfonate Surfactant Research Articles

Novel benzene sulfonate surfactants: Alkyl-tetralin sulfonates synthesized via coal chemical route

Benzene sulfonate surfactants are crucial anionic surfactants, commonly derived from petrochemical sources. Herein, we present a new method for synthesizing alkyl-tetralin sulfonate anionic surfactants using α-olefins (n-hexene, n-octene, n-decene) and tetralin sourced from the coal chemical industry as raw materials. The three-resulting alkyl-tetralin sulfonates (C6-THNS, C8-THNS and C10-THNS), obtained by alkylation and sulfonation of tetralin were characterized through HPLC, FTIR, LCMS and 1H NMR techniques. Their surfactant properties were also investigated and compared with commercially applied linear alkylbenzene sulfonate (LAS). We observed that C6 alkyl-tetralin sulfonate (C6-THNS) exhibited smaller critical micelle concentration (CMC=0.60 mM) and lower equilibrium surface tension (γCMC=33.43 mN/m). Similarly, C6-THNS also showed comparable foaming, wetting and emulsifying properties with LAS, which can be used as a substitute for LAS surfactants. This study shows that the synthesized alkyl-tetralin sulfonates is a potential surfactant, providing a route for efficiently using coal-based chemicals to synthesize surfactants.

The effectiveness of soil washing as a remediation method on oil spill contaminated soil (Case Study: Wonocolo Traditional Oil Mine)

The exploitation of petroleum in Wonocolo is conducted with traditional equipment, leading to contamination by oil spills. Oil Spill contamination has the potential damage to ecological, soil, and surface water, caused by the hydrocarbon content itself. Total Petroleum Hydrocarbon (TPH) test results on contaminated soil show the highest value at 17.4%. Experiments were carried out to analyze the effectiveness of soil washing using Alky Benzene Sulfonate surfactants to reduce the TPH number. Experiments are conducted with variations in surfactant concentrations such as 0%, 0.25%, 0.50%, 0.75%, and 1%. The results of the Soil Washing experiment showed that the surfactant concentration with the highest effectiveness was at a concentration of 0.25%. Concentration of 0.25% reduces TPH by 9% with 51.72% effectiveness.

Regulating adsorption-desorption through controlled modification of the 2D pores in layered double hydroxides

Selective transport and adsorption in two-dimensional (2D) materials depend on the affinity and molecular size of the adsorbate. However, until now studies have predominantly been restricted to small molecules (<1 nm), limiting their use in drug delivery, catalysis, and agriculture applications, which require the inclusion of larger molecules (∼1–3 nm). In this study, we utilize a simple methodology to modify the interlayer structure of layered doubled hydroxide (LDH). Using benzene sulfonate surfactants of increasing carbon tail length, we induce 2D pores ranging between 1.7–3 nm while maintaining a similar intergallery chemical environment. The synthesized composites were thoroughly characterized by XRD, FTIR, HRTEM, XPS, and ICP. Our findings reveal that the interlayer d-spacing is linearly correlated to the molecular size of the surfactant. Additionally, both the internal diffusion parameter of the Morris-Weber model (Kint), as well as the internal capacity of Methylene Blue (MB) were found to be linearly correlated to the interlayer d-spacing measured by XRD. Moreover, we found that the desorption trend of MB from the modified LDHs correlates with the chemical affinity to the modified LDH surface as well as the amounts of MB adsorbed internally and externally. Overall, the results highlight the potential of LDH-based materials to serve as a promising material platform with a controlled molecular adsorption capacity and diffusion rate.

