Study On Treatment Of Heavy Metal Wastewater With Corn Stalk And Reed

In recent years,the rapid development of various industries has brought us huge economic benefits,but also has brought many negative effects to our living environment.Heavy metal ions enter into the air and the environment through different ways,and the heavy metal pollution is formed through the enrichment of plants and production.Heavy metal is toxic,a small amount of heavy metal ions can make the body metabolism disorder.cause disease and even death.Therefore,the research on the treatment of heavy metal pollution has been widespread concerned,the wastewater containing heavy metals must be treated before discharging.There are many methods to deal with heavy metal wastewater,but the application of many technologies has been limited by technology and economy.The adsorption materials used in the adsorption process have high specific surface area or special functional groups,which can adsorb heavy metal ions in water.The treatment of heavy metal wastewater by adsorption method has the advantages of simple process,high efficiency,low energy consumption,low investment cost and no secondary pollution,which is considered to be the most promising method for the treatment of heavy metal wastewater.The source of corn straw and reed is very rich,and their calorific value is relatively low,the nutritional content is not high,a large number of com stalks are burned or discarded,resulting in a great waste.Com straw and reed have biological compatibility and biodegradability.the larger specific surface area,well-developed microporous structure and rich surface functional groups make it have certain adsorption properties.After modifying the raw material,the adsorption capacity of the adsorbent can be increased.In this paper,the adsorption of heavy metal ions in aqueous solution was carried out by using a simple and efficient adsorption method.In this study,sodium sulfite,sodium hydroxide and sodium hydroxide were used to modify corn leaves,corn cob,con bran,reed leaves and reed stems.It was used as a raw material to remove Pb2+,Cr3+ and Cd2+ ions from aqueous solutions and explore the best adsorbent and the best modifier.It turns out that the best solution is NaOH solution,the best adsorption material for adsorption of Pb2+ and Cr3+ is corn leaves,and the best adsorption material for Cd2+ is reed leaves.1.The experimental results show that the modification time,modification temperature,NaOH concentration,adsorption time and adsorption dose have influence on the adsorption of heavy metals.For the adsorption of 50 mL,250 mg/L of the above three kinds of heavy metal ions,the best NaOH mass concentration is 0.7%,the best adsorption dose is 1.6 g.The difference is that,for the treatment of Pb(?),the optimal temperature of corn leaves is 80?,the modification time is 50 min,the adsorption time is 45 min,and the adsorption rate can reach to 99.79%after modification;For the adsorption of Cr(?),the optimal temperature of corn leaves was 65oC,the modification time was 30 min,the adsorption time was 90 min,and the adsorption rate was up to 96.10%after modification;For the adsorption of Cd(?),the optimum temperature and time of reed leaves were 20? and 20 min respectively,and the 90 min adsorption time could be saturated,and the optimal adsorption rate could reach more than 95%.2.The raw materials were characterized by Fourier transform infrared spectroscopy,scanning electron microscopy and BET surface area and pore size analyzer.Research shows that the NaOH changed the chemical structure of the original com leaves and reed leaves,so that the original group may be changed,and the raw material structure of carboxylic acid carbonyl and aromatic double bonds involved in the chemical reaction,the double bond was broken,which made the hydroxyl radicals participate in the adsorption process increase,led to the increased adsorption.And the surface of com and reed leaves is not uniform,all over the large and small aperture,the surface area is relatively small.After the modification by NaOH,two kinds of material surface has obvious folds,the surface becomes more rough,specific surface area becomes larger.The com leaf surface area increases from original 5.7564 mZ/g to 11.1625 m2/g,reed leaf surface area increases from original 6.3897 m2/g to 13.4156 mZ/g.The contact area with heavy metal ions increased.Comprehensive analysis showed that after modified by NaOH,the adsorption rate of corn and reed leaves increased significantly.