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Lykke Preston opublikował 5 miesięcy, 2 tygodnie temu
Due to the large output and potential ecological risks, disposal of engineering abandoned soils (EAS) has become an enormous challenge for human society. Herein, EAS has been transformed into microporous analcime (ANA) zeolite material through a fast, energy-efficient, and straightforward conversion process. The as-synthesized ANA has been employed to remediate Cu-polluted soil, which shows a significant ecological restoration function in a vegetable pot experiment. With 25 g/kg ANA into Cu contaminated soil (total Cu concentration 200 ppm), the Cu accumulation concentration in vegetables has been decreased from 5.60 down to 1.80 mg/kg (approaching the background Cu level 1.70 mg/kg in vegetables). Detailed mechanism study combining with DFT calculations reveals that the Cu2+ in soil has been captured both inside the ANA pore channels and on the surface via ion-exchange and surface adsorption mechanism. The whole process, including ANA synthesis and Cu polluted soil remediation, has been optimized to show a valuable conceptual model to recycle EAS resource and in-situ remediate Cu polluted soil.A methodology for developing scenario-based leaching assessments as part of the Leaching Environmental Assessment Framework (LEAF) is illustrated using a hypothetical management/treatment scenario of contaminated soil from a copper and lead smelter. Scenario assessments refine the process beyond screening-level assessments by considering site- and scenario-specific information about the disposal or utilization environment. LEAF assessments assume (i) granular materials leach at local equilibrium with percolating water, while (ii) monolithic materials (e.g., low permeability solidified/stabilized soils) leach by diffusion-based mass transport toward surrounding contact water. Leaching concentrations, estimated using LEAF leaching test data and estimated or measured scenario information, are compared to threshold values. Demonstration results indicate that leaching from untreated soil is significantly (>10x) greater from solidified/stabilized soil than treated material, except for highly soluble constituents (Cl-, NO3-2) or when constituents have similar equilibrium concentrations in both materials (As, Pb). Comparison between wet and dry environments show that while dry environments lead to lower COPC mass-based rates of leaching, the leaching concentrations may be higher due to lower liquid-to-solid ratios. The presented assessment methodology can be used to evaluate treatment effectiveness when both physical and chemical retention characteristics of the material are altered.Sediment in fluvial-deltaic plains with high-As groundwater is heterogenous but its characterization of As and Fe oxidation states lacks resolution, and is rarely attempted for aqueous and solid phases simultaneously. Here, we pair high-resolution (> 1 sample/meter) Fe extended fine-structure spectroscopy (EXAFS, n = 40) and As X-ray absorption near-edge spectroscopy (XANES, n = 49) with groundwater composition and metagenomics measurements for two sediment cores and their associated wells (n = 8) from the Yinchuan Plain in northwest China. At shallower depths, nitrate and Mn/Fe reducing sediment zones are fine textured, contain 9.6 ± 5.6 mg kg-1 of As(V) and 2.3 ± 2.7 mg kg-1 of As(III) with 9.1 ± 8.1 g kg-1 of Fe(III) (hydr)oxides, with bacterial genera capable of As and Fe reduction identified. In four deeper 10-m sections, sulfate-reducing sediments are coarser and contain 2.6 ± 1.3 mg kg-1 of As(V) and 1.1 ± 1.0 mg kg-1 of As(III) with 3.2 ± 2.6 g kg-1 of Fe(III) (hydr)oxides, even though groundwater As concentrations can exceed 200 μg/L, mostly as As(III). Super-enrichment of sediment As (42-133 mg kg-1, n = 7) at shallower depth is due to redox trapping during past groundwater discharge. Active As and Fe reduction is supported by the contrast between the As(III)-dominated groundwater and the As(V)-dominated sediment, and by the decreasing sediment As(V) and Fe(III) (hydr)oxides concentrations with depth.In this paper, a bifunctional tri-site fluorescent probe was designed for the first time not only for visualization and quantitative analysis of sensing H2S in wastewater by coupling paper strip and smartphone (Color recognizer, Xiyi Technology) but also for sensitively monitoring GSH in living cells, which relied on different emission channels and the pH of solutions. The recognition properties of GH towards H2S/GSH were satisfactorily demonstrated through fluorescence, UV-vis, 1H NMR and DFT calculations. More importantly, integrated with the paper strip, portable smartphone-sensing platform with a color recognizer app would accomplish cost-effective and rapid assays for colorimetric water quality testing, which displayed huge application potential in fields of environmental monitoring.Biosynthetic crystals (BC) were prepared through microbially induced calcium carbonate precipitation (MICP) for fluoride (F-) removal from the groundwater. Batch experiments were conducted to evaluate the fluoride adsorption capacity and the impacts of critical factors (organic matter, pH, initial fluoride concentration and BC dosage) on defluorination efficiency of BC. The maximum adsorption amount and defluorination efficiency were recorded as 5.10 mg g-1 and 98.24%, respectively. The adsorption kinetics and isotherms studies showed that pseudo-second-order kinetic model and Freundlich isotherm model were best fitting to the reaction. Adsorption thermodynamic parameters indicated a spontaneous, endothermic and thermodynamically favorable adsorption process. Moreover, the mechanism of F- removal by BC was further analyzed by SEM, XPS, XRD and FTIR. The method can cope with the problem of applying the external organic substances in MICP, and avoid the microbial safety risk in the effluent. As an economically and environmentally friendly adsorbent, BC can be used for F- removal from groundwater.People typically spend most of their time indoors. It is of importance to establish