EOR mechanism of fracture oil displacement agent for ultra-low permeability reservoir

Due to the low permeability, small pore throat, and poor pore connectivity of ultra-low permeability reservoirs, fracturing was required to improve the flow environment of oil in the reservoir during its development. The combination of fracturing and oil displacement could reduce the complexity of the development of ultra-low permeability reservoirs. It was feasible to synthesize new surfactants to prepare fracturing oil displacement agents, but the research and development of new surfactants were difficult and costly. This paper aimed to experimentally investigate the imbibition displacement mechanism of fracturing flooding by combining the surfactant of chemical flooding with the fracturing fluid. With the conditions of the ultra-low permeability reservoir in block Y of Changqing Oilfield, the mechanism of remaining oil start-up and fractured oil displacement agent enhanced oil recovery in the ultra-low permeability reservoir was studied by microfluidic model experiment and NMR experiment. A mixture of fracture oil displacement agents was obtained by mixing heavy alkyl benzene sulfonate surfactant, a nonionic surfactant, and a betaine-type amphoteric surfactant. HAS-6C, HAS-5E, and HAS-5G were selected for their interfacial tension reaching 10−3 mN/m. Oil–water​ interfacial tension of HAS-5E was the lowest, which can be reduced to 10−4 mN/m. The ability to alter the wettability of HAS-6C was the most significant, which could make the contact angle go down to 64.5°. The multi-round dynamic and static imbibition experiments showed that the combination of selected surfactant and slickwater can greatly improve the imbibition recovery, of which HAS-6C could enhance oil recovery by 17%. The HAS-5E system with the lowest interfacial tension had the best effect of starting clustered residual oil, and the clustered residual oil saturation was reduced by 48.8%. The HAS-6C system with stronger wettability had the best effect of starting throat-like residual oil, and the throat-like residual saturation was reduced by 10.8%.

ULTRASOUND-ASSISTED ADSORPTION HG (II) USING KAOLIN ADSORBENTS MODIFIED WITH ANIONIC SURFACTANT

This study aims to test the reservoir wastewater containing domestic waste using a modified kaolinite adsorbent with Alkyl Benzene Sulfonate surfactant using ultrasonic technology (KM). First, the adsorbent to be used is characterized using several different techniques such as SEM analysis, and FTIR and the calculation of the efficiency of the adsorbent concerning contact time with wastewater. Meanwhile, the wastewater tested was tested for the effect of contact time on TDS and PH. The results of the analysis show that the maximum waste reduction efficiency occurs in modified kaolin (KM), where adsorption occurs faster than in unmodified natural kaolin (PK). The maximum percentage is 84, 21% for metal removal efficiency using modified kaolin at a contact time of 45 minutes and a weight of 1.8 g of adsorbent, while kaolin without modification has an efficiency of 62.47% at a contact time of 80 minutes and a weight of 1.8 g of adsorbent. The contact time test on the TDS value of wastewater that has been adsorbed with KM shows that the TDS value is getting lower over time, which indicates the Hg (II) ion has been dispersed and fused so that the Hg (II) metal in the water is reduced. The use of the adsorption method with the help of ultrasonic technology is proven to be more efficient in accelerating the removal of Hg (II) ions by increasing the surface dispersion of the adsorbent with metal ions in water. The contact time test on the TDS value of wastewater that has been adsorbed with KM shows that the TDS value is getting lower over time, which indicates the Hg (II) ion has been dispersed and fused so that the Hg (II) metal in the water is reduced. The use of the adsorption method with the help of ultrasonic technology is proven to be more efficient in accelerating the removal of Hg (II) ions by increasing the surface dispersion of the adsorbent with metal ions in water. The contact time test on the TDS value of wastewater that has been adsorbed with KM shows that the TDS value is getting lower over time, which indicates the Hg (II) ion has been dispersed and fused so that the Hg (II) metal in the water is reduced. The use of the adsorption method with the help of ultrasonic technology is proven to be more efficient in accelerating the removal of Hg (II) ions by increasing the surface dispersion of the adsorbent with metal ions in water.

