One-Pot Synthesis of Layered Disodium Zirconium Phosphate: Crystal Structure and Application in the Remediation of Heavy-Metal-Contaminated Wastewater

Abstract

Inorganic ion exchangers offer advantages whenever operation at high temperatures or in oxidizing environments is required. A novel two-dimensional disodium zirconium phosphate, Zr­(NaPO4)2·H2O, was reported and investigated as an ion exchanger for heavy metals. The material was synthesized by a novel minimalistic solventless approach, and its solid-state structure was determined from powder X-ray diffraction data. Zr­(NaPO4)2·H2O crystallizes in the space group P21/c with cell parameters a = 8.7584(1) Å, b = 5.3543(1) Å, c = 18.1684(3) Å, β = 109.053 (1)°, and Z = 4. Its layered structure is similar to that of α-zirconium phosphate, Zr­(HPO4)2·H2O. However, unlike α-zirconium phosphate which is limited in practical applications by its narrow interlayer spacing (d = 7.6 Å), the disodium zirconium phosphate has a larger spacing of 8.6 Å between planes. The material with inherent structural advantages displays excellent sorption for heavy metals such as Pb2+, Cu2+, Cd2+, and Tl+, maintaining its high selectivity with distribution coefficients, K d, of 104–105 mL/g even in the presence of a large excess of Na+, K+, Mg2+, and Ca2+, which are commonly present in underground water. In particular, the maximum sorption capacity for the highly toxic Tl+ is a record high, 5.07 mmol/g (1036 mg/g). The fast reaction kinetics indicate that the exchangeable positions in Zr­(NaPO4)2·H2O are readily accessible, in contrast to Zr­(HPO4)2·H2O. The ease of preparation, benign nature, and advantageous ion-exchange properties make Zr­(NaPO4)2·H2O a highly promising sorbent for the treatment of water polluted with heavy metals.

Polymer functional coatings modified by ZrP‐based composites: Preparation and applications on marine concrete

“…α‐ZrP has been extensively studied in the fields of catalysis, coatings, lubricants, medicine, and energy 43–45 . Clearfield reported the synthesis of α‐ZrP crystals and determined their structural composition 46 .…”

“…α-ZrP has been extensively studied in the fields of catalysis, coatings, lubricants, medicine, and energy. [43][44][45] Clearfield reported the synthesis of α-ZrP crystals and determined their structural composition. 46 α-ZrP has a hexahedral-type lamellar structure, whose planes are composed of zirconium atoms, phosphate groups attached to three zirconium atoms through three oxygen atoms, and water molecules attached to the oxygen atoms by hydrogen bonds.…”

Revisiting the Old and Golden Inorganic Material, Zirconium Phosphate: Synthesis, Intercalation, Surface Functionalization, and Metal Ion Uptake

“…Chuah et al recently demonstrated a new procedure for the synthesis of α and γ-ZrP by a minimalistic liquid protocol. ,− The minimal solvent approach is typically a solid-state synthesis, in which reactants are mixed in their as-obtained state and concentration. It is minimal in the sense that the only source of water comes from 85% H 3 PO 4 and the water of crystallization of ZrOCl 2 ·8H 2 O.…”

“…In conclusion replacement of H + by NH 4 + ions increases the gallery spacing with a very high enhancement in sorption performance. In another study, the same research group synthesized twodimensional disodium zirconium phosphate, Zr(NaPO 4 ) 2 • H 2 O by minimalistic synthetic strategy 70. Its layered structure is similar to that of α-ZrP; however, unlike α-ZrP, Zr(NaPO 4 ) 2 • H 2 O has a larger interlayer spacing of 8.6 Å.…”

Ion‐exchange Properties of γ‐Zirconium Phosphate

“…For many years, difficulties in synthesizing crystalline γ‐ZrP have hampered research into its ion‐exchange properties. Recently, our lab has successfully developed a convenient protocol to prepare crystalline zirconium phosphates of different phases [3g,5,11] . Bulk quantities of γ‐ZrP can readily be formed using this green methodology which is solventless, requires only a small overstoichiometry of reactants, low crystallization temperature and short synthesis times [5] .…”