The effects of soil properties and temperature on the adsorption isotherms of lead on some temperate and semiarid surface soils of Iran

Sorption of metal ions by soil and clay minerals is a complex process involving different mechanisms, and controlled by different variables that can interact. The aim of this work was to study the retention mechanisms of Pb ions on different soil samples. Surface soils were sampled from Guilan and Hamadan provinces in north and northwest of Iran with temperate and semiarid climates. The adsorption isotherms of Pb on the soils have been studied at 15, 27 and 37°C. The adsorption data for different soils were fitted into Langmuir and Freundlich models. Temperate soil samples had higher clay content, cation exchange capacity, dichromate (oxidable) organic carbon, total Kjeldahl-nitrogen, biological activity, amorphous and crystalline Fe and Al, but semiarid soil samples had higher sand content, pH, equivalent calcium carbonate, available P and K. Lead adsorption data obtained from semiarid soils against those obtained from temperate soils were better fitted in both Langmuir and Freundlich models. Langmuir constants Q ₀ for Pb adsorption in semiarid soils were considerably lower than those for Pb adsorption in temperate soils. However, the binding energy (K _L) of Pb and Freundlich constant n were higher for data of semiarid soils. The effect of temperature on the Pb adsorption was positive especially in temperate soils; however, soil properties had higher effects on Pb adsorption.     

Piezocatalytic removal of water bacteria and organic compounds: a review

Environmental Chemistry Letters - In the context of climate change, freshwater shrinkage and industrialization, human diseases are increasing due to water pollution by toxic chemicals and...     

Abundance,spatial distribution,and physical characteristics of microplastics in stormwater detention ponds

Despite extensive research on microplastics (MP) in marine environments, little is known about MP abundance and transport in terrestrial systems. There is, therefore, still little understanding of the main mechanisms driving the substantial transport of MP across different environmental compartments. Storm events can transport MP beyond boundaries, such as from the land to groundwater or the ocean, as has already been discovered for organic carbon transport. Urban stormwater detention ponds are suitable environments to study the impact of stormwater on the environmental fate and transport of MP. Herein, we investigate the longitudinal and vertical distribution of MP within two detention ponds with different physical characteristics. Soil samples were collected at various locations and from multiple depths (surface and subsurface layers) for measuring MP concentrations using fluorescence microscopy. Our findings show that MP are retained more near the inlet of the ponds, and MP of larger sizes were found more abundantly near inlets than outlets. We also found that MP mass and sizes decrease from surface soil to subsurface soil. In the pond, where vegetation (grass root network) was more considerable, MP were found more evenly distributed along the depth. In terms of shape, the fragments were the most abundant MP shape.     

Au nanoring arrays as surface enhanced Raman spectroscopy substrate for chemical component study of individual atmospheric aerosol particle

Monolayer-ordered gold nanoring arrays were prepared by ion-sputtering method and used as surface enhanced Raman spectroscopy (SERS) substrates to test the individual atmospheric aerosols particle. Compared to other methods used for testing atmospheric aerosols particles, the collection and subsequent detection in our work is performed directly on the gold nanoring SERS substrate without any treatment of the analyte. The SERS performance can be tuned by changing the depth of the gold nanoring cavity as originating from coupling of dipolar modes at the inner and outer surfaces of the nanorings. The electric field exhibits uniform enhancement and polarization in the ordered Au nanoring substrate, which can improve the accuracy for detecting atmospheric aerosol particles. Combined with Raman mapping, the information about chemical composition of individual atmospheric aerosols particle and distribution of specific components can be presented visually. The results show the potential of SERS in enabling improved analysis of aerosol particle chemical composition, mixing state, and other related physicochemical properties.     

