| With the continuous improvement of the productive forces of nature, human beings in more powerful influence. Humans in their own environment using technology to change the but also to the environment poses a serious negative effect causes a variety of environmental pollution. In the eutrophication of water pollution harm is more and more obvious. On the one hand under the influence of the outbreak in humans the water eutrophication features shorter; On the other hand whether rivers, lakes and oceans had appeared eutrophication, outbreak area wide, lasted for a long time, difficult to eliminate. Once the eutrophication of water appeared, no matter from landscape, smell or water to human body would cause damage and great economic losses. So the eutrophication of water treatment has a focus as a hot research subject, and how quickly, and better and more effective cure this phenomenon, received worldwide attention and research.Our country is a large agricultural nation, every year for planting crops will produce large amounts of crops straw, because the biomass energy technology has not yet promotion, a large number of straw didn't get rational use and disposal, burning and burying became the main approach, straw caused not only by a lot of solid waste landfill and waste of land, cause environmental pollution and safety hazards, burned will produce carbon dioxide, such as carbon monoxide, a pollutant and caused by photochemical role more serious secondary pollution, particulate can also cause deterioration of visibility, cause accidents and and aviation safety, also can produce like fire, destroying the soil structure and so on a series of problems. Therefore, to our country is concerned, how to reasonable and effective use of these crops straw, realize the reutilized, for good from China's reality, the urgent demand of the situation.Solid particles due to its surface properties and has certain adsorption ability, through specific modification can be greatly improved after in this role, with no introducing other contaminants; Particle sturdiness decided to use after using the stability, but by changing the external conditions make pollutants, adsorbent regeneration, took off with the precious metal recycling can also become a kind of method, so in recent years become a hopefully substitutes the chemical and biological method for water treatment method, natural mineral modified products and synthetic efficient absorbent performance, structure and utilization of the development of research has been widely.This article from agricultural solid waste comprehensive utilization and efficient phosphorus adsorbent development and utilization of the Angle at home and abroad, the comprehensive based on a number of literature, with crops straw as raw material, on its physical structure, chemical composition, surface chemical properties on the basis of the study on the chemical modification, and systematically study the different external conditions of aqueous solution under the adsorption performance of phosphoric root ions and mechanism.The results of the study show that, without modification carbonized straws surface potential is lower, the existence of electrostatic repulsion to limit its root ion adsorption ability of phosphoric acid, modified carbonized straws surface potential is greatly improve, can greatly enhance its phosphate adsorption ability of root ions.Through the mixing ratio of time and quality, pH and modified, the temperature of the four major factors are an orthogonal test better modification conditions. Experimental results show that the pH = 5, temperature at 20℃and time for 150 minutes, stirring time, quality for 3 as modified conditions than when has good modified effects by carbonized straws surface potential initial - 17mv ~ - 24mv rise to - 6mv ~ -9mv .Static adsorption test results show that the 100min when at about can achieve the adsorption balance; Adsorption effect with the increase of dosing quantity and improve, dosing quantity about 0.3 g, removal rate is basic to saturation; PH affected by water in phosphoric acid root morphology and influence of water in carbonized stalk the adsorption, pH of anionic elevated to facilitate its root of phosphoric acid, pH in adsorption 5 to 8 range adsorption effect is the best; With the improvement of initial concentration caused a shorter time of adsorption equilibrium, the equilibrium adsorption increased, but the removal rate would fall; Temperature rise of phosphate carbonized straws against modified roots adsorption, which showed that adsorption process is exothermic chemical process, reduce temperature can improve adsorption effect. Through the thermodynamics and kinetics of research shows that, lang ge distort your temperature type and friedrich isothermal type can describe adsorption processes, but lang pavilion's equation is more accurate, craftiness surface adsorption process that the calculation results macroscopic could meet lang pavilion's hypothesis, craftiness also explains the surface organic groups also can produce certain effect; Accurate description of the whole process from the equation with a single function variables no relationship, ion the chemical potential relationship is the only factor in the decision of adsorption equilibrium and adsorbent surface chemical potential role three aspects conducts the research to find; The adsorption process change, the enthalpy gibbs free energy, entropy change are decreased; Dynamic equation through first and quasi secondary equation allowed the simulation shows in different reaction stage have different adapt equation, reveals the different stages of the control factors in the process of different, adsorption, will play the diffusion inside the prominent role. |
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