The Preparation Of Ferroferric Oxide Matrix Composites And Study On Their Application In Water Treatment

With the development of the indursty and population in the world,pollution is becoming to the difficults of the world,especially the water pollution problem.Water pollution mainly refers to the concentration of pollutants in wastewater over the limited concentration of the WHO,which includes the main heavy metals?cadmium ions,chromium ions,copper ions,mercury ions,nickel ions?pollution and organic dyes?methylene blue,Congo red and Luo Danming B?pollution.Some methods have been applied to manage the life and industrial wastewater,which has a serious impact on the ecological environment and human health.The traditional water treatment methods include chemical precipitation,ion exchange,membrane permeation and photocatalytic oxidation method,but in terms of cost and the treatment effect,these methods are not suitable for use in industrial production.Now in the literature,mostly the use of adsorption methods to treat wastewater,and the commonly used adsorbent clay,activated aluminum,zeolite and activated carbon,etc.Because of their controllable pore architecture,high surface area,large pore volume,and hydrophobic affinity,activated carbon is an efficient adsorbent for pollutants removal.However,due to the relatively small density of activated carbon,it is easy to float on the surface of wastewater after adsorption,resulting in second pollution.In this paper,Fe₃O₄ matrix composite materials are studied,which is combined with different inorganic materials,are used for wastewater treatment.The main work is as follows:1 In this study,2D magnetite and carbon?Fe₃O₄@C?hybrid architectures were synthesised by a feasible template method via thermal treatment.The Fe₃O₄ nanoparticles were tightly embedded into the carbon sheets in the form of well-ordered arrays and disordered assembly.These architectures were then employed to remove Cr?VI?ion and different organic dyes from wastewater.Whatever the maximum Cr?VI?adsorption capacities were found to be about 1100 mg g-1 at 308 K in pH range of 4.8⁵.8.To our knowledge,these values were much larger than those reported for porous hierarchically metal-oxide and metal-hydroxide adsorbents and activated carbons in previous literatures.And these adsorbents can be easily magnetic separated from water by using a magnet.Easy separation and the high Cr?VI?adsorption capacities at different temperatures are highly promising for their widely potential applications in water treatment.However,the adsorption capacity of organic dyes is poor.2 In this work,apple,orange and banana peels were used as precursor materials for the mass production of Fe₃O₄@C adsorbents.A so-called “soak-calcination” method was employed by firstly soaking these waste fruit peels in FeCl3 aqueous solutions and secondly calcining these materials in the N2 atmosphere to yield final Fe₃O₄@C composites.It is quite simple and effective for these waste fruit peels to synthesize carbon-based adsorbents on an lagre scale.The as-produced Fe₃O₄@C adsorbents have appropriate ferromagnetism?about 4 emu g-1?,high adsorption capacities?several hundreds of milligrams per gram for adsorption of Congo red,methyl blue,rhodamine B and Cr6+ ions?,and good regenerability?reach to 85%?.3 In this work,Mg-Al-layered double hydroxides?LDH?and Fe₃O₄ particles are composited through stir,called Fe₃O₄@Mg-Al-LDH.According to the adsorption isotherm,the maximum adsorption capacity of Fe₃O₄@LDH on Cr?VI?is about 900 mg g-1.The adsorption of methyl blue,Congo red and Rhodamine B showed that the adsorption capacity of Fe₃O₄@LDH for organic dyes was very high.After 1 hours,the organic dye solution was changed to colorless,and the adsorption capacity could reach nearly 90%.