In this paper, an efficient adsorbent, manganese-modified activated carbon fiber (Mn3O4/ACF), was rapidly fabricated by microwave-assisted hydrothermal treatment strategy, which is used to remove As(V) from simulated wastewater. The adsorbent was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and N-2 sorption (BET). The characterization results showed that flake-like Mn3O4 particles in sizes of about 250 nm x 250 nm were homogeneously anchored on the surface of ACF. The goal of high As(V) removal efficiency was achieved with maximum adsorption capacity of 46.10 mg g(-1). The effects of temperature on thermodynamics and kinetics of As(V) adsorption were systematically studied. It was found that the adsorption of As(V) on the surface of Mn3O4/ACF is an endothermic process with a standard enthalpy change (AH) of 42.72 kJ mol(-1). Batch experimental result showed that almost all of the As(V) with initial concentration of 6.0 mg L-1 can be removed in the presence of Mn3O4/ACF, where the residual As(V) in filtrate is less than 0.01 mg L-1, below the tolerance level of drinking water suggested by World Health Organization (WHO). The presence of salt such as NaCl, Na2SO4 and MgSO4 shows little effect on the adsorption of As(V), indicating the promising application of Mn3O4/ACF in industrial wastewater treatment. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.