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.

New Breakthrough with Perovskite Solar Cells

pero

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

paper-battery

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 Device That Purifies Polluted Air While Producing Hydrogen

Air pollution is one of the key problems that need to be overcome in order to secure a more sustainable future for our planet. So it’s great news that a team of scientists from the University of Antwerp and KU Leuven, have devised a process that can both mitigate air pollution as well as provide a clean energy source in the form of hydrogen, at the same time. This device does so using nanomaterials and sunlight.

The nanomaterials are contained within the membrane of the device the team developed, where they are used as a catalyst in this process. Previously, this same type of membrane was used to extract hydrogen from water, but the team has now found that it’s possible for this material to also be used to extract it from polluted air. And on top of that, this membrane is also more efficient at doing so. To test it, the team has made a small prototype of the device, which measures just a few square centimeters, but they plan to scale it up to make it industrially applicable.

The energy for the process to run comes from sunlight, and the device which makes it possible is described as an “all-gas-phase unbiased photoelectrochemical cell”. It works by converting volatile organic pollutants into CO2 at one photoanode, and by harvesting hydrogen gas at the cathode. The device is most efficient when applied to organic pollutants in inert carrier gas, while if oxygen is present, the cell performs less efficiently though significant photocurrents are still generated, meaning that it can be effectively used to purify organic contaminated air.

It will most likely take some time before this device is ready for use on an industrial scale, but it does show a lot of promise. If they successfully scale it up, air pollution could become a source of clean energy instead of being an energy sink and a health hazard.

Water Producing Solar Panel

Zero Mass Water, an Arizona State University startup has created solar panel which produces water as well as electricity. The device is called SOURCE and it is standalone, meaning that it does not need any wiring or water input to harvest solar energy and produce drinking water at the same time. They have been running a pilot program since 2015 to test the system, which is already installed in a number of homes and communities.

One SOURCE unit measures 30 sq ft (2.8 sq m). It is capable of generating electricity via the solar photovoltaic panel, while it also has an integrated lithium-ion for storing the used electricity. The device then uses that electricity to power a cycle of condensation and evaporation, which produces 2 to 5 liters of water a day.

The system also includes an 8 gal (30 liter) reservoir for storing the waters that’s produced. Minerals are also added to the water here to improve taste. This reservoir can also be plumbed directly to the taps inside the building in which this system is installed. To meet the full needs of the household, multiple SOURCE units can be installed.

According to the creators, these units require minimal maintenance. The system only needs a new air filter once a year and a new mineral cartridge every five years. What also makes this system so unique is that it allows people to own their own water supply for the first time. They will also be very useful in areas where there is little to no access to drinking water.

To speed up deployment in these areas the company is starting an interesting program aimed at early adopters of the tech. They will ask customers who buy one of these SOURCE panels to split the cost of an additional panel with the company. This additional panel will be given to a family or community in need, and the customer will get to choose where it will be deployed. The household to which this panel will be given will only pay for installation and shipping.

The price is set at $4800 per unit, which is made up of $3200 for one SOURCE unit, and $1600 for the additional unit to be gifted to a family or community in need. It’s a thoughtful initiative, which will hopefully help several communities gain access to clean water.