Electrodeposition of layered double hydroxide intercalated with 2,3-dimercaptopropane sulfonate on carbon cloth and application for effective uptake of heavy metals

Abstract

In this work, Cu Cr-layered double hydroxide nanosheet intercalated with 2,3-dimercaptopropane sulfonate (DMPS-LDH) has been synthesized on a carbon cloth via a simple two-electrode electrodeposition method. The DMPS-LDH coated on the carbon cloth was used for the effective uptake of heavy metal ions and exhibits superior selectivity as well as a good adsorption capacity for Hg(II) ions in the presence of interfering ions. The selective Hg(II) ions-thiol groups interactions are the basis for the high selectivity of adsorbent. The adsorption isoterm of Hg(II) fitted with the Langmuir isotherm model and thus suggests a monolayer adsorption. The DMPS-LDH coated on the carbon cloth exhibits a high record saturation Hg(II) uptake capacity of over 2500 mg g−1 and distribution coefficients of 4.10 × 106 mL g−1, which place it at the top of adsorbents known for the uptake of Hg(II). The sorption kinetics for Hg(II) conform a pseudo-second-order model, that this model proposes a chemisorption reaction with the adsorption mechanism via M-S and M-SO4 bindings. Moreover, we observed efficient Hg(II) removal from tap water, well water, river water, and seawater samples. The excellent efficiency in recycling studies and good stability of the coating are other properties of the adsorbent.