August 2014, Vol. 26, No.8


Sponge adsorbs 50 times its weight in oil from water

A highly absorbent material that separates oil film from water could be a new tool to clean water. After removing oil, the silylated nanocellulose sponge keeps its shape enough to be removed with pincers from water, according to an Empa Swiss Federal Laboratories for Materials Science and Technology (Dübendorf, Switzerland) news release.  

Empa researchers Tanja Zimmermann and Philippe Tingaut, in collaboration with University of Bordeaux (Bordeaux, France) researcher Gilles Sebe, developed the material. In laboratory tests, the sponges absorbed up to 50 times their weight in mineral oil or engine oil, the news release says. 

Nanofibrillated cellulose, the basic material for the sponges, is extracted from cellulose-containing materials such as wood pulp, agricultural byproducts such as straw, or waste materials such as recycled paper. Water is added to these materials and the aqueous pulp is pressed through several narrow nozzles at a high pressure. The process produces a suspension with gel-like properties containing long and interconnected cellulose nanofibres. When water from the gel is replaced with air by freeze-drying, a nanocellulose sponge is formed, the news release says.  

Empa researchers modified the chemical properties of the nanocellulose by mixing a reactive alkoxysilane molecule into the gel before freeze-drying, ensuring the sponge only binds with oily substances, the news release says.  

In the laboratory, the sponge absorbed test substances of engine oil, silicone oil, ethanol, acetone, or chloroform within seconds. The researchers plan on fine-tuning the sponges so they can be used in real disasters, the news release says. 


Cruise ships moonlight as scientific vessels        

Commercial cruise lines are aiding the pursuit of science. Through the University of Miami’s Rosenstiel School of Marine and Atmospheric Science’s OceanScope Program, monitoring equipment installed on Royal Caribbean Cruises Ltd. (Miami) ships and now the Celebrity Cruises (Miami) Celebrity Equinox, tracks ocean circulation dynamics and measures atmospheric and oceanographic conditions, according to a university news release.  

The equipment transmits data gathered from around the world hourly through a satellite link. Larger data sets are transferred by Internet connection when the ships are at ports, the news release says. 

Scientists record ocean temperature, salinity, and chlorophyll concentration, as well as properties of the ocean’s surface such as reflectance and absorbance. In addition, they measure meteorological properties such as wind speed, wind direction, barometric pressure, and humidity. The data will help scientists monitor, understand, and forecast climate change, and its effects on marine ecosystems, the news release says. 


As dust settles in the Gulf, bacteria levels rise    

As temperatures rise, landscapes dry and dust rises. The dust plumes from the Saharan and Sahel deserts in Africa travel far, eventually being deposited in the Atlantic Ocean, Caribbean Sea, and the Gulf of Mexico, according to a Texas A&M University–Corpus Christi news release.  

Michael Wetz, assistant professor of Marine Biology at Texas A&M University–Corpus Christi is studying the effects of global climate change on the growth of such marine bacteria as vibrio. Bacteria absorb nutrients from dust that falls in oceans and use these nutrients to survive and multiply. More dust in oceans could trigger a population explosion of bacteria, the news release says.  

Wetz is working to understand how climate and human-driver environmental change affects coastal water quality, he said in the news release. He will collaborate with Erin Lipp and Liz Ottesen from the University of Georgia (Athens), Bill Landing from Florida State University (Tallahassee), Dale Griffin from the U.S. Geological Society, and Blair Sterba-Boatwright from Texas A&M–Corpus Christi. The project is set to take place in the Florida Keys, the news release says. 


Tracking local drug use through wastewater  

Scientists now can track trends in illicit drug use by sampling wastewater. The Sewage Analysis CORe group Europe (Oslo, Norway) network analyzed wastewater in more than 40 cities to explore the drug-taking habits of residents, according to a European Monitoring Centre for Drugs and Drug Addiction (Lisbon, Portugal) news release. 

The study was conducted to assess geographical differences and temporal changes in illicit drug use in metropolitan settings. By sampling a known source of wastewater, such as influent to a water resource recovery facility, scientists now can estimate the quantity of drugs used in a community by measuring the levels of illicit drugs and their metabolites excreted in urine, the news release says.  

The study analyzed daily wastewater samples in the catchment areas of facilities from London to Nicosia, Greece, and Stockholm to Lisbon during one week in April 2012 and March 2013. In 2012, the study involved 23 cities in 11 countries. In 2013, the study broadened to include 42 cities in 21 countries. Wastewater from approximately 8 million people was analyzed for traces of amphetamines, cannabis, cocaine, ecstasy, and methamphetamine, the news release says. 

Findings showed marked regional variations in drug use patterns. For example, traces of cocaine were higher in western and some southern cities. Weekly patterns also were identified. Cocaine and ecstasy levels rose sharply during weekends in most cities while methamphetamine and cannabis use appeared to be more evenly distributed throughout the week, the news release says. Findings from the study were published in the journal Addiction.    


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