Study Of Adsorption Of Typical Dyes And2,4-dichlorophenol Form Aqueous Solution By Modified Phoenix Tree Leaf

The natural phoenix tree leaf (NTL) was modified by NaOH andhexadecylpyridinium chloride monohydrate (CPC), and two kinds ofadsorbents(MTL1and MTL2) were obtained respectively. The characterization ofnatural phoenix tree leaf (NTL) and modified phoenix tree leaf (MTL1, MTL2) wereanalyzed by determination of point of zero charge, FTIR, differential thermal analysis,SEM, XRD, specific surface area analysis and elemental analysis.The modified phoenix tree leaf (MTL1, MTL2) and MB-loaded modifiedphoenix tree leaf (MTL3) were served as adsorbents, the contaminant of methyleneblue(MB), acid chrome blue(AK), congo red(CR) and2,4-dichlorophenol(2,4-DCP)were used as adsorbates. The adsorption process for these contaminants by modifiedphoenix tree leaf was studied in batch mode and the results were shown below.(1)In the adsorption of MB on MTL1, the optimum pH was about8; coexistedsalt had negative effect on adsorption; the adsorption of MB on MTL1wasspontaneous and endothermic process, the equilibrium adsorption data were fittedwell to Koble-Corrigan equation, the adsorption kinetic behaviour was best describedby the pseudo-second-order model.(2)In the adsorption of CR by MTL3, the suitable initial concentration of MBsolution in the first adsorption was determined as100mg·L-1by analysis of thedesorption rate and adsorption quantity. The effect of significant variables onadsorption was discussed: the appropriate pH of CR solution was about5; coexistingions was advantage of adsorption. The Koble-Corrigan model fitted well theadsorption isotherm of MTL3-CR system. The adsorption kinetic process of CR onMTL3was complicated and can be described by both pseudo-first-order andpseudo-second-order equations. Thermodynamic parameters indicated that thisadsorption was spontaneous and endothermic process.(3)In the adsorption of AK and2,4-DCP on MTL2，the appropriate pH was5and6.3, respectively. The presence of coexisted salt had positive effect on adsorption ofAK and negative influence on adsorption of2,4-DCP. The adsorption of AK on MTL2was described by Koble-Corrigan model and the pseudo-second-order kineticequation, respectively. The adsorption process of2,4-DCP by MTL2was fitted well toHenry equation and Elovich model. Both the adsorption of AK and2,4-DCP was endothermic process; the loaded MTL2was regenerated well by the agent of75%alcohol.(4)In the competitive adsorption between AK and2,4-DCP, adsorption capacityof MTL3reduced to some degree. And the competition had more serious effect onadsorption of2,4-DCP. While, the time of equilibrium adsorption hardly changed inthis two-component mixture.