Preparation Of Organo-modified Zeolite And Its Behavior And Mechanism Study Of Sorption Of Phthalic Acid Esters

PAEs (Phthalic acid ester) is a kind of important environmental hormones. Along with the development of plastics industry and the extensive use of plastic products, PAEs enter into the environment and become a most common pollutant in the environment. Natural zeolite is new nonmetallic mineral resources of present world, it has been widely used in three waste treatment because of excellent properties of absorbing and ion exchange.In this study, four kinds of organo-modified zeolites , CTMAB zeolite, TMAB/CTMAB zeolite, SDS/CTMAB zeolite and TWWEN/CTMAB zeolite were made from natural zeolite which using as raw material modified by a certain concentration of CTMAB and mixture of CTMAB and TMAB, CTMAB and SDS, CTMAB and TWEEN respectively. The organo-modified zeolites and natural zeolite were characterized by organic carbon contents, scanning electron microscope, infrared spectrum, X–ray diffraction and thermal analysis; Sorption of PAEs on organo-modified zeolites and natural zeolite from water were studied by static adsorption method; Quantitative contributions of partition and adsorption to total sorption on sorbent were researched. Correlation of partition and surfactant as well as PAEs were discussed.The main conclusions of this work are drawn:1. Organic carbon contents of four kinds of organo-modified zeolites were increased with different levels compared with nature zeolite. The testing results of IR, SEM and XRD show that CTMAB,TMAB,SDS and TWEEN were successfully embedded in zeolite or adsorbed on its surface, and not brought unfavorable influence to its structure, meanwhile, the thermal analysis result suggested that organo-modified zeolites had good heat resisting property.2. Kinetic experiments demonstrated that the adsorption balance time of PAEs on natural zeolite and organo-modified zeolites was 3h. The adsorption isotherm of PAEs on natural zeolite conforms to Freundlich adsorption isothermal and adsorption plays the main role. Also, the adsorption isotherms of the organo-modified zeolite conforms to linear adsorption isothermal and partition plays the main role.3. The four factors,such as ionic strengths, pH value, temperatures and humic acid effected the adsorption properties of PAEs on five kinds of sorbents from water in various degrees. It was found that the concentration variation of ionic strengths, pH value and humic acid had little effect on adsorption capacity of PAEs on organo-modified zeolites, while the adsorption capacity of PAEs increased with temperature. However, changes of four effects on PAEs sorption in natural zeolite were different:①Ionic strengths had inhibitory action on sorption of DMP, but had no effect on DEHP and DnOP.②The pH change on sorption of DMP had greater effect than DEHP and DnOP.③The sorption capacity of PAEs decreased with temperature increasing.④The sorption capacity of PAEs increased with humic acid concentration increasing.4. The quantitative contributions of adsorption and partition to total sorption of PAEs on natural zeolite and organo-modified zeolites were determined by isothermal adsorption decomposition method. Adsorption behavior of sorbents transited adsorption to partition with PAEs concentration increasing. At comparatively high equilibrium concentration of PAEs, the principal adsorption behavior of organo-modified zeolites was partition, while adsorption reached equilibrium; but adsorption of natural zeolite always occupied dominant position. The organo-modified zeolites had organic media which could dissolved PAEs, meanwhile PAEs are hydrophobic organic material, so the adsorption behavior of organo-modified zeolites easy to be partition.