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A novel modification of lignin on corncob-based biochar to enhance removal of cadmium from water

Luo, Mingke, Lin, Hai, Li, Bing, Dong, Yingbo, He, Yinhai, Wang, Liang
Bioresource technology 2018 v.259 pp. 312-318
Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, adsorption, biochar, biosorbents, cadmium, energy-dispersive X-ray analysis, heavy metals, ion exchange, lignin, pyrolysis, scanning electron microscopy, sorbents, temperature
In order to improve the adsorption capacities of corncob-based biochars for heavy metal, the different pyrolysis temperature (350 °C, 450 °C and 550 °C) of corncob-based biochars were modified with the acrylonitrile, and adsorption capacities of Cadmium from solution by biochars were studied. The results showed that only at 350 °C the biochar can be successfully modified. The Cd adsorption capacity (85.65 mg/g) by the biosorbent was higher than other methods of modifying biochars previously reported. SEM-EDS and FTIR confirmed that the CN group was grafted on the biochar at low pyrolysis temperature. Batch adsorption experiment including pH-dependence, adsorption kinetics, and isotherms and XPS results showed that the removal mechanism of Cd(II) by the modified biochar was ion exchange and adsorption-complexation. This research not only obtained a novel method to modify biochar but also furthered research into the lignin of biochar composition, and provided an efficient sorbent for heavy metal.