New water purification technology helps turn seawater into drinking water without tons of chemicals and could save billions of dollars globally

Good news! Desalination is salvation!

"Water desalination plants could replace expensive chemicals with new carbon cloth electrodes that remove boron from seawater, an important step of turning seawater into safe drinking water. ..."

From the abstract:

"Selective removal of trace contaminants from water remains a crucial challenge in water treatment. Boron is a trace contaminant that is ubiquitous in seawater and has been widely detected in groundwater.

Current boron removal methods, such as multi-stage reverse osmosis and ion-exchange adsorption, are chemical and energy intensive, necessitating the development of more sustainable technologies.

Here we address this challenge by developing surface functionalized microporous electrodes that enable boron-selective bipolar membrane-assisted electrosorption.

Our study demonstrates that micropore functionalization with oxygen-containing (hydroxyl, lactone and carboxyl) and boron-selective (dopamine, 3-methylamino-1,2-propanediol and N-methyl-d-glucamine) functional groups substantially improves electrode performance for boron removal and selectivity.

The functionalized electrodes exhibit a boron removal selectivity that is an order of magnitude higher than that of the pristine electrode, facilitating energy efficient boron electrosorption.

We identify hydroxyl groups as the key factor in enhancing boron removal performance and selectivity during electrosorption.

Molecular dynamics simulations demonstrate the underlying mechanisms of boron selectivity, highlighting the role of hydrogen bonding between hydroxyl groups and boron in governing the boron-selective electrosorption process."

New water purification technology helps turn seawater into drinking water without tons of chemicals

New water purification technology helps turn seawater into drinking water without tons of chemicals (original news release) "Cutting acid and base treatments from conventional desalination plants could save billions of dollars globally, making seawater a more affordable option for drinking water"

A highly selective and energy efficient approach to boron removal overcomes the Achilles heel of seawater desalination (no public access)

This diagram shows how boron is removed by the researchers’ electrodes.

First a majority of the salt ions are removed with reverse osmosis.

Then the water flows into a cell containing a membrane with positive (pink) and negative (orange) layers. Similarly charged electrodes face the membrane layers, and when a current is applied, water molecules at the interface of the membranes split into hydrogen and hydroxide ions. The hydroxide ions stick to boron, causing it to stick to the positive electrode.

Greater access to clean water by desalination, thanks to a better membrane

Good news! Desalination is salvation!

"... With an innovative material design, the Yale and Nanjing researchers have developed a reverse osmosis membrane that not only desalinates water but is also resistant to chlorine as well as fouling. Rather than using the industry gold standard of polyamide to develop these membranes, the researchers instead used polyester.  The choice of material is critical, as this polyester membrane allows for substantial water permeability, has a high rejection for sodium chloride and boron, and a complete resistance toward chlorine. The ultrasmooth, low-energy surface of the membrane also outdoes polyamide membranes in preventing fouling and mineral scaling.

Further, the team designed the membranes so that they could be easily adopted by the industry. ..."

From the editor's summary and abstract:

"Editor’s summary

Reverse osmosis membranes have been dominated by polyamide chemistry, which has sufficient performance in terms of water permeability and salt rejection but is vulnerable to degradation in the presence of chlorine or other strong oxidants. Polyesters are not typically used for water filtration membranes because they suffer from hydrolytic degradation when immersed in aqueous solution. Yao et al. show that the polymerization of 3,5-dihydroxy-4-methylbenzoic acid with trimesoyl chloride yields a polymer membrane with impressive resistance to hydrolytic degradation in acidic or basic conditions (up to pH 9) and a complete resistance to chlorine. ...

Abstract

Thin-film composite reverse osmosis membranes have remained the gold standard technology for desalination and water purification for nearly half a century. Polyamide films offer excellent water permeability and salt rejection but also suffer from poor chlorine resistance, high fouling propensity, and low boron rejection. We addressed these issues by molecularly designing a polyester thin-film composite reverse osmosis membrane using co-solvent–assisted interfacial polymerization to react 3,5-dihydroxy-4-methylbenzoic acid with trimesoyl chloride. This polyester membrane exhibits substantial water permeability, high rejection for sodium chloride and boron, and complete resistance toward chlorine. The ultrasmooth, low-energy surface of the membrane also prevents fouling and mineral scaling compared with polyamide membranes. These membranes could increasingly challenge polyamide membranes by further optimizing water-salt selectivity, offering a path to considerably reducing pretreatment steps in desalination."

Greater access to clean water, thanks to a better membrane | Yale School of Engineering & Applied Science

More resilient polyester membranes for high-performance reverse osmosis desalination (no public access)

Don't wait, desalinate: A new approach to water purification

Good news! Desalination is salvation! Desalination is without doubt another one of the most important research areas for humanity!

"... To save energy, the researchers streamlined the salt separation process with a chemical phenomenon called a redox reaction. The word redox is a portmanteau of the words reduction (which, in chemistry, describes adding electrons to create a negative charge) and oxidation (which means subtracting electrons to create a positive charge). Physically, triggering a redox reaction looks like adding a special polymer-based material to the wastewater before it’s filtered and purified.
Chemically, the results are transformative. Instead of splitting water molecules into positively and negatively charged slices to coax out the salt, the redox reaction changes the charge of the entire water molecule in one fell swoop, achieving the same degree of salty separation with about 90% less energy than traditional water-splitting. ..."

