| With the rapid development of Chinese economy, China's urbanization process has become very fast. While highly developed society, the deteriorating natural environment has become particularly serious. In recent years, due to the impact of human activities, into the water environment pollution are becoming more and more substance, pollutant content of ammonia in the water is also rising sharply, resulting in deteriorating water environment, water pollution is a serious threat to the stability of ecosystems and the safety of human life. However, the traditional approach not only ammonia removal high operating costs, removal rate, and the operation is complicated, is not conducive to the promotion. Therefore, the search for one kind of simple, reliable and good removal effect of the new denitrification becomes particularly important.Pumice, an inexpensive non-metallic minerals, and has a good adsorption performance, but also has a simple and easy process,while itself can be recycled and other advantages of the use of ammonia wastewater treatment has a certain practical significance. Therefore, this paper of pumice launched a series of studies, with a wide and profound significance.In order to improve the removal rate of ammonia nitrogen by pumice, pumice has been acid-modified, alkali-modified, salt and baking modified modified. The specific surface area as an index determined the hive by orthogonal experiment optimal modification conditions. The results showed that: salt modified manner pumice can maximize its surface area is increased, effectively improving ammonia removal. BET characterization showed that after the modified pumice surface area compared to the unmodified pumice have been increased to some extent. SEM scanning electron microscope image can be more intuitive differences were observed and the unmodified pumice structure surface modified by the presence of four ways. The modified pumice irregular particles groups mainly between the particles and particles mainly through surface contact, the contact surface side is connected to this decentralized structure facilitates communication skeleton pores and voids generated. Obtained by the Fourier transform infrared spectroscopy, pumice amphibolite main compound, magnesium, calcium, sodium, aluminum silicate minerals, pyroxene and morphology similar composition, and amphibole silicate containing OH- salt, its backbone structure of silicon-oxygen tetrahedron its crystal accommodate different cations may be provided. pumice static adsorptive capacity show: Modified pumice low concentration ammonia wastewater better removal efficiency increases with the initial concentration of ammonia, pumice removal of ammonia nitrogen decreased; for different concentrations of ammonia wastewater modified pumice adsorption of ammonia nitrogen adsorption with fast, slow balancing features in 20 min, the basic adsorption equilibrium; dosage modification hive stone in the 0.5 ~ 2g / 100 m L, the ammonia removal and dosing proportional relationship. With increasing dosage, ammonia removal and flatten slightly lower; the optimum p H range should be between 4 to 8.To better understand the mechanism of adsorption of modified pumice to wastwater, the paper pumice ammonia adsorption thermodynamics and kinetics, the results showed that: adsorption of modified pumice pattern Ammonia Langmuir and Freundlich equation, and the model fit well, RL and 1/n values are reflected pumice adsorption of ammonia relatively easy; modified pumice adsorption wastwater line with Lagergren pseudo second order model, throughout the process of adsorption, there is also a chemical adsorption; internal diffusion model also reflects the modified pumice during adsorption of ammonia, not only exist between particles and particle diffusion, as well as many other physical or chemical effect in the reaction. |
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