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Modification Of Multi-layered Clay Minerals For Heavy Metal Ion And Dye Adsorption Study

Posted on:2023-04-20Degree:MasterType:Thesis
Country:ChinaCandidate:H H LiuFull Text:PDF
GTID:2531306833987669Subject:Engineering
Abstract/Summary:PDF Full Text Request
Due to the rapid development of industrial activities and the increasing improvement of people’s living standards,water pollution has had an increasingly important impact on people’s lives.Among them,heavy metals Cr(Ⅵ)and methylene blue(MB)are difficult to be biodegraded,which will cause damage to the human body and the environment.In this paper,three different types of clay mineral materials(sepiolite,bentonite,kaolin)were used in the process of modifying nano-zero valent iron and hydrogels to remove Cr(Ⅵ)and MB,respectively.The materials were characterized by XRD,SEM,FT-IR,XPS and other characterization methods.1)Nano-zero-valent iron was successfully synthesized by the carbothermic method through the redox reaction of soluble iron salts and carbon-containing chelates at high temperature,and the modified nanocomposites were prepared by using clay as the carrier of nano-zerovalent iron to remove Cr(Ⅵ)efficiently.It studied the ability of nZⅥ synthesized by different chelates to reduce Cr(Ⅵ),and it was found that compared with iron oxides,pure nano-zero valent iron had better effect on the removal of Cr(Ⅵ),and the higher the chelating ratio,the better effect produced.The composite material nZⅥ-3C wine-kao modified by clay minerals has a maximum adsorption capacity of 99.87 mg/g for Cr(Ⅵ).The mechanism of removing Cr(Ⅵ)from nZⅥ-3C wine-kao is mainly adsorption reduction.The adsorption kinetics study showed that the reaction process conformed to the pseudo-second-order kinetic model,which was presumed to be a chemical adsorption process,and the Langmuir isotherm model was more in line with the experimental data.2)A hydrogel with a three-dimensional structural network is prepared by chemically initiated free radical polymerization,and modified with clay with high mechanical strength and chemical resistance,which improves the shortcomings of poor hydrogel strength and stability and effectively prevents the loss due to hydrophilic groups during the synthesis process,the modified hydrogel composites were used in the experiment of efficient adsorption of methylene blue MB.The proper addition of 5% clay would promote the adsorption,and the modified composite material CTS-AA-IA-5kao has the maximum adsorption capacity of 1570.94 mg/g.The mechanism of MB adsorption in hydrogel-clay composites is mainly due to electrostatic and hydrogen bonding interactions and the role of abundant hydrophilic groups.The adsorption kinetics study showed that the adsorption process conformed to the pseudo-second-order kinetic model,which was speculated to be a chemical adsorption process,and the Langmuir isotherm model was more in line with the experimental data...
Keywords/Search Tags:clay, heavy metal ion Cr(Ⅵ), methylene blue, nano-zero valent iron, hydrogel clay composites
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