"... electrodialysis. Just like dialysis of the blood, which, kidney-like, flushes salt and other toxins from our veins, electrodialysis removes salts and organic matter from wastewater to produce a clean, drinkable product. ..."

From the abstract:

"Robust, energy-efficient separation technologies for desalination and the removal of organic contaminants are critical in addressing growing concerns about water shortage and water pollution. Here, we propose a generalized strategy for advancing electrodialysis technologies using redox-flow concepts, by implementing a water-soluble redox-copolymer, poly(ferrocenylpropylmethacrylamide-co-[2-(methacryloyloxy)ethyl]trimethylammonium chloride), P(FPMAm-co-METAC), to eliminate the need for anion-exchange membranes (AEMs) and deploy cheaper and more robust nanofiltration membranes (NFs). The effective membrane retention of the redox material and stable redox activity facilitate the continuous desalination of various source waters, including brackish water, seawater, and wastewater, to produce potable water and remove organic contaminants without membrane fouling or polymer crossover. Leveraging the reversible redox reaction of ferrocene reduces energy consumption by 88% within a single-unit cell compared to conventional ED. In addition, utilizing reusable redox-copolymer and cost-effective NFs promotes economic feasibility, achieving a water production cost of $0.13 m–3. Overall, the combination of redox-copolymer in flow and NFs provides a new avenue to address water contamination caused by organic pollutants and water scarcity in an energy efficient manner."

Don't wait, desalinate: A new approach to water purification

Don’t wait, desalinate: the electrified future of clean water (primary news source) A water purification system developed by Beckman researchers separates out salt and other unnecessary particles with an electrified version of dialysis. Successfully applied to wastewater with planned expansion into rivers and seas, the method saves money and saps 90% less energy than its counterparts.

Redox-Copolymers for Nanofiltration-Enabled Electrodialysis (no public access)

Sunlight-activated "loofah hydrogel" excels at off-grid water purification without fouling

Good news! Like desalination, better water filters are salvation too!

Can you believe it, it can filter microplastics! (Caution: Irony)

"... the hydrogel is hydrophilic (water-attracting) at cool temperatures, but becomes hydrophobic (water-repelling) when heated. Pollutants such as organic dyes (which were used in lab tests) do get pulled in along with the water at cool temperatures, but because their molecules stick to the gel, they don't get expelled when the water is released at warmer temps. Droplets of oil pollution don't get drawn in in the first place, as the (then) hydrophilic gel rejects them. ... loofah hydrogel can be reused simply by rinsing it with diluted acid or ethanol. ..."

From the abstract:

"Hydrogels are promising soft materials for energy and environmental applications, including sustainable and off-grid water purification and harvesting. A current impediment to technology translation is the low water production rate well below daily human demand. To overcome this challenge, we designed a rapid-response, antifouling, loofah-inspired solar absorber gel (LSAG) capable of producing potable water from various contaminated sources at a rate of ∼26 kg m–2 h–1, which is sufficient to meet daily water demand. The LSAG─produced at room temperature via aqueous processing using an ethylene glycol (EG)–water mixture─uniquely integrates the attributes of poly(N-isopropylacrylamide) (PNIPAm), polydopamine (PDA), and poly(sulfobetaine methacrylate) (PSBMA) to enable off-grid water purification with enhanced photothermal response and the capacity to prevent oil fouling and biofouling. The use of the EG–water mixture was critical to forming the loofah-like structure with enhanced water transport. Remarkably, under sunlight irradiations of 1 and 0.5 sun, the LSAG required only 10 and 20 min to release ∼70% of its stored liquid water, respectively. Equally important, we demonstrate the ability of LSAG to purify water from various harmful sources, including those containing small molecules, oils, metals, and microplastics."

Sunlight-activated "loofah hydrogel" excels at purifying water

Quick-Release Antifouling Hydrogels for Solar-Driven Water Purification

Figure 1. Fabrication and hierarchical porous structures of the hydrogel. (a) Schematic of the fabrication method for L-PNIPAm and LSAG. (b) Schematic of the thermally driven water release process for LSAG. (c) Photograph and microstructure of natural loofah sponge and LSAG.

This Modern Day easy to use Miriam's Well From Israeli Startup Alumor Will Provide Cheap, & Clean Water For the Developing World

I thought, this is a fitting Christmas Story! Merry Christmas 2021!

"... Figures from World Health Organization (WHO) in 2017 suggest 2.1 billion people lack drinking water, 1.4 billion of which need an efficient and sustainable solution, like a household water treatment device, to purify their water to the point of use. The WHO states for those families that need these household water treatment systems, the systems need to be cheap and sterilize water to a high level. The water purification tech should ensure that all bacteria and viruses are killed.
Present solutions are either costly, ineffective, or just simply slow and cumbersome to use ..."

"The Miriam’s Well is a household device and is designed to operate without need for running water, electricity grid, or maintenance. The machine cleans dirty polluted water such that it is ready for drinking. The technology is a two stage process incorporating advanced UV-C technology."

"... Miriam’s Well is meant to be used in a village setting where one person would house the product and residents would come to a specific location for clean water. The village design would be sold for about $50 as a social good (not for profit) The company is currently in contact with various NGOs and governments that will be partners in distribution. ..."

This Modern Day Miriam's Well From Israeli Startup Alumor Will Provide Clean Water For The Masses

Miriam’s Well