Sludge biochar loaded with Fe–Mn oxides (FMBC) was prepared and employed to remove Cr(VI) from wastewater. The influences of solution pH, co-existing ion, contact time, adsorption temperature and Cd(VI) concentrations on removing Cr(VI) by FMBC were investigated. The Cr(VI) adsorption on FMBC had strong pH dependence. Additionally, Na⁺, Mg²⁺, Ca²⁺, SiO₃²⁻, NO₃⁻ and Cl⁻ ions exhibited no influence on Cr(VI) removal efficiency for FMBC, whereas there were inhibition effects of Pb²⁺, Cu²⁺, Ni²⁺, CO₃²⁻, SO₄²⁻, and PO₄³⁻ on removing Cr(VI). The Cr(VI) adsorption from solution for FMBC was well described by models of pseudo-second-order and Langmuir, and the largest Cr(VI) removal capacity of FMBC reached 172.3 mg g⁻¹. FMBC had good capacity for treating electroplating wastewater and mineral dissolving wastewater containing Cr(VI). After five regenerations, the 50 and 5 mg L⁻¹ Cr(VI) removing efficiency of FMBC was 82.34% and 97.68%, respectively. The Cr(VI) removal for FMBC involved adsorption-reduction and re-adsorption of Cr(III) generated by reduction. These results indicated that FMBC has good prospects for remediating Cr(VI)-containing wastewater.

中文翻译：

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负载铁锰氧化物的污泥生物炭去除废水中的 Cr(VI)

制备了负载铁锰氧化物（FMBC）的污泥生物炭，并用于去除废水中的Cr（ VI ）。研究了溶液pH、共存离子、接触时间、吸附温度和Cd( VI )浓度对FMBC去除Cr( VI )的影响。 FMBC 上Cr( VI ) 的吸附具有很强的 pH 依赖性。另外，Na ⁺、Mg ²⁺、Ca ²⁺、SiO ₃ ²⁻、NO ₃ ^-和Cl ^-离子对FMBC的Cr( VI )去除效率没有影响，而Pb ²⁺、Cu ²有抑制作用。⁺、Ni ²⁺、CO ₃ ²⁻、SO ₄ ²⁻和PO ₄ ³⁻去除Cr( VI )。准二级模型和Langmuir模型很好地描述了FMBC对溶液中Cr( VI )的吸附， FMBC的最大Cr( VI )去除能力达到172.3 mg g ^-1。 FMBC对含Cr( VI )电镀废水和溶矿废水具有良好的处理能力。经过5次再生后，FMBC对50 mg·L ^-1 Cr( VI )的去除率分别为82.34%和97.68%。 FMBC的Cr( VI )去除涉及吸附还原和还原产生的Cr( III )的再吸附。这些结果表明FMBC在修复含Cr( VI )废水方面具有良好的前景。