Abstract The extensive use of tetracycline (TC) as veterinary therapeutics and animal growth promoters has caused human health problems. Some adsorbents have been developed to remove TC, but the adsorption capacity is still unsatisfactory. Here, we synthesized octahedral cuprous oxide nanocrystals (oct-Cu2O NCs) by a hydrothermal method at room temperature. Surprisingly, the maximum adsorption capacity of oct-Cu2O NCs reached an astonishing amount of 1112.6 mg/g. Adsorption kinetics and isotherm experiments for TC removal were carried out to evaluate its potential as an adsorbent. The key factors like pH and solution ions as well as the mechanism of TC adsorption on oct-Cu2O NCs were also studied. The main adsorption process may be that the hydroxyl group (-OH) on the {111} facets surface of oct-Cu2O NCs is replaced by the amino group (-NH2) of TC. The high adsorption capacity is generated by the abundant Cu atoms with dangling bonds on the {111} facets surface and the strong chemical coordination between the -NH2 of TC and Cu(Ⅰ). This work provides an alternative with a promising application prospect for the treatment of TC in water.

中文翻译：

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四环素在暴露{111}面的八面体Cu2O纳米晶上的强吸附：吸附行为和机理洞察

摘要 四环素 (TC) 作为兽医治疗剂和动物生长促进剂的广泛使用已引起人类健康问题。已经开发了一些吸附剂来去除TC，但吸附能力仍然不能令人满意。在这里，我们在室温下通过水热法合成了八面体氧化亚铜纳米晶体（oct-Cu2O NCs）。令人惊讶的是，oct-Cu2O NCs 的最大吸附容量达到了惊人的 1112.6 mg/g。进行了 TC 去除的吸附动力学和等温线实验，以评估其作为吸附剂的潜力。还研究了pH和溶液离子等关键因素以及TC在oct-Cu2O NCs上的吸附机理。主要的吸附过程可能是oct-Cu2O NCs{111}晶面上的羟基（-OH）被TC的氨基（-NH2）取代。高吸附容量是由 {111} 面表面含有悬空键的大量 Cu 原子以及 TC 的 -NH2 与 Cu(I) 之间的强化学配位产生的。这项工作为处理水中的TC提供了一种具有广阔应用前景的替代方案。