Wang Lian-sheng

Adsorption of naphthalene derivatives on different macroporous polymeric adsorbents

Abstract The adsorption of 1-naphthol, 2- naphthol, 1-naphthylamine and 2- naphthylamine from aqueous solutions on macroporous polymeric adsorbents was studied. The equilibrium data were fitted to Freundlich-type isotherms and the equilibrium constants K F and n were obtained. The values of the adsorption capacity depend on the surface area of adsorbents, the chemical properties of naphthalene derivatives, as well as the polarity of adsorbents.

Solubilization of polycyclic aromatic hydrocarbons by β-cyclodextrin and carboxymethyl-β-cyclodextrin

Abstract The solubilization of six polycyclic aromatic hydrocarbons(PAHs) by β-cyclodextrin and carboxymethyl-β-cyclodextrin(CMCD) has been investigated. The presence of β-CD and CMCD greatly engance the solubility of PAHs in water. The solubilization effect of cyclodextrins is caused by formation of inclusion complexes of PAHs with cyclodextrin. The degree of solubilization power is related to the “fit” of PAH structure within the cavity of β-CD or CMCD. The better the fit of the molecule, the greater the solubilization power. β-CD shows higher solubilization power than CMCD at low concentration.

Studies on the precursors of strong mutagen [3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone]MX by chlorination of fractions from different waters

The strong mutagen, [3-chloro-4-(dichloromethyl)-5-hydroxy- 2(5H)-furanone] MX, was found to be one of the most potent mutagens in drinking water. In this study, dissolved organic matters from river water and lake water were separated into several compound classes by sorbtion on a series of resin absorbents. After chlorine treatment of the fractions, MX was determined with GC/MS in the selected ion monitoring mode. Humic substances produced more MX on a TOC-basis than other fractions and contributed more to MX formation in the chlorinated natural waters. Some phenols were detected in the oxidation products of humic substances and therefore formation of MX may occur when some phenolic precursor structures in humic substances are treated with chlorine.

Bioconcentration of Rare Earth Elements lanthanum, gadolinium and yttrium in algae (Chlorella Vulgarize Beijerinck): Influence of chemical species

Abstract In this paper, the species of Rare Earth Elements (La, Gd and Y) complexed with organic ligands EDTA (ethylenediamine tetraacetic), NTA (nitrilotriacetic acid) and Cit (citrate) were calculated in the test medium by MINTEQA — A program to calculate aqueous geochemical equilibrium. The influence of the species on the bioconcentration (kinetics and thermodynamics) processes of REEs by algae ( Chlorella Vulgarize Beijerinck ) were also studied. The results show that the bioconcentration processes of REEs by algae were highly dependent on chemical species. Adding organic ligands which can form RE-Organic species complex led to a great reduction of the REEs bioconcentration in algae. The order of BCFs from high to low is RE 3+ > RE-Cit > RE-NTA > RE-EDTA complex. The potential mechanism of bioconcentration may be the coordination reactions of REEs ions with the active sites on algae surface followed by the slow diffusion into the algae cell.

Fuzzy pattern recognition method for assessing groundwater vulnerability to pollution in the Zhangji area

Based on the widely used DRASTIC method, a fuzzy pattern recognition and optimization method was proposed and applied to the fissured-karstic aquifer of Zhangji area for assessing groundwater vulnerability to pollution. The result is compared with DRASTIC method. It is shown that by taking the fuzziness into consideration, the fuzzy pattern recognition and optimization method reflects more efficiently the fuzzy nature of the groundwater vulnerability to pollution and is more applicable in reality.

Effects of fulvic acid on the bioavailability of rare earth elements and GOT enzyme activity in wheat (Triticum aestivum).

