Community College, Taibah University-Al-Mahd Branch, Al-Mahd 42112, Saudi Arabia.
Institute of Chemical and Engineering Sciences, 1 Pesek Road, Jurong Island, Singapore 627833, Singapore.
Molecules. 2018 Sep 15;23(9):2364. doi: 10.3390/molecules23092364.
The organo-clays (OCs) were prepared by a cation exchange reaction between surfactant (cetyltrimethylammonium, C16TMA) from different counterions (Bromide, Chloride, and Hydroxide). The effect of the counterions was investigated on the physico-chemical properties of the prepared organo-clays. The highest uptake of organic cations (1.60 mmol/g) was achieved using cetyl trimethylammonium bromide solution and the lowest value (0.93 mmol/g) was obtained after modification with cetyl trimethylammonium hydroxide solution starting from the same initial ratio of mmol/g of clay greater than 2.40. The arrangement of C16TMA cations within the interlayer space was assumed to be perpendicular with a tilt angle of 32° to the plane of clay sheets instead of being parallel to the clay surface using C16TMAOH solution at the same ratio. Different techniques were used to characterize these materials. The thermal stability of these organ-clays was investigated using an in-situ X-ray diffraction (XRD) technique. The decomposition of the surfactant moiety occurred at temperatures higher than 215 °C and was accompanied with a shrinkage of the basal spacing value to 1.42 nm. These materials were applied in the removal of an acid dye "eosin." The removed amount of eosin depended on the initial concentrations and the content of surfactants in the organo-clays. The removal of eosin was found to be an endothermic process. The maximum amount of 90 mg/g was achieved. The preheated treatment temperature of two selected OCs did affect the removal properties of eosin. A progressive reduction was observed at temperatures higher than 200 °C. The regeneration of spent OCs was studied and acceptable removal efficiency was maintained after 4 to 6 cycles depending on the used initial concentrations.
有机粘土（OCs）是通过表面活性剂（十六烷基三甲基铵，C16TMA）与不同反离子（溴化物、氯化物和氢氧化物）之间的阳离子交换反应制备的。研究了反离子对制备的有机粘土的物理化学性质的影响。使用十六烷基三甲基溴化铵溶液实现了最高的有机阳离子吸收量（1.60 mmol/g），而使用十六烷基三甲基氢氧化铵溶液改性后，吸收量最低（0.93 mmol/g），起始摩尔比大于 2.40。假定 C16TMA 阳离子在层间空间中的排列垂直于粘土片的平面，倾斜角为 32°，而不是与 C16TMAOH 溶液在相同比例下平行于粘土表面。使用了不同的技术来表征这些材料。使用原位 X 射线衍射（XRD）技术研究了这些有机粘土的热稳定性。表面活性剂部分在高于 215°C 的温度下分解，并伴随着层间距值收缩到 1.42nm。这些材料应用于去除酸性染料“曙红”。曙红的去除量取决于初始浓度和有机粘土中表面活性剂的含量。曙红的去除被发现是一个吸热过程。最大去除量为 90mg/g。两种选定的 OCs 的预热处理温度确实会影响曙红的去除性能。在高于 200°C 的温度下观察到逐渐减少。研究了用过的 OCs 的再生，根据使用的初始浓度，在 4 到 6 个循环后保持了可接受的去除效率。
