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Mercury
Mercury is a naturally occurring element that is found in air, water and soil. It exists in several forms: elemental or metallic mercury, inorganic mercury compounds, and organic mercury compounds. [1] It has the chemical symbol Hg and atomic number 80. [2] It is the only common metal which is liquid at ordinary temperatures. Mercury is sometimes called quicksilver. It is a heavy, silvery-white liquid metal. It is a rather poor conductor of heat if compared with other metals but it is a fair conductor of electricity. It alloys easily with many metals, such as gold, silver, and tin. These alloys are called amalgams. The most important mercury salts are mercuric chloride HgCl2 (corrosive sublimate - a violent poison), mercuric chloride Hg2Cl2 (calomel, still used in medicine occasionally), mercury fulminate (Hg(ONC)2, a detonator used in explosives) and mercuric sulphide (HgS, vermillion, a high-grade paint pigment). Mercury metal has many uses. Because of its high density it is used in barometers and manometers. It is extensively used in thermometers, thanks to its high rate of thermal expansion that is fairly constant over a wide temperature range. Its ease in amalgamating with gold is used in the recovery of gold from its ores. [3]
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EPA proposes updates to air regulations for oil and gas to remove redundant requirements and reduce burden
The United States Environmental Protection Agency (EPA) proposed updates to the prior administration’s national standards for the oil and natural gas industry. The proposal would remove regulatory duplication and save the industry millions of dollars in compliance costs each year – while maintaining health and environmental regulations on oil and gas sources that the agency considers appropriate. This proposal is the result of EPA’s review of the 2016 New Source Performance Standards (NSPS) for the oil and natural gas industry, which was conducted in response to President Trump’s Executive Order 13783 - Promoting Energy Independence and Economic Growth. That order directs agencies to review existing regulations that potentially “burden the development or use of domestically produced energy resources,” including oil and natural gas. EPA’s regulatory impact analysis estimates that the proposed amendments would save the oil and natural gas industry $17-$19 million a year, for a total of $97-$123 million from 2019 through 2025. The U.S. Environmental Protection Agency (EPA) proposed updates to the prior administration’s national standards for the oil and natural gas industry. The proposal would remove regulatory duplication and save the industry millions of dollars in compliance costs each year – while maintaining health and environmental regulations on oil and gas sources that the agency considers appropriate. The proposal is the result of EPA’s review of the 2016 New Source Performance Standards (NSPS) for the oil and natural gas industry, which was conducted in response to President Trump’s Executive Order 13783 - Promoting Energy Independence and Economic Growth. That order directs agencies to review existing regulations that potentially “burden the development or use of domestically produced energy resources,” including oil and natural gas. EPA’s regulatory impact analysis estimates that the proposed amendments would save the oil and natural gas industry $17-$19 million a year, for a total of $97-$123 million from 2019 through 2025. “EPA’s proposal delivers on President Trump’s executive order and removes unnecessary and duplicative regulatory burdens from the oil and gas industry,” said EPA Administrator Andrew Wheeler. “The Trump Administration recognises that methane is valuable, and the industry has an incentive to minimise leaks and maximise its use. Since 1990, natural gas production in the United States has almost doubled while methane emissions across the natural gas industry have fallen by nearly 15%. Our regulations should not stifle this innovation and progress.” “EPA is committed to reforming duplicative requirements that impose costs on industry,” said EPA Regional Administrator Gregory Sopkin. “Our state partners and producers in EPA Region 8 have made substantial investments in reducing air emissions from oil and gas operations, and they will continue to do so without the burden of unnecessary federal mandates.” “I’m glad to see the EPA move forward with these critical, common sense reforms that reduce burdensome regulations on the oil and gas industry, which in turn is a huge win for Colorado. I look forward to seeing the industry continue the good work they’re doing to reduce methane emissions while maximising its safe production and use without the heavy hand of the government forcing them to do so,” said Congressman Ken Buck (R-CO). “I applaud Administrator Wheeler for correcting the Obama Administration’s improper regulatory overreach and for following the letter of the law. Today’s proposed rule will remove duplicative and unnecessary regulations which needlessly burden the development and use of our domestic energy resources. The fact is that the oil and gas industry will always have an economic incentive to limit methane because capturing it allows companies to sell more gas. That is why methane emissions have continued to decrease while energy production has increased over the same time period. Innovation and technology improvements within the oil and gas industry and not ideologically driven government regulation has made the U.S. the world’s leader in emissions reductions,” said Congressman Doug Lamborn (R-CO). EPA is co-proposing two actions, both of which would remove