Enhanced photocatalytic activities of silicon nanowires/graphene oxide nanocomposite: Effect of etching parameters

Homogeneous and vertically aligned silicon nanowires (SiNWs) were successfully fabricated using silver assisted chemical etching technique. The prepared samples were characterized using scanning electron microscopy, transmission electron microscopy and atomic force microscopy. Photocatalytic degradation properties of graphene oxide (GO) modified SiNWs have been investigated. We found that the SiNWs morphology depends on etching time and etchant composition. The SiNWs length could be tuned from 1 to 42 µm, respectively when varying the etching time from 5 to 30 min. The etchant concentration was found to accelerate the etching process; doubling the concentrations increases the length of the SiNWs by a factor of two for fixed etching time. Changes in bundle morphology were also studied as function of etching parameters. The SiNWs diameter was found to be independent of etching time or etchant composition while the size of the SiNWs bundle increases with increasing etching time and etchant concentration. The addition of GO was found to improve significantly the photocatalytic activity of SiNWs. A strong correlation between etching parameters and photocatalysis efficiency has been observed, mainly for SiNWs prepared at optimum etching time and etchant concentrations of 10 min and 4:1:8. A degradation of 92% was obtained which further improved to 96% by addition of hydrogen peroxide. Only degradation efficiency of 16% and 31% has been observed for bare Si and GO/bare Si samples respectively. The obtained results demonstrate that the developed SiNWs/GO composite exhibits excellent photocatalytic performance and could be used as potential platform for the degradation of organic pollutants.     

基于压电传感板的建筑疏散照明技术

在当今世界,电力、能源和安全是人们日常生活的基本要求。为了应对日益增长的能源需求,最终的解决办法是实施可再生能源,然后将其用于人类的安全。可再生能源需要以它们各自正确的方式实施。研究基于压电传感器片的迈步发电装置,并演示了如何利用这些能量实现建筑物疏散照明。我们在传感器的下方和顶部分别固定了木板和可移动网螺栓,利用压电传感器系统,行人可以通过迈步向发电装置施加电能,另外,将硅凝胶粘贴在位于下部木板空洞中的所有传感器顶部。当有人踩到板上时,就会自动施加压力。在木板的顶部和底部设置了一个孔,以便随时调整在底部和顶板之间安装的可移动网螺栓。烟雾传感器用于启动灯光。使用这种设备,我们实现了建筑物疏散路径上的LED灯正常运行。结果表明,这种安全发电的设计和方法具有一定的实用价值,同时也满足了全球对能源的需求。     

Analyzing the Variability of Remote Sensing and Hydrologic Model Evapotranspiration Products in a Watershed in Michigan

The goal of this paper was to statistically explore the spatiotemporal performance of remotely sensed actual evapotranspiration (ETa) datasets and a remotely sensed ensemble in a region that lacks observed data. The remotely sensed datasets were further compared with ETa results from a physically based hydrologic model (Soil and Water Assessment Tool) to examine the differences and determine the level of agreement between the ETa datasets and the model outputs. ETa datasets were compared on temporal (i.e., monthly and seasonal basis) and spatial (i.e., landuse) scales at both watershed and subbasin levels. The results showed a lack of consistent similarities and differences among the datasets when evaluating the monthly ETa variations; however, the seasonal aggregated data presented more consistent similarities and differences during the spring and summer compared to the fall and winter. Meanwhile, spatial analysis of the datasets showed the MOD16A2 500 m ETa product was the most versatile of the tested datasets, being able to differentiate between landuses during all seasons. Furthermore, the use of an averaging ensemble was able to improve overall ETa performance in the study area. This study showed that the remotely sensed ETa products are not similar throughout the year, but the appropriate application periods for different ETa products were identified. Finally, spatial variabilities of the ETa products are more in tune with landuse and climate characteristics.     

Enhanced uptake of Cd,Cr, and Cu in Catharanthus roseus (L.) G.Don by Bacillus cereus: application of moss and compost to reduce metal availability

Environmental Science and Pollution Research - Heavy metals (HMs) being the notorious and toxic are being introduced into the environment credited to natural and anthropogenic activities. The use...     

The effect of biochar on severity of soil water repellency of crude oil-contaminated soil

Environmental Science and Pollution Research - Crude oil contamination adversely affects soil water repellency. In this study the effect of biochar on this soil characteristic has been investigated...     

Bifenthrin exerts proatherogenic effects via arterial accumulation of native and oxidized LDL in rats: the beneficial role of vitamin E and selenium

Environmental Science and Pollution Research - The purpose of this study was to investigate, for the first time, the effects of Bifenthrin (Bif) chronic exposure on plasmatic and aortic lipid...