Key Laboratory of Clay Mineral Applied Research of Gansu Province, Center of Eco-material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, PR China.
Department of Material Science and Engineering, Faculty of Engineering, National University of Singapore, 21 Lower Kent Ridge Road, Singapore 119077, Singapore.
Sci Total Environ. 2019 Dec 15;696:133955. doi: 10.1016/j.scitotenv.2019.133955. Epub 2019 Aug 17.
Palygorskite (Pal) is a natural abundant environment-friendly adsorbent that has shown high efficiency to decontaminate dye in water. However, the dye removal results in transformation of Pal to a very stable Maya Blue-like structure or waste Pal clay (WPal), which could not be easily regenerated by a commonly used desorption process. This paper presents a use of WPal as the precursor material to synthesize a highly-efficient mesoporous silicate/carbon composite adsorbent. The composite adsorbent has a large specific surface area (427.9 m·g), a high negative potential (-40.6 mV) and a mesoporous size (3.48 nm). This adsorbent shows almost complete removal of tetracycline (TC), crystal violet (CV) and methylene blue (MB) (initial concentration, 200 mg·L) with the optimal adsorption capacities of 319.8 mg·g, 244.4 mg·g and 281.7 mg·g, respectively. The active -Si-O adsorption sites produced by the breaking of inert Si-O-Si (or M) bonds and the electrostatic interactions of negatively charged adsorbents to adsorbates play a major role in the adsorption process. Adsorption capacities of the developed composite are significantly higher than that of Pal, WPal and hydrothermally treated WPal (HWPal). Results demonstrate that the composite adsorbents have high potential in decontamination of organics in water efficiently.
坡缕石（Pal）是一种天然的、丰富的、环保型吸附剂，对水中染料的去除具有高效性。然而，染料的去除会导致 Pal 转变为非常稳定的玛雅蓝类似结构或废坡缕石粘土（WPal），而通常使用的解吸过程无法轻易再生。本文提出了一种利用 WPal 作为前体材料合成高效介孔硅酸盐/碳复合材料吸附剂的方法。该复合材料吸附剂具有较大的比表面积（427.9 m²·g）、高负电位（-40.6 mV）和介孔尺寸（3.48 nm）。该吸附剂对四环素（TC）、结晶紫（CV）和亚甲基蓝（MB）（初始浓度 200 mg·L）几乎可完全去除，其最佳吸附容量分别为 319.8 mg·g、244.4 mg·g 和 281.7 mg·g。吸附过程中，惰性 Si-O-Si（或 M）键的断裂产生的活性-Si-O 吸附位和带负电荷的吸附剂与吸附质之间的静电相互作用起主要作用。开发的复合材料的吸附容量明显高于 Pal、WPal 和水热处理的 WPal（HWPal）。结果表明，该复合材料吸附剂在高效去除水中有机物方面具有很高的潜力。
