In situ oxidation and simultaneous adsorptive removal of Arsenite by layered double hydroxide based solid hydrogen...

The improvement of oxidant can enhance the efficiency and enlarge the application range of Fenton process a lot. Herein, a high efficient layered double hydroxide (LDH) based solid hydrogen peroxide (LDHSHP) was designed, synthesized, and occupied as oxidant/adsorbent for the treatment of Arsenite (As(III)) in wastewaters. In LDHSHP, hydrogen peroxide was introduced in and connected to CO₃^2- interlayered, and the LDHSHP/Fe²⁺ system performed excellent in the range of pH 2.6-10.6. Hydroxyl radicals (·OH) played the main role in the oxidation of As(III), and the surface area of MgAl-LDH derived from LDHSHP was enlarged to about twice of that of LDHSHP. The increased surface area effectively promoted the adsorption of As(V). Almost 100 % of the obtained As(V) in water was immediately adsorptive removed. The adsorption capacity of LDHSHP derived MgAl-LDH for As(V) was detected to be 484.548 mg/g, and the adsorption fit the Langmuir model well and kinetic data was best described by the pseudo-second order model. The adsorption process was endothermic in the range of 298-308 K, while exothermic between 308 and 318 K. As(V) was calculated to be chemisorbed and reaction mechanism was proposed. LDHSHP is promising in the treatment of heavy metal-containing wastewaters.