Sorption characteristics of peat of Brunei Darussalam IV: equilibrium,thermodynamics and kinetics of adsorption of methylene blue and malachite green dyes from aqueous solution

Peat of Brunei Darussalam shows a great potential for the removal of methylene blue (MB) and malachite green (MG) dyes from aqueous solution. Carefully controlled batch experiments performed by changing one parameter at a time indicate that the optimum time periods of agitation and settling required for maximum removal of MB are 2.0 and 1.0 h, respectively, while these values for MG are 4.0 and 1.0 h, respectively. The optimum pH is determined to be the ambient value, and under the optimum conditions, 90 % removal of both dyes was determined under laboratory conditions. The equilibrium adsorption data analyzed for various isotherm models suggest that the Sips and Redlich–Peterson (R–P) models are valid for MB and MG, respectively. Further, thermodynamic studies show that the adsorption of both dyes on peat is spontaneous and endothermic. The adsorption capacities (q _max) of MB and MG dyes on peat are 0.45 and 0.31 mmol g^?1, respectively. Characterization of the surfaces of peat before and after treatment of dyes by SEM and FTIR provides conclusive evidence of adsorption of both dyes. Kinetics studies indicate that the adsorption of both MB and MG dyes is favored toward the pseudo-second-order model, with a little contribution of MG to the pseudo-first-order model. These results suggest that peat is a potential low-cost adsorbent for the removal of MB and MG dyes.     

A spatial statistical analysis of the occurrence of earthquakes along the Red Sea floor spreading: clusters of seismicity

The aim of this study is to apply spatial pattern analysis techniques to a seismic data catalog of earthquakes beneath the Red Sea to try and detect clusters and explore global and local spatial patterns in the occurrence of earthquakes over the years from 1900 to 2009 using a geographical information system (GIS). The spatial pattern analysis techniques chosen for this study were quadrant count analysis, average nearest neighbor, global Moran’s I, Getis–Ord general G, Anselin Local Moran’s I, Getis–Ord Gi*, kernel density estimation, and geographical distributions. Each of these techniques was implemented in the GIS so that computations could be carried out quickly and efficiently. Results showed that (1) these techniques were capable of detecting clusters in the spatial patterns of the occurrence of the earthquakes; (2) both global and local spatial statistics indicate that earthquakes were clustered in the study area beneath the Red Sea; (3) earthquakes with higher magnitudes on the Richter scale were notably concentrated in the central and southern parts of the Red Sea where seismic activities were most active; and (4) earthquakes with moderate magnitudes on the Richter scale were particularly concentrated in the northern part of the Red Sea where there is an area of late-stage continental rifting comprised of a broad trough without a recognizable spreading center, although there were several small, isolated deep troughs. We conclude that the pattern analysis techniques applied to the seismic data catalog of earthquakes beneath the Red Sea could detect clusters in the occurrence of earthquakes from 1900 to 2009.     

Magnetic field modulated dust streams from Jupiter in interplanetary space

High speed dust streams emanating from near Jupiter were first discovered by the Ulysses spacecraft in 1992. Since then the phenomenon has been re-observed by Galileo in 1995, Cassini in 2000, and Ulysses in 2004. The dust grains are expected to be charged to a potential of , which is sufficient to allow the planet's magnetic field to accelerate them away from the planet, where they are subsequently influenced by the interplanetary magnetic field (IMF). A similar phenomenon was observed near Saturn by Cassini. Here, we report and analyze simultaneous dust, IMF and solar wind data for all dust streams from the two Ulysses Jupiter flybys. We find that compression regions (CRs) in the IMF – regions of enhanced magnetic field – precede most dust streams. Furthermore, the duration of a dust stream is roughly comparable with that of the precedent CR, and the occurrence of a dust stream and the occurrence of the previous CR are separated by a time interval that depends on the distance to Jupiter. The intensity of the dust streams and their precedent CRs are also correlated, but this correlation is only evident at distances from the planet no greater than 2 AU. Combining these observations, we argue that CRs strongly affect dust streams, probably by deflecting dust grain trajectories, so that they can reach the spacecraft and be detected by its dust sensor.     

The COVID-19 pandemic and global environmental change: Emerging research needs

The outbreak of COVID-19 raised numerous questions on the interactions between the occurrence of new infections, the environment, climate and health. The European Union requested the H2020 HERA project which aims at setting priorities in research on environment, climate and health, to identify relevant research needs regarding Covid-19. The emergence and spread of SARS-CoV-2 appears to be related to urbanization, habitat destruction, live animal trade, intensive livestock farming and global travel. The contribution of climate and air pollution requires additional studies. Importantly, the severity of COVID-19 depends on the interactions between the viral infection, ageing and chronic diseases such as metabolic, respiratory and cardiovascular diseases and obesity which are themselves influenced by environmental stressors. The mechanisms of these interactions deserve additional scrutiny. Both the pandemic and the social response to the disease have elicited an array of behavioural and societal changes that may remain long after the pandemic and that may have long term health effects including on mental health. Recovery plans are currently being discussed or implemented and the environmental and health impacts of those plans are not clearly foreseen. Clearly, COVID-19 will have a long-lasting impact on the environmental health field and will open new research perspectives and policy needs.