A Zr-based stable metal-organic frameworks DUT-67 (Zr) was successfully synthesized as an adsorbent to remove trace mercury and methylmercury ions in aqueous solution. The removal efficiency of 90% and 55% of Hg2+ and CH3Hg+ was respectively achieved at pH 6 and 55°C. The S in thiophene has a relatively weak adsorption capacity for mercury and there could be the slight π-complexation between thiophere ring of DUT-67 (Zr) and Hg2+ besides physical absorption, while there only was physical adsorption between DUT-67 (Zr) and CH3Hg+. The developed methods were applied to remove trace Hg2+ and CH3Hg+ in the real water samples, and the removal efficiency was from 69% to 90% and from 30% to 77% respectively; when the concentrations of Hg2+ was lower than 20 μg L−1 in the samples, the remaining mercury concentration was lower than 1 μg L−1，which can meet the standard of the World Health Organization.
This study was aimed to analyze the thallium pollution and assess the potential ecological risks in the vicinity of coal mines in Henan province, China. We studied 90 surface farmland soil samples from 9 representative coal mines. The Tl concentrations were determined and the potential ecological risks were evaluated. Investigations revealed the farmland soils were modestly contaminated and the trace elements in coal mining areas transferred to the surface soils. Soil Tl contents and potential ecological risks in coal mining areas were significantly increased compared with the original soils which came from the villagers’ mud houses built 40 years ago. The soil Tl concentrations ranged from 0.25 to 0.77(mean = 0.46) mg∙kg−1, which were higher than the original level (0.42 mg∙kg−1). The potential ecological risk index of Tl ranged from 24.00 to 73.2 (mean 44.08), representing a moderate pollution level as a whole of the soils in Henan. In general, high Tl concentrations and high potential ecological risk were found around SHQ and DTG. The soil Tl concentrations exceed the original level and pose noticeable ecological risks.
The yak manure based biochar was produced at different temperatures of 300, 500 and 700 ℃ held for 3 h, which was characterized by BET surface area, X-ray diffraction, Fourier transform infrared spectroscopy, pH measurement, analysis, scanning electron microscopy and ultimate analysis. The resultant biochar had characteristics of high surface area, high pH, porous structure and rich nutrients such as N, P, Ca, Mg, and K, inferring that the yak manure-derived biochar could be used as a soil conditioner. The field experiment was conducted to study the effect of yak manure derived biochar amendment on the yield and biological traits of highland barley, revealing that adding biochar to soil could increase the yield and growth of highland barley in short-term although the long-term benefits remain to be quantified. The present results can be useful to fill the knowledge gap regarding the potential of yak manure derived biochar to soil improvement.
The effects of adding larch (Larix kaempferi) leaf litter and nitrogen (N) on microbial activity and phosphorus (P) fractions in forest soil were examined in a short-term (28-d) laboratory incubation study. The soil was analyzed using a modified Hedley sequential extraction procedure and an acid phosphatase assay. The addition of larch litter and N increased the acid phosphatase activity and decreased the labile P (H2O-P+NaHCO3-P) concentration. Compared with addition of larch litter only, addition of both inputs decreased the proportion of inorganic P (Pi) and increased that of organic P (Po) in the NaOH fraction, bound to aluminum and iron oxides. The results of nutrient (carbon, N, or P) addition indicated that acid phosphatase was synthesized to acquire P. This study suggests that, in this forest soil, P in the H2O-P+NaHCO3-P and in the NaOH-Pi fractions was available for soil microorganisms to decompose leaf litter and that increase in microbial activity eventually translated in an increase in the proportion of Po found in the NaOH fraction in this forest soil.
