Removal of arsenic(V) from aqueous solutions using 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane functionalized silica gel adsorbent

The 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane(AAAPTS) functionalized silica gel (AAAPTS/SiO2) was synthesized and used as a potential adsorbent for the As(V) removal from aqueous solutions. AAAPTS/SiO2 was characterized by IR, nitrogen adsorption and point of zero charge (pHpzc) measurements. The adsorption behaviors of As(III) and As(V), adsorption isotherms and dynamics of As(V) on AAAPTS/SiO2 adsorbent were investigated. It was found that As(V) could be selectively adsorbed on AAAPTS/SiO2 adsorbent within pH of 2.7–9.2, while As(III) could not be absorbed in the studied pH range. Equilibrium data fitted perfectly with Langmuir isotherm model compared to Freundlich isotherm model, and the maximum adsorption capacity was 13.9 mg·g− 1 for the AAAPTS/SiO2 adsorbent. Kinetic studies indicated that sorption followed a pseudo-second-order model. The results showed that AAAPTS/SiO2 adsorbent could be employed as an effective material for the removal of As(V) from aqueous solutions.

Research highlights
► We developed an amino-functionalized silica gel sorbent for the removal of arsenic.
► The synthesized functionalized sorbent exhibited better adsorption properties.
► The experimental data followed the Langmuir model of monolayer adsorption.
► The pseudo-second-order kinetic model fitted better with kinetic data.
► The functionalized sorbent can be promising for the removal of As(V) from water.