Preparation Of Environment Friendly Ti₃C₂T_x@CS Composites And Its Removal Mechanism Of Cr??? And Congo Red From Aqueous Solution

With the rapid development of industries including electroplating and smelting,the usage of Cr???was continuously increasing.Thus,part of Cr???would be inevitably discharged into the water and cause water pollution.Nearly 10-15%of Congo Red would be discharged into water and worsen the water environment.How to effectively remove Cr???and Congo red pollutants from water is a hotspot,which was difficult to deal with.More attention was paid to application of composite materials as adsorbent in wastewater treatment due to its lower cost,better remval efficiency,and simpler process.Based on the Ti₃C₂T_X?a kind of two-dimensional layered material?and chitosan?CS?,this research has successfully synthesized an environmentally friendly Ti₃C₂T_X@CS inorganic composite material and applied it in the removal of Cr???and CR from aqueous solution.The main research are maninly illustrated by follows:?1?Construction and characterization of Ti₃C₂T_X@CS compositesThe Ti₃C₂T_X@CS composite material prepared through solution method has a thin film shape and a compact texture.Microscopic morphology?SEM?image of the composite material revealed that CS was attached to the surface and interior of Ti₃C₂T_X,with a pore structure appeared on the surface.The main phase analysis results were illustrating that Ti₃C₂T_X was not chemically reacted with CS in the composite,mainly attributed to physical composite.X-ray diffraction photoelectron spectroscopy?XPS?and EDS spectroscopy analysis showed that Ti₃C₂T_X@CS could remove Cr???and Congo red from aqueous solution.?2?The adsorption mechanism of Cr???by Ti₃C₂T_X@CSThe adsorption rate of Cr???by Ti₃C₂T_X@CS increased with increasing Ti₃C₂T_X@CS dosage.The adsorption of Cr???by Ti₃C₂T_X@CS would reach its equilibrium at 480 min with equilibrium adsorption capacity of 50.6 mg/g.The kinetic model fitting datas show that the adsorption of Cr???by Ti₃C₂T_X@CS was mainly attributed to chemical reaction process.Thermodynamics experiment indicates that the adsorption process belongs to the monolayer adsorption at 25,35 and 45?,while their maximum adsorption capacity would reach 43.1,43.5 and 44.3 mg/g,respectively.The adsorption process is determined as a spontaneous endothermic reaction.The Ti₃C₂T_X@CS would reach the largest adsorption capacity for Cr???at p H of 4.After 5 cycles of regeneration,the adsorption capacity of Ti₃C₂T_X@CS decreased from 26.6 mg/g to 2.2 mg/g.?3?The removal process of CR by Ti₃C₂T_X@CSThe prepared Ti₃C₂T_X@CS would have very high CR removal efficiency,while the decolorization rate of CR by Ti₃C₂T_X@CS would reach up to 99.64%at 10 min.The removal of CR showed an upward trend and then a decrease with increasing dosage of Ti₃C₂T_X@CS.The decolorization rate of CR reached up to 99.72%at dosage of 30 mg.The decolorization rate of CR showed a downward trend with increasing temperature.With the increasing p H,the decolorization rate of CR would firstly increase and then decrease.The protonation degree of the composite material would be higher at lower p H condition,thus the neutralization and adsorption bridging effect could consume the CR.Negative electricity of Ti₃C₂T_X@CS?at p H of more than 9?is not conducive to the neutralization between Ti₃C₂T_X@CS and CR,thus the decolorization rate would be reduced.