prediction models to estimate PM2.5 concentration in indoor environments (e.g., residential households) to allow accurate assessments of exposure in epidemiological studies. This study aimed to develop models to predict PM2.5 concentration in residential households. PM2.5 concentration and related parameters (e.g., basic information about the households and ventilation settings) were collected in 116 households during the winter and summer seasons in Hong Kong. Outdoor PM2.5 concentration at households was estimated using a land-use regression model. The random forest machine learning algorithm was then applied to develop indoor PM2.5 prediction models. The results show that the random forest model achieved a promising predictive accuracy, with R2 and cross-validation R2 values of 0.93 and 0.65, respectively. Outdoor PM2.5 concentration was the most important predictor variable, followed in descending order by the household marked number, outdoor temperature, outdoor relative humidity, average household area and air conditioning. The external validation result using an independent dataset confirmed the potential application of the random forest model, with an R2 value of 0.47. Overall, this study shows the value of a combined land-use regression and machine learning approach in establishing indoor PM2.5 prediction models that provide a relatively accurate assessment of exposure for use in epidemiological studies.Behavior of veterinary antibiotics, the corresponding resistant genes in soil layer of constructed wetlands (red soil), and their response to different hydraulic loading rates (HLR) (2, 5, and 10 cm/d) were investigated. Results indicated that the soil layer had perfect performance for oxytetracycline and ciprofloxacin, yet sulfamethazine removal was unsatisfactory. Detection rates of oxytetracycline, ciprofloxacin and sulfamethazine in the effluent of simulation systems of soil layer were 8.33-36.36%, 8.33-47.83% and 100%, respectively. The model analysis of adsorption and hydrolysis indicated that physical adsorption, which was controlled by exchange reaction process based on diffusion, was the primary adsorption mechanism of target antibiotics in red soil, and the hydrolysis half-life values of antibiotics in the water of soil layer were shorter than them in wastewater. The removal response of oxytetracycline and ciprofloxacin to change of HLR was insignificant, yet the respective effluent concentrations of sulfamethazine at HLR of 2-10 cm/d were 41.90, 61.35 and 73.54 μg/L during treating synthetic livestock wastewater, which revealed significant positive correlation (P less then 0.05). The relative abundances of each target resistance genes in soil showed significant increase after treating wastewater (10-5-10-6 to 10-4-10-1), and the total level of those at different HLRs (2, 5, and 10 cm/d) were 3.02 × 10-2, 7.54 × 10-2 and 8.65 × 10-1, respectively. In summary, HLR could affect the removal efficiency of partial antibiotic in soil layer of constructed wetlands, and the expression of antibiotic resistance in the soil gradually increased with increase in the HLR.A novel lysine and EDA double cross-linked graphene aerogel (LEGA) was constructed. The prepared LEGA was utilized as a methylene blue (MB) adsorbent in the wastewater treatment. It exhibits a three-dimensional interconnected porous structure benefiting dye adsorption. Its compression property is highly enhanced with the addition of lysine. Adsorption isotherm and kinetics of MB onto LEGA were discussed. Their results show that MB adsorption onto LEGA was fitted to follow Langmuir adsorption isotherm model and the pseudo-second-order kinetic model. LEGA has an excellent adsorption capacity towards MB as high as 332.23 mg/g and its MB adsorption process is proved to be an exothermic process. The mechanism for MB adsorption onto LEGA was proposed as the ion exchange, electrostatic interaction, π-π stacking interaction and hydrogen bonding. Thus, LEGA is confirmed to be a sustainable and green MB adsorbent with highly removal efficiency in the treatment of wastewater.A photocatalyst based on the integration of reduced graphene oxide (rGO) with Bi4O5Br2 nanosheets was facilely prepared and was confirmed by transmission electron microscope, scanning electron microscope, X-ray diffraction and Raman spectroscopy. The integration of rGO can effectively improve the adsorption and the photocatalytic properties of Bi4O5Br2 nanosheets towards the target antibiotics under visible light irradiation. rGO/Bi4O5Br2 nanocomposite containing 1.0 wt% of rGO exhibits the optimal adsorption and photocatalytic activity towards ciprofloxacin (CIP), norfloxacin (NOR) and tetracycline (TC). The removal efficiencies of CIP, NOR and TC are 97.6%, 80.7% and 98.7%, which are higher than that obtained with Bi4O5Br2 nanosheets. The capture experiments and ESR data show that ·O2-, OH· and h+ are the main active species that participated in the photodegradation system. This work provides a simple strategy to integrate rGO with BixOyXz (X = Cl, Br, I) nanosheets to construct effective photocatalysts for the degradation of antibiotics.Sn0.9Sb0.1O2/TiO2 (ATO/TiO2) heterostructure is a potential visible light photocatalysts that function via an inter-semiconductor hole-transport mechanism. Herein we selectively deposited Au, Ag, or Pt onto the ATO surface of ATO/TiO2 to investigate charge-trapping behaviors of the noble metals and their effects on photocatalytic performance. We observed that Pt deposition greatly enhanced the photocatalytic activity whereas effects of Au or Ag depositions were not significant. The result of spectroscopic analysis also indicates that Pt is the most effective in scavenging the electrons from the ATO CB. Particularly, Pt/ATO/TiO2 (ATOTiO2 = 1585 in weight) produced CO2 of 42 ppmv in 2 h, which is 16 times and 4.8 times that of bare ATO/TiO2 and nitrogen-doped TiO2, respectively. Pt deposition on the ATO seems to suppress two independent charge recombination pathways, that is, recombination of electron-hole pairs in ATO and electron transport from the ATO CB to TiO2 VB.