%A Yang ZHANG,Zifu LI,Ibrahim B MAHMOOD %T Recovery of NH4+ by corn cob produced biochars and its potential application as soil conditioner %0 Journal Article %D 2014 %J Front. Environ. Sci. Eng. %J Frontiers of Environmental Science & Engineering %@ 2095-2201 %R 10.1007/s11783-014-0682-9 %P 825-834 %V 8 %N 6 %U {https://journal.hep.com.cn/fese/EN/10.1007/s11783-014-0682-9 %8 2014-11-17 %X

NH4+ ion, a main pollutant in aquatic systems, not only causes eutrophication in rivers and lakes but also contributes to fish toxicity. In this study, an eco-friendly biosorbent was prepared from the pyrolysis of corn cob, a low-cost agricultural residue. The biochars produced by pyrolysis of corn cob at 400°C and 600°C were characterized and investigated as adsorbents for NH4+-N from an aqueous solution. The biochars were characterized through elemental analysis, Brunauer–Emmett–Teller–N2 surface area analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. Batch experiments were conducted to investigate the NH4+ adsorption process of the corn cob biochars. The Freundlich isotherm model fitted the adsorption process better than the Langmuir and Dubinin–Radushkevich isotherm models. Moreover, the adsorption process was well described by a pseudo-second-order kinetic model. Results of thermodynamic analysis suggested that adsorption was a nonspontaneous exothermic process. Biochars produced at 400°C had higher adsorption capacity than those produced at 600°C because of the presence of polar functional groups with higher acidity. The exhausted biochar can be potentially used as soil conditioner, which can provide 6.37 kg NH4+-N?t-1 (N fertilizer per ton of biochar).