Enhanced removal of hexavalent chromium from aqueous media using a highly stable and magnetically separable rosin-biochar-coated TiO2@C nanocomposite

Balal Yousaf; Guijian Liu; Qumber Abbas; Ruwei Wang; Habib Ullah; Md Manik Mian; Amina; Audil Rashid

doi:10.1039/c8ra02860e

Enhanced removal of hexavalent chromium from aqueous media using a highly stable and magnetically separable rosin-biochar-coated TiO₂@C nanocomposite

RSC Adv. 2018 Jul 19;8(46):25983-25996. doi: 10.1039/c8ra02860e.

Authors

Balal Yousaf^{1

2}, Guijian Liu^{1

2}, Qumber Abbas¹, Ruwei Wang², Habib Ullah¹, Md Manik Mian¹, Amina³, Audil Rashid⁴

Affiliations

¹ CAS-Key Laboratory of Crust-Mantle Materials and the Environments, School of Earth and Space Sciences, University of Science and Technology of China Hefei 230026 PR China lgj@ustc.edu.cn +86-551-63621485 +86-551-63603714.
² State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences Xi'an Shaanxi 710075 China.
³ Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention, School of Resource and Environment, Anhui Agriculture University Hefei 230026 PR China.
⁴ EcoHealth Research Group, Department of Environmental Sciences, PMAS Arid Agriculture University Rawalpindi Pakistan.

Abstract

Recently, nanosized metal-oxides have been extensively investigated for their ability to remove metal ions from aqueous media. However, the activity and capacity of these nanosized metal-oxides for removing metal ions decrease owing to their agglomeration in aqueous media. Herein, we synthesized a highly stable and magnetically separable rosin-biochar-coated (RBC) TiO₂@C nanocomposite through a facile and environment-friendly wet chemical coating process, followed by a one-step heating route (pyrolysis) for efficient removal of Cr(vi) from aqueous solution. An array of techniques, namely, TEM, HRTEM, TEM-EDS, XRD, FTIR, VSM, BET and TGA, were used to characterize the prepared nanocomposite. The pyrolysis of rosin into biochar and the fabrication of Fe onto the RBC-TiO₂@C nanocomposite were confirmed by FTIR and XRD examination, respectively. Moreover, TEM and HRTEM images and elemental mapping using TEM-EDS showed good dispersion of iron and carbon on the surface of the RBC-TiO₂@C nanocomposite. Sorption of Cr(vi) ions on the surface of the RBC-TiO₂@C nanocomposite was very fast and efficient, having a removal efficiency of ∼95% within the 1^st minute of reaction. Furthermore, thermodynamic analysis showed negative values of Gibb's free energy at all five temperatures, indicating that the adsorption of Cr(vi) ions on the RBC-TiO₂@C nanocomposite was favorable and spontaneous. Conclusively, our results indicate that the RBC-TiO₂@C nanocomposite can be used for efficient removal of Cr(vi) from aqueous media due to its novel synthesis and extraordinary adsorption efficacy during a short time period.