unnecessary regulatory duplication in the 2016 rule. In its primary proposal, the agency would remove sources in the transmission and storage segment of the oil and gas industry from regulation. These sources include transmission compressor stations, pneumatic controllers, and underground storage vessels. The agency is proposing that the addition of these sources to the 2016 rule was not appropriate, noting that the agency did not make a separate finding to determine that the emissions from the transmission and storage segment of the industry causes or significantly contributes to air pollution that may endanger public health or welfare. The primary proposal also would rescind emissions limits for methane, from the production and processing segments of the industry but would keep emissions limits for ozone-forming volatile organic compounds (VOCs). These sources include well completions, pneumatic pumps, pneumatic controllers, gathering and boosting compressors, natural gas processing plants and storage tanks. The controls to reduce VOCs emissions also reduce methane at the same time, so separate methane limitations for that segment of the industry are redundant. In an alternative proposal, EPA would rescind the methane emissions limitations without removing from regulation any sources from the transmission and storage segment of the industry. The agency also is seeking comment on alternative interpretations of EPA’s legal authority to regulate pollutants under section 111(b)(1)(A) of the Clean Air Act. This proposal is in addition to a September 2018 technical action that proposed targeted improvements to help streamline implementation, reduce duplication of EPA and state requirements, and significantly decrease unnecessary burdens on domestic energy producers. EPA is currently reviewing comments received on that technical package and expects to issue a final rule in the upcoming months. EPA will take comment on the proposal for 60 days after it is published in the Federal Register and will hold a public hearing. Details of the hearing will be announced shortly. More information, including a pre-publication version of the Federal Register notice and a fact sheet, is available at: https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-industry
http://www.epa.gov
Rubik’s cube with a chemical twist
The Rubik’s cube—a popular toy puzzle that has confounded adults and children since the 1980s—has been recreated with chemistry. An international group of researchers have created a working Rubik’s cube held together only by chemical bonds (Adv. Mater. 2019, DOI: 10.1002/adma.201902365). In January 2018, University of Texas at Austin’s Jonathan Sessler was at a meeting presenting work his lab had done making 2-D patterns from tiles of coloured hydrogels. Philip A. Gale, a chemist at the University of Sydney who specialises in supramolecular chemistry and was a postdoc in Sessler’s lab in the 1990s, challenged him to make the materials into a Rubik’s cube. “The patterns in Jonathan’s arrays of gels reminded me of the face of a Rubik’s Cube,” Gale says. “I wondered whether it would be possible to construct a functioning cube from gel blocks which would allow the blocks to be easily reconfigured.” Sessler put postdoc Xiaofan Ji on the project right away. The seemingly whimsical task turned out to be a tremendous challenge. Ji had problems creating hydrogels with the six colours needed to make a Rubik’s cube while also retaining the material’s structural integrity. It was only when Ji moved on to a second postdoc, with Ben Zhong Tang at Hong Kong University of Science and Technology, that he discovered the right ingredients: compounds Tang developed that, thanks to aggregation, fluoresce when they’re embedded in solid films. They then needed material with variable stickiness so that the coloured tiles could be firmly attached, but the cubes could still be rotated to play the game. The team settled on a hydrogel that forms acylhydrazone crosslinks from the reaction of a diacylhydrazine precursor with a tetraformyl partner. After being in contact for a short period of time—about an hour—tiles made of this hydrogel can be stuck and unstuck with ease. But when enough acylhydrazone crosslinks are made—usually over a 24-h period—the material becomes permanently stuck, which makes the tiles stay together. The researchers created 27 small cubes with six coloured tiles attached to each and left them for a day. They then assembled the cubes into a 3 × 3 × 3 Rubik’s cube. After an hour, they were able to rotate the cube just as if it were the classic toy puzzle. “Because this is all chemical, if we want to cheat, all we do is pick up one cube, rotate it so that it matches the pattern and stick it back in,” Sessler says. “So, we can solve the Rubik’s cube in a way that you can’t with a plastic Rubik’s cube.” There is one hitch: after 24 h, the Rubik’s cube locks into place. The same mechanism that allowed the team to stick on the coloured tiles made the game unplayable. “We’ve basically made a material that, like plaster of Paris or modelling clay, over time becomes harder,” Sessler says. Although recreating the fad toy was fun, Sessler says that isn’t his ultimate aim. He’d like to create arrays from tiles of smart soft materials that rely on something like Tang’s fluorescent materials to change colour in the presence of chemical stimuli. Such arrays could communicate medical information when placed on a person’s skin or guide robots performing chemical reactions, such as an acid-base titration. “It’s elegant work and opens up a new approach to the production of arrays of sensors,” Gale says. “I’m delighted they’ve met the challenge.”
http://pubs.acs.org/cen/news
