Preparation Of NC-MoS₂ Adsorbent And Its Application For Pb（Ⅱ） Removal In Aqueous Solution

Water plays an important role both in food industry and daily life.Recently,water pollution has seriously become a crucial factor for food safty issue.Pb（II）is a highly toxic upon accumulation in the hunm and a thorough cleanup of this pollutant in water resources has become a rising world wide concern.To ensure the safty of drinking water,herein,a step-by-step approach for preparation of nitrogen-doped carbon-MoS₂ nanosheets（NC-MoS₂）composites was reported.And these materials were characterized and the removal of heavy metal lead was evaluated.This paper is mainly conducted in the following research work:（1）The NC-MoS₂ with a high surface area and multi-functional groups on the MoS₂skeleton were synthesized by a simple method.The as-prepared NC-MoS₂ were subjected to scanning electron microscopy（SEM）,energy dispersive X-ray spectrometer（EDAX）,X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FTIR）and Boehm’s titration method（Boehm）.SEM and EDAX presents multilayer regular nanosheets and the uniform distribution of C,N and O elements in the fabricated nanomaterials,respectively.XRD,FTIR spectroscopy and Boehm confirm the functionalization of oxygen-containing functional groups arising from the nitrogen-doped carbon.（2）The adsorption performance of NC-MoS₂ composite materials were studied with a series of batch adsorption experiments.The adsorption experiments were carried out in different pH values to analyze the performance of NC-MoS₂ on Pb（II）removal,and the adsorption capacity of NC-MoS₂ exhibits a higher performance at pH value of 5.It can be analyzed that the adsorption data of Pb（II）on the NC-MoS₂ nanohybrid is more consistent with the Langmuir isotherm and pseudo-second-order model,confirming that the adsorption of Pb（II）on the surfaces of NC-MoS₂ occurs via monolayer and chemisorption adsorption,and the maximum adsorption capacity is 439.09 mg/g.Moreover,the underlying mechanism of Pb（II）adsorption are verified through XPS and FTIR characterization.There are a large number of–OH,–COOH and–NH₂ functional groups integrating on the surface of NC-MoS₂.The possible Pb（II）adsorption mechanism maybe attributed to the anion-exchange reaction between the binding sites and target ions.（3）To investigate the anti-interference ability of the novel adsorbent NC-MoS₂ to Pb（II）,a series of batch adsorption experiments were studied.The adsorption behavior of the as-prepared nanocomposites was not suffering greatly influence.The as-prepared NC-MoS2exhibits good chemical stability and can be reused 7 times with a slight fading over 80%during cycling,which is essential for its practical applications.All of these demonstrate that NC-MoS2 can be an efficient material for selectively removal of Pb（II）,which suggest its great potential in the utilization of environmental cleanup.