The transformation of solid wastes from industrial production into effective adsorbents could significantly contribute to wastewater treatment. In this study, after acidizing and burning soft scale (SS) from coal gasification system, two magnetic adsorbents (mag-ASS and mag-BASS) were prepared via the combination of magnetite with ultrasonic, respectively. The treatment effects of mag-ASS and mag-BASS were then investigated for simulated wastewater containing macromolecular organic matter [i.e., methylene blue (MB)] and Ca²⁺. The results indicated that the pseudo second order kinetic, Elovich, Freundlich, Langmuir and Temkin model could well describe the adsorption behavior of MB and Ca²⁺ onto mag-ASS and mag-BASS. The maximum adsorption capacities of mag-ASS for MB and mag-BASS for Ca²⁺ were 600.53 mg/g and 102.54 mg/g, respectively. Surprisingly, the adsorption abilities of mag-ASS for MB and mag-BASS for Ca²⁺ show significantly higher than the others. The adsorption mechanisms of MB mainly included electrostatic interaction, π-π conjugate interaction and cation exchange, while those of Ca²⁺ were mainly electrostatic interaction and cation exchange. The diffusion of MB and Ca²⁺ onto the magnetic adsorbents might be controlled by the combined effects of intraparticle and liquid film diffusion. There was no significant reduction in adsorption capacity after 8 cycles of adsorption and desorption, indicating that SS-based magnetic adsorbents had good recyclability and stability. Moreover, the removal efficiency of mag-BASS for total hardness and total organic carbon in real coal gasification gray water (CGGW) was 82.60 and 64.10%, respectively. The treatment of CGGW and the resource of wastes would significantly promote the reasonable disposal of coal gasification scales.

Graphical abstract

中文翻译：

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基于煤气化系统结垢的可回收吸附剂同时去除亚甲基蓝（MB）和Ca2+

将工业生产中的固体废物转化为有效的吸附剂可以极大地促进废水处理。本研究对煤气化系统中的软垢（SS）进行酸化和燃烧后，通过磁铁矿与超声波的结合，分别制备了两种磁性吸附剂（mag-ASS和mag-BASS）。然后研究了mag-ASS和mag-BASS对含有大分子有机物[即亚甲蓝(MB)]和Ca ²⁺的模拟废水的处理效果。结果表明，伪二级动力学Elovich、Freundlich、Langmuir和Temkin模型可以很好地描述mag-ASS和mag-BASS对MB和Ca ²⁺的吸附行为。 mag-ASS对MB的最大吸附容量和mag-BASS对Ca ²⁺的最大吸附容量分别为600.53 mg/g和102.54 mg/g。令人惊讶的是，mag-ASS对MB的吸附能力和mag-BASS对Ca ²⁺的吸附能力明显高于其他吸附能力。 MB的吸附机理主要包括静电相互作用、π-π共轭相互作用和阳离子交换，而Ca ²⁺的吸附机理主要包括静电相互作用和阳离子交换。 MB 和 Ca ²⁺在磁性吸附剂上的扩散可能受到颗粒内扩散和液膜扩散的综合作用的控制。经过8次吸附和解吸循环后，吸附容量没有明显下降，表明SS基磁性吸附剂具有良好的可回收性和稳定性。此外，mag-BASS对真实煤气化灰水（CGGW）中总硬度和总有机碳的去除效率分别为82.60%和64.10%。 CGGW的处理和废物资源化将显着促进煤气化规模的合理处置。

图形概要