Studies On The Equilibrium Adsorption Of Cd²⁺?CrO₄^2- And Phenol On BS-12 And CTMAB Complex Modified Goethites

This paper is based on goethite,using cationic modified CTMAB and BS-12 was modified to prepare BS-12+CTMAB?BS+CT?of amphoteric modified goethite,according to the structure feature of TC,FTIR,specific surface area analysis and characterization of BS+CT amphoteric modified goethite,discusses the BS single amphoteric modification and BS+CT amphoteric compound modified goethite adsorbed phenol and organic pollutants heavy metal ions Cd2+and CrO₄^2-characteristics,influencing factors and the changes of thermodynamic parameters,and the adsorption mechanism was discussed.The main conclusions of this paper are as follows:1)FTIR confirms the modification of goethite by amphoteric surface modifier BS-12 and cationic surface modifier CTMAB.The total carbon,BS+CT modified goethite surface area and the modified type and the proportion of modification of surface modifier,in 50 BS,100BS and 150 BS modified goethite based on modified combination of different proportion of CT,total carbon content was higher than that of single BS modified goethite and goethite unmodified CK.The BS+CT amphoteric modified total carbon content of goethite with increase of CT compound modification ratio and volatility.2)The equilibrium adsorption of heavy metal cations Cd2+ showed that BS modification increased the adsorption ability of goethite to Cd2+.With the increase of BS-12 modification ratio,adsorption ability of modified goethite to Cd2+;in 50 BS,100BS and 150 BS modified goethite based on compound CT of Cd2+ adsorption capacity increased,the amount of Cd2+adsorbed on the whole increased with the increase of the ratio of CT modified phenol;coexistence has inhibitory effects on complex modification goethite adsorbed Cd2+;BS,BS+CT of amphoteric modified adsorption on goethite Cd2+ is described by Langmuir model.BS+CT amphoteric modified adsorption of Cd2+ on goethite with increasing positive effect;pH increased to Cd2+adsorption,and the increase of ionic strength for Cd2+adsorption;thermodynamic parameters.The results show that the modified goethite was spontaneously reduced to Cd2+ adsorption enthalpy control.From CK to BS amphoteric modified goethite and then BS+CT amphoteric composite goethite,the adsorption of Cd2+from endothermic to exothermic.3)The equilibrium adsorption of heavy metal anions of CrO₄^2-show that BS-12 can increase the adsorption capacity of goethite to CrO₄^2-,and increased with the increase of the ratio of BS modified BS+CT,modified goethite has obvious effect on improving the adsorption capacity of CrO₄^2-and pH increased;the ionic strength increases are not conducive to the CrO₄^2-adsorption thermodynamics;the parameters of the results show that the modified goethite is a spontaneous process of CrO₄^2-adsorption.From CK to BS and then to BS+CT compound amphoteric goethite goethite,the adsorption of CrO₄^2-on the show by endothermic transition exothermic,entropy features reduced BS+CT;amphoteric compound goethite adsorption isotherms of CrO₄^2-were best described by Freundlich model.4)The equilibrium adsorption phenol showed that in 50 BS,100BS and 150 BS amphoteric goethite based on cationic surfactant CTMAB compound improves the adsorption capacity of phenol,with the increase of the ratio of CT modified BS+CT,modified phenol adsorption on goethite increased;the presence of Cd2+inhibition test for the adsorption of phenol goethite;amphoteric modification of mixture adsorption isotherms of phenol on goethite was best described by Henry model;amphoteric compound modification of phenol adsorption by goethite with increasing negative effect,mainly by physical adsorption;pH rise is not conducive to the adsorption of phenol.The ionic strength in 0.01mol·L-1⁰.1mol·L-1range,the adsorption of phenol showed promotion effect;thermodynamic parameters showed that from CK to BS to BS+CT modified with amphoteric modified goethite,showing the characteristics of adsorption of exothermic entropy.The experimental results show that the modified goethite based on gender,cation modifier CT,can also enhance the adsorption of organic compounds of phenol and heavy metal cation Cd2+,anionic CrO₄^2-,confirmed by BS+CT amphoteric modified goethite can also effectively remove organic pollutants and heavy metal ions.