Synthesis of alkylbenzenes via the alkylation of benzene using α-olefin dimers and the surfactant properties of their sulfonates

Abstract Fischer-Tropsch syncrude prepared via the Fischer-Tropsch synthesis (FTS) using a Fe-based catalyst is featured by its high content of linear α-olefins (C5–C13). The utilization of C6–C8 α-olefins for the synthesis of alkyl benzene sulfonate surfactants was performed in the present work via dimerization, benzene alkylation, and sulfonation. The effects of the reaction conditions on benzene alkylation over a trimethyl amine hydrochloride-acidic anhydrous aluminum chloride ionic liquid catalyst (Et3NHCl-AlCl3) have been studied in detail using C6 α-olefin dimers as a model alkylation agent. Under the optimal reaction conditions (molar ratio of AlCl3 to Et3NHCl = 2, catalyst loading = 0.29 mol %, reaction temperature = 30 °C, and molar ratio of benzene to C6 α-olefin dimer = 10) the conversion of the C6 α-olefin dimer was 100% and the selectivity toward the mono alkylbenzene product was 91.0%. C6–C8 α-olefin dimer alkylbenzene sulfonates (C6–C8 DBS) were synthesized via sulfonation using chlorosulfonic acid and characterized using Fourier Transform Infrared (FT-IR) spectroscopy and Liquid Chromatography–Mass Spectrometry (LC–MS). The surfactant properties of the C6–C8 DBS, including their equilibrium and dynamic surface tension, foaming, wetting and emulsifying capabilities, were closely explored and compared with a commercial linear alkylbenzene sulfonate (LAS). The limiting surface tension (γ CMC = 34.62 mN m−1) and critical micelle concentration (CMC = 2.15 mmol L−1) of C6 α-olefin dimer alkylbenzene sulfonate (C6-DBS) were similar to those of LAS. Upon increasing the hydrocarbon chain length, the γ CMC of C6-DBS, C7-DBS, and C8-DBS remained unchanged, while the CMC decreased. C6–C8-DBS exhibited foaming, emulsifying, and wetting properties comparable to LAS.

Band gap tuning of TiO2 NP–SWCNT nanocomposite materials using surfactant synthesis techniques

Optimizing photocatalysts to function within the visible region offers enhanced economics considering that 40% of the sun’s energy is in the visible region, compared to just 4% in the UV region. To better utilize available solar flux, nanocomposite materials using TiO2 nanoparticles and single walled carbon nanotubes (SWCNTs) have been studied. Separating the SWCNT bundles using surfactants combined with a photo-assisted sol–gel preparation produced low band gap (<0.5 eV) materials. Infrared analysis showed the formation of Ti-O-C bonds that are attributed to photoactivity in the visible spectrum (i.e. red shift). The π–π stacking interactions between the benzene ring of the sodium dodecyl benzenesulfonate surfactant and the SWCNTs provided greater separation of the SWCNT fibers, increasing the coverage of TiO2 to SWCNT surfaces.

Strong influence of surfactants on virgin hydrophobic microplastics adsorbing ionic organic pollutants

Microplastic (MP) pollution has become an area of increasing concern because MPs accumulate various types of pollutants. Many previous studies have explored the interactions between MPs and hydrophobic pollutants. However, little research has been conducted on hydrophilic pollutants, which are of much higher concentration and ubiquitous in environment. Surfactants cause hydrophobic MPs to become hydrophilic, which may significantly enhance their capacities to adsorb hydrophilic pollutants. This study explored the influence of co-existing surfactants on the adsorption of ionic organic pollutants by MPs, and found that the presence of an ionic surfactant could significantly enhance the capacity of polyvinyl chloride (PVC, 0.2 mm) MPs to adsorb pollutants with opposite charges. The Langmuir methylene blue adsorption capacity of PVC could be increased from 172 to 4417 ppm in the presence of a sodium dodecyl benzene sulfonate surfactant. Nonionic surfactants impeded the adsorption of both cationic and anionic pollutants due to the steric resistance of the hydrophilic polyethelene glycol chains. The electrostatic interaction mechanism dominated the interfacial behaviors of ionic pollutants on surfactant-adsorbed MP interfaces. The effects of the surfactants were further verified using four different model pollutants and six surfactants. The adsorption capacities of real environmental MPs, including PVC, polyethylene (PE), polypropylene (PP), and polystyrene (PS), increased by three to twenty-six times. The adsorption properties of MPs may be determined by the presence of co-existing surfactants, rather than their polymer species or additives.

