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Switching desalination plants from carbon dioxide source to sink

A UK researcher has proposed a new process to decompose waste desalination brine using solar energy that could allow desalination plants to act as a sink rather than a source of atmospheric carbon dioxide, and help to neutralise ocean acidity.

Desalination plants

Phil Renforth, a geo-environmental engineer from Cardiff University, highlights that a major advantage of Davies’ process is that it can be appended to existing technology. ‘This approach may allow the industry to transform itself from a carbon dioxide villain into a force for good in the climate change debate.’


Read the full article in Chemistry World.


Read the full research paper for free* in Environmental Science: Water Research & Technology:
Solar thermal decomposition of desalination reject brine for carbon dioxide removal and neutralisation of ocean acidity

P. A. Davies
Environ. Sci.: Water Res. Technol.
, 2015, Advance Article
DOI:
10.1039/C4EW00058G, Communication


*Access is free through a registered RSC account
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Environmental Science: Water Research & Technology

Here is a few reminders of the great benefits of publishing with Environmental Science: Water Research & Technology:

Environmental Science Water
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Fast Publication (average of 40 days from receipt to acceptance)

– Wide exposure: free access to all content for the first 2 years after launch*

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Submit now!

*ES: Water Research & Technology was launched in 2015. Access is free through a registered RSC Publishing account.

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Removing phosphate from water

On 5th October 2014, Drake took a short swim in the lake in Lindon Harbor, Utah. Drake was a black Labrador retriever. Like most dogs, he loved to play in the water. After the swim, Drake started vomiting and became lethargic. Shortly after that, Drake died. “[D]og deaths have emerged as an unfortunate early warning…” An early warning of what?

When blooms aren’t beautiful and nutrients don’t nourish

Recent dog deaths have pointed to one suspect: pond scum – or more specifically – harmful algal blooms. Some algae produce toxins that have been linked to the deaths of cattle, elks, fishes, and even endangered species such as sea otters. These toxins can also bioaccumulate in shellfish and oysters. Eat enough seafood seasoned with these toxins, and you are at risk too.

What’s causing these algal blooms?

Natural waters contain small amounts of nutrients (mostly nitrate and phosphate). Under normal conditions, planktons and algae grow using these nutrients, fish feed on the plankton, and things are in balance.

But excess nutrients in the water can skew the balance in favour of the algae, allowing them to spread unchecked like weeds. Even if they don’t produce toxins the algae block light as they sun themselves on the water surface. These harmful algal blooms alter marine and freshwater habitats, smothering other forms of aquatic life. This map gives an idea of how bad the situation has become.

Why are nutrient concentrations increasing?

Excess nutrients enter the water when rain washes fertilizers from agricultural land into the nearby water bodies. Other major sources of nutrients are industrial and domestic wastewater. In short, the blame falls squarely on us humans – me and you.

Water treatment and nutrient removal

It is our mess and we have to clean it. Researchers have been actively developing more efficient ways for removing nutrients from drinking water and wastewater. In a recent article, Lalley et al. reported a novel method for removing phosphate (a growth-limiting nutrient).

The authors present clever modifications of an absorptive medium (originally developed for removing arsenic from water) using silver and manganese nanoparticles. One of these modifications involves tea extract.

What could the humble tea have to do with this method for phosphate removal? Find out by reading the full article for free*:

Phosphate removal using modified Bayoxide® E33 adsorption media
Environ. Sci.: Water Res. Technol., 2015, Advance Article
DOI: 10.1039/C4EW00020J

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About the webwriter

Paramjeet Pati is a PhD Candidate at the Virginia Tech Center for Sustainable Nanotechnology (@VTSuN).
You can find more articles by him in the VTSuN blog, where he writes using the name
coffeemug.

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Arsenic removal enhanced by humic acid

Schematic diagram of humic acid coating

Schematic diagram of humic acid coating on iron-based graphene composites

After tragic events like the devastating arsenic poisoning in Bangladesh in 2010, the exposure of drinking water to arsenic is a very serious concern worldwide.

Past studies have shown that removal of arsenic by nanoparticles in the presence of Humic Acid (HA) has a negative role. Now, for the first time, Blain Paul and colleagues have reported a positive influence of HA on graphene–Fe3O4 nano-composites for the removal of arsenic in water.

Contradictory to the general belief that HA has a negative effect on the ability of any system to absorb arsenic from water, this remarkable study demonstrates a role reversal of HA where it actually enhances the ability of graphene-Fe3O4 nano-composite to remove arsenic from ground water.

Researchers from the University of Johannesburg assembled Fe3O4 nanoparticles on graphene oxide sheets and coated with humic acid. The humic acid coating not only enhanced the nano-composites absorption ability, but almost doubled the removal efficiency of As(III) and As(V), opening a new dimension in the practical utilisation of nanotechnology in water research for arsenic removal.

Download the full paper for free* to find out how humic acid coating could significantly alter mechanism through π–π interactions, positively enhancing the removal of arsenic from water:

Graphene in the Fe3O4 nano-composite switching the negative influence of humic acid coating into an enhancing effect in the removal of arsenic from water
Blain Paul, Vyom Parashara and Ajay Mishra
Environ. Sci.: Water Res. Technol., 2015, Advance Article
DOI: 10.1039/ C4EW00034J

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