NEWS
COMMENT
EU PET bottle target unlikely to be met
Isabell Gilks | analyst, Wood Mackenzie Chemicals
MATERIALS Uranium sponge ANTHONY KING
Researchers in the US have developed a new material to suck up uranium from seawater. The polymer adsorbent selects uranium over other metals in seawater and can be recycled after use (Nature Commun., 2019, 10, 819). Uranium extraction has attracted
attention due to its use as a fuel to produce nuclear power. The new adsorbent, say its developers, is more practical and efficient than previous materials, many of which prefer vanadium ions. Despite a dissolved concentration
of ca 4mg/t of seawater, the estimated total content of uranium is 4bn t, over 1000 times more than is available from all known land deposits. The new material was inspired
by the chemistry of iron-hungry microorganisms, which use natural compounds called siderophores to siphon off nutrients like iron. ‘What’s special about our materials,’
says physical chemist Aleksandr Ivanov at Oak Ridge National Laboratory, US, ‘is that they stabilise complexes through the formation of strong dative chemical bonds with a metal by several centres, like claws’. The linear geometry of the uranyl , was held tight by six
ion, UO2+
groups on the adsorbent. ‘The size of our synthetic siderophore ligand matches the size of the uranyl ion, leading to preferential binding of this particular metal ion,’ says Ivanov.
Initial experiments found the material extracts about 100 mg of uranium per gram of adsorbent after 50 hours. The adsorbent ‘is the most selective and non-toxic material developed so far for the extraction of uranium over competing vanadium ions,’ says Ivanov. The uranium can be released from the polymer by treating it with sodium carbonate. Its regeneration ‘using mildly basic solutions is an advantage, compared with other materials that require strong acidic solutions,’ comments Daniel Giammar, environmental engineer at Washington University in St. Louis, US, adding that further testing will be needed to demonstrate its stability. Cost is also an issue, he points out, especially since the extraction of uranium from seawater is economically questionable. The concentration of uranium in seawater is extremely dilute, compared with good uranium-containing ore, which can be 20kg/t. Currently, the commercialisation
of seawater extraction of uranium ‘seems unlikely’, says Giammar. But he suggests that the new adsorbent could be used for treating contaminated groundwater with high uranium concentrations or separation processes in processing nuclear fuel. Describing the material, Ivanov says
it looks and feels like cotton fibres. ‘Similar to cotton, it can be potentially weaved into ropes or braids for ease of deployment in real seawater.’
The EU’s proposal of a 90% collection target for PET beverage bottles by 2029 is unlikely to be met without significant investment. To put this number into context, the 2017 European PET beverage bottle collection rate averaged 58%. In volume terms, the EU would need to collect twice as many bottles, by weight, in 2029, compared with 2017. Germany and Norway have already reached
this collection target; however, 2017 collection rates in Bulgaria and Greece stood at 17% and 29%, respectively. There will be considerable challenges in meeting the 90% target in Central and Eastern Europe – notably Poland, Bulgaria and Romania, where PET demand is forecast to grow by over 50% up to 2029. Importantly, in order to recycle this additional
volume, more than 60 new reprocessing plants, with an average annual capacity of 30kt each, would be required. Without investment in infrastructure and waste management collection, the target is unlikely to be met. If, however, EU member states do manage to reach the target, a larger volume of plastic waste will either be incinerated or sent to landfill. Included in the EU’s directive is the target to
incorporate 25% of recycled plastic from 2025, increasing to 30% from 2030, in all PET beverage bottles. This will lead to a six-fold increase in demand for recycled PET in Europe by 2030. Given the current levels of investment in new PET recycling facilities, this is an extremely ambitious target. However, it’s worth noting that the EU’s target
for recycled plastic in all PET beverage bottles is more modest than targets announced by industry, with a number of big brands targeting 50% use of recycled PET in their beverage bottles by 2030. As such, a strong demand for recycled PET is
to be expected leading up to 2030 and beyond, which may displace some virgin PET demand. The price of recycle flake is likely to rise substantially as demand increases; however, supply could well be constrained. Despite the ambitious nature of these targets,
it is likely that we will continue to see further product bans or additional charges on single-use item usage, as this has been an effective method in causing demand destruction.
06 | 2019 11
DAVID PARKER / SCIENCE PHOTO LIBRARY
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