Size-dependent As(V) adsorption of reduced graphene oxide/magnetite nanocomposites.

Arsenic (As(V)) contamination in aqueous resources poses a significant environmental, and public health risk due to its high toxicity. To address this challenge, we synthesized and characterized novel reduced graphene oxide/magnetite (rGO/Fe₃O₄) nanocomposites, which are efficient adsorbents for removing As(V). Using a co-precipitation method, we obtained three distinct sizes of rGO/Fe₃O₄ nanocomposites by controlling the salt concentration (Fe²⁺: Fe³⁺) ratios. Analysis of the adsorption ability of the samples shows that the adsorption efficiency can reach up to 98.10% within 90 min, and the adsorption capacity value reaches 20.55 mg/g. Furthermore, these test data are ably consistent with both the pseudo-second-order model and the Langmuir model, based on which the adsorption mechanism has been proposed. These results show that the rGO/Fe₃O₄ nanocomposites that we synthesized are a potential adsorbent for the removal of heavy metals from water.