Effect of Fine Bubbles on Removal of Linear Alkyl Benzene Sulfonate Surfactant during the Rinsing Stage of Laundry Washing

AbstractThe use of fine bubbles is a promising approach to remove surfactant efficiently during the rinsing process of clothing, to fulfill a requirement. Therefore, the influence of fine bubbles on the removal performance of surfactant from cloth during the rinse process of pulsator washing machine (top loading type) was investigated. The test apparatus was assembled by connecting a microbubble generation tank and a small washing machine with tubes and circulating fine bubble water to a small washing machine. Swatches of cloth with a specified amount of linear alkylbenzene sulfonate (LAS) adsorbed from aqueous solution, were rinsed with tap water, and the LAS concentration in the rinse water was examined with an HPLC system equipped with a high‐precision fluorescence detector. The average bubble diameter of the fine bubble water used was 0.13–1.4 μm. In the rinsing experiment, no difference was found in the final LAS removal efficiency between water with and without bubbles; but the former increased the LAS removal rate during the initial stage of rinsing. This tendency was particularly noticeable when the stirring power of the washing machine was weak. Therefore, it was concluded that the fine bubble effect on the removal of the surfactant is mainly a kinetic effect rather than an equilibrium effect.

Thermal performance analysis of mechanical draft cooling tower filled with rotational splash type packing by using nanofluids

In this study, effects of using nanofluid (distilled water as base fluid and aluminum oxide and copper oxide as nanoparticles) on thermal performance of mechanical draft cooling tower have been experimentally investigated and results have been compared with performance of the tower in presence of pure water. A counter flow wet cooling tower with non-uniform and rotational splash type packing has been used. Experiments have been carried out to investigate the effects of inlet temperature of nanofluid, concentration and type of nanofluid, and mass flow ratio of working fluid to air (L/G) on the thermal performance of the cooling tower. Preparation of the nanofluid has been accomplished in two-step method, by adding sodium dodecyl benzenesulfonate surfactant to improve the dispersion of particles and stability of suspension. Present results show that by using nanofluid, thermal performance of the cooling tower improved, and this improvement varies depending on inlet temperature of nanofluid, type and concentration of nanofluid. For instance, with an increase in the inlet temperature of aluminum oxide/water nanofluid (0.1 wt%) from 37.5 to 42.5 °C, effectiveness of the tower increased by 11%. However, using pure water with the same conditions, the effectiveness increased about 8.5%. Furthermore, by increasing the concentration of this nanofluid from 0 to 0.15 wt%, the effectiveness increased about 7.2%. Finally, by using copper oxide/water nanofluid, performance of the cooling tower improved with effectiveness about 5%.

Influence of solvents on the enhancement of thermophysical properties and stability of multi-walled carbon nanotubes nanofluid

Multi-walled carbon nanotubes (MWCNTs) are a contemporary class of nanoparticles that have a prominent thermal, electrical and mechanical properties. There have been numerous studies on the enhancement of thermophysical properties of nanofluids. However, there is only limited research on thermal and stability analysis of MWCNT nanofluids with various kinds of solvents or base fluids, namely propylene glycol, ethanol, ethylene glycol, polyethylene glycol, methanol and water. This paper reports the enhancement of thermophysical properties and stability of MWCNTs with six different base fluids in the presence of sodium dodecyl benzene sulfonate surfactant with a mass concentration of 0.5 wt%. Thermal and dispersion stabilities were determined using a thermogravimetric analyzer (TGA) and Zeta potential, along with a visual inspection method to evaluate the agglomeration or sedimentation of MWCNT nanoparticles over a period of one month. Ultraviolet–visible spectroscopy and Fourier transform infrared spectroscopy were utilized to identify the molecular components and light absorption of the formulated nanofluids at their maximum wavenumber (4500 cm−1) and wavelength (800 nm). In addition, thermophysical properties such as thermal conductivity, specific heat capacity, viscosity and density with a peak temperature of 200 °C were also experimentally evaluated. The TGA results illustrated that MWCNT/ethylene glycol nanofluid achieved maximum thermal stability at 140 °C and it revealed a maximum zeta potential value of −61.8 mV. Thus, ethylene glycol solution was found to be the best base liquid to homogenize with MWCNTs for acquiring an enhanced thermophysical property and a long-term stability.

