Phosphate removal and recovery with a synthetic hydrotalcite as an adsorbent

Phosphate adsorption from sewage sludge filtrate using zinc–aluminum layered double hydroxides

“…The regeneration rate was approximately 60% after six cycles indicating the accumulation of some interfering substance. The expiration of LDHs seemed slightly faster than in other studies (e.g., regeneration rate of almost 80% after six cycles [13]). This is probably due to lager quantities of impurities and coexisting ions contained in the real sludge filtrate vs. that found in pure phosphate solutions, which interfered with phosphate adsorption by binding a portion of the active sites on the LDHs.…”

“…NaCl solution was not suitable for exchanging PO 4 3− from P-loaded Zn-Al LDHs even at high concentration (20 wt%) when compared with the other two desorption solutions. Kuzawa et al [13] used 30 wt% NaCl solution to elute phosphate from granular Mg-Al LDHs and the desorption rate was even lower (14%). These results were expected due to the relatively low affinity of Cl − with LDHs compounds [21].…”

“…More recently some researchers studied the feasibility of phosphate adsorption from phosphate-rich streams. The various adsorbents used include industrial materials and byproducts (i.e., iron oxide tailings [5], fly ash [6], blast furnace slag [7] and red mud [8]), natural or synthetic minerals (i.e., goethite [9,10], dolomite [11] and alunite [12]), metal oxide/hydroxide (i.e., aluminum oxide, iron oxide, zirconium oxide [13] and zirconium hydroxide [14]) and other materials (i.e., ion exchange resin [15]). …”

“…Due to the high charge density of the sheets from M 2+ substitution by M 3+ and the exchangeability of the interlayer anions as well, LDHs have been employed in several studies for removing phosphate in different environment, such as phosphate solutions [13,[17][18][19], drain effluent [20] and seawater [21].…”

Research progress of novel adsorption processes in water purification: A review

“…Wherein, the use of HT as a kind of adsorbent in the water treatment was focused by many researchers. As reported, many kinds of ions, such as inorganic anions (Kuzawa et al, 2006;Yoshioka et al, 2007), organic acids (Silverio et al, 2007), and colored organics (Orthman et al, 2007;Bouraada et al, 2007), may enter the interlayer space of HT and consequently be adsorbed. Especially, after calcinations, the reconstruction of the original hydrotalcite with the positive charge layers was obtained.…”