Adsorption Properties Of Modified Luffa Celluloses For Pollutants

In this paper, adsorbents of Luffa cylindrical samples were synthesized after different methods ofchemical modifications. The efficiency of the modified Luffa fibers as sorbents in removing pollutants wasevaluated through static adsorption methods. The effects of solution pH, contact time, initial concentrations,adsorbent dosages and temperatures were investigated. The adsorption isotherm, kinetics andthermodynamics were also mentioned in this study.The results of the research contents were as follows:1. The modifications and characterizations of Luffa fibersThe Luffa fibers with different adsorption performance were prepared after treated with sodiumhydroxide, surfactant and quaternary amination reagents in this section. The characterizations of the Luffafibers were performed using Scanning Electron Microscope (SEM), Fourier Transform Infraredspectroscopy (FT-IR) and Thermo Gravimetric Analyzer (TGA). The SEM micrograph revealed a smoothsurface with more folds and sections after modifications, and this could provide advantages for adsorption.The FTIR spectra showed changes in the morphological structure with some adsorption peaks disappear orweaken after chemical modifications. Thermogravimetric analysis showed a better thermal stability aftermodified with surfactant and quaternary amination reagents.2. Experimental investigation of alkali-treated Luffa fibers for the adsorption of cetylpyrid bromideThe Luffa fibers were treated with sodium hydroxide and then were applied in cetylpyrid bromideremoval from aqueous solution. Results displayed that the alkali-treated Luffa fibers exhibited goodadsorption to cetylpyrid bromide. The solution pH has significant effects on adsorption process. Theadsorption capacity reached maximum value when pH=7. Beyond this point, there was no significantlychanges was observed with the increase of pH values. Studies also showed that the adsorption followspseudo-second-order kinetic model and isotherms could be well defined with Langmuir model.Thermodynamic study indicated the spontaneous and endothermic nature of the sorption.3. Adsorption behavior of1-naphthol onto surfactant modified Luffa fibersThe Luffa fibers was modified by cetylpyrid bromide, and used as an adsorbent for1-naphthol adsorption. The adsorption was found to be related with solution pH, contact time, adsorbent dosage andtemperature to the adsorption of1-naphthol. The adsorption favors in lower temperature. The kinetic andisotherm study indicated that the adsorption of1-naphthol could be well fitted with pseudo-second-orderkinetic model and Freundlich isothermal model. Other study revealed the physical nature of the adsorption,and can not occur spontaneously.4. Adsorption of2,4-dinitrophenol from aqueous solution by modified LuffaThe adsorption of2,4-dinitrophenol onto quaternized Luffa fibers was studied in this work. The effectof solution pH, adsorbent dosage and contact time on adsorption process was also discussed. Kineticstudies showed that the adsorption process in accordance with pseudo-second-order kinetic model. Thespontaneous and exothermic nature of the adsorption process was obtained from thermodynamic studies. Abetter elution efficiency of ammonia methanol solution was observed in column experiments, and therecovery increased with the proportion of ammonia in methanol solution.