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Abstract: Fullerenes-extracted soot, the by-product of fullerene synthesis, is a carbon composite. The application of this material for water treatment has not yet been developed. Herein, fullerenes-extracted soot in the form of powder containing amino groups was prepared by reacting the soot with ethylenediamine, and was used as an adsorbent of hexavalent chromium [Cr(VI)] for removing Cr(VI) from aqueous solutions; this removal was studied by batch adsorption experiments. The effect of experimental parameters such as the pH, initial Cr(VI) concentration, and agitation time on the adsorption process was investigated. The adsorption of Cr(VI) was highly pH-dependent and the optimal pH for the adsorption process was 3.0. The data of Cr(VI) adsorption by fullerenes-extracted soot modified with ethylenediamine (FES-ED) fit the Langmuir isotherm equation well. The maximum Cr(VI)-uptake capacity of FES-ED was 93 mg g−1. The desorption of Cr(VI) from the adsorbent was also studied. The adsorbed Cr(VI) was eluted with 20 mL of an aqueous solution with pH 12 and the percentage recovery of Cr(VI) was determined as 75%. The adsorption and desorption test using the same FES-ED powder was repeated in triplicate to examine the reusability of the adsorbent. The adsorption was 97% and the desorption was >70% through the adsorption–desorption cycles. The adsorption of methyl orange onto the FES-ED was also examined. The dye was almost quantitatively removed from the aqueous solution by the adsorbent (the initial concentration of methyl orange: 40 μg mL−1; the adsorbent added: 10 mg/40 mL). Thus, we concluded that the FES-ED can be used as a novel adsorbent for removing pollutants from water. [Copyright &y& Elsevier]

Ozonation combined with electrolysis (ozone–electrolysis) is a new advanced oxidation process for water treatment. The advantages of ozone–electrolysis are (1) that reagents such as hydrogen peroxide or ferrous salts are unnecessary, (2) there is less influence from chromaticity, and (3) electric power is only required for operation. However, electrolysis has a serious limitation, in that it requires electrical conductivity (EC). This research is aimed at developing an ozone–electrolysis reactor that is applicable to wastewater with low EC using a cation exchange membrane as solid electrolyte. Moreover, experimental evidence of hydroxyl radical (·OH) generation via the cathodic reduction of ozone was obtained. Competitive kinetics analysis, based on the experimental data from the ozone–electrolysis of a mixed solution of 1,4-dioxane and tert-butyl alcohol, revealed that ·OH contributed to 1,4-dioxane degradation. The ozone–electrolysis reactor was successfully applicable to degradation of 1,4-dioxane in both 1,4-dioxane solution (EC: less than 0.30μS/cm) and a landfill leachate treated by a low-pressure reverse osmosis membrane (EC: 0.06mS/cm). The use of a solid electrolyte was also very effective in reducing the electric power required for electrolysis. [Copyright &y& Elsevier]

Abstract: The pre-Holocene Cenozoic sequence outcrops in the terrestrial part of the eastern margin of the Mekong Basin. However, the stratigraphy of the sequence is still unclear. Its detailed stratigraphy and chronology were therefore studied along the Dong Nai River, southern Vietnam, and the lithofacies and the relations among the formations were investigated from the outcrops. The ages of the deposits were determined by using optically stimulated luminescence (OSL) dating. The Ba Mieu Formation was deposited about 176±52ka during marine isotope stage (MIS) 7–6. The Thu Duc Formation was deposited about 97±27ka during MIS 5. Both the Ba Mieu and Thu Duc formations are composed of fluvial and tidally influenced coastal deposits. The newly proposed Nhon Trach Formation was originally an eolian (blanket) deposit, but it has been partly reworked by fluvial processes. The Nhon Trach Formation was deposited about 10.9±4.7ka, in the last part of the Pleistocene to the beginning of the Holocene. The OSL ages for the Ba Mieu, Thu Duc, and Nhon Trach formations are younger than the ages previously assigned to these formations. [Copyright &y& Elsevier]

André proved the Dwork conjecture on the log-growth Newton polygon of p -adic differential equations. We consider conditions such that the left end points of generic log-growth Newton polygon and the left end point of special log-growth Newton polygon coincide. We give an upper bound of the highest slope of differential equations at generic point. This shows that these end points coincide if differential operator has rational function coefficients and the rank of differential operator is equal to 2. [ABSTRACT FROM AUTHOR]