Study On Graphene And Fluorosilane Modified Styrene-divinylbenzene Copolymer Carrier

With the rapid development of Chinese nuclear power,especially the construction of inland nuclear power plants in the future,the treatment of tritium-containing wastewater generated by nuclear power is becoming extremely urgent.So far,hydrogen-water liquid phase catalytic exchange（LPCE）technology is the key method for the treatment of tritium-containing wastewater.What’s more,hydrophobic catalyst is an important material in LPCE.Besides,Pt/SDB hydrophobic catalyst which takes styrene-divinyl benzene copolymer（SDB）as the carrier is the critical material of LPCE reaction.However,the available SDB generally has disadvantages such as insufficient hydrophobicity,low strength and small particle size.Therefore,it is necessary to obtain SDB carriers with superhydrophobicity,higher strength and larger particle size.This paper,we plan to prepare graphene and fluorosilane functionalized SDB carriers which have hydrophobic,and study the adsorption behavior that modificationed carriers adsorpt platinum ions.Synthesis of graphene-modified SDB:graphene（GNS）is modified withγ-methylallyoxypropyl（KH570）and hexadecyltrimethoxysilane（HDTMS）respectively to obtain KH570-GNS and HDTMS-GNS with good lipophilicity and uniform dispersion.Then,the organic phase containing KH570-GNS or HDTMS-GNS is added to the surfactant,under the evocating agent of benzoyl peroxide（BPO）initiate,KH570-GNS-SDB and HDTMS-GNS-SDB（D=2.5～4.5 mm）will be prepared by suspension polymerization.Structural characterization using FT-IR,XRD,Raman et al.to demonstrate successful functional modification.Using static water contact angle,SEM,BET,and thermal weight to demonstrate carriers function,the data showed that the CAs of KH570-GNS-SDB and HDTMS-GNS-SDB are 152.36^o（to superhydrophobic）and 149.33^o,which are higher than the CA of the basic SDB（128.94）.The KH570-GNS-SDB and HDTMS-GNS-SDB have a suitable particle size（up to 3.5-4.5 mm）.According to the particle hardness test,the modified SDB with a 1%graphene content is 189%harder than that of the base SDB of the same diameter.And as the particle diameter increases,the particle hardness increases.The specific surface area of KH570-GNS-SDB and HDTMS-GNS-SDB respectively reached 397.48m²/g,415.36m²/g,and them with better thermal stability than the basic SDB.The hydrophobic stability of carriers was tested by simulated LPCE temperature,and the results showed that the hydrophobic stability was goodafter modification.Synthesis of fluorosilane modified SDB:In the process of SDB polymerization,1H,1H,2H,2H-perfluorooctane triethoxysilane(F₁₃AS)was added into the organic phase,then ultrasonic shock to make F₁₃AS and organic phase mixed evenly.And then add it into the aqueous phase containing surfactants,fluorosilane doped modified SDB carrier was prepared by in-situ polymerization,denoted as F₁₃AS-SDB.In addition,the SDB was also modified by fluorosilane soaking:the prepared base SDB is soaked in an ethanol solution of 1H,1H,2H,2H-perfodecyl trimethoxysilane(F₁₇AS),and the fluorosilane immersion modified SDB carrier,recorded as F₁₇AS-SDB.FT-IR and XPS and other structures demonstrated successful functional modification.The properties were characterized by scanning electron microscopy,static water contact angle,BET and thermogravimetric analysis.It is found that F₁₃AS-SDB and F₁₇AS-SDB have smooth surfaces and good sphericity.The hydrophobic angle of F₁₃AS-SDB is 142.67°,and that of F₁₇AS-SDB is 148.76°,both of which are improved to some extent compared with basic SDB.The SBET,Vp and Dp of F₁₃AS-SDB are 327.815 m²/g,0.4073 cm³/g,and 3.621 nm,respectively.The SBET,Vp and Dp of F₁₇AS-SDB are 251.714 m²/g,0.9331 cm³/g,and 3.629 nm,respectively.According to the particle hardness test,the hardness of F₁₃AS-SDB is51.6N,which has no significant difference compared with the basic SDB,while the hardness of F₁₇AS-SDB is slightly improved.Study on platinum ion adsorption behavior of the modified SDB vector:Pt（Ⅳ）adsorption experiments were carried out by KH570-GMS-SDB,HDTMS-GMS-SDB and F₁₃AS-SDB vectors,and the performance was tested by ultraviolet spectrophotometry and characterized by standard curve method.Kinetic and thermodynamic equations were used to describe the adsorption characteristics between the carrier and platinum ions.In the adsorption of Pt（Ⅳ）solution,the adsorption capacity of the modified carrier KH570-GMS-SDB,HDTMS-GMS-SDB and F₁₃AS-SDB on Pt（Ⅳ）was compared.It was found that the adsorption capacity of HDTMS-GMS-SDB,KH570-GNS-SDB and F₁₃AS-SDB reached 52.471 mg/g,44.609 mg/g and 25.977 mg/g,respectively.The average adsorption capacity of HDTMS-GNS-SDB is the largest.The adsorption processes of Pt（Ⅳ）on the three carriers all conform to the F-type isotherm model,while the HDTMS-GNS-SDB carrier is also more consistent with the L-type isotherm model,indicating that the adsorption on the surface of HDTMS-GNS-SDB carrier belongs to single-layer adsorption and transition to multi-layer adsorption.KH570-GNS-SDB and F₁₃AS-SDB belong to multilayer adsorption.At the initial stage of the reaction,the three carriers all showed great adsorption rates for Pt（Ⅳ）,and reached adsorption equilibrium at 90℃for about 12 hours.The Lagrange pseudo-second-order kinetics can better characterize the adsorption characteristics of Pt（Ⅳ）on KH570-GNS-SDB,HDTMS-GNS-SDB and F₁₃AS-SDB,indicating that the adsorption of Pt（Ⅳ）on the three carriers mainly depends on the chemical bond,and the adsorption of Pt（Ⅳ）on F₁₃AS-SDB,Both physical adsorption at solid-liquid interface and chemical coordination with Pt ion are available.In the process of platinum ion adsorption,the adsorption of Pt（Ⅳ）by HTDMS-GNS-SDB,KH570-GNS-SDB and F₁₃AS-SDB carriers is endothermic reaction.And all are spontaneous,and when temperature risesΔG decreases,indicating that temperature rise promotes this spontaneous reaction;The system confusion increases during the adsorption process.In this paper,silane coupling agent and organosiloxane were used to modify graphene,and oil soluble graphene was doped to modify SDB.SDB was modified by suspension polymerization with fluorosilane and impregnated with fluorosilane.The hydrophobicity and compression resistance of SDB carrier were effectively improved.The adsorption behavior of Pt（Ⅳ）on SDB carrier before and after modification was studied.The research work has theoretical significance and practical value.