Synthesis Of Linde F(K) Series Zeolite And Its Adsorption Of Heavy Metals In Wastewater Treatment

Excessive levels of heavy metals in the environment will pose a serious threat to human health and environmental safety.Therefore,the standard discharge of heavy metal wastewater is very important to the regional water environment safety.At present,the methods of treating heavy metal wastewater mainly include:redox method,ion exchange method,chemical precipitation method,chemical flocculation method and adsorption method.Among these methods,adsorption method has become one of the important heavy metal wastewater treatment methods because of its advantages such as simple operation,high efficiency and controllable cost.The development of adsorbent is the core of adsorption technology.In this paper,for the treatment of heavy metals in wastewater,Linde F(K)zeolite material was developed and synthesized.This series of materials can realize efficient adsorption treatment of heavy metals in solution.Firstly,in this paper,the microsized Linde F(K)zeolite was synthesized from industrial solid waste fly ash.The results show that the microsized Linde F(K)zeolite presents a microhexahedral structure,the microsized is about1μm to 3μm,and the specific surface area of the liquid phase is about 332 m~2/g.Micron K zeolite has a good adsorption effect on heavy metals,the best p H value is about 7,the most economical adsorbent dosage is about 5 g/L,the theoretical limit adsorption capacity of Cd and Zn is 20.8 mg/g and 35.4 mg/g,respectively.The quasi-second-order adsorption kinetics model and Langmuir adsorption isotherm equation can better describe the adsorption process of Cu and Zn in solution by micron K zeolite.The adsorption of Cu and Zn on micron K zeolite is a spontaneous endothermic reaction.On the basis of the above research,in order to fully explore the adsorption potential of Linde F(K)zeolite for heavy metals,this paper carried out research on reducing the microsize of Linde F(K)zeolite.The research results show that:Linde F(K)zeolite with nanometer size(200-500 nm)can be successfully synthesized by adding the template(propane bis[octadecyldimethyl ammonium chloride])in the synthesis process.The liquid specific surface area of nano K zeolite is up to about 2123.6 m~2/g.The synthesis rate of nanomaterials can be accelerated by increasing the reaction temperature appropriately.The method of pure water cleaning and extraction can effectively remove the residual template in the synthesized product and maintain good adsorption characteristics.On the basis of the above research,the adsorption performance of nano-sized K zeolite on heavy metals was studied in this paper.The results showed that the adsorption effect of nano-sized K zeolite on heavy metals was good,and was significantly better than that of micron K zeolite.With the increase of solution p H,the adsorption capacity of Cu and Cd increases obviously.The Zeta potential on the surface of the material decreases with the increase of p H.The adsorption capacity of nano-sized K zeolite for Cd is greater than that for Cu in both single and compound adsorption systems.The adsorption capacities of nanometer K zeolite for Cu and Cd are 120 mg/g and 190 mg/g,respectively,which are obviously better than that of micron K zeolite.The quasi-second-order kinetic equation and Langmuir isotherm equation can well describe the adsorption behavior of Cu and Cd by K zeolite.On the basis of the above research,this thesis focuses on the study of the process of using nano-K zeolite to adsorb multiple heavy metals in the liquid phase.The effects of p H value of the solution,reaction temperature and time on the adsorption effect of heavy metals were investigated.The apparent kinetics and diffusion kinetics of the adsorption process were studied using the conventional kinetic equation and the diffusion kinetic equation;the correction of the classical Langmuir adsorption isotherm model and its application were carried out;based on the classical adsorption isotherm equation,By introducing the concept of"advanced"equation,deduced the"advanced"adsorption isotherm equation suitable for explaining the process of nano-K zeolite enhanced adsorption of heavy metals;applying the obtained"advanced"adsorption isotherm equation to Fitting the adsorption experimental data of Cu,Ni,Pb and Cd in the liquid phase of nano-K zeolite.The order of the adsorption effect of nano-K zeolite on heavy metals is Pb>Cd>Cu>Ni.From the perspective of diffusion kinetics,within 2 minutes of the beginning of the adsorption reaction,the entire adsorption process is in the outer diffusion stage,and then the mixing of the outer and inner diffusion stages gradually transitions to the reaction stage dominated by inner diffusion;in the multi-adsorption system In this case,the active adsorption site on nano-K zeolite is no longer monopolized by a certain type of heavy metal ion.In this case,the more dominant ion in the competition,the stronger its ability to maintain its own adsorption process.Based on the concept of“formula”equation,by introducing new conceptual parameters such as effective adsorption area,virtual heavy metal ions,and adsorption area distribution function into the isotherm equation,a suitable method for fitting and explaining heavy metal ions on nano-K zeolite can be established.(Monary and multi-component systems)The"advanced"adsorption isotherm equation of the adsorption process.On the basis of the above research,the magnetic adsorption material of nano-sized K zeolite and fly ash magnetic bead composite was studied in this paper.The results show that the surface of spherical fly ash magnetic bead particles(MS)is completely wrapped by nano-sized Linde F(K)zeolite(MNZ@MS).The MNZ@MS material has obvious magnetic properties,and its saturation magnetization is about 17.7 emu/g,which can realize magnetic solid-liquid separation.The quasi-second-order kinetic model and Langmuir isotherm adsorption model are more suitable for fitting adsorption kinetics and isotherm.The maximum adsorption capacities of Cu,Cd and Pb on MNZ@MS are 59.9 mg/g,188.6 mg/g and 476.1 mg/g,respectively.Under the competitive adsorption system,the adsorption process of Pb is the least easily disturbed,while that of Cd is the most easily disturbed by other heavy metals.