Deciphering the role of premicellar and micellar concentrations of sodium dodecyl benzenesulfonate surfactant in insulin fibrillation at pH 2.0

Amyloid fibril formation by proteins and their deposition in cells and tissues are associated with several amyloid-based disorders. Understanding the mechanism of amyloid fibril formation is thus of the utmost importance for the designing ligands that could prevent or inhibit the fibrillation process and help to treat of such disorders. We describe the stimulatory effect of sodium dodecyl benzenesulfonate (SDBS) on insulin amyloid fibrillation at pH 2.0 and the characterization of SDBS-induced insulin aggregation using spectroscopy and microscopy. We found that SDBS induced amyloid-like aggregates of insulin at sub-micellar (0.1–1.2 mM), but not post-micellar (≥2.0 mM) concentrations. The amyloid fibrillation of insulin induced by SDBS was kinetically rapid and escaped the lag phase. Far-UV CD findings suggested that the α-helical content of insulin transformed into cross-β structure and mixed α and β structures when incubated with sub-micellar and post-micellar SDBS concentrations, respectively. The overall results indicated that low, but not high SDBS concentrations induce amyloid-like insulin aggregates and fibrils.

Degradation of surfactant waste of leather tanning using Fe2O3/activated carbon catalyst

The development of the tannery industry in addition to being beneficial for the economic growth of the community also has a negative impact on the environment due to the disposal of waste produced. Components of waste produced from the leather tanning industry include residual protein and fat, surfactants, anti-bacterial, anti-fungal, coloring and tanning agents. One component that is found in surfactants and often pollutes waters is alkyl benzene sulfonate and linear alkyl benzene sulfonate surfactants. Alkyl benzene sulfonate (ABS) is an anionic surfactant that has a very long and branched carbon chain that is difficult to degrade by microorganisms in nature. Characterization and testing of the activity of porous/activated carbon catalysts will be carried out. The type of porous activated carbon used is coconut shell carbon with microspores character. The stages of this research consisted of the process of impregnation of iron oxide on porous carbon, the surfactant waste degradation process and the characterization of the catalysts produced. Based on the research that has been done, it can be concluded that the catalyst Fe2O3/coconut shell activated carbon is very effective to be applied for the degradation of surfactant waste. The degradation capacity of surfactant wastes increases with increasing concentration of active site Fe. The capacity of the surfactant waste degradation reaction using coconut shell catalyst at t = 3 hours for variations in the concentration of Fe 2%, 4% and 6% respectively 6.77 mmol/gram catalyst, 3.18 mmol/gram catalyst and 1.61 mmol/gram catalyst. The data show that the surfactant waste degradation reaction capacity increases with the increase in the composition of iron oxide added to the surface of the porous carbon support.

