Preparation Of Corncob Based Activated Carbon And Its Adsorption Of Zinc Ion(Ⅱ)

Activated carbon is a porous carbonized material; its surface contains oxygen and hydrogen, which is in the form of a functional group such as carboxyl, hydroxyl, phenol, internal lipids, quinones and others. So, activated carbon can chemically react with the adsorbate. At the same time, activated carbon also has a highly developed pore structure and huge specific surface area. Thus, it shows adsorption ability, good chemical stability, high mechanical strength, easy regeneration failure after use and other characteristics. It is a kind of great potential carbon adsorbent material.In this paper, the waste corncob crop, which is cheap and easy to get, was used as raw materials of preparation of activated carbon using phosphoric acid activation method. The iodine value, specific surface area, infrared spectroscopy, Boehm titration and scanning electron microscopy were employed to characterize the charcoal physical structure and surface chemistry characterization of nature. The further study of corn-based activated carbon adsorption properties for Zn2 + was carried out.Optimal conditions for the preparation of activated carbon was described as follows: concentration of phosphoric acid 70%, the weight ratio of H3PO4/ corncob( impregnation ratio) 0.6, impregnation time 12 h, activation temperature 500℃, activation time of 0.5h. Corn-based activated carbon is an amorphous active carbon, and it has a surface reticular structure, and holds a large number of channels. It specific surface area is of 936 m2/g, with a total pore volume of 0.4938cm3/g and average pore size of 2.1nm. It contains a variety of oxygen-containing surface hydroxyl group, a carboxyl group, lactone group and a functional group such as a carbonyl group and phosphorus-containing functional groups.The best conditions for the prepared activated carbon adsorption of Zn2 + was described as follows: solution initial p H is 3, with a activated carbon dosage of 50g/L, Zn2 + initial concentration of 0.12 mg / m L, the temperature of 20℃, adsorption time of 50 min. Under these conditions, the adsorption efficiency is 89.6 %.