The development of carbon-based sorbents that are simple to fabricate, possess high sorption capacity and are easily collected and reusable has been of great interest for oily wastewater remediation. A magnetic carbon nanotube (CNT) oil sorbent is proposed to cleanup of oily wastewater, offering effortless and complete recovery and enabling reusability. The sorbent, characterized by easy preparation of multi-walled CNT (MWCNT) with -cresol for macronization, is coupled with a space-holder technique that employs salts for open pore formation for oil sorption. Four sorbents were prepared with varying ratios of sodium chloride (NaCl) and monosodium L-glutamate (MSG), resulting in surface open pores corresponding to salt particle sizes. The sorbents formed an extensive macropore network of more than 200 μm while enhancing the specific surface area. Their bulk densities ranged from 126 kg/m to 139 kg/m, indicating CNT powder densification and suitability for wastewater oil absorption. With its elongated rectangle shape, the MSG-prepared sorbent, exhibited the widest specific surface area and diverse macropores, including those larger than 800 μm. The sorbents exhibited sorption capacities of 2.37–13.60 g of oil/g of sorbent and volume gains of 44–123 %, depending on the oil and solvent types. These values were comparable to or exceeded those of previous carbon-based sorbents. The sorption capacities of the sorbents remained consistent over ten sorption-heat treatment cycles, highlighting recyclability. Sorbents of MWCNT grown from iron catalysts exhibited easy recovery by a magnet after oil sorption, with surface magnetism. Despite their promise for oily wastewater treatment, CNT sorbents must address challenges related to capacity improvement, scalability, economic viability, and environmental impact to be practical for widespread application.

中文翻译：

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用于含油废水处理的盐形成大孔磁性碳纳米管吸附剂


开发制造简单、具有高吸附能力、易于收集和可重复使用的碳基吸附剂对于含油废水修复具有极大的兴趣。提出了一种磁性碳纳米管 (CNT) 吸油剂来净化含油废水，提供轻松、完全的回收并实现可重复使用。该吸附剂的特点是易于用对甲酚制备多壁碳纳米管（MWCNT）进行宏观化，并与空间保持技术相结合，该技术利用盐形成开孔以进行油吸附。用不同比例的氯化钠 (NaCl) 和 L-谷氨酸一钠 (MSG) 制备四种吸附剂，产生与盐颗粒尺寸相对应的表面开孔。吸附剂形成了超过200μm的广泛大孔网络，同时提高了比表面积。它们的堆积密度范围为 126 kg/m3 至 139 kg/m3，表明 CNT 粉末致密化并且适合废水油吸收。味精制备的吸附剂具有细长的矩形形状，表现出最宽的比表面积和多样化的大孔，包括大于 800 μm 的大孔。吸附剂的吸附能力为 2.37–13.60 克油/克吸附剂，体积增益为 44–123%，具体取决于油和溶剂类型。这些值相当于或超过了以前的碳基吸附剂。吸附剂的吸附能力在十个吸附热处理循环中保持一致，突出了可回收性。由铁催化剂生长的多壁碳纳米管吸附剂在吸油后易于通过磁体回收，并具有表面磁性。 尽管碳纳米管吸附剂有望用于含油废水处理，但它必须解决与容量提高、可扩展性、经济可行性和环境影响相关的挑战，才能广泛应用。