Recovery bitumen from asbuton with sodium tripolyphospate and SDBS surfactant as wetting agent

The objective of this research is to develop a more-environmental friendly method of bitumen extraction from Asbuton, which also has high rate of percentage recovery, by using a mixture of sodium tripolyphosphate (Na5P3O10/NTP) and sodium dodecyl benzene sulfonate (SDBS) surfactant in several temperatures process. The extraction process itself has three steps of reactions, first is premixing, second is digesting and third is separating. Separated layer of bitumen after separation process will be analyzed to obtain bitumen percentage recovery during extraction. The purpose of premixing step is reducing viscosity of Asbuton by adding DEX up to 60 percent (w/w) of the total mass and then mixing it for 30 minutes. The digesting step is carried out by adding a mixture of DEX Asbuton with wetting agent. Wetting agent is a mixture solution of sodium dodecyl benzene sulfonate surfactant (SDBS) and Na5P3O10 (NTP) in various concentration. This mixture is being stirred at 1500 rpm using controlled temperature at 60, 70, 80 0C for 30 minutes. We use various surfactant ratio of SDBS from 0.125%; 0.25%; 0.37%, 0.5% (w/w) to the total mass ratio, and for NTP ratio is 0.125%; 0.25%; 0.37%; 0.5% (w/w). Separation process is done by adding water to form three layers of solution, the top layer, DEX-bitumen solution, will be weighed and measured for its weight and density to obtain the percentage recovery of bitumen. It can be concluded that the combination of SDBS and NTP mixture as wetting agent, can bring better result on bitumen extraction from Asbuton asphalt. The highest percentage of bitumen recovery is 74.63% at 80°C of temperature, and with SDBS concentration of 0.125% and Na5P3O10 concentration of 0.25%.

Corona discharge plasma-based degradation of simulated residual linear alkylbenzene sulphonate and dodecyl benzene sulfonate surfactants

Synthetic surfactants are used in a wide range of products ranging from household cleaning detergents to pesticide formulations. Due to their widespread use, residual surfactants are often released in large quantities into the environment, especially via wastewater and can act as potential toxicants. The present study explored the applicability of a non-thermal plasma, namely corona discharge plasma jet (CDPJ), for the degradation of residual surfactants so as to minimize their harmful effects to aquatic life. The plasma was generated using 20 kV DC power supply, with different input currents (1.00, 1.25 and 1.50 A) and at various electrode-to-sample distances (20, 25 and 30 mm). For degradation treatments, simulated residual surfactants (sodium dodecylbenzene sulfonate [DBS] and sodium linear alkylbenzene sulfonate [LAS]) and DBS-containing dishwashing detergents dispersed on slide glasses were exposed to CDPJ for predetermined periods of time (0–120 min). Results indicated that under optimal treatment conditions of 1.5 A current and 20 mm electrode-to-sample distance, the tested surfactants and surfactants in detergents were maximally degraded to about 57% following the plasma treatment for 120 min. Modeling of degradation kinetics indicated that Weibull distribution was the best-fit model, and decimal degradation times (δ) were calculated for different treatment conditions. The pure surfactants were degraded to a greater extent than surfactants in detergents.

Interfacial Properties and Monolayer Collapse of Alkyl Benzenesulfonate Surfactant Monolayers at the Decane-Water Interface from Molecular Dynamics Simulations.

The molecular structure of a surfactant molecule is known to have a great effect on the interfacial properties and the type of nanostructures formed. In this work, we have performed molecular dynamics simulations on six isomers of an alkyl benzenesulfonate surfactant to investigate the effect of the degree and position of aromatic substitution on the interfacial properties and on the collapse of the surfactant monolayer at a decane-water interface. The surface pressure of the monolayers was shown to increase with increasing surface coverage, until some of the monolayers become mechanically unstable and form large undulations. Shifting the primary alkyl chain of the surfactant from the para to the meta position was found to significantly affect the orientation of the surfactant head groups, while the attachment position of the benzene ring along the primary alkyl chain plays a greater role in the orientation of the surfactant tails. In general, to the extent considered in this work, our results suggest that additional alkyl substitution and meta substitution of the primary alkyl chains increase both the effectiveness and efficiency of the surfactants, and accelerate the onset of monolayer collapse. The interface was found to consist of an inner Helmholtz layer of partially dehydrated counterions in contact with the surfactant head groups, an outer Helmholtz layer of hydrated counterions, and a diffuse layer. The di- and trisubstituted surfactants formed nearly spherical swollen micelles encapsulating pure decane, which effectively solubilizes decane in water as a microemulsion. The monosubstituted surfactants formed elongated buds that protrude from the interface, but did not detach from the monolayer. To our knowledge, the role of aromatic substitution on interfacial properties has not been investigated by molecular simulations previously. The results from this work could provide insights to design improved surfactants by exploiting aromatic substitution to encapsulate material for drug delivery and other applications.

