Mechanism of combination membrane and electro-winning process on treatment and remediation of Cu2+ polluted water body.
Mechanism of treatment and remediation of synthetic Cu2+ polluted water body by membrane and electro-winning combination process was investigated. The influences of electrolysis voltage, pH, and electrolysis time on the metal recovery efficiencies were studied. Relationship between trans-membrane pressure drop (DeltaP), additions ratio, initial Cu2+ concentration on operating efficiency, stability of membrane and the possibility of water reuse were also investigated. The morphology of membrane and electrodes were observed using scanning electron microscopy (SEM), the composition of surface deposits was ascertained using combined energy dispersive X-ray spectroscopy (EDX) and atomic absorption spectrophotometer. The results showed that using low pressure reverse osmosis (LPRO), Cu2+ concentration could increase from 20 to 100 mg/L or even higher in concentrated solutions and permeate water conductivity could be less than 20 microS/cm. The addition of sodium dodecy/sulfate sodium dodecyl sulfate improved Cu2+ removal efficiency, while EDTA had little side influence. In electro-reduction process, using plante electrode cell, Cu2+ concentration could be further reduced to 5 mg/L, and the average current efficiency ranged from 9% to 40%. Using 3D electrolysis treatment, Cu2+ concentration could be reduced to 0.5 mg/L with a current efficiency range 60%-70%.
Species-specific heavy metal accumulation patterns of earthworms on a floodplain in Japan.
We identified all earthworm species found on a floodplain contaminated by heavy metals (Cu, Zn, Cd, and Pb) from an old mine in central Japan and compared their abundance, biomass, and heavy metal concentrations in tissue. There were six species belonging to three families: Megascolecidae, Moniligastridae, and Lumbricidae. Earthworm community structure seemed to be influenced mostly by soil properties, especially pH and clay fraction. Despite the same endogeic characteristics, species-specific patterns of heavy metal accumulation were observed: species in Megascolecidae and Lumbricidae had relatively lower concentrations compared to those in Moniligastridae. Within Moniligastridae, Drawida sp. accumulated Cu and Pb markedly higher than Drawida japonica. Based on heavy metal concentrations in extracts of CaCl(2) and diethylenetriaminepentaacetic acid, the aging caused remarkably low concentrations in pore water, indicating low availability by dermal uptake. Therefore the different patterns of heavy metal accumulation among species would partly result from species-specific gut process.
Do Arab public opinion support policies of regional powers in MENA? View from Tunisia
ABSTRACT The Arab Uprisings and subsequent events continue to transform policies of regional and major powers toward the Middle East and North Africa. These powers have shown different approaches toward the Uprisings, ranging from support for the status quo to endorsing regime changes. Their policies have also exerted a significant impact on the course of events. Despite this growing importance and implications of policies of regional powers on the Uprisings and the Syrian conflict, we still do not know much about how the public assesses these policies and to what extent domestic cleavages shape these assessments. Using a nationally representative original survey conducted in 2014 in Tunisia, this study examines the perceptions of the policies of France, Turkey, and Saudi Arabia towards the Uprisings and the Syrian conflict. It finds that French and Turkish policies about the Uprisings have garnered substantial support among citizens, whereas most citizens negatively assess the Saudi policies. On the other hand, the majority of Tunisians negatively assess all these countries’ policies toward the Syrian conflict. Another major finding suggests that political identity reflecting secular/religious cleavages shapes how citizens view the policies of these three countries toward both issues, but its effect is higher in assessing the Uprisings.