Enhanced adsorption of Cd(II) using a composite of poly(acrylamide-co-sodium acrylate) incorporated LDH@MoS²₄−

ABSTRACT

The Mg/Al layered double hydroxide (Mg/Al-LDH) intercalated with the ${\text{MoS}}_4^{2-}$ (MoS₄-LDH) impregnated into poly(acrylamide-co-sodium acrylate) (PP) was synthesized as layered double hydroxides-PP (LDHS-PP), whose characterization, adsorption properties and mechanisms were investigated. The maximum adsorption capacity (q_m) for Cd(II) was ∼2789.58 mg/g by 1% LDHS-PP, while it was ∼1893.09 mg/g by PP, which indicated that the MoS₄-LDH greatly improved the Cd(II) uptake for PP in aqueous solution. In strongly acidic conditions (∼pH 3.0), there was still a good removal efficiency of about 45.65% by the 1% LDHS-PP, while that of PP was almost zero. At pH 5.0 the removal efficiency increased to 85.17% by the 1% LDHS-PP. The sorption kinetics for the 1% LDHS-PP was described well by a pseudo-second-order kinetic model. X-ray photoelectron spectrometry (XPS) and elemental distribution maps further confirmed the presence of MoS₄-LDH in the PP and most of the Cd(II) chemisorption based on the Cd-S bonding. Due to its high removal efficiency and acid resistance, LDHS-PP is a promising in-situ fixation agent for the remediation of agricultural soil polluted with Cd(II) at low pH.

GRAPHICAL ABSTRACT

KEYWORDS:

• Polymer
• MoS₄²⁻
• Mg/Al-layered double hydroxide
• acid resistance
• cadmium

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Mei Yang http://orcid.org/0000-0001-9017-3279

Liang Peng http://orcid.org/0000-0002-2125-980X

Qingru Zeng http://orcid.org/0000-0003-2814-1764

Jihai Shao http://orcid.org/0000-0002-3983-9538

Si Luo http://orcid.org/0000-0001-6348-7627

Additional information

Funding

This work was supported by Natural Science Foundation of Hunan Province: [Grant Number No. 2017JJ2112]; National Centre for Research and Development: [Grant Number No. SQ2017YFNC060064]; The National Natural Science Foundation of China: [Grant Number No. 41401260]; the ‘1515’ Talent Fund of Hunan Agricultural University.