Fe-Mn binary oxide incorporated into porous diatomite (FMBO-diatomite) was prepared in situ and regenerated in a fixed-bed
column for arsenite [As(III)] and arsenate [As(V)] removal. Four consecutive adsorption cycles were operated under the following
conditions: Initial arsenic concentration of 0.1 mg·L−1, empty bed contact time of 5 min, and pH 7.0. About 3000, 3300, 3800, and 4500 bed volumes of eligible effluent (arsenic
concentration ⩽ 0.01 mg·L−1) were obtained in four As (III) adsorption cycles; while about 2000, 2300, 2500, and 3100 bed volumes of eligible effluent
were obtained in four As(V) adsorption cycles. The dissection results of FMBO-diatomite fixed-bed exhibited that small amounts
of manganese and iron were transferred from the top of the fixed-bed to the bottom of the fixed-bed during As(III) removal
process. Compared to the extremely low concentration of iron (<0.01 mg·L−1), the fluctuation concentration of Mn2+ in effluent of the As(III) removal column was in a range of 0.01–0.08 mg·L−1. The release of manganese suggested that manganese oxides played an important role in As(III) oxidation. Determined with
the US EPA toxicity characteristic leaching procedure (TCLP), the leaching risk of As(III) on exhausted FMBO-diatomite was
lower than that of As(V). 相似文献
A plant bio-electrochemical system(PBES) was constructed for organic pollutant removal and power generation. The bio-cathode, composed of granular activated carbon(GAC), stainless wire mesh and a plant species(Triticum aestivum L.), was able to catalyze cathodic reactions without any requirement for aeration or power input. During the 60-day-long operation, an average voltage of 516 m V(1000 Ω) and maximum power density(Pmax) of 0.83 W/m~3 were obtained in the PBES. The total nitrogen removal and total organic carbon removal in the PBES were 85% and 97%, respectively. Microbial community analyses indicated that bacteria associated with power generation and organic removal were the predominant species in the bio-cathode, and plant-growth-promoting rhizobacteria were also found in the PBES. The results suggested that the coupling of plants with the GAC cathode may enhance the organicmatter degradation and energy generation from wastewater and therefore provide a new method for bio-cathode design and promote energy efficiency. 相似文献
Environmental Science and Pollution Research - China’s power sector has received great research attention because of its large energy consumption and CO2 emissions. This study assesses the... 相似文献
• The first study on micro(meso)plastics (MMPs) in the Liaohe River Reserve is reported.• Diverse MMP were detected in surface water and sediment at all 32 sites.• The abundance of MMPs decreased in the course of the river.• The MMPs abundance in water is significant association with the county population. Microplastics pollution has received growing attention worldwide in recent years. However, data on microplastics in the freshwater environment are still limited, especially in high-latitude nature reserves in Northern China. The first study on microplastic pollution in the Liaohe River Reserve in Northern China is reported here, and mesoplastics were also incorporated. Surface water and sediment samples were collected from 32 sites along the nature reserve. The abundance, type, shape, color, and size of micro- and mesoplastics were measured using density extraction, optical microscopy, and FTIR spectroscopy. The data showed that diverse micro- and mesoplastics were found widespread in the 32 sites, and the average abundance of these plastics was 0.11±0.04 10−2 items/L in surface water and 62.29±54.30 items/kg in sediment. Moreover, 70% and 66% were smaller than 2000 μm in surface water and sediment, respectively. Fiber accounted for 91.86% in surface water and 43.48% in sediment, indicating that the major source of micro- and mesoplastics in the Liaohe River Reserve may be domestic sewage and aquaculture. A total of 16 and 27 polymers were identified in surface water and sediment, respectively, and mostly consisted of rayon, polyester, polystyrene, and poly(ethylene terephthalate). Moreover, both the risk index and the pollution load index demonstrated a low risk of micro- and mesoplastics in surface water and sediment in the Liaohe River Reserve. 相似文献
The association between allergic respiratory diseases, such as asthma and allergic rhinitis (AR), and green space (GS) remains controversial. Our study aimed to summarize and synthesize the association between individual GS exposure and the incidence of asthma/AR. We systematically summarized the qualitative relationship between GS exposure and asthma and AR. The pooled odds ratio (OR) with 95% confidence intervals (CIs) was used to estimate the effect of the Normalized Difference Vegetation Index (NDVI) on asthma and AR. A total of 21 studies were included for systematic review, and 8 of them underwent meta-analysis. In the meta-analysis of current asthma, the 0?<?radius?≤?100 m group, 100?<?radius?≤?300 m group, and 500?<?radius?≤?1000 m group presented weak negative associations between the NDVI and current asthma. For ever asthma, slight positive associations existed in the 0?<?radius?≤?100 m group and 300?<?radius?≤?500 m group. In addition, the NDVI might slightly reduce the risk of AR in radius of 100 m and 500 m. Our findings suggest that the effects of GS exposure on asthma and AR were not significant. Differences in GS measurements, disease diagnoses and adjusted confounders across studies may have an impact on the results. Subsequent studies should consider potential confounding factors and use more accurate GS exposure measurements to better understand the impact of GS exposure on respiratory disease in the population.