Pyrazole-3,5-dicarboxylic acid intercalated LDH: A highly selective structured adsorbents for Cu2+ ions removal.

We reported herein a highly efficient and selective structured adsorbent of PAN@LDH-Hpdc, which can remove 10 ppm of Cu2+ ions to 3 ppb in 60 min with a removal efficiency of 99.97%. And a maximum adsorption capacity of 200.0 mg/g for Cu2+ ions can be obtained. [Display omitted] • When 10 ppm of Cu2+ ions was treated with 1.3 g L−1 of PAN@LDH-Hpdc, the concentration of Cu2+ ions can be decreased to 3 ppb in 60 min. • The PAN@LDH-Hpdc exhibited maximum adsorption capacity of 200.0 mg/g for Cu2+ ions. • The PAN@LDH-Hpdc showed excellent selectivity for Cu2+ ions. • The adsorption mechanisms involved the coordination by the intercalated Hpdc2- and surface adsorption by LDH laminate. The effective removal of Cu2+ ions from contaminated wastewater is greatly significant for environmental remediation. Herein, the PAN@LDH-Hpdc (PAN = polyacrylonitrile; LDH = layered double hydroxide; Hpdc = pyrazole-3,5-dicarboxylate) was prepared using the "Seeds Embedded-Epitaxial Growth-Ion exchange" strategy. Benefiting from the high surface area and abundant exposed active sites, the PAN@LDH-Hpdc showed the removal efficiency of 99.6 % in 25 min, and the Cu2+ ions (10 ppm) can be decreased to reach the WHO drinking water standard in 10 min. When the concentration of Cu2+ ions was ∼ 1000 ppm, the adsorption capacity of PAN@LDH-Hpdc was as high as 200.0 mg/g. In addition, the PAN@LDH-Hpdc exhibited high selectivity for Cu2+ ions with the removal efficiency of 99.9 % in the mixed solution containing Na+, Mg2+, K+, Ca2+, Cu2+, Ni2+, Zn2+ and Co2+ ions. The adsorption mechanisms of PAN@LDH-Hpdc involved the coordination by the intercalated Hpdc anions and surface adsorption by the LDH laminate. [ABSTRACT FROM AUTHOR]