Nitrate removal from aqueous solution using polyaniline modified activated carbon: Optimization and characterization

• Published in: Journal of Molecular Liquids Vol. 309; p. 113057
• Main Authors: Hu, Qili, Liu, Hengyuan, Zhang, Zhenya, Xie, Yanhua
• Format: Journal Article
• Language: English; Japanese
• Published: Elsevier B.V 01.07.2020; Elsevier BV
• Subjects: Activated carbon; Adsorption; Nitrate; Polyaniline; Response surface methodology; Nitrate; Response surface methodology; Adsorption; Polyaniline; Activated carbon
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2020.113057

Based on high surface area and porosity of activated carbon and special doping mechanism of polyaniline, the polyaniline modified activated carbon (PAN/AC) composite was prepared to effectively remove nitrate form groundwater using the chemical oxidative polymerization. The surface physicochemical properties were analyzed by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscope (TEM), specific surface analyzer (BET), X-ray diffraction analyzer (XRD), Fourier transform infrared spectrometer (FTIR) and X-ray photoelectron spectroscopy (XPS). The effects of adsorbent dosage, initial concentration, pH and coexisting oxyanions on nitrate adsorption were investigated. The response surface methodology was employed to optimize nitrate adsorption according to the single-factor experimental results. Both error statistics and residual plot were used to determine the optimal kinetic and isotherm models. The maximum adsorption capacity predicted by the Sips model was 11.04 mg g−1 (as NO3−–N) or 48.9 mg g−1 (as NO3−) at 25 °C. The nitrate adsorption mechanisms were mainly electrostatic attraction and anion exchange. The good acid-alkaline resistance, short equilibrium time and easy regeneration prompted the PAN/AC composite to become a promising adsorbent for nitrate removal. [Display omitted] •PAN/AC composite is prepared to efficiently remove nitrate from aqueous solution.•PAN/AC composite has rapid adsorption kinetics and good acid-alkali resistance.•Nitrate removal is subject to different chemical species of coexisting oxyanions.•Residual plot is employed to evaluate the validity of kinetic and isotherm models.