Study on mechanism and influential factors of the adsorption properties and regeneration of activated carbon fiber felt (ACFF) for Cr(VI) under electrochemical environment

An efficient adsorbent, activated carbon fiber felt (ACFF), was used to study the mechanism and influence factors of the Cr(VI) adsorption under electrochemical environment. Physicochemical properties of original ACFF were characterized by N2 adsorption/desorption analysis; scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze the properties of saturated ACFF (ACFF-Cr). Batch adsorption experiments were conducted under different electric field, ionic strength and initial pH values to evaluate the adsorption performance of ACFF towards the removal of Cr(VI) from aqueous solution. The concentration of total Cr in the aqueous solution was also recorded to study the mechanism of adsorption and regeneration. In-situ regeneration and readsorption experiments were also conducted. The reduction percentage of Cr(VI) to Cr(III) onto the adsorbent was confirmed by the XPS analysis results. The adsorption of Cr(VI) onto ACFF performed best under appropriate pH (pH = 4), ionic strength (1 g/L NaCl) and electrochemical (5 V voltage) environment. Electrochemical regeneration ratio can be up to 100% under suitable condition (1 g/L NaCl, 5 V of voltage). Results showed that the integration technology of electrochemical adsorption and regeneration of ACFF performed well on the treatment of water containing Cr(VI).