There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Reverse osmosis desalination: Water sources, technology, and today's challenges

Direct And Mediated Anodic Oxidation of Organic Pollutants

Removal of heavy metal ions from wastewater by chemically modified plant wastes as adsorbents: A review

Microbial and plant derived biomass for removal of heavy metals from wastewater.

This paper reports an investigation into the adsorption of methylene blue (MB – as representative of a group of potentially polluting chemicals) by modified Luffa cylindrica (LC). A simple and efficient preparation was employed to treat LC which then successfully and rapidly adsorbed methylene blue in the presence of light. The combination of photodegradation and adsorption of MB occurred simultaneously. The effects of contact time, solution pH, temperature, and initial adsorbate concentration are described. The LC was characterized by Brunauer–Emmett–Teller, Fourier transform infra-red, and scanning electron microscopy with energy-dispersive X-ray analyses. The treated LC adsorbed methylene blue dye from aqueous solution within 5 min at an optimum pH of 7. The experimental data best fitted the Freundlich model, with R2 = 0.998 and a maximum adsorption capacity of 98.5% at pH 7. There is a difference in adsorption capacity in dark and light conditions. The kinetic data was represented by the pseudo-second-order (PSO) model. This study shows the potential of chemically modified LC to treat wastewater contaminated by methylene blue dye and similar chemicals.

/pdf/light-assisted-adsorption-of-methylene-blue-dye-onto-luffa-49129u1q0y.pdf

Light-assisted adsorption of methylene blue dye onto Luffa cylindrica

. The main technique for removing bacteria from water for various applications is chemical disinfection. However, this method has many disadvantages such as producing disinfectant by-products (DBPs), biofilm formation and either rendering the water unpotable (at high residual disinfection) or leaving a potential for lethal diseases such as Cholera (if the residual disinfection is too low). Recently, a process was developed for continuous removal of bacteria from water using the principle of froth flotation through compressed air only without any chemicals (Hassan, 2015). This work examines the extent to which chemical free froth flotation can purify drinking water. The experiments were carried out using two flotation columns with different column lengths, each equipped with ceramic air sparger. Raw water containing bacteria was fed into the column from the top. Air was pumped through the water enough to produce a froth which separated the bacteria and, when removed, the bacterial content measured. The results show that the bacterial concentration can be reduced by 55% of its original concentration under the optimal experimental conditions so far found. This suggests that the technique can be used as a pre-purification step to minimize the use of disinfectants; hence their byproducts, and to control biofilm growth.

/pdf/bio-purification-of-drinking-water-by-froth-flotation-8rgctj03dv.pdf

Bio-purification of drinking water by froth flotation

Henry Clifton Sorby (1826–1908) is best known to geologists for his pioneering use of the petrological microscope and for instigating the systematic study of fluid inclusions. He also introduced microscopy to many other areas of science. Sorby belongs to that great tradition of amateurs who have made substantial contributions to science. Being unhindered by the needs of funding bodies, Sorby’s research ranged widely and touched on many topics that are still current today.

/pdf/the-chemical-precipitates-of-henry-sorby-3dfk48ip21.pdf

The Chemical Precipitates of Henry Sorby

This work investigates the effectiveness of seawater pre-treatment for the prevention of membrane fouling during reverse osmosis (RO) using an upstream nano-aluminia depth filter. Data from atomic force and scanning electron microscopy, and attenuated total reflectance-Fourier transform infra-red spectroscopy, show that there is a substantial reduction in fouling of RO membranes when a nano-alumina depth filter is used. The filter improved the performance of the RO membranes by removing the majority of substances that cause membrane fouling, including transparent exopolymer particles, micro-organisms and metals. This result demonstrates that nano-alumina filters are an effective and low-cost approach to the pre-treatment of RO membrane systems.

Robert G. J. Edyvean

Papers

Light-assisted adsorption of methylene blue dye onto Luffa cylindrica

Bio-purification of drinking water by froth flotation

The Chemical Precipitates of Henry Sorby

Prevention of SWRO membrane fouling using nano-alumina depth filter