Evaluation of dried amorphous ferric hydroxide CFH-12® as agent for binding bioavailable phosphorus in lake sediments
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Kuupäev
2018
Kättesaadav alates
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Elsevier
Abstrakt
Metal hydroxides formed from aluminum (Al) and iron (Fe) salts can be used as phosphorus (P) adsorbents in
lake restoration, but the application entails problems in low-alkaline lakes due to acid producing hydrolysis
and potential formation of toxic metal ions. Therefore, we tested the potential of applying CFH-12® (Kemira) –
a dried, amorphous Fe-oxide with no pH effect – in lake restoration. Since Fe3+ may become reduced in lake sed-
iments and release both Fe2+ and any associated P we also evaluated the redox sensitivity of CFH-12® in com-
parison with freshly formed Fe(OH)3. CFH-12® was added to undisturbed sediment cores from three Danish
lakes relative to the size of their mobile P pool (molar Fe:PMobile dose ratio of ~10:1), and P and Fe fluxes across
the sediment-water interface were compared with those from untreated cores and cores treated with freshly
formed Fe(OH)3. Under anoxic conditions, we found that CFH-12® significantly reduced the P efflux from the
sediments (by 43% in Lake Sønderby, 70% in Lake Hampen and 60% in Lake Hostrup) while the Fe 2+ efflux
remained unchanged relative to the untreated cores. Cores treated with freshly formed Fe(OH)3 retained more
P, but released significantly more Fe 2+
, indicating continued Fe3+ reduction. Finally, experiments with pure
phases showed that CFH-12® adsorbed less P than freshly formed Fe(OH)3 in the short term, but was capable
of adsorbing up to 70% of P adsorbed by Fe(OH)3 over 3 months. With product costs only 30% higher than Al
salts we find that CFH-12® has potential for use in restoration of low-alkaline lakes.
The study was supported by Junta de Andalucía (project P10-RNM- 6630, Spain), MINECO CTM (project 2013-46951-R, Spain) and by the European Regional Development Fund (ERDF). Funding was also ob- tained from the Danish Centre for Lake Restoration (a Villum Centre of Excellence).
The study was supported by Junta de Andalucía (project P10-RNM- 6630, Spain), MINECO CTM (project 2013-46951-R, Spain) and by the European Regional Development Fund (ERDF). Funding was also ob- tained from the Danish Centre for Lake Restoration (a Villum Centre of Excellence).
Kirjeldus
Märksõnad
lake restoration, P sorbent, iron oxyhydroxide, iron reduction, internal P loading, articles