Water Filtration Using Wood Fibers

 

One of the key components of living off-the-grid is an effective method of water filtration, and a team of researchers at the Swedish KTH Royal Institute of Technology has uncovered a simple and affordable way of doing that. They have developed a technique to filter water using wood fibers.

The main aim of this project is to provide clean water in refugee camps, though the method could easily be used in any setting where a green and off-grid water filtration is needed.

The team created a new material out of wood fibers and a positively-charged polymer, which binds bacteria to its surface. In this way, the bacteria in the water are removed and the water is purified. Another use for this new material is also prevention of infection, since it can be used in bandages and plasters.

However, the main aim of this project is providing an affordable and easy to use filter for a portable water purification system, which isn’t reliant on electricity. All that’s needed for it to do its job is gravity, which forces the water through it. The bacteria is removed from the water by the material, while the filter itself doesn’t cause any toxic chemicals to enter the water as is the case with many currently used on-site water filtration options.

The filter they created works on the basis of the positively-charged polymer attracting the negatively charged bacteria and viruses in the water. The bacteria which are stuck to the surface of the polymer in this way cannot get unstuck or reproduce, and they eventually die. No chemicals or antibacterial agents are used in this process, which also means that creating bacterial resistance is not an issue.

Disposal is also easy, since the wood filter can simply be burned once it is no longer effective.

Solar Cells That Harvest Energy All Day Every Day

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One huge drawback of going solar is the fact that it only makes sense in areas which get abundant sunshine year-round. However, a team of scientists from China has now come up with a new solar cell, which can harvest energy even when it’s raining.

This solar cell is made using graphene, which has proven to be a very promising material for use in the production of solar cells in the past. One of these properties of graphene is its conductivity, which is such that it allows electrons to flow freely across its surface. So when this material is put into an aqueous solution, the so-called Lewis acid-base reaction occurs, namely that pairs of positively charged ions bind with the material’s negatively charged electrons. Studying this property of graphene, the team developed a solar cell, which can generate power from raindrops.

Raindrops are comprised of various salts, which have positively and negatively charged ions. So when rainwater hits graphene the positive ions bind with the negative ions on its surface. Where the rainwater and graphene come into contact, they form a double-layer of electrons and positively-charged ions, which creates a so-called pseudocapacitor. The two layers thus have a difference in potential, which is sufficient to generate a voltage and current.

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The scientists have produced a prototype dye-sensitized solar cell and applied a thin film of graphene to it. They tested this cell in a lab, using salty water made to closely resemble rain. The cell they tested successfully generated hundreds of microvolts and had the solar to electricity conversion efficiency of 6.5 percent. Their next step will be to further refine the cell, and they are confident that they will succeed in creating a market-ready all-weather solar cell soon.

New Breakthrough with Perovskite Solar Cells

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As you’re probably already aware, perovskite solar cells have the greatest potential of being the most prominent source of solar energy in the near future. They’re cheap to make and flexible enough to be applied to most any surface.

And now a team of researchers from the University of New South Wales (UNSW) in Sydney, Australia has made a breakthrough by creating the biggest perovskite solar cell so far, and setting a new efficiency record with it.

According to them, they have managed to achieve a 12.1 percent energy conversion efficiency rating for a 6.3 sq in (16 sq cm) perovskite solar cell. This cell is also about 10 times larger than any existing high-efficiency perovskite cell. The team also managed to achieve 18 percent efficiency for a 0.5 sq in (1.2 sq cm) single perovskite cell, as well as 11.5 percent for a 6.3 sq in (16 sq cm) four-cell perovskite mini-module. They are also confident that they can achieve a 24 percent efficiency within a year or so.

These cells get their name from the crystals they are made of, which are grown into a structure called perovskite. Due to their special characteristic, such as the smooth layers of perovskite with large crystal grain sizes, these cells can absorb more light than solar cells made of silicon. They are also much cheaper to produce.

Perovskite cells can also be created in different colors, or be transparent due to their chemical composition. This means that they can be used to cover virtually any surface, such as the sides or roofs of buildings, gadgets, cars and even windows.

One of the major downsides of perovskite solar cells is the fact that they are not very durable. However, the team believes that they can also improve their durability as they strive for even higher levels of efficiency.

Battery Made From a Sheet of Paper

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As bacteria feed on organic waste electrons are produced, so they could potentially be used as a source of power. A team of researchers at Binghamton University, NY have found a way to incorporate microbial fuel cells into a battery that is made of paper and also foldable. Since this new battery is paper-based, it is also completely biodegradable.

The battery they created can be paired with low-power biosensors, and then easily disposed of in an environmentally friendly way once it is no longer needed. It is also extremely cheap to make. This battery is perfectly suited for use in environmental sensors or medical procedures, as it can create power from virtually anything where microbes are present, such as water, soil or even the human body. It can also work using any liquid, including body fluids, namely blood, sweat, urine, or saliva.

To create the battery the scientists placed an anode on one side of the paper, which is made from a reservoir of bacteria-filled water and from a conductive polymer. On the other side of the paper, a small amount of silver nitrate encased in a thin layer of wax forms the cathode. As the paper is folded an electric current is produced. An accordion-style fold creates the most electricity, while the paper can also be folded in different ways to generate different levels of electrical output.

This is the upgraded version of the paper-based origami-style battery that lead researcher on the team, Seokheun “Sean” Choi built some time ago. It doesn’t need as many layers of paper as the previous version, since all the components are integrated into a single sheet of paper.

The uses for this innovative new battery are many and varied. It could be used in disaster relief situations, on battlefields, as well as in medical clinics in remote areas. In addition, they can also easily be used to detect pathogens and toxins in the environment.

A Breakthrough in Sustainable Hydrogen Production

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A shift to using renewable sources of energy to fuel our lifestyle is a must if we want to ensure a sustainable future. But finding such sources that are reliable, scalable, affordable and eco-friendly has been a challenge. Hydrogen is certainly one such potential source, if it could be produced and stored more efficiently, and using renewable energy to do so. But all this has proven difficult. However, the company HyperSolar has recently come up with a solution, which they believe could change all that.

HyperSolar have made a breakthrough in producing low-cost, scalable, and renewable hydrogen, using polluted or dirty water as its main source. They created a device called the H2 Generator to do the job. The device is powered by sunlight, and has a solar array attached to it, meaning it doesn’t need an additional or separate array to run. The device is a “self-contained Photoelectrochemical Nanosystem” and the technology was designed in a way that mimics photosynthesis. They claim that the nanoparticle-based system they developed leads to a significantly more efficient electrolysis process compared to a system that would be powered by a separate solar unit. Since the device has the solar array attached to it, there is also very little energy loss. The entire device, including the solar array can be submerged in water.

According to HyperSolar, the device optimizes the science of water electrolysis, using sunlight to separate hydrogen from any available source of water to produce clean and environmentally friendly renewable hydrogen. To work, the H2 Generator does not need conventional electrolyzers that are energy intensive and expensive.

They are currently testing the lab-scale prototype of the H2 Generator, but they believe it could easily be scaled up and set to work turning wastewater into energy. Let’s hope this tech becomes available soon.