Magnetic biochar combining adsorption and separation recycle for removal of chromium in aqueous solution

• Published in: Water science and technology Vol. 75; no. 5-6; pp. 1177 - 1184
• Main Authors: Xin, Ouyang, Yitong, Han, Xi, Cao, Jiawei, Chen
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01-03-2017
• Subjects: Adsorbents; Adsorption; Analytical methods; Aqueous solutions; Arachis - chemistry; Arsenic removal; Biomass; Capacity; Charcoal; Charcoal - chemistry; Chromium; Chromium - isolation & purification; Contaminants; Desorption; Drinking water; Ferric chloride; Fluorides; Fourier analysis; Fourier transforms; Heavy metals; Hulls; Infrared radiation; Infrared spectra; Infrared spectroscopy; Magnetic saturation; Magnetization; Metals; Petroleum production; Pollutant removal; Pyrolysis; Raw materials; Recycling; Remediation; Removal; Saturation; Separation; Sodium hydroxide; Solutions; Specific surface; Spectrometry, X-Ray Emission; Spectroscopy, Fourier Transform Infrared; Surface area; Surface chemistry; Temperature; Water Pollutants, Chemical - isolation & purification; Zea mays - chemistry
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2016.610

Biochar has been developed in recent years for the removal of contaminants such as Cr (VI) in water. The enhancement of the adsorption capacity of biochar and its recyclable use are still challenges. In this study, magnetic biochar derived from corncobs and peanut hulls was synthesized under different pyrolysis temperatures after pretreating the biomass with a low concentration of 0.5 M FeCl
solution. The morphology, specific surface area, saturation magnetization and Fourier transform infrared spectroscopy (FT-IR) spectra were characterized for biochar. The magnetic biochar performed well in combining adsorption and separation recycle for the removal of Cr (VI) in water. The Cr (VI) adsorbance of the biochar was increased with the increase in pyrolysis temperature, and the magnetic biochar derived from corncobs showed better performance for both magnetization and removal of Cr (VI) than that from peanut hulls. The Langmuir model was used for the isothermal adsorption and the maximum Cr (VI) adsorption capacity of corncob magnetic biochar pyrolyzed at 650 °C reached 61.97 mg/g. An alkaline solution (0.1 M NaOH) favored the desorption of Cr (VI) from the magnetic biochar, and the removal of Cr (VI) still remained around 77.6% after four cycles of adsorption-desorption. The results showed that corncob derived magnetic biochar is a potentially efficient and recoverable adsorbent for remediation of heavy metals in water.