Does soluble starch improve the removal of Cr(VI) by nZVI loaded on biochar?

Ecotoxicology and Environmental Safety

Wenjie Yang¹  Xiaoliang Li²  Chazhong Ge²  Lu Li²  Chun Yang³  Aijun Lin³  Bin Wang⁴ 

[1] Qinhuangdao Bohai Biological Research Institute of Beijing University of Chemical Technology, Qinhuangdao, Hebei 066000, China;Chinese Academy for Environmental Planning, Beijing 100012, China;Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China;Qinhuangdao Bohai Biological Research Institute of Beijing University of Chemical Technology, Qinhuangdao, Hebei 066000, China;

关键词: Soluble starch;    Reduction;    Adsorption;    Coprecipitation;    Hexavalent chromium;   

DOI  :  

来源: DOAJ

【 摘 要 】

A novel material that nano zero valent iron (nZVI) loaded on biochar with stable starch stabilization (nZVI/SS/BC) was synthesized and used for the removal of hexavalent chromium [Cr(VI)] in simulated wastewater. It was indicated that as the pyrolysis temperature of rice straw increased, the removal rate of Cr(VI) by nZVI/SS/BC first increased and then decreased. nZVI/SS/BC made from biochar pyrolyzed at 600 °C (nZVI/SS/BC600) had the highest removal efficiency and was suitable for a wide pH range (pH 2.1–10.0). The results showed that 99.67% of Cr(VI) was removed by nZVI/SS/BC600, an increase of 45.93% compared to the control group, which did not add soluble starch during synthesis. The pseudo-second-order model and the Langmuir model were more in line with reaction. The maximum adsorption capacity for Cr(VI) by nZVI/SS/BC600 was 122.86 mg·g−1. The properties of the material were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) mapping, Brunauer-Emmett-Teller (BET), Fourier-transform infrared (FTIR), and X-ray diffraction (XRD). The results showed that the nZVI particles were uniformly supported on the biochar, and the BET surface areas of nZVI/SS/BC was 40.4837 m2·g−1, an increase of 8.79 times compared with the control group. Mechanism studies showed that soluble starch reduced the formation of metal oxides, thereby improving the reducibility of the material, and co-precipitates were formed during the reaction. All results indicated that nZVI/SS/BC was a potential repair material that can effectively overcome the limitations of nZVI and achieve efficient and rapid repair of Cr(VI).

【 授权许可】

Unknown