Nagoya University scientists have developed a one-step fabrication process that improves the ability of nanocarbons to remove toxic heavy metal ions from water. The findings, published in the journal ACS Applied Nano Materials, could aid efforts to improve universal access to clean water.
Various nanocarbons are being studied and used for purifying water and wastewater by adsorbing dyes, gases, organic compounds and toxic metal ions. These nanocarbons can adsorb heavy metal ions, like lead and mercury, onto their surfaces through molecular attraction forces. But this attraction is weak, and so they aren't very efficient adsorbents on their own.
To improve adsorption, scientists are considering adding molecules to the nanocarbons, like amino groups, that form stronger chemical bonds with heavy metals.
They are also trying to find ways to use all available surfaces on nanocarbons for metal ion adsorption, including the surfaces of their inner pores. This would enhance their capacity to adsorb more metal ions at a time.
Materials scientist Nagahiro Saito of Nagoya University's Institute of Innovation for Future Society and colleagues developed a new method for synthesizing an "amino-modified nanocarbon" that more efficiently adsorbs several heavy metal ions compared to conventional methods.
They mixed phenol, as a source of carbon, with a compound called APTES, as a source of amino groups. This mixture was placed in a glass chamber and exposed to a high voltage, creating a plasma in liquid.
The method they used, called "solution plasma process," was maintained for 20 minutes. Black precipitates of amino-modified carbons formed and were collected, washed and dried.
A variety of tests showed that amino groups had evenly distributed over the nanocarbon surface, including into its slit-like pores.
"Our single-step process facilitates the bonding of amino groups on both outer and inner surfaces of the porous nanocarbon," says Saito. "This drastically increased their adsorption capacity compared to a nanocarbon on its own."
They put the amino-modified nanocarbons through ten cycles of adsorbing copper, zinc and cadmium metal ions, washing them between each cycle. Although the capacity to adsorb metal ions decreased with repetitive cycles, the reduction was small, making them relatively stable for repetitive use.
Finally, the team compared their amino-modified nanocarbons with five others synthesized by conventional methods. Their nanocarbon had the highest adsorption capacity for the metal ions tested, indicating there are more amino groups on their nanocarbon than the others.
"Our process could help reduce the costs of water purification and bring us closer to achieving universal and equitable access to safe and affordable drinking water for all by 2030," says Saito.
The article, "Liquid-Phase Plasma-Assisted in Situ Synthesis of Amino-Rich Nanocarbon for Transition Metal Ion Adsorption," was published in the journal ACS Applied Nano Materials on December 27, 2019, at DOI:10.1021/acsanm.9b01915.
This work was supported by JST-SICORP Grant JPMJSC18H1 and JST-OPERA Grant JPMJOP1843.
About Nagoya University, Japan
Nagoya University has a history of about 150 years, with its roots in a temporary medical school and hospital established in 1871, and was formally instituted as the last Imperial University of Japan in 1939. Although modest in size compared to the largest universities in Japan, Nagoya University has been pursuing excellence since its founding. Six of the 18 Japanese Nobel Prize-winners since 2000 did all or part of their Nobel Prize-winning work at Nagoya University: four in Physics - Toshihide Maskawa and Makoto Kobayashi in 2008, and Isamu Akasaki and Hiroshi Amano in 2014; and two in Chemistry - Ryoji Noyori in 2001 and Osamu Shimomura in 2008. In mathematics, Shigefumi Mori did his Fields Medal-winning work at the University. A number of other important discoveries have also been made at the University, including the Okazaki DNA Fragments by Reiji and Tsuneko Okazaki in the 1960s; and depletion forces by Sho Asakura and Fumio Oosawa in 1954.
Nagahiro Saito | EurekAlert!
The Smallest Microelectronic Robot in the World
23.03.2020 | Technische Universität Chemnitz
On the trail of organic solar cells’ efficiency
20.03.2020 | Technische Universität Dresden
Researchers at the University of Zurich show that different stem cell populations are innervated in distinct ways. Innervation may therefore be crucial for proper tissue regeneration. They also demonstrate that cancer stem cells likewise establish contacts with nerves. Targeting tumour innervation could thus lead to new cancer therapies.
Stem cells can generate a variety of specific tissues and are increasingly used for clinical applications such as the replacement of bone or cartilage....
An international research team led by Kiel University develops an extremely porous material made of "white graphene" for new laser light applications
With a porosity of 99.99 %, it consists practically only of air, making it one of the lightest materials in the world: Aerobornitride is the name of the...
Researchers at Graz University of Technology have developed a framework by which wireless devices with different radio technologies will be able to communicate directly with each other.
Whether networked vehicles that warn of traffic jams in real time, household appliances that can be operated remotely, "wearables" that monitor physical...
Terahertz waves are becoming ever more important in science and technology. They enable us to unravel the properties of future materials, test the quality of...
An international team of researchers from Switzerland, Germany, the USA and Great Britain has uncovered an anomalous metallic behavior in an otherwise insulating ceramic material. The team used ultrashort light pulses with a wide range of colors to watch what happens when the insulating quasi two-dimensional material La2CuO4 (LCO) becomes a three-dimensional metal through laser irradiation. Surprisingly, the researchers found that specific vibrations of the crystal lattice are involved in this metallization process. A careful computational investigation revealed that the same vibrations that show up in this ultrafast movie can destabilize the insulating behavior all by themselves.
The condensed-matter physics world was shaken up when high-temperature superconductivity was reported in a copper oxide material in 1986 by Alex Müller and...
23.03.2020 | Event News
03.03.2020 | Event News
02.03.2020 | Event News
23.03.2020 | Physics and Astronomy
23.03.2020 | Power and Electrical Engineering
23.03.2020 | Power and Electrical Engineering