Ecological Behavior of Linear Alkylbenzene Sulfonate (LAS) in Soil-Plant Systems

More and more linear alkylbenzene sulfonate (LAS) has contaminated the water and soil ma pollution discharge, making it important to identify the ecological behavior and toxicity of LAS so as to carry out measures that will reduce its negative effects on the ecosystem. The ecological behavior of LAS. including degradation, migration, and plant uptake, in both soil-paddy rice and soil-soybean systems was studied. Reduction of LAS in pot and field plots followed the first order reaction kinetics with degradation half-lives of 35-50 days with LAS decreasing to very low concentrations after a season of crop growth. Strong migration ability for LAS was found and the breakthrough time in a 1.5 in soil monolith was significantly shortened to 23 days by preferential flow. Leachate volumes of soil-paddy and soil-soybean systems at preferential breakthrough were much different, while the leachate volumes at equilibrium governed by soil adsorption/desorption processes were very similar. Significant uptake of LAS in both paddy rice and sovbeans was observed in pot and field experiments (P < 0.05). In aquatic culture, 20 μg mL-1 and above of LAS significantly inhibited the growth of paddy seedlings (P < 0.05). The critical concentration for LAS in soil inhibiting the growth and yield of paddy was 160 μg g-1; when higher, there was a strong negative influence, with decreases in height, spike length, and production, when lower than 80 μg g-1, paddy growth was stimulated. There was little effect of LAS on soybeans.

Simulation of Suspension Catalytic Distillation for Synthesis of Linear Alkylbenzene

Suspension catalytic distillation (SCD) has been developed recently as an innovative technology in catalytic distillation. In this paper, a brief introduction to SCD is given and an equilibrium stage (EQ) modei is developed to simulate this new process for synthesis of linear alkylbenzene (LAB) from benzene and 1-dodecene. Since non-ideality of this reaction systern is not strong, EQ modei developed could be applied to it successfully. Simulation results agree well with experimental data, and indicate some characteristics of SCD process as an advanced technology for the production of LAB: 100% conversion of olefins, low temperature (90-100℃) and low benzene/olefin mole ratio.

Surfactant Linear Alkylbenzene Sulfonate Effect on Soil Cd Fractions and Cd Distribution in Soybean Plants in a Pot Experiment

A pot experiment was conducted to study the effect of an anionic surfactant linear alkylbenzene sulfonate(LAS) application on cadmium(Cd)fractions in soils and Cd distribution in different tissues of soybean(Glycine max)plants as well as soil pH.Soil samples were treated with three levels of Cd(0,5,and 10 mg kg^(-1))and five levels of LAS(0,5, 15,50,and 100 mg L^(-1)).Results indicated that compared to the control soils(no Cd and no LAS treatment),soil pH increased and available Cd decreased in the soil treated with external Cd and watered with LAS solutions.Meanwhile, soil exchangeable Cd and Cd bound to carbonates decreased;Cd bound to amorphous iron and manganese oxides and Cd bound to organic matter increased.In addition,LAS application could reduce enrichment of Cd in soybean plants, resulting in decreased Cd in the soybean plants.Thus,suitable LAS application could decrease bioavailability and mobility of soil Cd.

Effect of Dermal Exposure to Paraphenylenediamine and Linear Alkylbenzene Sulphonate in Guinea Pigs

To study the effects of paraphenylenediamine （PPD） and linear alkylbenzene sulphonate （LAS） alone and in combination on the skin. Methods Forty-eight guinea pigs were divided equally into 4 groups and exposed to PPD （4 mg/kg）, LAS （12 mg/kg） and PPD （4 mg/kg） plus LAS （12 mg/kg） for 30 days. The biochemical parameters such as acid phosphatase, gtutathione-s-transferase, glutathione peroxidase, glutathione, lipid peroxidafion and histamine contents in exposed skin were estimated. The histopathological examination of the exposed skin was also carried out. Results The skin enzymes, lipid peroxidation, and histamine increased while glutathione decreased in skin. The simultaneously exposed group showed additive toxic effects. The histopathological examination showed severe hyperkeratosis, thickening of collagen fibres and vacuolisation of epidermal cells in PPD plus LAS exposed skin. Conclusion The findings of the present study suggest that simultaneous exposure to PPD and LAS has additive toxic effects.

