Phosphate-Mediated Remediation of Metals and Radionuclides

Abstract

Worldwide industrialization activities create vast amounts of organic and inorganic waste streams that frequently result in significant soil and groundwater contamination. Metals and radionuclides are of particular concern due to their mobility and longterm persistence in aquatic and terrestrial environments. As the global population increases, the demand for safe, contaminantfree soil and groundwater will increase as will the need for effective and inexpensive remediation strategies. Remediation strategies that include physical and chemical methods (i.e., abiotic) or biological activities have been shown to impede the migration of radionuclide and metal contaminants within soil and groundwater. However, abiotic remediation methods are often too costly owing to the quantities and volumes of soils and/or groundwater requiring treatment. The in situ sequestration of metals and radionuclides mediated by biological activities associated with microbial phosphorus metabolism is a promising and less costly addition to our existing remediation methods. This review highlights the current strategies for abiotic and microbial phosphatemediated techniques for uranium and metal remediation.

Efek Pelaparan dan Akumulasi Polifosfat terhadap Biopresipitasi Uranium pada Bacillus cereus A66

“…Di antara mekanisme interaksi bakteri dengan uranium, immobilisasi uranium yang dimediasi fosfat merupakan strategi yang layak untuk sekuestrasi uranium dalam jangka panjang. Bioremediasi uranium yang dimediasi fosfat berkaitan dengan aktivitas hidrolase organofosfat dan metabolisme polifosfat pada bakteri [3]. Aktivitas hidrolase organofosfat merupakan proses biomineralisasi yang mengandalkan peran gen PhoN (gen fosfatase asam) dan gen PhoK (gen fosfatase alkali).…”

“…Dalam pendekatan biologis diketahui terdapat beberapa enzim yang berperanan dalam metabolisme polifosfat yaitu antara lain : polifosfat kinase (PPK), exopolifosfatase (PPX), endopolifosfatase, polifosfat glukokinase, dan polifosfat AMP fosfotransferase [10]. Pada E.coli, metabolisme polifosfat digerakkan oleh gen ppk yang mengkatalisis polimerisasi ortofosfat intraselular dan gen ppx yang mengkatalisis hidrolisis granula-granula polifosfat [3].…”

“…Fenomena lain yang dapat diamati adalah bahwa keberadaan polifosfat intraselular memegang peranan kunci dalam pengurangan uranium dari larutan. Hal ini seperti yang dinyatakan oleh Martinez et al [3] bahwa keberadaan polifosfat sitosol memudahkan sekuestrasi logam-logam seperti Cd, Cu, Hg, Pb, U, dan Zn pada beberapa strain bakteri hasil rekayasa genetika dan juga beberapa strain bakteri dan arkhaea di alam (wild strains). Pembuktiannya dapat dilihat pada sel bakteri perlakuan 1 dengan konsentrasi P intraselular tertinggi maka pengurangan uranium dari larutan juga tertinggi (Gambar 1a).…”

Treatment of Cd2+ and Cu2+ Ions Using Modified Apatite Ore

“…Using apatite ore for treating heavy metals in soil is applied in many countries in the world, such as in situ remediation techniques and phosphate-induced metal stabilization. Apatite can treat almost heavy metals and radioactive substances such as Cu, As, Zn, , Ac, U, Pu, Sr, Cd, Se, Cs, Tc, and Pb to prevent the pollution to the water [22][23][24][25][26][27][28]. PO 4 3− groups in apatite can react with heavy metals to form precipitation and Ca 2+ ions in the structure of apatite can be replaced by heavy metals ions [29].…”

Functionalised magnetic nanoparticles for uranium adsorption with ultra-high capacity and selectivity

“…Phosphate molecules have been shown to form complexes with uranium (VI) when exposed to a particular pH environment [19,20] and organo-phosphorous ligands have been applied for U(VI) bonding in solvent extraction (SX) since 1900 [21][22][23][24]. Previous investigations have applied P-O-functionalised nanomaterials to water remediation from U(VI) [12,17,18,[25][26][27][28][29][30], and shown a capacity ranging from 166.7 mg/g [17] to as high as 1250 mg/g (pH 7) [29], with sorption equilibrium reached in 3 hours [17] and 24 hours [29], respectively. Faster U(VI) removal kinetics have been observed for SiO 2 coated Fe 3 O 4 NPs functionalised with quercetin [11], however a capacity of 12.3 mg/g was reported in this work.…”