School of Metallurgy and Environment, Central South University, Changsha, 410083, People's Republic of China.
Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, People's Republic of China.
Environ Sci Pollut Res Int. 2017 Aug;24(22):18168-18178. doi: 10.1007/s11356-017-9466-7. Epub 2017 Jun 20.
Red mud-modified biochar (RM-BC) has been produced to be utilized as a novel adsorbent to remove As because it can effectively combine the beneficial features of red mud (rich metal oxide composition and porous structure) and biochar (large surface area and porous structure properties). SEM-EDS and XRD analyses demonstrated that red mud had loaded successfully on the surface of biochar. With the increasing of pH in solution, arsenate (As(V)) adsorption on RM-BC decreased while arsenite (As(III)) increased. Arsenate adsorption kinetics process on RM-BC fitted the pseudo-second-order model, while that of As(III) favored the Elovich model. All sorption isotherms produced superior fits with the Langmuir model. RM-BC exhibited improved As removal capabilities, with a maximum adsorption capacity (Q) for As(V) of 5923 μg g, approximately ten times greater than that of the untreated BC (552.0 μg g). Furthermore, it has been indicated that the adsorption of As(V) on RM-BC may be strongly associated with iron oxides (hematite and magnetite) and aluminum oxides (gibbsite) by X-ray absorption near-edge spectroscopy (XANES), which was possibly because of surface complexation and electrostatic interactions. RM-BC may be used as a valuable adsorbent for removing As in the environment due to the waste materials being relatively abundant.
赤泥改性生物炭（RM-BC）已被制备用作新型吸附剂以去除砷，因为它可以有效地结合赤泥（丰富的金属氧化物组成和多孔结构）和生物炭（大的表面积和多孔结构特性）的有益特性。SEM-EDS 和 XRD 分析表明，赤泥已成功负载在生物炭表面上。随着溶液 pH 的增加，砷酸盐（As(V)）在 RM-BC 上的吸附减少，而亚砷酸盐（As(III)）增加。RM-BC 上的砷酸盐吸附动力学过程符合准二级模型，而砷酸盐的吸附更符合 Elovich 模型。所有的吸附等温线都与 Langmuir 模型产生了很好的拟合。RM-BC 表现出改善的砷去除能力，对 As(V)的最大吸附容量（Q）为 5923μg g，约为未处理的 BC（552.0μg g）的十倍。此外，通过 X 射线吸收近边光谱（XANES）表明，As(V)在 RM-BC 上的吸附可能与氧化铁（赤铁矿和磁铁矿）和氧化铝（水铝石）强烈相关，这可能是由于表面络合和静电相互作用。由于废物相对丰富，RM-BC 可能作为一种有价值的吸附剂用于去除环境中的砷。