Linear Alkylbenzene Sulfonates in the Groundwater and Surface Waters： Ergene Basin Case Study

Ergene Basin is one of the most important industrial centers due to the geographical location in Turkey. Uncontrolled and rapidly increasing industrialization brings together a large number of environmental problems in the basin. In this study, pollution was investigated in the water samples taken at time intervals and different parts of groundwater and surface water resources located within Ergene Basin by methylene blue anionic surfactants （MBAS） analysis method. Turbidity, temperature, pH, electrical conductivity （EC）, concentrations of total P and linear alkylbenzene sulfonates （LAS） were simultaneously determined in the investigated water resources. The results were compared with the Turkish Water Pollution Control Regulation specified in the Quality Criteria of the Inland Water Resources according to their class. The total P and LAS concentrations of surface waters are generally higher than groundwater. In terms of LAS concentrations, the groundwater is Ⅰ-Ⅱ class and the surface water is Ⅱ-Ⅳ class.

Synthesis of Linear Alkylbenzene in a Novel Liquid-Solid Circulating Moving Bed Reactor

For the alkylation of benzene with long-chain olefins, using Hβzeolite catalyst as replacement of HF or AlCl3 has the advantages of no corrosion, less environmental pollution, and much more 2-phenyl isomer, which has the highest biodegradability and solubility, and better detergent properties among the related isomers. The characterization of the coke shows that the deactivation of catalyst is caused by the jam of bulkier molecules, such as naphthalene, indane and linear alkylbenzenes, which are too big to move quickly in the intracrystalline pores of catalyst. The deactivated catalyst can be regenerated by benzene washing at higher temperature. To make the processes of reaction and regeneration continuous, a novel moving bed reactor is developed. Comparing with the processes with fixed bed reactors, the processes in this work have the advantages of continuous operation, low temperature, low pressure, low mole ratio of benzene to olefins, and high weight hourly space velocity.

Nafion/SiO_2 Nanocomposites:High Potential Catalysts for Alkylation of Benzene with Linear C_9-C_(13) Alkenes

High surface area Nafion/SiO2 nanocomposites with nano-sized Nafion resin particles entrapped and dispersed within the highly porous silica matrix exhibited significantly enhanced activity, high selectivity and long-term stability for the alkylation of benzene with linear C9-C13 alkenes owing to the increased accessibility of Nafion resin-based acid sites to reactants.

Investigating the potential of using acoustic frequency on the degradation of linear alkylbenzen sulfonates from aqueous solution

The effectiveness of using acoustical （sonochemical） reactor for degradation of linear alkylbenzen sulfonate （LAS） from aqueous solution was investigated. LASs are anionic surfactants, found in relatively high amounts in domestic and industrial wastewaters. In this study, experiments on LAS solution were performed using methylene blue active substances （MBAS） method. The effectiveness of acoustical processor reactor for LAS degradation is evaluated with emphasis on the effect of treatment time and initial LAS concentration. Experiments were performed at initial concentrations of 0.2, 0.5, 0.8 and 1.0 mg/L, acoustic frequency of 130 kHz, applied power of 500 W and temperature of 18℃-20℃. At the conditions involved, LAS degradation was found to increase with increasing sonochemical time. In addition, as the concentration increased, the LAS degradation rate decreased in the acoustical processor reactor.

Studies on Degradation Characteristic of LAS High-resistance Strain

A IAS degradation strain with high resistance, which could take linear alkylbenzene sulphonate （LAS） as only carton origin for growth, was isolated from the drain canal of Hangao Detergent Plant of Xuzhou. The characteristic of its degradation was researched and the results showed that the optimum conditions of this strain for degrading LAS were 30℃, pH 6.0, 150 ml solution in 500 ml triangle vase, 120 r/min, LAS concentration of 200 - 600 mg/L. The growth amount of the bacteria were up to 0. 443 （ OD400 ） and the degrading rate was up to 89.4%. The ability of the bacterium to degrade LAS could be as high as concentration of 1 200 mg/L.

Effects of temperature and surfactants on naphthalene and phenanthrene sorption by soil

Adsorption experiments were carried out to investigate the sorption behaviors of naphthalene and phenanthrene in six different soils and to determine the effects of temperature, linear alkylbenzene sulfonate （LAS） and cetylrimethyl ammonium bromide （CTAB） on sorption. The results show that for a given sorbent phenanthrene exhibited greater nonlinear and stronger sorption than naphthalene. There was a strong negative correlation for the Koc values with organic carbon content （foc）. The increase of temperature was not favorable to sorption. Sorption decreased along with the increasing aqueous LAS concentration from 0 to 1000 mg/L. At low CTAB concentration （〈 100 mg/L）, the adsorption increased as CTAB hemimicelles formed on the soil surface. At high concentration, CTAB decreased the adsorption by occupying active hydrophobic adsorption sites and solubilization of naphthalene and phenanthrene.

