Removing toxic metals from tannery waste

By -
Researchers find that a fungal biomass does the job
Removing hexavalent chromium from industrial effluents, particularly untreated tannery waste, will become easier and more efficient thanks to the work by a team of researchers from the Indian Institute of Chemical Biology (CSIR-IICB), Kolkata. Importantly, the heat-dried fungal biomass converts Cr(VI) — which is neurotoxic, genotoxic and a carcinogen — to a non-toxic trivalent form of chromium, thus eliminating the problems of disposing Cr(VI)-containing waste. Cr(VI) is found in very high concentration in tannery waste. The results were published in the journal, Scientific Reports.
A team led by Sucheta Tripathy from the Structural Biology and Bio-Informatics Division at IICB isolated a fungus, Arthrinium malaysianum, and used the fungus biomass to remove Cr(VI). In experiments carried out in the lab using potassium dichromate solution, the adsorption capacity of the biomass was found to be as high as over 100 mg per gram of dry weight. In the case of untreated tannery waste, the fungal biomass was able to remove over 70% of Cr(VI). It can also remove other toxic metals such as lead and arsenic, which are normally found in tannery waste.

The positively charged functional groups found on the surface of the fungus binds to Cr(VI) ions. These groups were found intact even after heat drying. The functional groups have more ability to adsorb the negatively charged Cr(VI) through strong electrostatic attraction in acidic conditions. “Though the tannery waste is slightly alkaline, the fungus was still able to adsorb heavy metals,” says Rajib Majumder from the Structural Biology and Bio-Informatics Division at IICB and the first author of the paper. Once Cr(VI) gets adsorbed, the reducing functional groups found on the fungus converts it to Cr(III), which is not toxic. “The efficiency of conversion of Cr(VI) to Cr(III) was unaffected even when the concentration of Cr(VI) was increased 10 times,” he adds.
Besides adsorbing and converting the toxic form of chromium to a non-toxic form, the fungus biomass can also be reused by removing the adsorbed material. “We were able to reuse the biomass three times efficiently, beyond which it became unusable,” says Mr. Majumder.
Having tested the ability of the heat-dried fungus biomass in removing chromium and other heavy metals, the team is working to immobilise the biomass on a glass or ceramic substrate. “We are trying to produce a biomaterial to increase the surface area for real-time applications,” Dr. Tripathy explains

Comments

Post a Comment

Popular posts from this blog

'EA Sports UFC 2' update 6 adds 4 new fighters; brings changes to roster, gameplay and menu

By -
Image
Four new fighters have been added as part of the content update #6 to "EA Sports UFC 2."Twitter/EASPORTSUFC Publisher EA announced content update #6 (patch 1.09) for "EA Sports UFC 2" mixed martial arts fighting video game that brings changes in roster, gameplay and menu. It also adds four new fighters to the game. The four new fighters: Abel Trujillo (Men's Lightweight), Evan Dunham (Men's Lightweight), Rashid Magomedov (Men's Lightweight) and Sean O'Connell (Men's Light Heavyweight) were added as part of the new update. The roster update brings U.S. professional MMA fighter Donald Cerrone to "EA Sports UFC 2." Cerrone is a former professional kickboxer. The content update also brings changes to gameplay and menu: Gameplay updates Added the ability to end a round "The Holloway" when you taunt with Max Holloway in the last 20 seconds of the round and your opponent taunts back. Added Grapple Advantage Meter wh...
Read more

re-writeable paper ?

By -
Image
  Heard of re-writeable CD or drives , ever heard of re-writeable paper ?                            Printing has come a long way since the computer landed on the desktop. First,there were daisy-wheel printers, then dot-matrix printers, then inkjet and laser printers . The problem with all of these output devices, of course, is that they require paper -- lots of it -- and expensive consumables, like toner. Why can't someone invent an inkless, tonerless printer that allows the operator to reuse paper? As it turns out, this isn't a new idea. Xerox has been working with so-called electronic paper since the 1970s. Its most promising solution is a type of paper called "Gyricon." A Gyricon sheet is a thin layer of transparent plastic containing millions of small oil-filled cavities. A two-colored bead is free to rotate inside each cavity. When a printer applies a voltage to the surface of the she...
Read more

5 smartphones that have the best battery life

By -
Image
As they say, life with a smartphone is like having a second brain in your pocket. However, there are times when this second brain goes dead because of something as trivial as your phone running out of battery.  With most buyers focusing on phones with bigger displays and faster and more power-hungry processors, the humble battery pack that actually brings all the magic to life is often forgotten. But having said that, a big battery on a low spec, or worse a badly designed phone is also of no use. So here's our list of phones that not just offer great battery life but also come with best specs (well, almost).   Moto E4 Plus Kicking things off is the recently launched Moto E4 Plus which brings with it a massive 5000 mAh battery pack, a 5.5-inch 720p display, a fingerprint sensor running on Android 7.1.1. It's also equipped with a capable MediaTek MT 6737 quad-core processor clocking at 1.3GHz paired with 3GB RAM. There's also 32GB of inbuilt storage...
Read more