Study On The Preparation Process And Adsorption Characteristic Of Graphene Oxide And Ferric Chloride Composite Modified Zeolite

The rapid development of industrialization process poses increasingly heavier micro-pollution in China's potable water source.And the limited capacity of traditional water treatment process makes people increasingly keen on advanced ones.Filtration is the last barrier for traditional water treatment technology.Moreover,significant improvement effect of conventional processes for micro-polluted water was observed by replacing traditional filter with modified ones to enhance filtration.Therefore,the major subject in this paper is to develop a new modified filter.The investigation used natural zeolite?ROZ?as carrier,graphene oxide?GO?as modifier.Then we changed dosage ratios between Fe Cl3 and ROZ,between GO and Fe Cl3,and altered calcination temperature,calcination time and other parameters to prepare GOFMZ.The evaluation indexes for preparing GOFMZ were the removal of humic acid,modifier loading amount as well as its loading rate.The purpose of this paper was to investigate the optimum preparation conditions for GOFMZ as well as adsorption characteristics of GOFMZ for humic acid?HA?,copper ion(Cu²⁺)and methyl orange?MO?.The results show that the optimum conditions for preparing GOFMZ were as follows.In the first stage?ROZ modified by FeCl₃?,optimum conditions were that the addition ratio of FeCl₃ to ROZ was C1=0.125 ml·g^-1,calcination temperature T1 = 290 ? and calcination time t1 = 2.5h.While the corresponding values in the second stage?surface modification to FeCl₃ modified zeolite by GO?were that the addition ratio of GO to FeCl₃ modified zeolite)was C2 = 10 ug·g^-1,calcination temperature T2 = 190?,and calcination time t2 = 1.5h.The loading rate and loading amount of GOFMZ surface modifier were 95.38% and958.39 ug · g^-1,respectively under the optimum preparation conditions.At the same condition,the removal of GOFMZ and ROZ was 97.01% and 16.2%?it is 5.9 times of the ROZ?,indicating that FeCl₃ and GO had significant effect on the compound modification of zeolite.The surface structure of GOFMZ was complex than ROZ.Meanwhile,the specific area of GOFMZ was 11.7852m2·g^-1?it is 2.785 times of ROZ?.The percentages of GOFMZ surface elements accounting for the total mass are 17.604% of C,44.881% of O,5.485% of Al,27.392% of Si as well as 4.637% of Fe.C and Fe in GOFMZ surface derived from themodifiers of GO and Fe Cl3,respectively.Moreover,C and Fe increased positive charge and active sites in GOFMZ.the same peak value of GOFMZ was observed at 1619 cm^-1and1724 cm^-1,the peak of the functional group?C = C,C = O?was consistent with GO.The intensity peak coincided with the GO standard map at 2? = 10.5°.The removal of humic acid and Cu²⁺ by GOFMZ was less than 80% under acidic and alkaline conditions.under the condition of pH = 7,More than 70% of humic acid removal by GOFMZ was occurred at the humic acid concentrations between 2 and 25 mg/L;Besides,above 80% of Cu²⁺ removal by GOFMZ was presented at Cu²⁺ concentrations between 2 and10 mg/L,while which were 97.5% and 88.5% respectively at the concentrations of HA and Cu²⁺were 2mg/L.The adsorption of GOFMZ for humic acid,Cu²⁺and MO could all be described using Langmuir and Freundlich adsorption isothermal adsorption characteristics,The correlation coefficients were :R²_Freundlich?0.9766?>R²_Langmuir?0.9494?,R²_Freundich?0.9133?<R²_Langmuir?0.9873?,and R²_Freundich?0.9405?<R²_Langmuir?0.992?respectively.Among all these,humic acid adsorption by GOFMZ was more agreement with Freundlich isothermal adsorption model,While the adsorptions of Cu²⁺and methyl orange were both more consistent with the Langmuir isothermal adsorption characteristic model,Physical and chemical sorption were all existed in these adsorption,but physical sorption on multi-molecular layer was stronger to humic acid,but chemical adsorption was stronger to Cu²⁺ and methyl orange.The adsorption rate equations of GOFMZ for humic acid,Cu²⁺ and methyl orange were in accordance with the quasi-second order kinetic adsorption equation.These equations were y = 16.385x+124.35 for humic acid,y = 17.077 x +114.26 for Cu²⁺ and y=16.584x+127.99 for methyl orange,respectively.The corresponding correlation coefficients R2 were 0.9885,0.992 and 0.9861,respectively.The corresponding adsorption rate constants k/g·?mg·min?^-1were 2.159,2.5523 and 2.0538,respectively.And,the corresponding adsorption capacities Qe/mg·g^-1were 0.061,0.0586 and 0.0603,respectively.While the corresponding adsorption equilibrium time was all at 60 min.