Surface Modification Of Natural Mordenite And Its Efficient Removal Of Heavy Metals In Aqueous Solution

Recently,the problem of heavy metal pollution in water is frequent,and it is of great significance to develop efficient,stable,low-cost environmental protection and easy-to-use treatment methods.Geochemical engineering technology shows great advantages in the field of environmental remediation because of its environmental protection,simplicity,high efficiency,and low cost.The direct application or modification of natural geochemical materials for adsorption,degradation,and removal of pollutants is one of the important methods of geochemical engineering technology.Natural zeolites have strong adsorption and ion exchange capacity due to their unique porous and framework structure.As a geochemical material,it has the characteristics of low cost,significant and stable effect,and no secondary pollution.In order to achieve rapid“grab”and adsorption of heavy metal ions in solution,it is necessary to modify the surface of the natural zeolite or coat the new structure under the premise of maintaining the porous structure of the natural zeolite,and to develop a modified zeolite material with a novel nano-mesoporous structure.Herein,the hydrolysis of ethyl silicate to form SiO₂ is combined with natural zeolite.Through various characterizations,the composite has the advantages of both natural zeolite and nano-SiO₂ pore structure.The composite material was used to remove the five main heavy metal ions in water,the removal time experiment,the coexistence heavy metal removal experiment,and the cycle regeneration experiment.The migration pathway of heavy metal ions was also discussed.The main research contents and conclusions are as follows:1.The samples were characterized by SEM,TEM,XRD and BET.The results show that the SiO₂ hydrolyzed by ethyl orthosilicate can be combined with natural mordenite to form a novel“SiO₂/mordenite”modified mordenite material.The surface of the original zeolite is coated with the new nano-SiO₂ pore structure without damaging the original mordenite.The porous structure enables the modified mordenite material to have both advantages,increase the effective adsorption surface,increase the adsorption removal efficiency,and greatly enhance the adsorption capacity of heavy metal ions.2.The optimum dosages of modified mordenite for Pb²⁺,Cd²⁺,Zn²⁺,Cu²⁺,and Mn²⁺were 0.5 g/L,2 g/L,2 g/L,and 2 g/L,5 g/L respectively.The removal rates of these five ions are:Pb²⁺98%,Cd²⁺97%,Zn²⁺94%,Cu²⁺96%,and Mn²⁺97%,which can be used for subsequent large-scale projects.3.The adsorption removal rate of Pb²⁺,Cd²⁺,Zn²⁺,Cu²⁺,and Mn²⁺by the modified mordenite material in water for 0.5 h is:Pb²⁺99.3%,Cd²⁺97.1%,Zn²⁺98.3%,Cu²⁺98.9%,Mn²⁺45.7%,with very little desorption,shows significant and stable results,easy operation,low cost,and environmental friendliness.4.In the experiment of adsorption removal of heavy metals coexisting in aqueous solution,five heavy metal ions such as Pb²⁺,Cd²⁺,Zn²⁺,Cu²⁺and Mn²⁺were competitively adsorbed.Modified mordenite material had the most adsorption to Pb²⁺in the coexistent solutions of various heavy metal ions.5.Modified mordenite has excellent recycling performance.After 4 cycles,the removal rate of Pb²⁺remained at 83.8%.6.It was confirmed that as the adsorption reaction time advances,Pb²⁺can migrate into the interior of the modified mordenite,which has the advantage of stable adsorption removal.7.To provide a new idea for the removal of heavy metal ions from natural geochemical materials through simple modification applied to heavy metal polluted water bodies.