State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, People's Republic of China.
Environ Sci Pollut Res Int. 2018 Aug;25(24):24293-24304. doi: 10.1007/s11356-018-2500-6. Epub 2018 Jun 14.
The pollution of toxic and persistent heavy metals commonly exist in water environment; such multi-component pollutants pose a serious threat to human beings and other organisms. Herein, to make full use of the advantages of both layered double hydroxide (LDH) and rice husk ash (RHA), a novel Mg-Fe-LDH-RHA functional material was synthesized by assembling LDH on the biochar derived from RHA and used as an adsorbent for removal of heavy metal ions including Pb, Cu, Co, Ni, Zn, and Cd. The adsorption kinetics and isotherms of heavy metal ions in a mono-component system, the adsorption capacities in mixed multi-metal ion system, and the regeneration of the adsorbent were studied in detail. The results showed that the synthesized Mg-Fe-LDH-RHA might efficiently remove the above six heavy metals in water under optimized experimental conditions. Interestingly, the removal performance toward Pb(II) showed high static distribution coefficients (K) of ~ 10 mL/g and maximum capacity of ~ 682 mg/g. Besides, further characterizations of the adsorbent have been conducted, and the result suggested the formation of abundant functional groups including hydroxyl, carbonyl, and carboxyl groups. The removal mechanism of the metal ions might be related to ion-exchange, surface precipitation, complexation, and hydrogen binding during the interactions between the LDH-RHA material and pollutants. Such a facile and environmentally friendly approach, efficient removal performance suggests that the LDH-RHA material thus has potential for efficient removal of heavy metals in practical application.
水环境中普遍存在有毒和持久性重金属等多种污染物，这些多组分污染物对人类和其他生物构成了严重威胁。在此，为了充分利用层状双氢氧化物（LDH）和稻壳灰（RHA）的优势，通过将 LDH 组装在由 RHA 衍生的生物炭上，合成了一种新型的 Mg-Fe-LDH-RHA 功能材料，并将其用作吸附剂，用于去除包括 Pb、Cu、Co、Ni、Zn 和 Cd 在内的重金属离子。详细研究了单一组分体系中重金属离子的吸附动力学和等温线、混合多金属离子体系中的吸附容量以及吸附剂的再生。结果表明，在优化的实验条件下，合成的 Mg-Fe-LDH-RHA 可以有效地去除水中的上述六种重金属。有趣的是，对 Pb(II)的去除性能表现出约10 mL/g 的高静态分配系数 (K)和约682 mg/g 的最大容量。此外，还对吸附剂进行了进一步的表征，结果表明形成了丰富的官能团，包括羟基、羰基和羧基。金属离子的去除机制可能与 LDH-RHA 材料与污染物之间的离子交换、表面沉淀、络合和氢键作用有关。这种简单且环保的方法、高效的去除性能表明，LDH-RHA 材料在实际应用中具有有效去除重金属的潜力。