Exploring the effect of the O-(1-heptylnonyl) benzene sulfonate surfactant on the nature of the linear hydrocarbons/water interface by means of an atomistic molecular dynamics simulation

Exploring the effect of the O-(1-heptylnonyl) benzene sulfonate surfactant on the nature of the linear hydrocarbons/water interface by means of an atomistic molecular dynamics simulation

Experimental study on minimal nanolubrication with surfactant in the turning of titanium alloys

The superiority of minimal nanolubrication for effective, efficient and cleaner machining environment has been widely discussed in the literature. However, due to their high surface energy, nanoparticles coagulate or agglomerate easily, which makes it difficult to disperse them in the base fluid. Hence, the addition of a small amount of surfactant should be able to overcome this issue. This research elucidates and extends fundamental knowledge regarding the effect of a sodium dodecyl benzene sulfonate surfactant mixed with different nanoparticle concentrations towards the sustainable machining of titanium alloy using design of experiment methodology. The experimental results indicate that the inclusion of a sodium dodecyl benzene sulfonate surfactant in aluminium oxide nanolubricant provides the best lubricating properties for the machining of the titanium alloy. At 0.4 wt% of nanoparticles and a feed rate of 0.1 mm/rev, minimum values of surface roughness and power consumption can be achieved. Meanwhile, minimal tool wear can be attained by application of a 0.6 wt% nanoparticle concentration and 0.1 mm/rev feed rate. Further statistical analyses emphasized that the feed rate was the most significant factor that influenced the surface roughness and power consumption, while the mixture of nanoparticles with surfactant and feed rate has the greatest effect on the tool wear resistance of the cutting insert.

Preparation of mesoporous TiO2 with enhanced photocatalytic activity towards tannery wastewater degradation.

Ordered mesoporous TiO2 materials are successfully synthesized via a sol-gel route using butyl titanate as a precursor and sodium dodecyl benzene sulfonate surfactants as soft templates. The as-prepared TiO2 samples possess a relatively high surface area of 40.03 m2/g and the center of pore diameter distribution of 13.04 nm. They exhibit excellent photocatalytic activity towards degradation of organic pollutants in tannery wastewater under UV-light and natural sunlight irradiation. The effect of the catalyst dosage, the pH value of the solution and the concentration of H2O2 are discussed in detail. This work would pave an avenue for purifying various industrial wastewaters through an advanced photocatalytic oxidation process.

Aqueous stability and mobility of C60 complexed by sodium dodecyl benzene sulfonate surfactant

Surfactant complexation may have significant effects on the environmental behavior of nano-particles. In order to understand the ecological exposure of nano-materials, it is important to determine the stability and mobility of surfactant-complexed nano-materials in aqueous systems. In this study, the aggregation and transport of C60 complexed by the surfactant sodium dodecyl benzene sulfonate (SDBS) were investigated. It was found that SDBS-complexed C60 had a ζ-potential of −49.5mV under near-neutral pH conditions and remained stable during an aging period of 15days. It had a critical coagulation concentration of 550mmol/L for NaCl, which was higher than common natural colloids and many kinds of raw nano-materials, and was comparable to those of many kinds of surface-modified nano-materials. SDBS enhanced the stability of C60 colloid; however, at the same time, it also enhanced the colloidal particle aggregation rate. Much higher mobility was found for SDBS-complexed C60 than C60 colloid. Increase in ionic strength, Ca2+ concentration or Al3+ concentration decreased the mobility. In general, SDBS-complexed C60 had high stability and mobility.