North University of China, School of Energy and Power Engineering & School of Material Science and Engineering, Taiyuan 030051, PR China.
North University of China, School of Energy and Power Engineering & School of Material Science and Engineering, Taiyuan 030051, PR China; State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084, PR China.
Sci Total Environ. 2021 Mar 10;759:144317. doi: 10.1016/j.scitotenv.2020.144317. Epub 2020 Dec 9.
Once the adsorbent is selected, almost introducing larger specific surface area and more surface functional groups becomes the only way to improve its adsorption performance. However, this approach is generally limited in practical application for intricate and costly engineering steps. Herein, we provided a novel avenue for boosting adsorption activities towards specific metal ions in wastewater. Solar-driven interfacial water evaporation produces the localized temperature field and concentration gradient of metal ions inside small pores, endowing with a new sorption mechanism. By using chemically-treated carbonized wood as all-in-one solar absorption and metal ion adsorption system, we achieved higher water evaporation rate and heavy metal ion removal efficiency than carbonization-only wood reported previously. In particular, this system exhibited a strong dependence of specific metal ion adsorption capacity on solar intensity. Pb adsorption capacity was enhanced by over 225% with the solar intensity increased to 3.0 kW·m. This could originate from the formed temperature field localized specially on the surface of adsorbents that not only induces Pb concentration gradient near to solid-liquid interface but also activate inactive adsorption sites. Besides, the chemical-treated & carbonized wood showed excellent cyclic stability and can be directly utilized for wastewater treatment, recovery and reuse.
一旦选择了吸附剂，几乎引入更大的比表面积和更多的表面官能团就成为了提高其吸附性能的唯一途径。然而，这种方法在实际应用中通常受到复杂和昂贵的工程步骤的限制。在这里，我们提供了一种提高废水处理中特定金属离子吸附活性的新途径。太阳能驱动的界面水蒸发在小孔内产生局部温度场和金属离子的浓度梯度，赋予了一种新的吸附机制。通过使用化学处理的碳化木材作为一体化的太阳能吸收和金属离子吸附系统，我们实现了比以前报道的碳化木材更高的水蒸发率和重金属离子去除效率。特别是，该系统表现出对太阳能强度的特定金属离子吸附容量的强烈依赖性。随着太阳能强度增加到 3.0kW·m，Pb 的吸附容量提高了 225%以上。这可能源于专门在吸附剂表面形成的温度场，该温度场不仅在固液界面附近诱导 Pb 浓度梯度，而且还激活了非活性吸附位。此外，化学处理和碳化木材表现出优异的循环稳定性，可以直接用于废水处理、回收和再利用。
