From the ACS Press Room

ACS Central Science

Access to clean water is being strained as the human population increases and contamination impacts freshwater sources. Devices currently in development that clean up dirty water using sunlight can only produce up to a few gallons of water each day. But now, researchers in ACS Central Science report how loofah sponges inspired a sunlight-powered porous hydrogel that could potentially purify enough water to satisfy someone’s daily needs even when it’s cloudy.

Previously, researchers have suggested that sunlight-driven evaporation could be a low-energy way to purify water, but this approach doesn’t work well when it’s cloudy. One solution could be temperatureresponsive hydrogels, specifically poly(Nisopropyl acrylamide) (PNIPAm), that switch from absorbing water at cooler temperatures to repelling it when heated. However, conventional PNIPAm gels can’t generate clean water fast enough to meet people’s daily needs because of their closed-off pores. Conversely, natural loofahs, which many people use to exfoliate in the shower, have large, open and interconnected pores. So, Rodney Priestley, Xiaohui Xu, and colleagues wanted to replicate the loofah’s structure in a PNIPAm-based hydrogel, yielding a material that could rapidly absorb water at room temperature, and rapidly release purified water when heated by the sun’s rays under bright or cloudy conditions.

The researchers used a water and ethylene glycol mixture as a uniquely different polymerization medium to make a PNIPAm hydrogel with an open pore structure, similar to a natural loofah. Then they coated the opaque hydrogel’s inner pores with polydopamine (PDA) and poly(sulfobetaine methacrylate) (PSMBA), and tested this material using an artificial light equivalent to the power of the sun. It absorbed water at room temperature and, when heated by the artificial light, released 70% of its stored water in 10 minutes a rate four times greater than the one for a previously reported absorber gel. The researchers say that, at this rate, the material has the potential to meet a person’s daily demand. And under lower light conditions, replicating partly cloudy skies, it took 15 to 20 minutes for the material to release a similar amount of stored water.

Finally, the new loofah-like material was tested on samples polluted with organic dyes, heavy metals, oil and microplastics. In all of the tests, the gel made the water substantially cleaner. For example, in two cycles of treat-

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The Doherty Award is given for excellence in chemical research or chemistry teaching, meritorious service to ACS, new chemical methodology (for the industry), solution of pollution problems, and advances in curative or preventive chemotherapy. Nominees may come from industry, academia, government, or small business. The nominee should be a resident member in the area served by the ACS DFW Local Section, and the work should have been performed here. The award is $1500 and an engraved plaque.

The Schulz Award is given to high school chemistry teachers, who, like the late Dr. Werner Schulz, bring that something extra to the teaching of chemistry. The nominee and/or nominator need not be ACS members. Nominees should show excellence in chemistry teaching, as demonstrated by testimonials from students and fellow teachers, results in student competitions, and diligence in updating and expanding scientific/teaching credentials. The award is $1500 and an engraved plaque.

The DFW Section instituted the Chemistry Ambassador Award to recognize an outstanding Section member who has made a significant impact by promoting chemistry to the community. The 2023 Chemistry Ambassador of the Year award is based on peer or self-nominations to the selection committee. Submissions should be one page in length and address the community outreach activities either through teaching, service, or working with legislators to affect public policy. Submissions will be evaluated on the impact made, which may include but not limited to how many people were reached, impact on individual people in the community, and exemplary commitment to the promotion of chemistry in the community. The award is $1000.

Each nomination should contain a completed nomination form, a cover letter highlighting the nominee’s accomplishments, and a copy of the CV. One or two additional letters may accompany nominations. The nomination package should be sent by email as a single pdf file to Mrs. Karen Compton at karen.compton@pisd.edu. Nominations remain active for five years but should be updated annually.

The deadline for submission of nominations is May 01, 2023.

The Dallas Fort Worth (DFW) local section of the American Chemical Society (ACS) is organizing a photography contest during the “ 2023 Chemists Celebrate Earth Week”. Please send ONE ORIGINAL picture to mihaela@utdallas.edu before April 15, 2023, for consideration in this science-art contest. Only one picture will be accepted per contestant. Different students from the same lab can individually submit. Both undergraduate and graduate students from schools in the DFW local section area (which includes schools from Dallas to Abilene) are eligible to participate. Please make sure you include your name, school, and what the submitted picture represents in the submission email.

Submitted pictures can be of colorful reactions in the lab, images (AFM, TEM, SEM), cell images, and fluorescent compounds.

The winners will be announced during the 2022 Meeting in Miniature on April 22, 2023. The winning pictures will be posted on our ACS DFW webpage and the Facebook page of the local section.

We will select three pictures as winners. The first prize will be $250, the second prize $200, and the third prize $150.

Around the Area

UT Dallas

The Chemistry and Biochemistry Department welcomes Dr. Monu Joy, Ph.D. Clarkson University, as the new Director of their X-Ray Facility. Assistant Professor and CPRIT Scholar, Filippo Romiti, gave an invited talk at the DFW Young Investigator's Symposium. Madison Berger, Cisneros Group, defended her Ph.D. Dissertation and published a first-author work in JACS.

From Sweet Potatoes

continued on page 11 flour and a traditional wheat one. Regardless of drying temperature, grinding once damaged just enough of the starch to make it ideal for fermented products, such as gluten-free breads. Grinding twice further disrupted the starch’s crystallinity, producing thickening agents ideal for porridges or sauces. When baked into a loaf of bread, the hightemperature-dried, single-ground sample featured higher antioxidant capacity than both the store-bought version and the wheat flour. The researchers say that these findings could help expand the applications for orange sweet potato flour, both for home cooks and the packaged food industry.

The authors acknowledge funding from Consejo Nacional de Ciencia y Tecnología (CONACYT) under Research Grant B-S3869 and the Universidad de Sonora..

From ACS Press Room

Continued

“Iodized table salt”

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Iodine-free salt options, such as kosher salt and Himalayan salt, should be used if home cooks want to boil pasta in salted water.

As the team explains, boiling pasta without a lid allows vaporized chlorinated and iodinated compounds to escape, and straining noodles removes most of the contaminants. Adding iodized salt after cooking should reduce risk of byproduct formation, but noniodized salts are recommended if salting the water before boiling.

The authors acknowledge funding from the University of South Carolina and the National Natural Science Foundation of China.

Continued from page 14 ment, water samples with around 40 parts per million (ppm) chromium were absorbed, then released with less than 0.07 ppm chromium the allowable limit for drinking water. The researchers say the unique hydrogel structure that they created could be useful in additional applications, such as drug delivery, smart sensors and chemical separations.

The authors acknowledge funding from a Princeton University Presidential Postdoctoral Fellowship, a National GEM Consortium Fellowship, the U.S. National Science Foundation, the Eric and Wendy Schmidt Transformative Technology Fund at Princeton University, the Project X Fund at Princeton University and the Princeton Catalysis Initiative.