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Abstract：
This paper deals with the preparation of a novel nanocomposite consisted of magnesium-aluminum layered double hydroxide (Mg-Al LDH) and ethylenediaminetetraacetic acid (EDTA) as well as melamine (MA) as an adsorbent. This nanocomposite was utilized to adsorb different dyes such as rhodamine B (RhB) and methylene blue (MB) from water. The prepared adsorbent was characterized using FT-IR, EDS, XRD, TGA, and FE-SEM analyses. The effects of various parameters such as concentration, time, adsorbent dosage, temperature, and pH were tested to investigate their influence on adsorption conditions. Both methylene blue and rhodamine B dyes showed pseudo-second-order adsorption kinetics, and their adsorption followed the Langmuir isotherm. Moreover, the maximum adsorption capacities for methylene blue and rhodamine B were found to be 1111.103 mg/g at 45 °C and 232.558 mg/g at 60 °C, respectively. Additionally, the adsorption processes were found to be spontaneous (ΔG°< 0, for both dyes) and exothermic (ΔH° = -12.42 kJ/mol for methylene blue and ΔH° = -25.84 kJ/mol for rhodamine B) for both dyes. Hydrogen bonding and electrostatic forces are responsible for the interactions occur between the nanocomposite and the functional groups in the dyes. The experimental findings demonstrated a greater adsorption rate of MB than RhB, suggesting the adsorbent\'s stronger affinity for MB. This preference is likely due to MB\'s size, specific functional groups, and smaller molecule size, enabling stronger interactions and more efficient access to adsorption sites compared to RhB. Even after recycling 4 times, the dye adsorption percentages of the adsorbent for MB and RhB dyes were 90 % and 87 %, but the desorption percentages of the adsorbate dyes were 85 % and 80 %, respectively. The prepared adsorbent boasts several unique properties, such as the swift and effortless adsorption of MB and RhB dyes, straightforward synthesis, mild adsorption conditions, remarkable efficiency, and the ability to be recycled up to 4 times without a significant decrease in activity.
摘要：
本文研究了一种新型纳米复合材料的制备，该复合材料由镁铝层状双氢氧化物（Mg-AlLDH）和乙二胺四乙酸（EDTA）以及三聚氰胺（MA）作为吸附剂组成。该纳米复合材料用于从水中吸附不同的染料,例如罗丹明B(RhB)和亚甲基蓝(MB)。用FT-IR对制备的吸附剂进行了表征,EDS,XRD,TGA,和FE-SEM分析。各种参数的影响，如浓度，时间,吸附剂用量,温度,和pH进行了测试，以研究它们对吸附条件的影响。亚甲基蓝和罗丹明B染料均表现出拟二级吸附动力学,它们的吸附遵循Langmuir等温线。此外，亚甲基蓝和罗丹明B的最大吸附容量在45°C时为1111.103mg/g，在60°C时为232.558mg/g，分别。此外,发现吸附过程是自发的（对于两种染料，ΔG°<0）和放热的（对于亚甲基蓝，ΔH°=-12.42kJ/mol，对于罗丹明B，ΔH°=-25.84kJ/mol）两种染料。氢键和静电力是纳米复合材料与染料中官能团之间发生相互作用的原因。实验结果表明，MB的吸附率高于RhB，表明吸附剂对MB的亲和力更强。此首选项可能是由于MB的大小，特定的官能团，和更小的分子大小，与RhB相比，能够实现更强的相互作用和更有效地进入吸附位点。即使回收4次，吸附剂对MB和RhB染料的吸附率分别为90%和87%，但是吸附物染料的解吸百分比分别为85％和80％，分别。制备的吸附剂具有几种独特的性能，如MB和RhB染料的快速和毫不费力的吸附，简单的合成，温和的吸附条件，显著的效率,并且可以循环使用多达4次，而活性不会显着降低。