Fulvic acid (FA) was extracted and purified from natural soil and the effects of such FA on the bioaccumulation of rare earth elements (REEs, La3+, Gd3+ and Y3+) in wheat seedling were investigated. The results indicated that low concentration of FA (<0.4 mg C/l to root, <0.7 mg C/l to tops (stem and leaves)) could increase the bioaccumulation values of REEs in wheat, but when the concentration of FA was high (>0.4 mg C/l to root, >1.5 mg C/l to tops) the bioaccumulation values were decreased. Kinetic experimental results suggested that bioaccumulation values of REEs in roots for 30 days were correlated with the kinetic linear growth equation, and correlation coefficients were higher than 0.861. The kinetic bioaccumulation pattern of REEs in tops was different from that in root. The bioaccumulation values of REEs in wheat root were much higher than in wheat tops. Variations of glutamic oxaloacetic transaminase (GOT) enzyme activities in wheat root and tops were determined. A good correlation existed between the bioaccumulation values of REEs and GOT enzyme activities, and the correlation coefficients were higher than 0.922. GOT is an important parameter influencing the bioavailability of REEs.

Hydrolysis of phenylthio, phenylsulfinyl and phenylsulfonyl acetates, and neighboring group effect

Abstract Batch data for hydrolysis of phenylthio, phenylsulfinyl and phenylsulfonyl acetates have been determined at various pH values and temperatures. The dual regression equations of logk vs. pH and 1 T were obtained. Neighboring group participation in the hydrolysis of phenylthio acetates was discovered, and the relationship between anchimeric assistance(A) and pH was established.

The species of spiked rare earth elements in sediment and potential bioavailability to algae (Chlorella Vulgarize Beijerinck)

Abstract In this investigation, the species of spiked Rare Earth Element La, Gd, Y, Ce and Sm in sediment were defined as water soluble, acid extractable and organic/sulphide bound species, the correlation relationship of these species to the bioavailability of algae (Chlorella Vulgaris Beyerinck) were established by linear regression. The results indicated that there existed good correlation between the concentrations of REEs in algae and the concentrations of three species in sediment, respectively. Among three species in the sediment, the water soluble species had the best correlation relationship to the bioavailability of algae, this suggested that the release of REEs from the sediment were the most important factor affect the bioavailability of REEs to algae.

Effects of sulfate on speciation and bioavailability of rare earth elements in nutrient solution.

Abstract In this study, data of La3+, Gd3+ and Y3+were carefully selected from the published thermodynamic data base, and were then added to the thermodynamic database of the MINTEQA2 procedure. The species of rare earth elements (REEs, La, Gd, Y) in a nutrient solution were calculated out by MINTEQA2 procedure. The results showed that the precipitation of REEs would take place when the pH was greater than 7.5. Meanwhile, the species of light (La3+)_medium (Gd3+) and heavy (Y3+) REEs with SO42− were calculated using MINTEQA2. The effects of sulfate on the bioavailabilities of three REEs in wheat (Triticum) were investigated by experiments on culture. The results showed that bioaccumulation of La3+ and Gd3+ in roots was inhibited after adding SO42− to the nutrient solution containing 2.0 mg L−1 REE, but Y3+ was promoted. Only Gd3+ became increasingly bioaccumulated in tops (stem and leaves) after adding SO42− to three REE solutions. Kinetic experimental results indicated that bioaccumulation values of REEs in roots fit the linear growth equation (correlation coefficients were higher than 0.94) in nutrient solution containing 2.0mg L−1 REE + 0.01mol L−1 SO42−, and the high bioaccumulation values of REEs in the tops (stem and leaves) during the initial culture time were higher than those in the following few days. The species of REEs with sulfate and the bioavailabilities of REEs had no obvious correlation.

Quantitative structure-activity relationship and prediction of mixture toxicity of alkanols

Alkanols, which are narcotic compounds, were studied. The acute toxicities (15min-EC50) of 15 alkanols, which have a large span of hydrophobicity, to Photobacterium phosphoreum were measured. Quantitative structure-activity relationship (QSAR) analysis of single toxicity of alkanols was conducted by using octanol-water partition coefficient (logKow). The polynomial expression was used instead of linear equation to develop QSAR model, and a QSAR model with a good predictive potential was achieved. Furthermore, the mixture toxicity of alkanols was studied. In order to predict joint toxicity of mixtures that contain very hydrophobic alkanols, the adjustment of octanol-water partition coefficient was performed, considering the influence of volume effect. And equivalent octanol-water partition coefficient was introduced. The QSAR model of mixture toxicity was developed by using equivalent mixture octanol-water partition coefficient. The result showed that even a linear model could predict mixture toxicity well by using equivalent mixture octanol-water partition coefficient.