Effect of Dodecylbenzene Sulfonic Acid Used as Additive on Residue Hydrotreating

The effect of additive—dodecylbenzene sulfonic acid(DBSA)—on residue hydrotreating was studied in the au toclave. The results showed that the additive improved stabilization of the colloid system of residue, which could delay th aggregation and coke formation from asphaltenes on the catalyst, and make heavy components transformed into light oi The residue conversion in the presence of this additive increased by 1.94%, and the yield of light oil increased by 1.53%when the reaction time was 90 min. The surface properties of the catalyst in the presence of this additive were better tha that of the blank test within a very short time(30 min) and deteriorated rapidly after a longer reaction time due to highe conversion and coke deposition. Compared with the blank test, the case using the said additive had shown that the structur of hydrotreated asphaltene units was smaller and the condensation degrees were higher. The test results indicated that th additive could improve the hydrotreating reactivity of residue via permeation and depolymerization, the heavier componen could be transformed into light oil more easily, and the light oil yield and residue conversion were higher for the case usin the said additive in residue hydrotreating process.

Response of a Submersed Macrophyte Hydrilla verticillata (L.f) Royle,to Sodium Dodecylbenzene Sulfonate Stress

The acute toxicity of Sodium dodecylbenzene sulfonate （SDBS） to subcamersed macrophyte Hydrilla verticillata （L.f） Royle was studied. Chlorophyll contents and the activities of 3 antioxidant enzymes： superoxide dismutase （SOD, EC 1.15.1.1）, catalase （CAT, EC 1.11.1.6）, peroxidase （POD, EC 1.11.1.7） in the leaves were investigated under different concentrations of SDBS, The chlorophyll contents in leaves of experimental plants decreased gradually, while the electrical conductivity of culture solution increased gradually with the increased dose of SDBS. Under higher concentrations of SDBS （32 mg/L and 128 mg/L） treatment, SOD lost its activities completely after 24 h. The native PAGE analysis indicated the diversity of POD isoenzymes was obvious under different concentrations of SDBS stress.

Deciphering the effect of sodium dodecylbenzene sulfonate on up-flow anaerobic sludge blanket treatment of synthetic sulfate-containing wastewater

In this study,the effects of organic sulfur on anaerobic biological processes were investigated by operating two up-flow anaerobic sludge blanket(UASB)reactors with sodium dodecylbenzene sulfonate(SDBS)as a representative of organic sulfur.The results indicated that the specific methanogenic activity(SMA)and chemical oxygen demand(COD)removal efficiency of R2(with SDBS added)were higher than those of R1(without SDBS)when the COD/SO_(4)^(2−)ratio was above 5.0.However,when the COD/SO_(4)^(2−)ratio was lower than 5.0,the sulfate reduction efficiency of R2 was higher than that of R1.These results and the observed SDBS transformation efficiency in anaerobic reactors indicate that low concentrations of SDBS accelerate methane production and the continuous accumulation of SDBS does not weaken the reduction of sulfate.Similarly,the calculated electron flux for a COD/SO_(4)^(2−)ratio of 1.0 indicates that the utilization intensity of electrons by sulfate-reducing bacteria(SRB)in R2 was 36.48%higher than that of SRB in R1 and exceeded that of methane-producing archaea(MPA)under identical working conditions.Moreover,the addition of SDBS in R2 made sulfidogenesis the dominant reaction at low COD/SO_(4)^(2−),and Methanobacterium and Methanobrevibacter with H_(2)/CO_(2)as the substrate and Desulfomicrobium were the dominant MPA and SRB,respectively.However,methanogenesis was still the dominant reaction in R1,and Methanosaeta with acetic acid as the substrate and Desulfovibrio were the dominant MPA and SRB,respectively.

A case study of aggregation behaviors of titanium dioxide nanoparticles in the presence of dodecylbenzene sulfonate in natural water

The present work aims to ascertain the mechanisms of surfactant（dodecylbenzene sulfonate; DBS） effects on the aggregation behaviors of TiO2 nanoparticles（TiO2-NPs） in natural water samples. Aggregation experiments were conducted at a TiO2-NPs concentration of 10 mg/L in deionized water and in natural water samples via dynamic light scattering and Zeta potential determination. Average attachment efficiency was calculated to compare the aggregation behaviors of nanoparticles in the two aqueous media. Results showed that the effects of DBS on aggregation could be interpreted by both Derjaguin–Landau–Verwey–Overbeek（DLVO） and non-DLVO mechanisms. In natural water samples,aggregation did not occur rapidly and was able to develop slowly under all conditions, and the roles of DBS were obvious at high DBS concentration owing to the impacts of inherent components of natural water samples, such as colloids and natural organic compounds.Future aggregation studies should concentrate on multi-factor, multi-colloidal and dynamic aspects under similar environmental conditions.

Rapid europium-sensitized fluorescent determination of ulifloxacin,the active metabolite of prulifloxacin,in human serum and urine

A new fluorescent method was developed based on the ulifloxacin-europium（Ⅲ）-sodium dodecylbenzene sulfonate system for the determination of ulifloxacin,the active metabolite of prulifloxacin.Sodium dodecylbenzene sulfonate formed a ternary complex with ulifloxacin-europium（Ⅲ）and significantly enhanced the characteristic fluorescence of europium（Ⅲ）.The enhanced fluorescence intensity showed a good linear relationship with the concentration of ulifloxacin in the range of 5.0×10^-8-2.0×10^-6M with a detection limit of 2.0×10^-10 M（3σ）.This method is rapid and sensitive,and has been successfully applied to the determination of ulifloxacin in human urine and serum samples.

Effect of vacuum annealing on the characteristics of composite pellets containing DBSA-doped polyaniline and Fe nanoparticles

The DBSA-PANI-Fe composite powder with 50wt% of Fe nanoparticles was prepared by mechanically mixing the DBSA-doped polyaniline powder and Fe nanoparticles. The composite powder was compacted to pellets and the pellets were annealed in vacuum at 443,493,543, and 593 K for 60 and 120 min. The conductivity of the pellet increases markedly with increasing the annealing temperature up to 493 K, and then decreases with further increasing the annealing temperature. When the pellet was annealed at 493 K for 60 min, the increment of conductivity reaches a maximum value, and the conductivity is 2.6 times as large as that of the pellet unannealed. The conductivities of the pellets annealed under the conditions of 543 K/120 min, 593 K/60 min, and 593 K/120 min are lower than the conductivity of the pellet unannealed. For all the pellets, the variation in conductivity with temperature reveals that the charge transport mechanism can be considered to be 1-D variable-range-hopping （1-D VRH）. The composite pellet shows a magnetic hysteresis loop independent of the annealing condition. The saturation magnetization is about 5.4×10^4 emu/kg. The saturation field and the coercivity are estimated to be 4.38×10^5 and 3.06×10^4 A/m, respectively. The crystalline structure ofFe nanoparticles in the composites does not change with the annealing condition. The annealing condition cannot destroy the polymer backbones.