Study On The Heavy Metals And Phenol Adsorption Performance Of Modified Zeolite

The absorption is a simple, inexpensive method of water treatment toremove heavy metal ions, and the adsorbed metal ions are not dissolvedeasily. Zeolite is a natural mineral, not only rich source, but also low-cost.Meanwhile, the zeolite with strong catalytic and adsorption functions dueto its own special chemical composition and crystal structure, is expectedto become the new wastewater treatment material.In the present study, the adsorption of Pb²⁺and Cr（Ⅲ） fromwastewater by inorganic coagulant polymeric Al/Fe（PAFC） modifiedclinoptilolite and phenol by HDTMA （hexadecyltrimethylammoniumbromide）-organically modified zeolite were mainly investigated.Meanwhile, several conditions affecting the removal of Pb²⁺and Cr（Ⅲ）were studied, such as the adsorption time, pH value of solution, initialconcentrations of metals, temperature, ionic strength and other factors.Furthermore，the adsorption of Pb²⁺, Cu²⁺and Zn²⁺from single and mixedsolutions by polymeric Al/Fe（PAFC） modified clinoptilolite were discussedby adsorption isotherm model and distribution coefficient. Finally, the effect of Ca²⁺, Mg²⁺, Na⁺, K⁺on adsorption of phenol by HDTMA-organically modified zeolite was under consideration. Those tests were allcomparied with the un-modified zeolite.The results showed that, initial concentrations of metals and pH valuewere obvious among many factors affecting the removal of Pb²⁺and Cr（Ⅲ）,and the optimum pH was about7. In the same experimental conditions, theadsorption of Cr（Ⅲ）(4.44,5.35mg·g^-1) and Pb²⁺(60.24,63.29mg·g^-1) onthe PAFC modified zeolite have greater affinity and saturation adsorptioncapacity than on the unmodified zeolite. In binary isometric competitionadsorption, adsorption capacities of Pb²⁺, Cu²⁺and Zn²⁺by zeolite andPAFC modified zeolite decreased compared with single systems.Chemicalstability and the ability of combining with adsorption sites of Pb> Cu> Znfrom isometric and non-isometric competition. In general, the strength ofadsorption followed the order of Pb> Cu> Zn and the order of PAFCmodified clinoptilolite> clinoptilolite. When pH <9, the presence of Na⁺and K⁺ions had no effect on the phenol adsorption performance ofHDTMA-modified zeolite or un-modified zeolite, but Ca²⁺and Mg²⁺had.In the presence of Ca²⁺or Mg²⁺ions, the phenol adsorption performance ofHDTMA-modified zeolite was further improved when pH>9. Theformation of neutral ion pair of metal-phenol and increasing hydrophlbicinteractions were contributed to such phenomenas,...