硅酸盐-磷酸盐对酸法地浸采铀退役采区模拟地下水的修复

为探索酸法地浸采铀退役采区地下水的原位修复技术,本研究先从西北某酸法地浸采铀退役采区采取地下岩心样,同时制备了酸法地浸采铀退役采区地下水模拟水样,构建模拟修复反应的微模型;再向微模型中分别加入硅酸钠溶液、磷酸二氢钾溶液、硅酸钠-磷酸二氢钾混合溶液以考察其对地下水的修复效果。结果表明：加入的硅酸钠-磷酸二氢钾与铀反应形成了胶磷钙铁矿(Ca₆Fe₉(PO₄)₉O₆(H₂O)₆.3H₂O)、偏钠铀矿物(Na(UO₂)(PO₄).3H₂O)和(NaPUO₆.3H₂O)三种矿物;沉淀物中铁锰氧化物交换态铀的含量增加到了41%;铀的去除率达到了99.72%。     

Traffic costs of air pollution: the effect of PM2.5 on traffic violation

Environmental Science and Pollution Research - Although emerging studies have investigated the effect of air pollution on traffic crashes, it is unclear to scholars whether air pollution affects...     

Exogenous fulvic acid enhances stability of mineral-associated soil organic matter better than manure

Environmental Science and Pollution Research - Mineral-associated soil organic matter (MAOM) is seen as the key to soil carbon sequestration, but its stability often varies with types of exogenous...     

Experimental studies and kinetic modeling of the growth of phenol-degrading bacteria in turbulent fluids

Understanding the interaction between microorganisms and fluid dynamics is important for aquatic ecosystems, though only sporadic attention has been focused on this topic in the past. In this study, particular attention was paid to the phenol-degrading bacterial strains Microbacterium oxydans LY1 and Alcaligenes faecalis LY2 subjected to controlled fluid flow under laboratory conditions. These two strains were found to be able to degrade phenols over a concentration range from 50 to 500 mg/L under different turbulence conditions ranging from 0 to 250 rpm. The time it took to reach total phenol degradation decreased when the turbulence was increased in both strains, with increasing energy dissipation rates ranging from 0.110 to 6.241 W/kg, corresponding to changes in the bacterial diffusive sublayer thickness (δ) and enhanced oxygen uptake. Moreover, the maximum specific growth rates of the two strains also increased with the enhancement of turbulence. A model integrating growth inhibition and fluid motion was proposed based on the self-inhibition Haldane model by introducing a turbulence parameter, α. The resulting modified Haldane model was designed to include fluid motion as a variable in the quantification of the physiological responses of microorganisms. This modified Haldane model could be considered a useful laboratory reference when modeling procedures for water environment bioremediation.

Cell nutrition uptake cartoon schematic diagram for M. oxydans LY1 under different turbulent condition (50 and 200 rpm).

     

糖蜜、淀粉与乳品废水厌氧发酵法生物制氢

采用连续流厌氧发酵法研究了糖蜜废水、淀粉废水与牛奶废水生物制氢,讨论了有机物中3大类物质的厌氧发酵产氢的可行性,并对几种底物的产氢稳定性进行了探讨.结果表明,糖蜜废水与淀粉废水都是较好的厌氧发酵法生物产氢底物,在3大类有机物中碳水化合物是目前技术条件下最具有可能性的原材料.在碳水化合物中,溶解性好的糖比溶解性差的淀粉在目前的技术条件下具有生物产氢可行性,而淀粉比溶解性糖更具有产氢前景.不同底物厌氧生物制氢的生态位范围有所不同,对于溶解性好的糖,稳定运行的工程控制参数为pH 4.5±0.3,而溶解性较差的淀粉废水为pH 4.0±0.2;厌氧发酵产氢的ORP值也随底物的不同而不同,但总体必须低于-220mV,在-300mV左右时较好.牛奶废水不适用于作为CSTR反应器中发酵法生物制氢底物.     

生物炭促进硫诱导土著硫杆菌调控土壤铅形态

外源硫杆菌可以促进植物修复重金属污染土壤,然而硫杆菌对土壤中铅的活化作用机理尚不明确。通过土培实验,研究了单质硫和生物炭对土著硫杆菌的诱导作用和对土壤铅形态的作用机理。结果表明,单质硫能够诱导并富集土壤中的土著硫杆菌,相对丰度从0.02%增加至6.99%。生物炭促进了诱导作用,添加生物炭和单质硫,硫杆菌相对丰度增加至13.33%。同时添加3%(质量分数)生物炭和0.5%(质量分数)单质硫培养60 d后,土壤pH从7.83降低至6.64,Eh先降低至230 mV,后逐渐增加至299 mV;有机碳从19.40 g·kg⁻¹增加至28.29 g·kg⁻¹;土壤中铅由可还原态向酸可溶态、可氧化态和残渣态转变,可还原态铅减少了20.13%,酸可溶态、可氧化态和残渣态分别增加了53.76%、35.29%和69.40%。单质硫和生物炭能够富集土著硫杆菌,提高铅的生物有效性,同时对部分铅起到钝化固定作用。本研究可为提高土壤中铅的生物有效性以促进植物修复铅污染土壤提供参考。     

A rapid and sensitive fluoroimmunoassay based on quantum dot for the detection of chlorpyrifos residue in drinking water

A rapid and sensitive indirect competitive fluorescence-linked immunosorbent assay (cFLISA) method based on quantum dots as the fluorescence label coupled with secondary antibody (Ab₂) for the detection of chlorpyrifos in drinking water has been developed. The cFLISA method allowed for chlorpyrifos determination in a liner working range of 15.2–205.5 ng mL^?1. The 50 % inhibition value (IC₅₀) and the limit of detection (LOD) of the cFLISA were 50.2 ng mL^?1 and 8.4 ng mL^?1, while the IC₅₀ and the LOD of the conventhional enzyme linked immunosorbent assay (ELISA) were 95.3 ng- mL^?1 and 16.2 ng mL^?1, respectively. When the concentrations of chlorpyrifos were 200, 100 and 50 ng mL^?1, the recoveries ranged from 90.8 % to 108.2 % with a coefficient of variation (CV) of 7.5 %–15.2 %. In water sample analysis, the results of cFLISA were similar to those obtained from a cELISA and a high performance liquid chromatography (HPLC) method, while the detection time by cFLISA was reduced 0.5 h compared with ELISA. It showed that cFLISA could be used as a new screening method for the detection of pesticide residue.     

Photocatalytic oxidation of propoxur in aqueous titanium dioxide suspensions

Abstract

The photocatalytic oxidation of propoxur, a nitrogen‐containing pesticide, has been investigated using aqueous TiO₂ suspensions as catalyst in this study. The operating variables considered in the study were initial pH, temperature, [H₂O₂] and TiO₂ loading. Results showed that 1 g/l of TiO₂ was the optimum dosage for oxidizing propoxur in this system. Hydrogen peroxide can increase the oxidation rate with increasing its initial concentration. There was no obvious difference in the rate of propoxur oxidation at the initial pH of 4, 6 and 9, and the final pHs of reaction solutions were around 5.5. However, propoxur degraded slower at initial pH 2, and the pH did not vary during the period of photocatalytic reaction. The photocatalytic oxidation of propoxur using TiO₂ suspensions as the photocatalyst was reaction‐controlled as indicated by the activation energy.     

Highly promoted phytoremediation with endophyte inoculation in multi-contaminated soil: plant biochemical and rhizosphere soil ecological functioning behavior

Environmental Science and Pollution Research - Rhizosphere soil ecological functioning behavior is of critical importance for regulating phytoremediation efficiency during microbial-assisted...