Commercial Laundry Water Characterisation

Surfactants are the major active ingredients of laundry detergents. Therefore, special attention should be focused on the treatment and disposal of laundry wastewater. The aim of this study was to characterise the wastewater from a commercial laundry over 30 days. Physicochemical analyses were performed, monitoring the content of nitrogen, phosphate, heavy metals, linear alkylbenzene sulphonate (LAS), volatile organic acids and alcohols. The pH was approximately 5.6 and the COD approximately 4800 mg·L-1. The average concentrations of sulphate, sulphide, N-ammoniacal organic nitrogen compounds and heavy metals were below the maximum limit, in accordance with local and national environmental legislation, and the average total suspended solids was 0.08 g·L-1. Among the metals analysed, iron was observed with the highest concentrations (0.037 mg·L-1 and 0.72 mg·L-1). Phosphate was detected in 93% of samples (94.65 mg·L-1 average). LAS was detected in all samples (12.24 mg·L-1 to 1023.7 mg·L-1). Thirty-three different xenobiotic organic compounds were identified in the laundry wastewater with the qualitative screening. The major groups of the compounds were fragrances, preservatives, solvents and some surfactants. Although the characterisation indicated low values for many parameters, this does not eliminate the need for specific treatment before its disposal at the sewage system.

Effects of Self-purification of River Water on Laundry Wastewater

[Objective] This study was conducted to investigate the effect of laundry wastewater on the quality of river water and the dilution purification effect of river water on laundry wastewater. [Method] The effects of laundry wastewater on the contents of total nitrogen(TN), total phosphorus(TP), suspended solids(SS), chemical oxygen demand(COD) and linear alkylbenzene sulfonic acid(LAS) were studied in 7 rivers of Shaoxing City. [Result](1) The contents of TN, TP, SS, COD and LAS increased by 92%, 99%, 340%, 351% and 923%, respectively, at the discharging moment of laundry wastewater; and(2) the five pollutional indexes significantly decreased over time, and especially 2 h after the discharge of laundry wastewater, compared with former the discharge of laundry wastewater, the contents of TN, TP, COD and LAS increased by 6%, 11%, 9% and13%, respectively,while the contents of SS still increased by 76%, i.e., SS required a longer time to achieve self-purification. [Conclusion] Laundry wastewater has some influence on thequality of river water, and the self-purification function of river water could effectively remove pollutants.

Assessment of water-based cutting fluids with green additives in broaching

In order to improve the cutting performance in broaching,the lubrication and cleaning effects offered by water-based cutting fluids with green additives need to be studied from the viewpoint of green manufacturing.Therefore,water-based solutions with castor oil,surfactant(linear alkylbenzene sulfonate,LAS),and nanographite were prepared by ultrasonic agitation and sprayed into the zone of broaching via atomization.The performances of the cutting fluids,in terms of the viscosity,specific heat,wetting angle,and droplet size,were evaluated to discuss their effects on the broaching load.Among the fluids,the addition of LAS into oil-in-water(WO-S),where its cutting fluid with 10 wt.%castor oil and 1.5 wt.%surfactant,exhibited the lowest broaching force.With regard to the lubricating and cleaning mechanisms,WO-S has good wettability and permeability,and hence,can lubricate the cutting edge of the tool to decrease the cutting load,cool the cutting edge to keep it sturdy,and clean the surface of the cutting edge to keep it sharp.The results reveal that the simultaneous addition of castor oil and LAS had remarkable effects on the lubrication and cleaning,and resulted in a broaching load reduction of more than 10%compared to commercial cutting fluids.However,the addition of nanographite could not improve the lubrication owing to its agglomeration.

High Selective Determination of Anionic Surfactant Using Its Parallel Catalytic Hydrogen Wave

A faradaic response of anionic surfactants (AS),such as linear alkylbenzene sulfonate (LAS),dodecyl benzene sulfonate and dodecyl sulfate,was observed in weak acidic medium. The faradaic response of AS includes (1) a catalytic hydrogen wave of AS in HAc/NaAc buffer that was attributed to the reduction of proton associated with the sulfo-group of AS,and (2) a parallel catalytic hydrogen wave of AS in the presence of hydrogen peroxide,which was due to the catalysis of the catalytic hydrogen wave of AS by hydroxyl radical ·OH electrogenerated in the reduction of hydrogen peroxide. The parallel catalytic hydrogen wave is about 50 times as sensitive as the catalytic hydrogen wave. Based on the parallel catalytic hydrogen wave,a high selective method for the determination of AS was developed. In 0.1 mol/L HAc/NaAc (pH=6.2±0.1)/1.0×10 -3 mol/L H_2O_2 supporting electrolyte,the second-order derivative peak current of the parallel catalytic hydrogen wave located at -1.33 V (vs. SCE) was rectilinear to AS concentration in the range of 3.0×10 -6 —2.5×10 -4 mol/L,without the interference of other surfactants. The proposed method was evaluated by quantitative analysis of AS in environmental wastewater.