Preparation Of Bentonite And Its Magnetic Microspheres For Adsorptive Removal Of Alkaline Dyes In Water

Printing and dyeing wastewater is difficult to be treated because of its large quantity,many components and high chromaticity.As a method with the advantages of low cost,simple operation,high efficiency,no secondary pollution and recyclability,adsorption method has attracted more and more attention.At present,people are mainly looking for adsorbents with low cost,easy separation and good reusability.Therefore,it is the key to find functional materials with good adsorption properties.Bentonite is a clay mineral mainly composed of montmorillonite,which has excellent cation exchange performance and is called "universal soil".However,bentonite is generally powder,which is difficult to separate and recycle,so the preparation of materials with a certain shape,such as spherical and blocky materials,is one of the methods to solve these problems.In this paper,magnetic and non-magnetic bentonite microspheres were prepared based on powder bentonite,and alkaline magenta and magenta were selected as the target pollutants to explore their development and application by studying the adsorption properties of the two materials.(1)Magnetic bentonite microspheres and bentonite microspheres were prepared by using calciumalginate cross-linking fixed bentonite/Fe3O4 or bentonite.The two kinds of microspheres were characterized by Fourier transform infrared spectroscopy,X-ray diffraction and scanning electron microscopy.The results showed that the surface groups(hydroxyl and carboxyl)of calcium alginate and bentonite were preserved,and the crystal structure of magnetic bentonite was also complete.(2)The adsorption properties of magnetic bentonite microspheres and bentonite microspheres on basic magenta and basic magenta blue in aqueous solution were studied by static adsorption experiments,including the influence of adsorption conditions,kinetics and isotherms.Results show that two kinds of microspheres can effectively remove two kinds of basic dye,adsorption kinetics data conform to the secondary dynamic equation,and the Freundlich isotherm data and Langmuir isotherm model are in good agreement,magnetic microspheres of bentonite and bentonite microspheres for maximum absorption of alkaline royal blue were 163.4 and 185.7 mg/g,adsorbed fuchsine maximum of 70.30 and 63.46 mg/g.In this paper,magnetic bentonite and bentonite are used as the basic materials,and calcium alginate is used for functional modification.Two kinds of bentonite-based microspheres are synthesized,which show good adsorption properties for basic magenta and basic blue dyes in water.And it can quickly recover the adsorbent completed by the reaction through magnetic separation equipment or sedimentation,which has great application value.