Removal and recovery of phosphate and fluoride from water with reusable mesoporous Fe3O4@mSiO2@mLDH composites as sorbents

Pretreatment by recyclable Fe3O4@Mg/Al-CO3-LDH magnetic nano-adsorbent to dephosphorize for the determination of trace F− and Cl− in phosphorus-rich solutions

“…LDHs promising ion-exchangers 17 for applications to adsorb the PO 4 3À anion. [17][18][19][20][21][22][23][24][25][26][27][28][29][30] To efficiently adsorb PO 4…”

“…, the interlayer anion choice will play a key role. Based on LDHs, there are some good options to use the Cl À anion, 17,20,[22][23][24]31 or NO 3 À anion, 19,21,32 or Cl À and SO 4 2À anions 25 as the interlayer anion. They can be used to adsorb PO 4 3À effectively, but their adsorption efficiencies are inevitably affected by carbon dioxide (CO 2 ) or carbonate (CO 3 2À )…”

“…from the preparation process of the LDH, the solution environment and even the atmosphere. 17,19,25 Employing CO 3 2À as the interlayer anion, Zn-Al-LDH, 18 Zr-modied MgFe-LDH(CO 3 ), 27 Fe 3 O 4 @Mg-Al-LDH, 26 Mg-Fe LDH 28 and Fe 3 O 4 @gelatin-encapsulated hydrotalcite 33 were prepared to adsorb PO 4 3À successfully by a co-precipitation method. By comparison, the hydrothermal method is a better way to prepare LDH with the CO 3 2À interlayer anion using urea, which can well control the size and crystallinity of the prepared nanoparticle.…”

“…During the phosphate adsorption process, a lot of CO 3 2À anions will be exchanged in the solution, which will further inhibit the adsorption of trace F À and Cl À anions. Moreover, if some OH À anions exist in solution, the adsorption efficiencies 19 will further decline due to the combined effects of increasing competition from the OH À anion and the Coulomb repulsion between the negativecharged surface of the LDH adsorbent and F À or Cl À . If there is insufficient positive charge such as H + on the surface of the LDH adsorbent, and there are enough anions such as CO 3…”

Controlled Fabrication of the Biomass Cellulose–CeO2 Nanocomposite Membrane as Efficient and Recyclable Adsorbents for Fluoride Removal

“…For instance, Li et al successfully prepared the core−shell hierarchical structured MgAl−LDH nanocomposite for the fluoride removal from wastewater through a stable magnetic separation technique. 16 The nanocomposite adsorbents exhibit large surface areas and high fluoride adsorption capacities. However, in practical applications, nanoadsorbents tend to aggregate, lose their specific surface area, and make the adsorption process challenging to operate due to the high surface energy of nanoparticles.…”