Department of Analytical Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. C. Sklodowska Sq. 3, 20-031, Lublin, Poland.
Department of Analytical Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. C. Sklodowska Sq. 3, 20-031, Lublin, Poland.
J Environ Manage. 2022 Aug 15;316:115260. doi: 10.1016/j.jenvman.2022.115260. Epub 2022 May 12.
Raspberry stalks-derived biochar (BC), magnetic biochar-iron oxide composite (BC-Fe) and its derivative modified with urea (BC-Fe-U) were synthesized, characterized and tested as(V) and Cr(VI) ion sorbents. The surface area of BC, BC-Fe and BC-Fe-U was 259, 163 and 117 m g, respectively. The structure of BC was dominated by micropores, while in BC-Fe and BC-Fe-U mesopores predominated. Based on the XRD results, it was found that the magnetic properties of the biochar-iron oxide composites are due to the presence of ferrimagnetic magnetite (FeO) and maghemite (FeO). The optimal pH of As(V) and Cr(VI) adsorption onto the studied sorbents is in the range of 2.3-5.7. Pristine biochar (BC) does not adsorb As(V) ions; however, it enables rapid adsorption of Cr(VI) with the static adsorption capacity of 19.2 mg g. The maximum static adsorption capacities of As(V) and Cr(VI) ions onto BC-Fe and BC-Fe-U are within the range of 13.5-16.3 mg g. For most adsorption systems tested, adsorption equilibrium is reached within 4 h, though even a few minutes is enough to reach half of the adsorption static value. Phosphates over 0.005 mol L hinder adsorption of As(V) and Cr(VI) ions. Application of at least 5 mol L nitric acid allows about 95% of Cr(VI) and As(V) to be desorbed from adsorbate-loaded BC-Fe material. For other materials, the desorption efficiencies are significantly lower. BC-Fe and BC-Fe-U materials were successfully used for simultaneous Cr(VI) and As(V) removal from river water.
树莓茎衍生生物炭（BC）、磁性生物炭-氧化铁复合材料（BC-Fe）及其用尿素改性的衍生物（BC-Fe-U）被合成、表征并测试为（V）和 Cr（VI）离子的吸附剂。BC、BC-Fe 和 BC-Fe-U 的比表面积分别为 259、163 和 117 m²/g。BC 的结构主要由微孔组成，而在 BC-Fe 和 BC-Fe-U 中，中孔占主导地位。根据 XRD 结果，发现生物炭-氧化铁复合材料的磁性是由于存在亚铁磁性磁铁矿（FeO）和磁赤铁矿（Fe₂O₃）。研究吸附剂对 As（V）和 Cr（VI）吸附的最佳 pH 值范围为 2.3-5.7。原始生物炭（BC）不吸附 As（V）离子；然而，它能够快速吸附 Cr（VI），静态吸附容量为 19.2 mg/g。BC-Fe 和 BC-Fe-U 对 As（V）和 Cr（VI）离子的最大静态吸附容量在 13.5-16.3 mg/g 的范围内。对于大多数测试的吸附系统，吸附平衡在 4 小时内达到，尽管几分钟足以达到吸附静态值的一半。超过 0.005 mol/L 的磷酸盐会阻碍 As（V）和 Cr（VI）离子的吸附。至少 5 mol/L 硝酸的应用可使约 95%的 Cr（VI）和 As（V）从负载吸附剂的 BC-Fe 材料中解吸。对于其他材料，解吸效率明显较低。BC-Fe 和 BC-Fe-U 材料成功地用于从河水中同时去除 Cr（VI）和 As（V）。
